# 70D vs D7100 ISO Comparison at 100%



## MichaelTheMaven (Aug 30, 2013)

Ill be posting a bunch of tests between these 2 cameras. Im learning a lot of really interesting things, and so far it has been an absolute slugfest. The Nikon has been surprising me in positive ways, and then the 70D comes back and crushes the D7100 in others. Ill have a full write up available soon. 

Check this out. No commentary on my part, decide for yourselves. Quick and dirty test with description of what I did here:

http://www.michaelthemaven.com/?postID=2894&canon-70d-vs-nikon-d7100-iso-noise-chart


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## mountain_drew (Aug 30, 2013)

MichaelTheMaven said:


> Ill be posting a bunch of tests between these 2 cameras. Im learning a lot of really interesting things, and so far it has been an absolute slugfest. The Nikon has been surprising me in positive ways, and then the 70D comes back and crushes the D7100 in others. Ill have a full write up available soon.
> 
> Check this out. No commentary on my part, decide for yourselves. Quick and dirty test with description of what I did here:
> 
> http://www.michaelthemaven.com/?postID=2894&canon-70d-vs-nikon-d7100-iso-noise-chart



Thanks, that's going to be interesting. From another test, I have the impression that the canon is especially bad at low-iso with purple and blue to a lesser extent. Myabe there's something on the Canon with the blue channel.


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## ajfotofilmagem (Aug 30, 2013)

Through my eyes, the 70D images look much better, and I do not care if DXO says otherwise. 8) However, the auto white balance makes strange colors randomly. I also realized that exposure varies greatly in different ISO. You used aperture and shutter speed manual or automatic? Thank you in advance.


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## Marsu42 (Aug 30, 2013)

MichaelTheMaven said:


> Quick and dirty test with description of what I did here



It's great you're doing reviews on your blog and are the first one to occupy the search engines by carpet-bombing forums, but "quick and dirty" won't do here, and you most likely know it - esp. in this case you gotta be joking :-\ ... _"I shot a color chart, *hand held*, in fluorescent light, with *AWB* on both cameras, standard *ISO noise reduction turned on*."_

One thing it might show is that Canon has some stronger edge contrast enhancement in place which might also explain the magical sharpness increase some people noticed in res charts.


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## MichaelTheMaven (Aug 31, 2013)

@Marsu42...no, not joking. 

This is the only forum I have posted on, so I wouldn't call that "carpet bombing"as you say. I've found some sincere people on here have great recommendations, feedback, suggestions for future tests, etc. 

The results speak for themselves, if you disagree, show us your data. 

If you can't do that, well.... then you can't authoritatively say anything can you?


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## Aglet (Aug 31, 2013)

Marsu42 said:


> MichaelTheMaven said:
> 
> 
> > Quick and dirty test with description of what I did here
> ...



You think this might turn into another long bumpy ride? ;D


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## ME (Aug 31, 2013)

Where are the shots of bbq grills, walls and dr comparison shots? Any comparisons without these is not a valid analysis. And 300% would be better. Images of color charts alone is not enough, though the 70D colors are more pleasing to me. :


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## pedro (Aug 31, 2013)

Well. looks pretty well to my eyes. Is that RAW already? The candles on the posted link look great at 6400 and 12800. Looking forward to Canon's improvements in coming FF sensors.


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## Marsu42 (Aug 31, 2013)

MichaelTheMaven said:


> This is the only forum I have posted on, so I wouldn't call that "carpet bombing"as you say.



I really have to excuse for that assumption, just seemed very probable given the quick & dirty approach - so sorry, I'll check next time. 



MichaelTheMaven said:


> The results speak for themselves, if you disagree, show us your data. If you can't do that, well.... then you can't authoritatively say anything can you?



Imho if it is to be worth anything, it has to be done not handheld but with no shake (tripod or similar, contrast af, timer + mlu) - only then it could count as a quick comparisons of jpeg engines and awb metering.


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## Skulker (Aug 31, 2013)

MichaelTheMaven said:


> If you can't do that, well.... then you can't authoritatively say anything can you?



;D ;D

I thought the first post was design to court controversy! Then this! I did literally Laugh out loud. I don't know if you mean it as a joke, but it worked for me.


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## neuroanatomist (Aug 31, 2013)

Marsu42 said:


> ...in this case you gotta be joking :-\ ... _"I shot a color chart, *hand held*, in fluorescent light, with *AWB* on both cameras, standard *ISO noise reduction turned on*."_



+1 



MichaelTheMaven said:


> The results speak for themselves, if you disagree, show us your data.



The results say nothing useful - I can quite authoritatively state that your method is badly flawed, which renders your 'results' uninterpretable and no conclusions can be drawn. As Marsu42 points out, AWB and NR are major confounds to a test like this, and handheld shooting doesn't help matters. 

Sorry, but the fact that those factors are so easily controllable (you mentioned that you shot under fluorescent lighting, why wouldn't you just set WB to fluorescent?) makes me question the validity of any other such 'test' you perform.


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## Jim O (Aug 31, 2013)

ankorwatt said:


> What are we looking at
> Different profiles, different contrast curves, different USM and default noise
> settings
> 
> Give me the raw files and I let you know what can be seen or not



Thus spaketh the true maven of all things photographic.


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## ajfotofilmagem (Aug 31, 2013)

neuroanatomist said:


> Marsu42 said:
> 
> 
> > ...in this case you gotta be joking :-\ ... _"I shot a color chart, *hand held*, in fluorescent light, with *AWB* on both cameras, standard *ISO noise reduction turned on*."_
> ...


So Neuro. That's what happens when you reaches 10,000 posts?  A title of "CR GEEK" under your avatar ... : I understand that some tests are done in a hurry, but need to be repeatable in similar situations. I for one would like a quick test that showed the effectiveness of the JPEG engine and noise reduction in the camera. Since it excludes other variables with auto WB, and hand-held camera.


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## Badger (Aug 31, 2013)

Good lord! No good deed goes unpunished! 
Take it for what its worth, or don't.
Thanks for taking the time and effort Mike.


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## Jim O (Aug 31, 2013)

Badger said:


> Good lord! No good dead goes unpunished!
> Take it for what its worth, or don't.
> Thanks for taking the time and effort Mike.



Is spreading potentially inaccurate information a "good deed"? If one wants to publish something even semi-scientific, then one needs to use some semblance of the scientific method. At the very least, one should control as many variables as possible. Using the same tripod in the same location for both cameras would have been a good start. Using the same lens - perhaps a Tamron made for each line of camera, would also help.

I think there are reasonable criticisms here that, IMMHO, make any conclusions suspect. They may well be borne out with more rigorously controlled testing, but without that, they're really just pictures.


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## neuroanatomist (Aug 31, 2013)

Ok, I conclude that the D7100 has problems with color fidelity and exposure metering that occur specifically at ISO 800. Maybe it wasn't a useless test after all... :


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## ajfotofilmagem (Aug 31, 2013)

neuroanatomist said:


> Ok, I conclude that the D7100 has problems with color fidelity and exposure metering that occur specifically at ISO 800. Maybe it wasn't a useless test after all... :


That's good to know.  Just never use the D7100 in ISO800 and everything is great! ;D ;D ;D ;D


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## Badger (Aug 31, 2013)

I was just curious to see how these two cameras did, hand held with auto white balance at different ISOs


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## ishdakuteb (Aug 31, 2013)

ankorwatt said:


> Give me the raw files and I let you know what can be seen or not



number of people in this forum have been asking for your raw files for more almost 2 years. have you posted one? none... then why bother to ask people to send you a raw file?



