# Patent: Canon 100-400mm f/5.6-7.1



## Canon Rumors Guy (Feb 20, 2020)

> Canon News has uncovered a patent for an APS-C 100-400mm F5.6-7.1 optical formula.  (Richard also messed it up by not noticing it was APS-C at first)
> Does this mean that the EOS-M is getting a super telephoto consumer lens? The optical elements are fairly lightweight and the lens optics diameter would be somewhere around 52mm, which seems to fit with the EOS-M ecosystem.  Or is this a sign of an RF APS-C camera coming out.  The need for an APS-C 100-400 is puzzling if it’s for the RF mount though.
> *Canon RF/EF-M 100-400mm f/5.6-7.1:*
> 
> ...



Continue reading...


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## Joules (Feb 20, 2020)

Image Height of 13.6 mm indicates this is an APS-C lens (sqrt(22^2 + 15^2) / 2 = 13). In which case I'm more disappointed in this than the RF 100-500 or 24-105 going to 7.1. Although as a compact lens and the right price it will likely still make for an awesome lens. Are we sure this is RF and not EF-M though*?

Also not a fan of calling it a 100-400mm if it's really just a 3X zoom at 120-360mm. But maybe they'll be a bit more honest in the actual name, this is just a patent after all.

*Edit: Note that 360 mm / 7.1 = 51 mm, so less than Canon's standard diameter for EF-M lenses. So it would fit in that system, even though f/7.1 on APS-C is still quite rough.


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## AlanF (Feb 20, 2020)

Oh dear:

Focal length: 119.97mm 218.00mm 360.96mm
F-Number: 5.50 6.50 7.10
That's floored even the positive side of me. Anyway, let's hope it is a cheap consumer lens alongside a stellar 100-500mm L.


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## LensFungus (Feb 20, 2020)




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## gdanmitchell (Feb 20, 2020)

That can't possibly be a successor to the current 100-400 with that aperture at 400mm.

That f/7.1 aperture report also makes one wonder if some of the details about a prospective 100-500 lens are getting mixed up with this thing.


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## Joules (Feb 20, 2020)

gdanmitchell said:


> That can't possibly be a successor to the current 100-400 with that aperture at 400mm.
> 
> That f/7.1 aperture report also makes one wonder if some of the details about a prospective 100-500 lens are getting mixed up with this thing.


This is not related to the EF 100-400mm L lens at all. The patent is for an APS-C lens.

And the RF 100-500 mm is something Canon officially announced. I'm not sure if I understood that correctly, but it sounded like you implied that the f/7.1 aperture in that lens could be misinformation. It is not.


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## canonnews (Feb 20, 2020)

Joules said:


> Image Height of 13.6 mm indicates this is an APS-C lens


Yes, I updated my posting and sent an email off to craig about it. Sorry for the confusion. It's becoming so automatic that if it's a mirrorless patent, it's a full frame RF that it just blew right by me.

My addendum;

_It totally skipped by me that this is an APS-C lens because the image height is 13.66mm.

This is kind of an odd duck patent application either meant for the RF mount or the EOS-M mount. It seems unlikely it would for the EOS-M mount considering they seem to be diameter constrained at 61mm in diameter. However, technically a F7.1 400mm would have around a 55mm front element, so it's possible that this is for the EOS-M mount, but I think it's highly unlikely the lens body could be made that small._


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## Sharlin (Feb 20, 2020)

Joules said:


> Image Height of 13.6 mm indicates this is an APS-C lens (sqrt(22^2 + 15^2) / 2 = 13). In which case I'm more disappointed in this than the RF 100-500 or 24-105 going to 7.1. Although as a compact lens and the right price it will likely still make for an awesome lens. Are we sure this is RF and not EF-M though*?



Good point! This must be an EF-M design. If I had to guess I'd say that this is a byproduct patent of the RF 100–500 design work, but I haven't checked whether the designs are even remotely similar. 360mm f/7.1 wouldn't be totally bad if it's sharp at max aperture.


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## Joules (Feb 20, 2020)

Sharlin said:


> 360mm f/7.1 wouldn't be totally bad if it's sharp at max aperture.


Sure thing, I shoot my Sigma 150-600 mm C at 7.1 a lot in my 80D and get results I'm happy with. But at 600 mm and third party, I'm also more forgiving than I'd be on a Canon lens in this focal length.

I guess what would be could about it is that (subtracting the flange) at ~ 160 mm physical length it is just 50 mm longer than my EF-S 55-250 mm IS STM. And that lens is lovely compact and affordable for what it does.


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## Chaitanya (Feb 20, 2020)

This feels like replacement to 70-300mm lenses more than a proper replacement for 100-400mm L mk2.


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## slclick (Feb 20, 2020)

Chaitanya said:


> This feels like replacement to 70-300mm lenses more than a proper replacement for 100-400mm L mk2.


It's already been edited/corrected that this is a crop lens. fwiw, the 100-400 doesn't need a replacement, it's damn near perfect.


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## mpmark (Feb 20, 2020)

I'll keep my current 100-400ii, no reason to replace it, should work great on the R5


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## russb (Feb 20, 2020)

If this becomes an RF mount lens, it portends an APS-C RF camera, if it becomes an EOS-M mount lens, it shows Canon's continued interest in the smaller bodies. Good news whichever way it might happen.


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## Inspired (Feb 20, 2020)

I would prefer a fast lens than one that is not which could hinder me from completing an assignment


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## Chaitanya (Feb 20, 2020)

slclick said:


> It's already been edited/corrected that this is a crop lens. fwiw, the 100-400 doesn't need a replacement, it's damn near perfect.


100-400mm Mk2 is certainly the beast. Since this is a crop lens it would still be competing with 70-300/55-250 which are both popular among beginers with a little extra reach at tele end.


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## Hyperion (Feb 20, 2020)

Now what? 85 5.6?


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## AJ (Feb 20, 2020)

Hmmm... It sounds a bit like sticking a 1.4x TC on an EF-S 55-250 (doesn't fit, I've tried)


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## docsmith (Feb 20, 2020)

I'd like to see some new EFm releases. While this is slow, it does seem small, which is consistent with the EFm lineup. Most important to me is to see some higher end glass that will match the 32 MP of the M6 II. I would drop $ tomorrow on a high quality EFm general purpose zoom.


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## Kit. (Feb 20, 2020)

AJ said:


> Hmmm... It sounds a bit like sticking a 1.4x TC on an EF-S 55-250 (doesn't fit, I've tried)


Might work with an RF TC and RF-EF adapter.


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## Pape (Feb 20, 2020)

oh woah could be amazin birdler lense for M cameras . Sharpest supertele ever made if made well?
Thank you canon confusing me even more about what to do next 
So M5ii must be coming , and M barrel diameter isnt unbreakable law.
There isnt IS so M5ii got ibis?
Guys i would love to see your face if next M camera would be M1  would make some :O
It even makes sense ,camera for professional bird shooters


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## melgross (Feb 20, 2020)

7.1 is the new 6.3.


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## TMACIOSZEK (Feb 20, 2020)

I'm sure Canon has a perfectly good reason for these lenses ending in f/7.1... but it's a mystery to me.


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## TMACIOSZEK (Feb 20, 2020)

LensFungus said:


> View attachment 188838



That there's funny, I don't care who you are.


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## Iskandar (Feb 20, 2020)

I would absolutely buy a native 100-400 on an EF-M Mount. This is the biggest thing I think the M cameras are missing - a lightweight long tele. I am fine with 7.1 if it means it’s small to carry on hikes.


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## Sharlin (Feb 20, 2020)

TMACIOSZEK said:


> I'm sure Canon has a perfectly good reason for these lenses ending in f/7.1... but it's a mystery to me.



The reason is: because it's possible. Now that there's no artificial f/5.6 restriction to AF anymore.


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## Act444 (Feb 20, 2020)

The only way this makes sense, IMO, is as an M lens. It would be nice, actually, to have the option of a native EF-M lens with more than 200mm of reach, even if that means f7.1 at the long end to keep it compact. Whatever. 

Personally I think I’d rather hold out for a 600mm FF lens, though. Shots taken back in the day with my 7D left me wanting in terms of detail, etc...


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## Roy Hunte (Feb 20, 2020)

TMACIOSZEK said:


> I'm sure Canon has a perfectly good reason for these lenses ending in f/7.1... but it's a mystery to me.


According to camera conspiracies it's called the Canon cripple hammer.


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## koenkooi (Feb 20, 2020)

Sharlin said:


> The reason is: because it's possible. Now that there's no artificial f/5.6 restriction to AF anymore.



The new restriction is that DLA starts happening around f/5.1 on the M6II. But DLA is not a cliff, so f/7.1 could very well be 'good enough'.


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## Pape (Feb 20, 2020)

koenkooi said:


> The new restriction is that DLA starts happening around f/5.1 on the M6II. But DLA is not a cliff, so f/7.1 could very well be 'good enough'.


yeah i think all phone cameras go 2 stop under DLA straight to verge of cliff


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## Pape (Feb 20, 2020)

I think they seriously try now make super sharp M lense ,lack of IS hints it.
Now we see what is possible when no need protect 1 serie and big whites


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## Dragon (Feb 20, 2020)

Pape said:


> oh woah could be amazin birdler lense for M cameras . Sharpest supertele ever made if made well?
> Thank you canon confusing me even more about what to do next
> So M5ii must be coming , and M barrel diameter isnt unbreakable law.
> There isnt IS so M5ii got ibis?
> ...


Given the layout, I think this will fit into the standard 61mm M series barrel diameter. If not, it will come very close. Take this, the 18-150, and the 11-22 and you have 17.6-576mm equivalent in a very small package with good to excellent IQ. I think M is here to stay for quite a while.


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## sulla (Feb 20, 2020)

Why are lenses for the EOS M restricted to 61mm diameter? As long as the rear diameter of the lens elements fits the bayonett, can't the front diameter be whatever it takes?


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## sulla (Feb 20, 2020)

I would't consider a 120-360mm lens a "100-400". That stretches the concept of rounding a bit toooo much for my taste.


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## koenkooi (Feb 20, 2020)

sulla said:


> Why are lenses for the EOS M restricted to 61mm diameter? As long as the rear diameter of the lens elements fits the bayonett, can't the front diameter be whatever it takes?



We can only guess to why, but Canon seems to really stick to that self-imposed restriction.


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## Cat_Interceptor (Feb 20, 2020)

Ugh. So Canon lets it's engineers off the chain for camera bodies and the cripple hammer attack the lenses instead.