Aglet said:


> You think this might turn into another long bumpy ride? ;D



where is the link to your photography page? should you be proud to let people see your artist side lol


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## risc32 (Aug 31, 2013)

probably because that swatch turns orange at all iso settings except red at iso800 on the nikon. i'm not on a calibrated monitor right now, and i can't say what is more accurate, but certainly iso 800 looks much different then any of the others.


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## neuroanatomist (Aug 31, 2013)

ankorwatt said:


> neuroanatomist said:
> 
> 
> > Ok, I conclude that the D7100 has problems with color fidelity and exposure metering that occur specifically at ISO 800. Maybe it wasn't a useless test after all... :
> ...



Isn't it obvious? The ISO 800 shot from the D7100 is underexposed and the color balance is off, compared to the other D7100 shots. Therefore, based on this test, the D7100 has a problem at ISO 800. : : :


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## ishdakuteb (Aug 31, 2013)

ankorwatt said:


> i have lent people my raw files, Im relatively new here but at preview they are used to get my raw files since 2001 where Im a senior member
> 
> I have not be printing a business card since 10 years, back i took down my Picture Bank years ago, you se I have enough of customers and need not to show off my self, but you can always google at my name
> questions?




1. "i have lent people my raw files": please raise your hands if there is a person in this forum has received ankorwatt raw file
2. "Im relatively new here": yes, you are new with a new nick name but pretty old with nick Mikael Risedal which was banned
3. "need not to show off my self": i am not sure what you can show off in this forum? at least not to me. but i do respect mr. MichaelTheMaven since i did learn something from his youtube videos back to the day when i fisrt start with dslr
4. "i took down my Picture Bank": i have seen some of your SNAPSHOTS taking in indochina, but nothing interested... want to see some interested images taking in the same places? here is one of the link: http://www.peterphamphotography.com/ or search for Don Hong-Oai for photo painting
5. "but you can always google at my name" for what? since there is nothing that i can learn from you. if you offer some great tutorials helping me taking great images, i will certainly look for your name. but i do not think you have this chance any more with available light since i am way pass your skills in this area. well, i am starting to learn strobist... know strobist or some skills like Erik Johansson? put up some tutorials, i put your name into my search list LOL

questions?


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## horshack (Aug 31, 2013)

The High ISO performance between two competing bodies of the same generation are very close, which means two things:

1) The differences aren't that important in actual, practical use.

2) To measure those small differences you have to use an exacting methodology. This means the same absolute exposure (aperture/shutter speed) with the same lighting. Matching the aperture requires using the same lens on both bodies, which for Canikon means using a Nikon-mount lens with a manual aperture ring, and adapting the lens to the Canon body using a F-mount -> EF mount adapter. Failing to use the same lens on both bodies means the actual aperture/t-stop can vary by up to or more than a 1/2 stop, which is larger than the actual High ISO difference between most bodies of the same sensor size. Naturally you also have to use a tripod, timer release, MLUP, and identical framing.


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## scottkinfw (Aug 31, 2013)

Regardless of results, I am not about to "jump ship", like a recent poster, just for a test. Now if a new Canon body or lens came out that had some great feature or spec that I had to have, that would be another story. However, the point has been mad many times, it is the whole system that counts. Not withstanding the validity of this test.


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## Marsu42 (Sep 1, 2013)

horshack said:


> 1) The differences aren't that important in actual, practical use.



I wouldn't say that, since iso noise is the main limiting factor on crop even a 1/2 stop gain might very well make a difference to some - it's not much, but it will show on each and every image you produce. And when you downsample the 24mp d7100 to 18mp and compare with the current Canon crop sensor, there will be more than nothing to see.



horshack said:


> 2) To measure those small differences you have to use an exacting methodology.



+1


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## neuroanatomist (Sep 1, 2013)

ankorwatt said:


> neuroanatomist said:
> 
> 
> > ankorwatt said:
> ...



Wait, wait...are you suggesting that someone can conduct a 'test' in such a way that it appears there's a 'problem' or 'defecit' with the camera's performance, but it's really just the fault or bias of the person conducting the 'test'? What an amazing idea... Gee, I wonder if that's happened anywhere else on this forum?


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## Jim O (Sep 1, 2013)

ankorwatt said:


> as I said, google
> is there anything you particularly want to know? I was among the first in Sweden to go to the digital process and that I have scanned film about 10years before digital camera came along, I've been co authors of numerous articles, I have 30 long years of working experience as a photographer?



I do not plan to argue with you but I am curious. I am new here and you seem, well you seem to be fairly opinionated. I have googled you and find little more than argumentative posts here and elsewhere, a few photos from Lund University, and one on Wiki of Martin Saarikangas. By the way, are his teeth really that yellow? I didn't find any serious articles but perhaps they are hard to find hidden among your rants, raves, insults, and boasts here and elsewhere. Can you point us to say, a half dozen or even better a dozen of these "numerous articles". It's ok if they're in Swedish. I can use Google Translate.


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## Marsu42 (Sep 1, 2013)

ankorwatt said:


> BOB N has now presented the figures for 70D regarding read out noise, DR etc



Interesting - I can understand the large dr difference, but would anybody please care to explain to poor /me what read noise and saturation mean for real world shooting?

I tried to look at the explanations (from http://www.clarkvision.com/articles/digital.sensor.performance.summary/index.html) - but they are very technical and according to these numbers, both the 5d3 and 70d have to be complete junk @iso100 which doesn't seem to hinder even pros using them. So what's the real world difference?


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## celestyx (Sep 1, 2013)

ankorwatt said:


> BOB N has now presented the figures for 70D regarding read out noise, DR etc
> here we can se 70d in comparison with one Toshiba and one Sony made sensor
> The read out noise is 4,35 times higher , compare this to 5dmk3 vs d800 there 5dmk3 has 12,2 times higher read out noise.



Why is it the measured ISO are so different from the reported ISO?
Shouldn't this be taken into account when we compare the noise of cameras at high iso?


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## neuroanatomist (Sep 1, 2013)

ankorwatt said:


> if you take a look at dpreview and 800iso from d7100 and 70D there is not any strange with 800iso from any camera



Thanks to you and your 30 years experience for clearing that up, I'm sure glad to know the D7100 doesn't have a problem at ISO 800. Now I feel a little embarrassed for all those posts I almost made on Nikonrumors about the "D7100 ISO 800 problem," silly me. But you've cleared it all up for me, Mikael - I really thought the test reported here was valid and well executed. Or did I? Let's take a look and se what I wrote above, and try to *read and understand* about tests and validity.


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## Marsu42 (Sep 1, 2013)

celestyx said:


> Why is it the measured ISO are so different from the reported ISO? Shouldn't this be taken into account when we compare the noise of cameras at high iso?



Imho no, because the measured iso is just an intermediate layer nobody cares about - the more the companies cheat on the iso value, the more underexposed the shots will get and *that* is the thing to compare because it will raise the noise level.