No sorry but 7.1 is just one big fat noooooooooooooooooooooooope


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## TMACIOSZEK (Feb 20, 2020)

Cat_Interceptor said:


> Ugh. So Canon lets it's engineers off the chain for camera bodies and the cripple hammer attack the lenses instead.
> 
> No sorry but 7.1 is just one big fat noooooooooooooooooooooooope



They've developed the very fast (RF f/1.2) and very slow (RF f/7.1)... perhaps they have a happy middle in store for us next?


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## AlanF (Feb 20, 2020)

Pape said:


> yeah i think all phone cameras go 2 stop under DLA straight to verge of cliff


The DLA for a new iPhone is about f/2.4 and the various lenses vary from f/1.8 for the main to f/2.4 for the wide angle. The advantage of these very short focal lenses is that it is easy to get wide f-numbers to compensate for the small pixels of about 1.4 microns.


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## Sharlin (Feb 20, 2020)

Cat_Interceptor said:


> Ugh. So Canon lets it's engineers off the chain for camera bodies and the cripple hammer attack the lenses instead.



Your comment is hardly worth replying to, but most likely it’s the exact opposite to what you think: the disappearance of the f/5.6 limitation lets engineers explore more of the space of plausible lens designs.


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## dwarven (Feb 20, 2020)

So the "this new RF mount will allow some wild new lens designs, we can't wait to see what's in store" hype became "just get an adapter and use older glass".


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## SecureGSM (Feb 20, 2020)

Hyperion said:


> Now what? 85 5.6?


500/F8. I have one of these from my film days sitting in my closet


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## Cat_Interceptor (Feb 20, 2020)

Sharlin said:


> Your comment is hardly worth replying to, but most likely it’s the exact opposite to what you think: the disappearance of the f/5.6 limitation lets engineers explore more of the space of plausible lens designs.



Sorry but 7.1 is too damn slow. Physics is a bitch and all that especially in lower light - I'm no Tony Northrup (who according to some turned his family into bokeh) but I do like to have SOME background seperation and not run larger ISO numbers. f5.6 is a compromise of size and speed I'm okay with) - 7.1? Just absolutely 100% no


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## AlanF (Feb 20, 2020)

Cat_Interceptor said:


> Sorry but 7.1 is too damn slow. Physics is a bitch and all that especially in lower light - I'm no Tony Northrup (who according to some turned his family into bokeh) but I do like to have SOME background seperation and not run larger ISO numbers. f5.6 is a compromise of size and speed I'm okay with) - 7.1? Just absolutely 100% no


Physics is not a bitch. For a start, the dof of a 500mm f/7.1 is pretty much the same as a 400mm f/5.6 (check it out on a dof calculator if you don't believe me) and as I keep pointing out the S/N in a cropped image viewed at the same size from a 400/5.6 and a 500/7.1 at a 2/3 stop higher iso is about the same.


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## davo (Feb 21, 2020)

I am dreaming of a 16-35 f/4 - f7.1


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## Czardoom (Feb 21, 2020)

AlanF said:


> Physics is not a bitch. For a start, the dof of a 500mm f/7.1 is pretty much the same as a 400mm f/5.6 (check it out on a dof calculator if you don't believe me) and as I keep pointing out the S/N in a cropped image viewed at the same size from a 400/5.6 and a 500/7.1 at a 2/3 stop higher iso is about the same.



I doubt actual information will stop the crybabies from crying. If the lenses were 5.6 and considerably heavier and more expensive, they would whine about that. I was curious when the 7.1 aperture was announced for some of these new lenses. So I took some shots with the same shutter speed and ISO and used 5.6 and 7.1 apertures, metering to have the 5.6 be as correct as possible. Obviously, the 7.1 was slightly darker. Not so dark that I couldn't have used the actual pic, but certainly within the range of pics that can easily be lightened in post by even the most simple program. As I mentioned in another thread, almost every photographer has probably lightened numerous photos that they have taken that were slightly underexposed the same amount and didn't give it a second thought.

What it comes down to is the usual whining from folks who will always find something to whine about no matter what.


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## canonnews (Feb 21, 2020)

I updated the article.

I guess I'll have to ask forgiveness from Craig afterward - But I know he's in Cartagena and surrounded by pretty Latinas so he's pretty distracted right now 

I felt it needed to be changed.


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## trounds (Feb 21, 2020)

Higher quality ("L") lens with "M" mount would be great. I would buy one or more in a heartbeat.


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## Cat_Interceptor (Feb 21, 2020)

> If the lenses were 5.6 and considerably heavier and more expensive, they would whine about that



Except I for one completely accept that and already said that. I'm being specific in that I know what conditions I can shoot in and f7.1 is not really going to work


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## SteveC (Feb 21, 2020)

I for one like the M-series; I think it's the best APS-C out there, and I'd love to see it get some better lenses (even if they have to be a teeny bit fatter than 61 mm...which isn't the case here anyway).


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## Dragon (Feb 21, 2020)

Cat_Interceptor said:


> Ugh. So Canon lets it's engineers off the chain for camera bodies and the cripple hammer attack the lenses instead.
> 
> No sorry but 7.1 is just one big fat noooooooooooooooooooooooope


And a M6 mark II has the same DR at ISO 400 as a 7D at ISO 100. Seems like if you could get a good shot at f/5.6 with a 7D, then 7.1 gives you over a stop to play with in relative terms. This is about good pictures in a SMALL kit. Yes, you can do better with much bigger and heavier gear, but for most uses, most people won't be able to tell the difference. This lens will be measured in grams, not kilograms.


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## brad-man (Feb 21, 2020)

SteveC said:


> I for one like the M-series; I think it's the best APS-C out there, and I'd love to see it get some better lenses (even if they have to be a teeny bit fatter than 61 mm...which isn't the case here anyway).


I'm a fan of the M as well, still hopefully waiting for an M5 mkll. The new question of the hour is will Canon introduce IBIS to the system? Inquiring minds want to know...


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## slclick (Feb 21, 2020)

7.1 is the new 5.6!


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## privatebydesign (Feb 21, 2020)

slclick said:


> 7.1 is the new 5.6!


it seems that way, but I will never buy one as I personally have zero use for anything that slow.


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## slclick (Feb 21, 2020)

privatebydesign said:


> it seems that way, but I will never buy one as I personally have zero use for anything that slow.


We would expect nothing less of you but there are many who would. They just don't frequent photography forums.


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## privatebydesign (Feb 21, 2020)

slclick said:


> We would expect nothing less of you but there are many who would. They just don't frequent photography forums.


Agreed. And in truth improved iso has surpassed the slowing down of lenses so shutter speeds can still be fast enough in mot situations to get the shot, the 'problem' if there is one, is that you just don't get the DOF control with such slow lenses, but what do I know? I am an average photographer at best and a terrible businessman!


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## Pape (Feb 21, 2020)

AlanF said:


> The DLA for a new iPhone is about f/2.4 and the various lenses vary from f/1.8 for the main to f/2.4 for the wide angle. The advantage of these very short focal lenses is that it is easy to get wide f-numbers to compensate for the small pixels of about 1.4 microns.


Thanks ,i counted it myself and must admit i am not good on math


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## Dragon (Feb 21, 2020)

AlanF said:


> The DLA for a new iPhone is about f/2.4 and the various lenses vary from f/1.8 for the main to f/2.4 for the wide angle. The advantage of these very short focal lenses is that it is easy to get wide f-numbers to compensate for the small pixels of about 1.4 microns.


Not too hard to make those lenses fast, but wide, fast, and sharp all at once is not so easy. Funny thing is that with those small imagers, a telephoto is really hard because it will be slow enough to hit the DLA, so they just keep adding pixels and make the wide lens into a telephoto with the center of the imager because it is about a push with the slow telephoto they could fit in the phone. Maybe they can use an EUV imager for edge enhancement  .


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## Pape (Feb 21, 2020)

sulla said:


> I would't consider a 120-360mm lens a "100-400". That stretches the concept of rounding a bit toooo much for my taste.


They wanted make 400mm but that darn 61mm made it imposible  I guess there was someone who is bad loser or cant accept excuses like physic 
Maybe stradegic boss announced other bosses they will be making 100-400mm M lense without asking engineers.


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## canonnews (Feb 21, 2020)

Cat_Interceptor said:


> Sorry but 7.1 is too damn slow. Physics is a bitch and all that especially in lower light - I'm no Tony Northrup (who according to some turned his family into bokeh) but I do like to have SOME background seperation and not run larger ISO numbers. f5.6 is a compromise of size and speed I'm okay with) - 7.1? Just absolutely 100% no



it's 2/3's of a stop different than f/5.6

the difference of DOF at 
50 feet = 1 ft versus 1.26 ft. 
100 feet = 4.04ft versus 5.09ft
200 feet = 16.3 ft versus 20.6ft 

.. while larger it's not exactly going to cause that much visual difference between the two for target separation

ISO.. 2/3's of a stop these days is pretty trival.


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## canonnews (Feb 21, 2020)

Pape said:


> They wanted make 400mm but that darn 61mm made it imposible  I guess there was someone who is bad loser or cant accept excuses like physic
> Maybe stradegic boss announced other bosses they will be making 100-400mm M lense without asking engineers.


If they make it for the M's and it's 61mm x 160mm will be an interesting optic to carry around not to mention use. Not to mention most 100-400's use a generous rounding error at the long end anyways.


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## canonnews (Feb 21, 2020)

brad-man said:


> I'm a fan of the M as well, still hopefully waiting for an M5 mkll. The new question of the hour is will Canon introduce IBIS to the system? Inquiring minds want to know...


probably not. If they do, IMO it will be gimped and not have IBIS+IS, not because of crippling as I'm sure some will say just because of the communication differences between the EF and RF mounts.


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## koenkooi (Feb 21, 2020)

canonnews said:


> probably not. If they do, IMO it will be gimped and not have IBIS+IS, not because of crippling as I'm sure some will say just because of the communication differences between the EF and RF mounts.



I think I read on some site called canonnews about some patents to mitigate that


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## freejay (Feb 21, 2020)

If this is really an M lens and it really has no IS then IBIS is definitely coming to the M series, hopefully an M5 Mark II! Because a super tele without stabilization is pretty unusable (at least for me).

I'm giggling with anticipation


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## Kit. (Feb 21, 2020)

koenkooi said:


> I think I read on some site called canonnews about some patents to mitigate that


...or to prevent the competition from mitigating that


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## canonnews (Feb 21, 2020)

koenkooi said:


> I think I read on some site called canonnews about some patents to mitigate that


I only saw one patent that described a way to lessen the communication burden, but all the other patents described a really homogeneous solution that had everything talking to each other.