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## Pi (Sep 1, 2013)

ankorwatt said:


> BOB N has now presented the figures for 70D regarding read out noise, DR etc
> here we can se 70d in comparison with one Toshiba and one Sony made sensor
> The read out noise is 4,35 times higher , compare this to 5dmk3 vs d800 there 5dmk3 has 12,2 times higher read out noise.



Where did you get this, it is not on sensorgen yet?

The d7000 has an amazing saturation level, a stop above the typical for a crop camera.


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## neuroanatomist (Sep 1, 2013)

Mikael, sorry I confused you again and again and again. *I was joking.* Sarcasm. You don't get it, that's ok, just let it drop.


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## Pi (Sep 1, 2013)

ankorwatt said:


> Marsu42 said:
> 
> 
> > ankorwatt said:
> ...



In addition - the high saturation level of the d7000 - twice as much as usual, makes this sensor an ISO 50 one, if you consider the rest of the crop bunch to be ISO 100. This allows you to allow for more light, when possible (SS, etc.), and get a lower noise, which is perceived as better tonality. You get the tonality of FF sensors basically. For that, you need to ETTR properly. This, combined with the read noise kept under control increases the DR even further. 

EDIT: not quite right: I forgot that the d700 has 16mp "only".


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## AlanF (Sep 1, 2013)

I tend to shoot at 320-640-1250 for wild life. Am I right in interpreting from those data kindly provided from BobN that the sensors tend to be much similar there?


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## Marsu42 (Sep 1, 2013)

Pi said:


> You get the tonality of FF sensors basically.



Thanks for the explanations - and oh my, does that mean if you shoot at base iso (landscape & architecture w/ tripod) with Nikon crop and the 24mp are enough for you vs. d800 you don't need a ff sensor anymore, esp. not a Canon ff? That's ignoring the lenses and software, of course.


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## Pi (Sep 2, 2013)

Marsu42 said:


> Pi said:
> 
> 
> > You get the tonality of FF sensors basically.
> ...



I was not quite right there. I forgot that the d7000 has 16mp, I thought it is like the d7100. So the d7000 is 1 stop behind the D800 in terms of light collection, instead of 1 stop and 1/3 or so. Not enough to get close to FF, and the D800 is not just any FF.

Even if it had the D800 tonality, the resolution difference due to the pixel count and the enlargement factor still would stay.


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## Jim O (Sep 2, 2013)

ankorwatt said:


> My first test is from 1978 Leica summicron-vs a zoom Nikkor 80-200
> then search at for example in old Photodo magazines.
> is this the best you and others can do , when the arguments runs short, trow garbage at others, it would be better if you and others could met me and argue with facts



If this was a "response" to my questions, it is several things but it didn't answer any of the questions I posed. 

I am still waiting for answers. I _have_ searched. Please provide the links since evidently I am too stupid to find them.

Bye the way, that was sarcasm, but I still want the links to your oh so many articles. Saying they're there, and their actually being there are two different things. It's time to walk the walk, not just talk the talk.


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## aj1575 (Sep 2, 2013)

MichaelTheMaven said:


> Ill be posting a bunch of tests between these 2 cameras. Im learning a lot of really interesting things, and so far it has been an absolute slugfest. The Nikon has been surprising me in positive ways, and then the 70D comes back and crushes the D7100 in others. Ill have a full write up available soon.
> 
> Check this out. No commentary on my part, decide for yourselves. Quick and dirty test with description of what I did here:
> 
> http://www.michaelthemaven.com/?postID=2894&canon-70d-vs-nikon-d7100-iso-noise-chart



Thanks for the work you put in, but this is not really helpfull. These kinds of tests can be seen at dpReview easely. If you really like to make a test, then show us some real world examples, with decent quality (not like the ones of candles you posted, where some pictures are out of focus.


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## Pi (Sep 2, 2013)

aj1575 said:


> MichaelTheMaven said:
> 
> 
> > Ill be posting a bunch of tests between these 2 cameras. Im learning a lot of really interesting things, and so far it has been an absolute slugfest. The Nikon has been surprising me in positive ways, and then the 70D comes back and crushes the D7100 in others. Ill have a full write up available soon.
> ...



The test means nothing if they were not exposed the same way, and there is no mentioning of that. Also, NR is on, one of the shots is misfocused, etc.


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## Skulker (Sep 2, 2013)

ankorwatt said:


> Here is an discussion group 2001 and regarding scanners (before the real digital SLR time)http://www.lexa.ru/FS/msg12761.html



hi ankorwatt

did you really mean to link to a post were you said "you are totally wrong" and then had to correct less than 2 hours later with "my mistake, sorry".

I was just wondering if you really think that link improves your credibility?


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## aj1575 (Sep 2, 2013)

Pi said:


> The test means nothing if they were not exposed the same way, and there is no mentioning of that.  Also, NR is on , one of the shots is misfocused, etc.



I do not agree with the active NR is a negative point about the test; it just depends what you like to test. Is it only the sensor, or the image pipeline as a whole, or the camera. Since I buy a camera, I'm interested what the camera ca do, this includes NR. If the NR withhin one camera is better than within another, than this is a selling point.


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## Skulker (Sep 2, 2013)

ankorwatt said:


> Skulker said:
> 
> 
> > ankorwatt said:
> ...



I know we all make mistakes Ankorwatt, but I was just puzzled. Someone was questioning your credibility and you gave a reference that was just a comment over a decade old were you were correcting yourself for clearly saying someone else was "totally wrong" when it was you who was in fact "totally wrong".

There was no problem with spelling or translation. You were simply wrong when you said, rather rudely, that someone else was wrong. 

I still do not understand why you chose that link when Jim was asking for a link to something you have written or published to give you credibility. To me it seems just to undermine your credibility without proving anything other than that you have been rather "burdus" for the last 12 years. Why did you choose it?


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## Pi (Sep 2, 2013)

aj1575 said:


> Pi said:
> 
> 
> > The test means nothing if they were not exposed the same way, and there is no mentioning of that.  Also, NR is on , one of the shots is misfocused, etc.
> ...



What if you can tweak the NR (standard, strong)? Then you need tests with all those parameters. Also, how do you define "better"? You need to see what detail is lost vs. the loss of noise, and you need a well focused shot for that. 

The main point however is that "the same ISO" means nothing. You need the same exposure.


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## Skulker (Sep 2, 2013)

ankorwatt said:


> then show me, so we know what you mean



I was asking you to explain. I can't "show you" why you chose to link to your own mistake.


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## neuroanatomist (Sep 2, 2013)

Skulker said:


> I know we all make mistakes Ankorwatt, ... you were correcting yourself for clearly saying someone else was "totally wrong" when it was you who was in fact "totally wrong".
> 
> To me it seems just to undermine your credibility without proving anything other than that you have been rather "burdus" for the last 12 years.



Actually, it showed something else. 12 years ago, he was capable of _admitting_ that he was wrong. He seems to have unlearned that behavior since then (and is retrospectively applying his current behavior, by implying that his factual error was due to spelling or translation).


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## Skulker (Sep 2, 2013)

neuroanatomist said:


> Skulker said:
> 
> 
> > I know we all make mistakes Ankorwatt, ... you were correcting yourself for clearly saying someone else was "totally wrong" when it was you who was in fact "totally wrong".
> ...



I think you may have a good point there.


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## Jim O (Sep 2, 2013)

ankorwatt said:


> Jim O said:
> 
> 
> > ankorwatt said:
> ...



Well that's still not an "article". It's something from a mailing list.

As for me, well I'm just an average joe trying to learn something from an expert, something you purport to be, so far with little to back it up. I'm not trying to *defame* you at all. Rather I am giving you a chance to back up what you say about yourself. So far you have come up with zilch, except to try to deflect it back at me. You seem to feel very persecuted by simple questions.


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## neuroanatomist (Sep 2, 2013)

ankorwatt said:


> Feel free to direct questions . Several have previously tested my skills as neuro and jrista here at CR a sort of admission test where they have challenge me in many ways.



Tested, challenged, and found wanting.


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## Apop (Sep 2, 2013)

So is this still serious? or is it just comedy....
It's making me laugh and feel smugly.

Ankorwatt is trolling ? or?
Ankorwatt must have some serious issues, maybe even a complex?
The need to proof himself , wanting to be a skillful credible person ?, Why do you need peoples approvement? Why should they credit you or see you as a skillful person?

Also I think appreciation and admiration is not recieved by a person who is screaming for it.
Summing up all you ''achievements'' and titles is misplaced arrogance and will make most people disgust.
If you have great skills and knowledge, there is no need for yourself to address it , people will see and experience it and complement you for it.

Also, the most credible persons can talk a lot of rubbish


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## neuroanatomist (Sep 2, 2013)

ankorwatt said:


> I admit if Im wrong show me please what you are talking about
> and if not fu... of
> tired of your innuendo
> so up to proof



Do you remember how you earned the sobriquet 'Mikael half-the-photons Risedal'? You insisted - repeatedly, despite being corrected by many people - that enabling the HTP setting reduces by half the number of photons reaching the sensor. Did I just miss your admission that you were wrong somewhere in the repeated handwaving and denials?


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## neuroanatomist (Sep 2, 2013)

ankorwatt said:


> neuroanatomist said:
> 
> 
> > ankorwatt said:
> ...



Same old Mikael, wrong still. When I'm in manual mode (that's the one with the M, where the user sets the aperture and shutter speed, in case you didn't know that), and then I enable HTP, the number of photons hitting the sensor *does not change*. The shutter speed does not change. The aperture does not change. How is the number of photons changing in anything except your own imagination?

Go back and study what a photon is, and what determines how many reach the sensor (hint: it's not ISO) or just read your camera's manual, it's all in there. 

Thanks for proving yourself wrong, intransigent, and generally making yourself look silly, once again.


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## neuroanatomist (Sep 2, 2013)

neuroanatomist said:


> ankorwatt said:
> 
> 
> > neuroanatomist said:
> ...


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## neuroanatomist (Sep 2, 2013)

ankorwatt said:


> I have shown you



You have shown me you're still wrong. You asked for an error of yours to be pointed out, where you refused to admit your mistake. I did so, and you're still not admitting it. 

M mode, 1/100 s, f/8, ISO 400, change HTP from disabled to enabled, what happens to the number of photons? Nothing. No difference. Av mode, f/5.6, ISO 200, change HTP from disabled to enabled, what happens to the number of photons? Nothing. No difference. 

If your 'explanation' only applies in a very specific case, it's a bad explanation. If you cannot understand that you're explanation is poor and often wrong, then you have a limited grasp of the relevant concepts. Yet you always tell those who thoroughly grasp the concepts that they 'should study'. 

Whatever. It was pointless the first time, it's even more so now. 30 years of experience, maybe after 30 more you'll have learned something, but I doubt it.


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## mjbehnke (Sep 2, 2013)

ankorwatt said:


> BOB N has now presented the figures for 70D regarding read out noise, DR etc
> here we can se 70d in comparison with one Toshiba and one Sony made sensor
> The read out noise is 4,35 times higher , compare this to 5dmk3 vs d800 there 5dmk3 has 12,2 times higher read out noise.



Dumb question? Why is the sensor for the Canon dated 10/1/2010 on this chart? Isn't that a little odd if the 70D uses a new sensor??


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## Jim O (Sep 2, 2013)

neuroanatomist said:


> M mode, 1/100 s, f/8, ISO 400, change HTP from disabled to enabled, what happens to the number of photons? Nothing. No difference. Av mode, f/5.6, ISO 200, change HTP from disabled to enabled, what happens to the number of photons? Nothing. No difference.



This is basic physics, assuming of course the situation external to the camera is controlled. Anyone who does not understand this can easily learn it. Admitting one is wrong is another story evidently.

Again, assuming controlled lighting from outside the camera, the number of photons hitting the sensor can only be changed by exposure settings - the f-stop and the amount of time the shutter is open. No artificial computer driven setting in the camera's software can magically create photons or destroy them. That is contrary to the laws of physics.


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## ME (Sep 3, 2013)

ankorwatt states "Your camera has not indicate that the time as a example are now 1/125sec instead of 1/60sec with same f-stop= halving the in falling light/photons to the sensor due 1 stop shorter exposure time?"

It sounds like he believes that by switching on HTP the shutter speed automatically changes to a faster shutter speed, thereby decreasing the number of photons hitting the sensor. I am fairly ignorant on this and am trying to learn. I wonder if this is a fact or not, and does the exif info indicate a different shutter speed than what was set in M mode before switching on HTP. If it does indicate a faster shutter speed, then ankorwatt is correct. If not, then obviously he is wrong. Sounds like a simple way to prove who is right or not. I cant try it because I dont have the option to use HTP on my camera.


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## Apop (Sep 3, 2013)

Jim O said:


> neuroanatomist said:
> 
> 
> > M mode, 1/100 s, f/8, ISO 400, change HTP from disabled to enabled, what happens to the number of photons? Nothing. No difference. Av mode, f/5.6, ISO 200, change HTP from disabled to enabled, what happens to the number of photons? Nothing. No difference.
> ...



Hi, How does changing the Exposure increase or decrease the amount of photons hitting the sensor?
It does make sense(brighter/darker image), but i'm just wondering what actually happens.


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## Sporgon (Sep 3, 2013)

Apop said:


> Jim O said:
> 
> 
> > neuroanatomist said:
> ...



According to theoretical physics photons flow, and so aperture physically restricts the amount that can pass, and shutter speed restricts the amount in time.

But from what I understand, it is theoretical physics, the emphasis being on theoretical.


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## Sporgon (Sep 3, 2013)

neuroanatomist said:


> ankorwatt said:
> 
> 
> > I have shown you
> ...



I believe there is an appropriate old saying for this;

'There's no fool like an old fool'.


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## AlanF (Sep 3, 2013)

Here is a nice experimental approach to what HTP actually does. There is a lot of rubbish on the internet, but these results are very clear.

http://www.galileosolutions.co.uk/blog/highlight-tone-priority-with-canon-cameras-review/


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## Jim O (Sep 3, 2013)

Apop said:


> Jim O said:
> 
> 
> > neuroanatomist said:
> ...