I'm just not sure how all the improvements and little things that Canon did for IBIS+IS in all the other patents would work with a slower protocol in practice.


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## Del Paso (Feb 21, 2020)

mpmark said:


> I'll keep my current 100-400ii, no reason to replace it, should work great on the R5


Me too, my second most often used lens!


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## AlanF (Feb 21, 2020)

Del Paso said:


> Me too, my second most often used lens!


It's my most used. The big question is will the R5 work sufficiently well on it?


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## Tom W (Feb 21, 2020)

The first question I would have, and I admittedly haven't read all the commentary, is 'would this possibly be a lens for the M mount?'. Definitely APS-C, and could be a very compact lens, given the small aperture and dimensions. 

Perhaps a new lens to coincide with an M5 Mk II body?


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## slclick (Feb 21, 2020)

AlanF said:


> It's my most used. The big question is will the R5 work sufficiently well on it?


idk why not, there are glowing reports of nearly all Canon lenses performing as well if not better on the R. Things can only get better, right?


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## AlanF (Feb 21, 2020)

slclick said:


> idk why not, there are glowing reports of nearly all Canon lenses performing as well if not better on the R. Things can only get better, right?


It depends what you mean by better. For static shots, I am sure the R5 will be excellent. But, for birds in flight, the only mirrorless up to DSLR standards is the Sony A9. I would love the R5 to be the next one. There are some very nice shots of flying birds from the R, but they are more difficult to get.

(ps slclick - I read CR in "Dark style" and your signature appears as black upon near black).


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## docsmith (Feb 21, 2020)

AlanF said:


> It depends what you mean by better. For static shots, I am sure the R5 will be excellent. But, for birds in flight, the only mirrorless up to DSLR standards is the Sony A9. I would love the R5 to be the next one. There are some very nice shots of flying birds from the R, but they are more difficult to get.
> 
> (ps slclick - I read CR in "Dark style" and your signature appears as black upon near black).



Very true. I will say the evidence is mounting that Canon mirrorless may be there or on the verge of there. For starters, I am starting to see reports of the 1DX III in liveview doing well and capturing good images of BIF. Then, I bought the M6 II to replace my M3. I recently tested it on some seagulls (I know....I know), but it actually did very well even with the EFM 55-200 lens. 

Here's to hoping that we are on the verge.


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## slclick (Feb 21, 2020)

AlanF said:


> It depends what you mean by better. For static shots, I am sure the R5 will be excellent. But, for birds in flight, the only mirrorless up to DSLR standards is the Sony A9. I would love the R5 to be the next one. There are some very nice shots of flying birds from the R, but they are more difficult to get.
> 
> (ps slclick - I read CR in "Dark style" and your signature appears as black upon near black).


Thanks but your response is more about the bodies than the glass isn't it? I was just stating a general view on adapting, regardless of shooting style or single shot vs servo.


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## Deleted member 381342 (Feb 21, 2020)

AlanF said:


> It depends what you mean by better. For static shots, I am sure the R5 will be excellent. But, for birds in flight, the only mirrorless up to DSLR standards is the Sony A9. I would love the R5 to be the next one. There are some very nice shots of flying birds from the R, but they are more difficult to get.
> 
> (ps slclick - I read CR in "Dark style" and your signature appears as black upon near black).


Maybe we need to wait for the R1 body, which will surely market its lower and lower EFV latency with every revision, much like the old 1D body and its startup time.


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## AlanF (Feb 21, 2020)

slclick said:


> Thanks but your response is more about the bodies than the glass isn't it? I was just stating a general view on adapting, regardless of shooting style or single shot vs servo.


Just taking a holistic approach. I am a very attached to the 100-400mm II, but maybe the combination of an RF 100-500mm L with an R body will respond better? Who of knows? I don't.


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## slclick (Feb 21, 2020)

AlanF said:


> Just taking a holistic approach. I am a very attached to the 100-400mm II, but maybe the combination of an RF 100-500mm L with an R body will respond better? Who of knows? I don't.


Just wait until you put it on the R7!


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## fox40phil (Feb 21, 2020)

If you thought there could be something more brighter (f-stop) (because of the new and bigger mount!) tele-zoom lenses... we are getting now 7.1f and starting at 5.6f lenses....w t f!!!

I hoped about a 100-400 5.6f or a 200-500/600 5.6f!! not those crappy tele-zooms ....


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## AlanF (Feb 21, 2020)

fox40phil said:


> If you thought there could be something more brighter (f-stop) (because of the new and bigger mount!) tele-zoom lenses... we are getting now 7.1f and starting at 5.6f lenses....w t f!!!
> 
> I hoped about a 100-400 5.6f or a 200-500/600 5.6f!! not those crappy tele-zooms ....


A new and bigger mount doesn't make for a brighter lens, it's the other end that determines brightness. In any case, the new mount isn't bigger, it's the same size as the old EF.


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## slclick (Feb 21, 2020)

fox40phil said:


> If you thought there could be something more brighter (f-stop) (because of the new and bigger mount!) tele-zoom lenses... we are getting now 7.1f and starting at 5.6f lenses....w t f!!!
> 
> I hoped about a 100-400 5.6f or a 200-500/600 5.6f!! not those crappy tele-zooms ....