Without intending to be rude I'll have to answer that you'd need to understand what a photon is, or at least what it is theorized to be. Around 100 or so years ago Albert Einstein realized that the wave theory of electromagnetic energy could not explain all observed phenomena with respect to light. So he proposed a particle theory. A photon a quantum particle of light. All photons of the same wavelength contain the same amount of light energy. There are no "bright photons" or "weak photons" at the same wavelength. Exposure is determined by how many photons hit the sensor and the sensor's sensitivity to them (ISO).

The sensor (or film) may act a little differently during prolonged exposures, but for the numbers that neuro gave, this rule holds true.

So if you open the aperture, thus doubling its size, twice the number of photons pass per unit of time. If you halve the exposure time, half the number of photons pass per unit of time. That's why we know that an image made at f/2.0 and 1/500th will have the same exposure as an image made under the same light and ISO at f/2.8 and 1/250th. The second image will have the half the number of photons per unit of time, but will have twice the amount of time. Changing sensor settings like ISO will not change the number of photons reaching the sensor, it only changes the sensor's sensitivity to each photon. Same thing with film.


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## Apop (Sep 3, 2013)

Sporgon said:


> Apop said:
> 
> 
> > Jim O said:
> ...



Oke, i Must have misunderstood , I thought he meant 3 things ( not 2)

I misinterpreted it for exposure compensation , the part of aperture and shutter speed was clear.

But i still wonder what exposure compensation actually does, is it an electronic signal boost?


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## jrista (Sep 3, 2013)

Apop said:


> Sporgon said:
> 
> 
> > Apop said:
> ...



Exposure Compensation is usually only available in modes that are not fully manual. Av, Tv, even M with Auto ISO, you often have EC. Simply put, EC changes one of the "automatic" variables to achieve your chosen "exposure". 

In Av or Tv, EC usually adjusts the factor not controlled by your dial. If you EC in Av, that will usually change shutter speed, unless shutter cannot be changed...in which case, if ISO is auto, EC will change ISO. Same goes for Tv, except that EC will change aperture when it can. Exposure Compensation is not something mystical or magical, or having to do with electronics. It is simply changes one of the settings you are already intimately familiar with.


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## Apop (Sep 3, 2013)

jrista said:


> Apop said:
> 
> 
> > Sporgon said:
> ...



Thanks a lot for the explanation(!) and useful information.


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## jrista (Sep 3, 2013)

Apop said:


> Jim O said:
> 
> 
> > neuroanatomist said:
> ...



Photons move from their source over time. They also disperse from their source over time, covering a larger area. We could get into some complicated math, using solid angles, light intensity measurements like cd/m^2, etc. But none of that is really necessary to actually understand the answer to your question.

Lets say you have a 60watt light bulb. That bulb produces light. That means it produces a continuous flow of photons, emitted from the bulb's entire surface area, every moment. If you take a photograph of the bulb with a DSLR camera, there are two things that will affect the "exposure" of the image: aperture and shutter speed. Why these two? Why is ISO not a factor?

If we think of the distance between the bulb and our camera's aperture as a water pipeline, we can come up with an analogy for aperture. For a given quantity of water, a large pipeline can move a large volume of water at a low pressure, and a small pipeline can move a smaller volume of water at a higher pressure. Volume and pressure are both important here, but for now, I'll only cover volume. A large aperture is like a large pipeline...it allows a lot of light to flow through in a given amount of time. Similarly, a small aperture is like a small pipeline, it allows a lesser amount of light to flow through in a given amount of time. Aperture changes the total volume of light passing through the lens.

Shutter speed is a very simple concept. It is simply the time factor for exposure. Since light from the bulb "flows" over time...since a certain amount of photons are emitted in any given unit time, changing shutter speed affects how many photons actually reach the sensor. Shutter changes exposure time at the sensor plane.

Let's say that an exposure of 1/500s f/4 of our light bulb produces a reasonable exposure...the bulb is not blown, but it is very bright. We can do one of two things to reduce the exposure by a factor of two, such that we can start to see some detail in our bulb. Since aperture affects the volume of light passing through the lens, we can reduce the aperture by "one stop" to reduce the volume of light by a factor of two. That gives us 1/500s f/5.6. Similarly, we could double the shutter speed, again a "one stop" change, to reduce the amount of light reaching the sensor by a factor of two. That gives us 1/1000s f/4. 

I mentioned that ISO does not actually affect exposure. From a literal standpoint, ISO is not an exposure factor. It is technically a post-exposure factor. From a logical standpoint, ISO as far as the average photographer is concerned, is an "exposure" factor. ISO simply takes the actual exposure on the sensor, and amplifies it. ISO 100 is base ISO for the vast majority of cameras. Increasing ISO from base always has the effect of making an exposure brighter. Changing ISO, however, *does not affect the amount of light!!* It uses electronic signal amplification and digital boost to *simulate *a brighter exposure, hence the reason noise increases as you increase ISO.



Finally, I compared aperture to a water pipeline. There was a specific reason for this, and it has to do with diffraction. A more realistic analogy would actually have been to compare a lens to a water pipe with a variable exit opening...which is basically the same thing as an aperture. If you force water through a large pipe, lets say a pipe with a 1-foot diameter, at a fixed pressure, it will exit the other end and spread out a little bit. If you double the pressure in the pipe, the amount the water will spread out as it exits the pipe will increase. Double the pressure again, and water will start to spray out at almost a 180 degree angle to the direction of the pipe. Pressure can be changed by adding a cap to the end of the pipe with differing hole sizes...or apertures. We could call the uncapped pipe f/1, so to double the pressure, we add a cap that produces an f/1.4 hole (8.6" diameter), and to double again we add a cap that produces an f/2 hole (6" diameter). Water moving through the pipe is technically a longitudinal wave, and therefor it experiences diffraction when it encounters the cap.

Light also behaves as a wave, so when it passes through a lens and encounters the diaphragm, it must spread out. Reducing aperture therefor must increase the diffraction of light, as it bends more around the edges of the aperture opening by an increasing degree as aperture diameter approaches the wavelength of light. (Similarly, in the case of a telescope, rather than light bending around the edges of the diaphragm blades, it bends around the secondary mirror support in the center.)


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## neuroanatomist (Sep 3, 2013)

ankorwatt said:


> I have explain what is actually does several times in this thread



Yes, and every time you've explained it incorrectly.

*Mikael, why do you think that typing your explanation for how HTP works in bold will make it correct? You're still wrong. Even if you use ALL CAPS AND A LARGER FONT, you'll still be wrong.*

Ok to be fair, you're not _totally_ wrong. You are correct, in an analogous way to a broken/stopped analog clock that is correct twice per day.

You have (repeatedly) asserted that HTP reduces by half the number of photons reaching the sensor. In some cases, you specifically state that shutter speed/time value is changed. In other cases, you mention f/stop might change, too. That is true under the following conditions:


Turning on HTP with the camera set to ISO 100 and Av changes the shutter speed to reduce by half the number of photons reaching the sensor
Turning on HTP with the camera set to ISO 100 and Tv mode changes the aperture to reduce by half the number of photons reaching the sensor
Turning on HTP with the camera set to ISO 100 and P mode changes the shutter speed or aperture (usually the former) to reduce by half the number of photons reaching the sensor

It does that because ISO 100 is not available as a selection when HTP is enabled, so if ISO 100 is selected when HTP is enabled, the camera changes it to ISO 200. If you _happen to be in an autoexposure mode_, the camera then changes another parameter (aperture or shutter speed) to maintain the metered exposure. Setting HTP at ISO 100 is an oxymoron - if you enable HTP, your camera isn't set to ISO 100 anymore. 