Unreleased items aren't crappy, they are non existent.


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## deleteme (Feb 23, 2020)

Canon’s current emphasis on a batch of compact lenses is a direct consequence of consumer demand. Consumers have been clamoring for cheaper, smaller lenses and Canon is delivering. Just as they delivered fast, optically excellent lenses in the 85 f1.2 and the 28-70 f2. So one might be upset about the slow lenses but they are also listening to your prayers for faster lenses. They are ignoring you on your whining about price though.


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## deleteme (Feb 23, 2020)

AlanF said:


> It's my most used. The big question is will the R5 work sufficiently well on it?


I see no reason it wouldn’t as the current EF lenses work flawlessly with my much maligned R.


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## Czardoom (Feb 23, 2020)

Normalnorm said:


> Canon’s current emphasis on a batch of compact lenses is a direct consequence of consumer demand. Consumers have been clamoring for cheaper, smaller lenses and Canon is delivering. Just as they delivered fast, optically excellent lenses in the 85 f1.2 and the 28-70 f2. So one might be upset about the slow lenses but they are also listening to your prayers for faster lenses. They are ignoring you on your whining about price though.



Here's my take (for whatever it's worth)...Canon is giving consumers a choice with these 7.1 lenses that people are going ape-sh!! over. Unlike the forum-dwellers that look at mirrorless replacing DSLRs (and the sooner the better) Canon understands that DSLRs are still here and will be for a while (still over 50% sales in 2019). And it will take a few years to have an RF lens lineup that begins to cover the most popular choices. If someone wants a faster big zoom - well, they already have that choice with their EF offerings. These 7.1 lenses are not meant to be an RF replacement, but rather a choice for those wanting a smaller, lighter and cheaper alternative. Making the exact same big zoom in both EF and RF means that most consumers will choose only one - and those with the EF versions will probably just stick with those and use an adapter. But some of those folks that have the EF, might also buy the RF 7.1 version if it is significantly lighter. More choices, more sales.


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## AlanF (Feb 23, 2020)

Normalnorm said:


> I see no reason it wouldn’t as the current EF lenses work flawlessly with my much maligned R.


You missed my posts with slcick. The current 100-400mm works very well on the R and RP. But, for birds in flight, the lens on the R is not the best for the more difficult shots. If a new RF 100-500mm on a newer R series is good for BIF, I’ll get both. If not, I’ll stick to my DSLRs until Canon produces what I want.


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## scyrene (Feb 23, 2020)

Cat_Interceptor said:


> Sorry but 7.1 is too damn slow. Physics is a bitch and all that especially in lower light - I'm no Tony Northrup (who according to some turned his family into bokeh) but I do like to have SOME background seperation and not run larger ISO numbers. f5.6 is a compromise of size and speed I'm okay with) - 7.1? Just absolutely 100% no



Here's an old shot with good background separation. What aperture do you think I used? Hint: it's narrower than f/7.1*. A lot of other factors are at play - subject distance, background distance, field of view, etc.




*It's f/10, and ISO 1250, taken in woodland - so let's get some perspective please!.


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## Kit. (Feb 23, 2020)

scyrene said:


> Here's an old shot with good background separation. What aperture do you think I used?


The lens entrance pupil (in diameter) is about 3 times as large as the bird's eye. Good enough for subjects with such small eyes.


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## AlanF (Feb 23, 2020)

scyrene said:


> Here's an old shot with good background separation. What aperture do you think I used? Hint: it's narrower than f/7.1*. A lot of other factors are at play - subject distance, background distance, field of view, etc.
> 
> View attachment 188877
> 
> ...


Beautiful shot! I like the nature of the blurred background as well. There is a nice texture about it that gives the feel that the bird is in woodland but without it being intrusive.


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## Bert63 (Feb 23, 2020)

mpmark said:


> I'll keep my current 100-400ii, no reason to replace it, should work great on the R5




Me as well. Nothing to look forward to in the 100-500L from where I'm sitting.


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## Bert63 (Feb 23, 2020)

scyrene said:


> Here's an old shot with good background separation. What aperture do you think I used? Hint: it's narrower than f/7.1*. A lot of other factors are at play - subject distance, background distance, field of view, etc.
> 
> View attachment 188877
> 
> ...




Focal length? Did I miss it somewhere?


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## scyrene (Feb 23, 2020)

AlanF said:


> Beautiful shot! I like the nature of the blurred background as well. There is a nice texture about it that gives the feel that the bird is in woodland but without it being intrusive.



Thanks very much! As is often the case, I got lucky


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## scyrene (Feb 23, 2020)

Bert63 said:


> Focal length? Did I miss it somewhere?



The FL is 1000mm, so a fair bit longer than what we're talking about in the lens this thread is about, but it's rather beside the point I'm trying to make - people are dismissing f/7.1 out of hand, whereas I contend a lot of other factors are important, too. You can get good long lens shots at narrower apertures, under some circumtances, contrary to the naysayers. I'd expect a lens like this to have a much closer MFD than my 500L, which would help, and it's on a crop sensor, which will make a difference, too.


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## tron (Feb 24, 2020)

scyrene said:


> The FL is 1000mm, so a fair bit longer than what we're talking about in the lens this thread is about, but it's rather beside the point I'm trying to make - people are dismissing f/7.1 out of hand, whereas I contend a lot of other factors are important, too. You can get good long lens shots at narrower apertures, under some circumtances, contrary to the naysayers. I'd expect a lens like this to have a much closer MFD than my 500L, which would help, and it's on a crop sensor, which will make a difference, too.