In M mode, enabling HTP changes neither aperture nor shutter speed, and the number of photons reaching the sensor is unchanged. So, in M mode, your explanation of what HTP does is wrong. At ISO 200 or higher, enabling HTP changes neither aperture nor shutter speed and the number of photons reaching the sensor is unchanged, and again your explanation of how HTP works is wrong.

Therefore, as a general explanation of how HTP works, your statement that it works by halving the number of photons reaching the sensor is WRONG. 

I know you understand the goal of HTP. Guess what? So do I (despite your repetitive and annoying suggestions to the contrary). I also fully grasp how HTP works. Maybe you partially (or even fully) grasp how it works, but no one would know that, because you can't explain it properly. 

Maybe you should try reading Emil Martinec's explanation of HTP, he does a much better job: 

[quote author=Emil Martinec]Instead of using the ISO gain set by the user, the camera uses a lower ISO (*but exposes with the indicated aperture and shutter speed*), effectively underexposing the image; this provides more highlight headroom. In post-processing, the image data can be brought back up while preserving the highlights with a modified tone curve in higher exposure zones. The place where image quality suffers is in shadows at lower ISO, precisely as the above quantitative model predicts.[/quote]
Does he mention a reduction in the number of photons? No. He states that the exposure is "with the indicated aperture and shutter speed," and if that's the case, how exactly is the number of photons being reduced, as you have repeatedly stated is occurring? 

Maybe you think that an analog clock with the hands stopped gives the right time, because it just happens to do so twice per day. But the reality is that such an analog clock is broken, just like your explanation of HTP.


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## Marsu42 (Sep 3, 2013)

ankorwatt said:


> I think people here can read by them self what kind of escape you are trying to do



As one of the people here it is beyond me why you are so insistent to make this into an unfriendly flamewar, and neuro in this case repeats what has been figured out on CR by multiple people some time ago because what htp does is certainly not self-explanatory. 



ankorwatt said:


> I'm going to strip you naked



Congratulations, my ignore list now contains one name, and that's yours.


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## jrista (Sep 3, 2013)

ankorwatt said:


> So please explain what happens if you set your cameras at M and base iso 100 HTP and if the exposure time or f-stop is not changed? (have I understand you correctly) And why there are a choice of HTP in other modes as AV etc



He already did explain, but maybe a preschool level explanation is necessary here.

*If you enable HTP, you cannot use ISO 100.* Not in any auto mode. Not in any semi-auto mode. Not in manual mode. The lowest user-selectable ISO is 200. Plain and simple.


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## jrista (Sep 3, 2013)

ankorwatt said:


> Neuro wrote:
> Therefore, as a general explanation of how HTP works, your statement that it works by halving the number of photons reaching the sensor is WRONG.
> 
> same here, I have time after time explained that at base iso you must create a head room
> ...



Neuro does get it, it is you who does not. The camera does not change aperture or shutter. You, the user, do. By restricting the lowest possible ISO setting to ISO 200, you effectively shift the USER into a mode of actively selecting a higher shutter or a narrower aperture to compensate for the METERED exposure, which is a stop higher when HTP is enabled. 

As a user, if I would normally use 1/100s f/4 to photograph a scene at ISO 100, when I enable HTP, in manual mode, *I must compensate* for the fact that my ISO settings are now one stop brighter. That means *I will select* 1/200s f/4 or 1/100s f/5.6 instead. The camera will then "preserve" my highlights by using an ISO setting one stop lower (technically speaking, the camera didn't preserve anything...I did by manually reducing exposure by a stop). If ISO 200 was selected, then the camera will use IS0 100. If ISO 400 was selected, then the camera will use ISO 200. Etc.

The camera does not change aperture or shutter in HTP...the user does! HTP, and similarly ADL for Nikon, is a _user conditioning_ setting. It does not actually change the exposure (which is solely controlled by aperture and shutter speed). It _changes the users behavior_ by forcing the user to change exposure, then compensates by using a different ISO (which changes a post-exposure adjustment, but not the exposure itself.) 

It couldn't work any other way...ISO is the sole "side effect free" setting (noise isn't a side effect in this context). If the camera changed the shutter speed or the aperture, it could potentially change things other than exposure...such as depth of field, motion blurring, etc. that the photographer EXPLICITLY CHOSE to use.


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## jrista (Sep 3, 2013)

ankorwatt said:


> jrista said:
> 
> 
> > ankorwatt said:
> ...



You are going to get yourself banned with the attitude, man... ??? 

You seem to have the assumption that everyone else on this forum is dumber than you, and that everyone should always listen to everything you say without questioning any of the discrepancies that constantly stream out of your posts. Why not take your own advice, eh?


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## Sporgon (Sep 3, 2013)

Is there a psychiatrist in the house ?






With a *LOT* of time to spare


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## jrista (Sep 3, 2013)

ankorwatt said:


> jrista said:
> 
> 
> > ankorwatt said:
> ...



Wow...not much from you surprises me, but the arrogance in that line is rather surprising...did you not understand what I just wrote? Eh, it doesn't even matter anyway... ???



ankorwatt said:


> I have reported Neuro twice now, or does he have a free ticket to make him funny over other persons posts?




You can report us all you want. The only one here who is being directly and actively degrading of other members is you. Neuro, and now myself, are addressing a technical misunderstanding you seem to have regarding HTP. The debate is regarding verifiable facts, and the fact that we engage in that debate with you is not a commentary on your person (i.e. we are _not_ calling you an idiot), it is a commentary on your words (i.e. we are saying your _facts_ are wrong).

I just replied regarding HTP. Read my answer, see if you understand what Neuro, and pretty much anyone else who understands the feature and has commented on the topic of HTP or ADL, is trying to say. There is no ISO 100 in HTP, because it is ISO...not shutter or aperture...that the camera changes. The user's selected _exposure _remains the same, how that exposure is _treated _by the electronics or post-processing software is what changes.


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## ajfotofilmagem (Sep 3, 2013)

Why hijack the topic? Those people who need to write hundreds of words to prove that they are always right, I do not deserve to lose my time.


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## jrista (Sep 3, 2013)

ankorwatt said:


> no explain, and keep it short, i have some problem to read your posts, 5% information and the rest a lot of words
> so please explain
> *do you mean that this forum could not be better with all people like Pi and Hulls knowledge as two example ?*
> That neuro has not been understanding or misunderstood
> ...



I'll happily admit Pi often knows exactly what he is talking about. I think he sometimes comes from an _unconventional angle_, but he has frequently backed up his claims with very solid information (such as the excellent Equivalence article he linked to in a recent thread.) Key point there...*he backed up his claims*. Once I read the information he provides, his angle becomes clear, and his perspective on the subject usually makes sense. Sometimes that is necessary.

You are, seemingly, trying to compare yourself to Pi, with the claim that you have superior knowledge than any Canon user on these forums. That is an arrogant claim, and one which, given the lackluster and frequently incorrect content of so many of your posts, has no backing. Maybe sometimes you do know what your talking about, and there may simply be a language barrier/cultural gap that is preventing people from understanding you...but you rarely back up your claims. When you do sort of try to provide references or evidence, it is usually contrived or incomplete, or linked reference material actually backs up what other members are saying and not what you are saying...and people can't help but question why.

So, once again...why not try to take your own advice? Why not listen to what other members here have to say, instead of just blindly assuming you always have superior knowledge and that no one else here could possibly know what they are talking about? I don't think there are very many members here who truly want to get involved in a conversation, let alone a debate, with you...it is a taxing endeavor that always leads nowhere. You eventually become highly antagonistic, aggressive, arrogant, and insulting. No one wants to listen to you insult them all the time, Mikael. No one wants to be on the receiving end of endless antagonism (and there is no question you are the supreme antagonist in the ongoing story of Canon Rumors. ) 

It is also human nature to retaliate, especially if someone thinks they have the upper hand...and when you say something that comes across as factually incorrect, well, that gives your opponents the upper hand...


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## Apop (Sep 3, 2013)

ankorwatt said:


> no explain Jrista , and keep it short, i have some problem to read your posts, 5% information and the rest a lot of words
> so please explain
> *do you mean that this forum could not be better with all people like Pi and Hulls knowledge as two example ?*
> I know David from dpreview since years back
> ...




Neuro and Jrista strike me as the people who like to share their knowledge, but also read others opinions which might influence their beliefs/point on certain topics.

I like the way they constructively explain things, in a ''slightly'' less aggressive way than yourself.
It seems like you feel the need to attack anyone that disagrees with your pov, how can that ever lead to a serious discussion? 

The reason that people won't question them as much as you, Is that they actually explain things or support it with facts/research. The way they approach people (and ignorance) is also working for them .

I asked a rather stupid question about exposure/exposure compensation, instead of getting flamed at that I am a dumb idiot that doesn't understand how a camera works and that the one accusing me of being so has been doing it for 30 years and has great knowledge, they just fed my ignorance with information ...(actual useful information).

That you don't like a lot of words seems to support my feeling you have a rather short fuse.
And the 5% you do read is most likely what you had filtered out and interpreted as an insult.

This forum would be better if there weren't as many flaming people around like yourself,
If anyone is to get a ban ( I doubt it), it's more likely you than Neuro .
( that can be based on the fact alone that the admins eyes disagrees with dxo mark results, so i don't expect him to be in your corner  lol)


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## jrista (Sep 3, 2013)

ankorwatt said:


> End of discussion for me in this thread
> 
> an apology can I probably not expect from a man who has committed jokes at my expense, and where he has shown great ignorance.



Why would you expect an apology from someone you have been insulting for much longer than he's been making jokes at your expense? As I said...it is human nature to retaliate. Maybe if you apologized to him for all the insults and derogatory comments you've made about him, he might apologize to you for the jokes.

As for me, you regularly bring my name up in threads I have never participated in, just to include me in an insult of one kind or another. I have no interest in hiding my dislike of you, Mikael, but I'll apologize for any insults I may have levied at you in the past. That does not change the fact that I think you are continually, and pointlessly, antagonistic here on CR forums, and that we would probably be much better off without you around at all...but here is my apology nevertheless. I'm sorry if I've ever insulted you.


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## ME (Sep 3, 2013)

neuroanatomist said:


> ankorwatt said:
> 
> 
> > I have explain what is actually does several times in this thread
> ...


Does he mention a reduction in the number of photons? No. He states that the exposure is "with the indicated aperture and shutter speed," and if that's the case, how exactly is the number of photons being reduced, as you have repeatedly stated is occurring? 

Maybe you think that an analog clock with the hands stopped gives the right time, because it just happens to do so twice per day. But the reality is that such an analog clock is broken, just like your explanation of HTP. 
[/quote]

Thanks for your explanation of HTP Neuro. Another poster gave what seems to be much confusing garbage as an explanation.


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## Factor7 (Sep 3, 2013)

Hope you're happy, MichaelTheMaven..! 
;D


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## Pi (Sep 3, 2013)

jrista said:


> Light also behaves as a wave, so when it passes through a lens and encounters the diaphragm, it must spread out. For a given light illumination in the scene, you have a fixed incoming "light pressure". Reducing aperture therefor must increase the diffraction of light.



OMG!


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## ME (Sep 3, 2013)

*[size=24pt]DO YOU HAVE FACTS TO SUPPORT YOUR HYPOTHESIS ANKORWATT SUCH AS EXIF INFO AND HOW YOU SET YOUR CAMERA (ISO,SHUTTER SPEED & APERTURE) BEFORE ENGAGING HTP & AFTER SNAPPING THE SHUTTER? BEFORE & AFTER INFORMATION, THAT IS. EVIDENCE. FACTS.*


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## Jim O (Sep 4, 2013)

ankorwatt said:


> *End of discussion for me in this thread*
> 
> an apology can I probably not expect from a man who has committed jokes at my expense, and where he has shown great ignorance.






ankorwatt said:


> facts about what?



I guess you were wrong...


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## jrista (Sep 4, 2013)

ankorwatt said:


> jrista said:
> 
> 
> > ankorwatt said:
> ...



So, it's clear apologies don't actually matter to you. Figures.




ankorwatt said:


> and go back and look how this started, neuro accuse me to be wrong
> later on he now confirm everything and have also learn what a head is and why it must be created so HTP works at base iso
> 
> and to you other, if you do not understand how HTP works, read again my earlier posts, it is nothing hard to understand



I've read your explanations. They are wrong. You claim the camera changes the shutter speed, in manual mode, at ISO 100. That is incorrect. 

First, you cannot use ISO 100 in manual mode when HTP is active. Your lowest selectable ISO setting is 200. The camera does not change either aperture or shutter speed when HTP is active. It uses whatever aperture and shutter speed you select. The camera reduces ISO by one stop from what you have selected (or, from what the camera originally metered was necessary.) This is a fact. It is not an assumption. Therefor, your explanation that the use of HTP (or ADL, for that matter) requires the camera to "halve" the amount of light reaching the sensor either by increasing shutter speed or reducing aperture is wrong. The camera does nothing to change the exposure (total amount of light over time reaching the sensor)...all HTP or ADL does is force the USER to change exposure. 

I am sorry, Mikael, but I do not accept your explanation of how HTP works. I do not need your assistance in _learning_ how it works. I agree it is not hard to understand, but it is clear *you* do not understand it. Hence the debate.


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## jrista (Sep 4, 2013)

ankorwatt said:


> ask me strait question then
> short and concise
> 
> ds/ps ,* you have been writing the same as I have from the beginning*
> ...



Well, it seems you've changed your explanation now. Originally, you were saying the camera changed the shutter speed with HTP enabled in order to halve the actual amount of light. That is the point at issue. If you are using manual mode, with HTP on, and select a shutter speed and aperture that over-exposes enough to clip highlights, then you've over-exposed. HTP can't fix that. Nothing can fix that. _The user is still in control of the exposure._ As I said before, it is a _user-conditioning_ setting...HTP has the *tendency* to force users to select a faster shutter or slower aperture...but that does not guarantee the user will comply. 