I am sorry FLand aperture used are not beside the point.

Having a 500mm f/4 you had the luxury of 1000mm f/8 or f/10 so closing by 2/3 of a stop at your case. Would you have the sam e luxury with f/7.1 which would make it f/14 and f/16 if you close by 2/3 of a stop?

ISO would become 2000.
7.1 would up to the DLA limit of a future R at 45Mpixels so f/10 is OK I guess but f/16? 

I am sure it would make a wonderful portable lens of course. This portability would make it successful depending of course on IQ and fast focusing capability.

Let's wait until it is out.


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## scyrene (Feb 24, 2020)

tron said:


> I am sorry FLand aperture used are not beside the point.
> 
> Having a 500mm f/4 you had the luxury of 1000mm f/8 or f/10 so closing by 2/3 of a stop at your case. Would you have the sam e luxury with f/7.1 which would make it f/14 and f/16 if you close by 2/3 of a stop?
> 
> ...



You're missing my point so I will reiterate as clearly as I know how.

So on all these threads about -f7.1 zoom a number of people have said it's unusable. That is, _f/7.1 is an unusable aperture_ (in the case of this patent and the recently-announced -500mm f/7.1 zoom)_ for long lens work, birds in forests, etc_. *These have been blanket statements about aperture*, without regard to focal length.

I don't have a photograph to hand taken at 500mm f/7.1 - I could take one with the bare 500L. But I don't need to do that to make my point (which I have repeated on a number of threads), which is that* I have done a tonne of bird photography at f/10 and it's been fine* - not too dark most of the time, and the backgrounds are adequately blurred.

Obviously using a zoom with a maximum aperture at the long end of f/7.1 is not precisely the same as using a 500mm + 2x TC stopped down a little. Obviously I have more reach*. But that is not the point being made here. *One last time: f/7.1 is perfectly usable for bird photography* (and many other types), sometimes even in low light.

DLA is irrelevant to this discussion, but since you brought it up, the photograph I posted above was taken on a 5Ds, which has even smaller pixels than the rumoured R5. Unless you are cropping more heavily on a higher res sensor, diffraction is no more apparent regardless of resolution.

*as an aside, a shorter FL can produce equally- or even more blurred backgrounds if the MFD is shorter, and I'd expect these zoom lenses to focus closer than the supertelephoto primes.


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## SecureGSM (Feb 24, 2020)

scyrene said:


> The FL is 1000mm, so a fair bit longer than what we're talking about in the lens this thread is about, but it's rather beside the point I'm trying to make - people are dismissing f/7.1 out of hand, whereas I contend a lot of other factors are important, too. You can get good long lens shots at narrower apertures, under some circumtances, contrary to the naysayers. I'd expect a lens like this to have a much closer MFD than my 500L, which would help, and it's on a crop sensor, which will make a difference, too.


here is Sigma 100 400 5 -6.3 at 400/F6.3.. 500 at F7.1 should give a similar look. see if you like it:



https://www.birdforum.net/attachment.php?s=77b46e017ca26dc86cbab8030cddd870&attachmentid=645140&d=1509699325





https://www.birdforum.net/attachment.php?s=77b46e017ca26dc86cbab8030cddd870&attachmentid=645153&d=1509699728



and here is more for your judgement:









Sigma 100-400 f/5.0-6.3


New leaks suggest there will soon be an announcement of a Sigma 100-400mm f/5.0-6.3 https://petapixel.com/2017/02/20/photos-4-new-sigma-lenses-leaked-3-new-art-lenses-coming-soon/ The fact it's 6.3 at the long end places it below the usual 100-400 options in terms of size and weight, as does...




www.birdforum.net


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## AlanF (Feb 24, 2020)

scyrene said:


> The FL is 1000mm, so a fair bit longer than what we're talking about in the lens this thread is about, but it's rather beside the point I'm trying to make - people are dismissing f/7.1 out of hand, whereas I contend a lot of other factors are important, too. You can get good long lens shots at narrower apertures, under some circumtances, contrary to the naysayers. I'd expect a lens like this to have a much closer MFD than my 500L, which would help, and it's on a crop sensor, which will make a difference, too.


Doubling the focal length does make a lot of difference to the depth of field. I am no expert in this area and may have it wrong. But, my understanding is the depth of field, all else being equal, increases linearly with f-number but decreases inversely with the focal length squared. So, if you double the focal length of the lens, the dof decreases by a factor of 4. Shooting a 1000mm lens at f/10 gives the same depth of field and subject separation as shooting a 500mm lens at f/2.5. Similarly, shooting a 400mm at f/5.6 gives the same depth of field as shooting a 500mm lens at f/8.75. But, it gets more complicated if you crop the shorter focal length image and view at the same size as for the longer. I think you then have to divide the dof by the crop factor. So, after cropping, the 1000mm lens at f/10 will give the dof of the 500mm shot at f/5. And the 500mm at f/7.1 will give the very close to the same dof and subject separation as a 400mm at f/5.6.

*Take home message is that the 500mm/7.1 gives us croppers the same subject separation from background as a 400/5.6.* Please correct me if I am wrong.

Edit SecureGSM posted just as I was posting and so it seems my maths is correct.