As for your headroom figure, I think that is inaccurate...at least, as far as how Canon sensors work (and Nikon uses sensors from so many sources, I couldn't say if that diagram conforms to any of the sensors they use.) Highlight headroom is, in my opinion, a misnomer. You don't really have any highlight headroom (rather, you have shadow footroom)...highlights cut off where they cut off, regardless of ISO setting. If you expose past that point, any "headroom" values are simply clamped to the white point. I believe Canon sensors work more like this diagram demonstrates:







When it comes to HTP, highlight headroom, or shadow footroom for that matter, doesn't come into play. HTP forces the user to assume a higher minimum ISO setting that does not actually get applied when the exposure is made. The user assumes they must compensate for a higher ISO, therefor reduces exposure by selecting a lower one with their chosen shutter and aperture. The camera then exposes, according to their selection, at a one-stop lower ISO setting. That's all. There isn't any electronic trickery, or headroom, or anything special about the hardware here. It is all virtual...actual trickery, and the user is the gullible culprit.


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## ME (Sep 4, 2013)

Thanks AlanF for the link to Galileo Solutions. One line from this article "It is clearly evident from my findings that the effects of HTP are quite different to what is achieved by underexposing by 1EV, which simply gives an underexposed image". I suggest that angkor what? could benefit from reading this article. http://www.galileosolutions.co.uk/blog/highlight-tone-priority-with-canon-cameras-review/ . ankorwatt, how did you come up with the idea for your avatar? That's not a copyright infringement is it? 3 shots from you would help clarify what you are trying get across: 1)Use another camera to take a picture of the settings you are using on your HTP camera. 2)Activate HTP, and take another picture of iso,shutter speed, and aperture used.3)Snap your picture. Get the exif info. Post all 3 on cr. Very simple to prove your point, or not. :


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## Pi (Sep 4, 2013)

A much less artistic but more telling picture of how Canon sensors work is at sensorgen.info. You can see there the clip point in photons per pixel, and the read noise. How the converter and the user processes this, is another conversation. 

Roughly speaking, for low ISO, each stop of increase of the ISO halves the saturation capacity (even if more photons are actually registered by the sensor, the AD circuit clips them). The read noise halves as well, approximately. This keeps the DR more or less flat up to ISO 800. Sony/Nikon sensors have more consistent read noise, less dependent on the ISO.


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## jrista (Sep 4, 2013)

ankorwatt said:


> jrista said:
> 
> 
> > ankorwatt said:
> ...



You repeatedly mentioned manual mode and ISO 100 in your earlier posts about HTP. 

Your diagram does not illustrate dynamic range, though. Your diagram, as currently drawn, indicates that each ISO setting has the same dynamic range, which isn't the case. The sensor itself has a constant dynamic range (the ratio between read noise and FWC at ISO 100). As ISO is increased, the white and black points change within that dynamic range (in the case of Nikon, the black point is fixed without a bias offset, so only the white point changes), but from a hardware standpoint, it is a fixed attribute. Your diagram doesn't really portray that.


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## neuroanatomist (Sep 4, 2013)

ankorwatt said:


> So please explain what happens if you set your cameras at M and base iso 100 HTP and if the exposure time or f-stop is not changed? (have I understand you correctly) And why there are a choice of HTP in other modes as AV etc
> 
> *from now and in the future, meet me with facts *


When I have my camera in M mode at ISO 100 and I enable HTP, the ISO is changed to 200 and the exposure _meter reading_ is increased by 1 stop. The meter reading only, not the exposure. The aperture is not changed. The shutter speed is not changed. That is not theory, that is a *fact*. If the aperture and shutter are not changed by enabling, the number of photons reaching the sensor is also not changed by enabling HTP, and that is also a *fact*.

Say, for example, that with my M mode settings of 1/100 s, f/8, and ISO 100 resulted in a 1-stop underexposure based on the camera's meter. If I then enable HTP, the ISO is set to 200, and the exposure reading is centered. But the exposure is unchanged, the same number of photons would hit the sensor whether I captured the image at 1/100 s, f/8, ISO 100 without HTP or 1/100 s, f/8, ISO 200 with HTP. The same number of photons, not half the photons. So, your explanation that HTP means Half The Photons is wrong. I don't know how I can make it any clearer.

I cannot set my "cameras at M and base iso 100 HTP." Can you? I challenge you to do so - enable HTP and set ISO to 100. Show me a picture of your camera's rear LCD, like this one below, where the display in the upper right shows *ISO 100* and the *D+* symbol which indicates that HTP is enabled. Meet me with facts, Mikael.









ankorwatt said:


> I'm going to strip you naked


I'm not sure what you mean by that, but it sounds immoral and possibly illegal. I assume you're not threatening me with a physical assault of some sort, are you, Mikael? That would be a mistake. Regardless, it's a threat of some sort, and totally inappropriate.




ankorwatt said:


> I have reported you to the moderator- lies and falsification of my posts and data


In what way have I falsified your posts and data? Refuting your bogus claims and misunderstandings is quite different than faslifying your posts. Trying to correct your factual errors so that others who don't have your 30 years of experience aren't confused by your incorreect statements is quite different than falsifying your posts and data. 




ankorwatt said:


> End of discussion for me in this thread


Well, we can add that to the list of things you were wrong about. I count 6 posts by you in this thread after that statement. Maybe 'end of discussion' means something different to you. 




ankorwatt said:


> an apology can I probably not expect from a man who has committed jokes at my expense, and where he has shown great ignorance.


Yes, call me ignroant then by all means expect an apology. You've called me worse in the past. That's about as logical as your reasoning on other subjects, so no surprise there.

Please recall that this whole discussion started when you questioned a statement I made in jest. I assumed it would be obvious that if I initially stated that the 'test' conducted in the original post was, "Uninterpretable and no conclusions can be drawn," subsequently concluding that, "The D7100 has problems with color fidelity and exposure metering that occur specifically at ISO 800," was a joke. I already apologized for confusing you with that joke. You subsequently offered the following: 



ankorwatt said:


> I admit if Im wrong show me please what you are talking about
> and if not fu... of


and 



ankorwatt said:


> if you still going on- i tell you to f... of


Is that how you conduct yourself in everyday life, telling people you disagree with to ****** off, and then threatening them?

Regardless, I proceeded to tell you exactly where you were wrong (one example of many, I've provided two more in this post already)...and you proceeded to _not_ admit it. 




ankorwatt said:


> read what I have write, I have said nothing about M


Really? You, who tells everyone else to read, don't even read your own posts, do you? You mentioned M mode in the first post that I quoted above. So, wrong one more time. I'm losing count of your factual errors and conceptual misunderstandings, Mikael.


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## bvukich (Sep 4, 2013)

Mikael, you are hereby banned for life. Don't make a new account, don't come back. You will be noticed, and we're not going to give you another chance.

You are knowledgeable and and can bring a much needed voice of dissent at times, and because of that we regret doing this, but you bring out the worst in everyone here, and your behavior can no longer be tolerated.

EVERYONE ELSE....

Your behavior in this thread has been no better. You should be ashamed of yourselves. Act like adults, and have civil discussions.


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