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## scyrene (Feb 24, 2020)

AlanF said:


> Doubling the focal length does make a lot of difference to the depth of field. I am no expert in this area and may have it wrong. But, my understanding is the depth of field, all else being equal, increases linearly with f-number but decreases inversely with the focal length squared. So, if you double the focal length of the lens, the dof decreases by a factor of 4. Shooting a 1000mm lens at f/10 gives the same depth of field and subject separation as shooting a 500mm lens at f/2.5. Similarly, shooting a 400mm at f/5.6 gives the same depth of field as shooting a 500mm lens at f/8.75. But, it gets more complicated if you crop the shorter focal length image and view at the same size as for the longer. I think you then have to divide the dof by the crop factor. So, after cropping, the 1000mm lens at f/10 will give the dof of the 500mm shot at f/5. And the 500mm at f/7.1 will give the very close to the same dof and subject separation as a 400mm at f/5.6.
> 
> *Take home message is that the 500mm/7.1 gives us croppers the same subject separation from background as a 400/5.6.* Please correct me if I am wrong.
> 
> Edit SecureGSM posted just as I was posting and so it seems my maths is correct.



I wasn't saying the results would be precisely the same. I knowingly didn't post a shot with precisely the same specs as this thread, or the other thread's lenses. My point is that you can get good subject separation at f/7.1. I said 'subject and background distance are important too'. And of course FL matters, as does sensor size. But these are all beside the point I was trying to make. But I should know better on here.

I'll just repeat one last time: people who claim f/7.1 is unusable are wrong. That's it! That's the only point I was making.


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## tron (Feb 24, 2020)

scyrene said:


> You're missing my point so I will reiterate as clearly as I know how.
> 
> So on all these threads about -f7.1 zoom a number of people have said it's unusable. That is, _f/7.1 is an unusable aperture_ (in the case of this patent and the recently-announced -500mm f/7.1 zoom)_ for long lens work, birds in forests, etc_. *These have been blanket statements about aperture*, without regard to focal length.
> 
> ...


I do not disagree about the use of f/7.1 but about maximum use which includes teleconverters! 

I have also used 5DsR + 500 + 2XIII successfully and I was very happy with the result. 

It is just that you cannot achieve the same max results if needed. 

And I cannot stress enough the portability of the 100-500.


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## AlanF (Feb 24, 2020)

scyrene said:


> I wasn't saying the results would be precisely the same. I knowingly didn't post a shot with precisely the same specs as this thread, or the other thread's lenses. My point is that you can get good subject separation at f/7.1. I said 'subject and background distance are important too'. And of course FL matters, as does sensor size. But these are all beside the point I was trying to make. But I should know better on here.
> 
> I'll just repeat one last time: people who claim f/7.1 is unusable are wrong. That's it! That's the only point I was making.


My comments were meant to support what you wrote and that I agreed with you!


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## scyrene (Feb 24, 2020)

tron said:


> I do not disagree about the use of f/7.1 but about maximum use which includes teleconverters!
> 
> I have also used 5DsR + 500 + 2XIII successfully and I was very happy with the result.
> 
> ...



Oh well, I'd absolutely agree that use of teleconverters on a lens that's already f/7.1 to begin with will cause issues, though I would add on a 1.4x with no worries, on a modern mirrorless body that can still AF with that. I used to stack teleconverters and shoot birds at f/14, and sometimes the extra reach was enough to justify (to my satisfaction at least) the loss of sharpness. No AF though!


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## scyrene (Feb 24, 2020)

AlanF said:


> My comments were meant to support what you wrote and that I agreed with you!



Oh, sorry. Thanks! I'm grumpy today


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## AlanF (Feb 24, 2020)

scyrene said:


> Oh, sorry. Thanks! I'm grumpy today


I am very grateful to your post because it got me thinking more deeply about dof and focal length and aperture. And I now understand more than I did.


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## SecureGSM (Feb 24, 2020)

AlanF said:


> Doubling the focal length does make a lot of difference to the depth of field. I am no expert in this area and may have it wrong. But, my understanding is the depth of field, all else being equal, increases linearly with f-number but decreases inversely with the focal length squared. So, if you double the focal length of the lens, the dof decreases by a factor of 4. Shooting a 1000mm lens at f/10 gives the same depth of field and subject separation as shooting a 500mm lens at f/2.5. Similarly, shooting a 400mm at f/5.6 gives the same depth of field as shooting a 500mm lens at f/8.75. But, it gets more complicated if you crop the shorter focal length image and view at the same size as for the longer. I think you then have to divide the dof by the crop factor. So, after cropping, the 1000mm lens at f/10 will give the dof of the 500mm shot at f/5. And the 500mm at f/7.1 will give the very close to the same dof and subject separation as a 400mm at f/5.6.
> 
> *Take home message is that the 500mm/7.1 gives us croppers the same subject separation from background as a 400/5.6.* Please correct me if I am wrong.
> 
> Edit SecureGSM posted just as I was posting and so it seems my maths is correct.



Measuring 25, 50, 100 meters to subject. 
DOF of 500 at F7.1 is equivalent to DOF of 400 at F4.6 approx. or 300 at F2.6

Meaning that at the 500mm Bokeh should be more pronounced than 400/5.6 but at 400 mm lens bokeh will be harsher being F6.3 vs F5.6 of the EF 100-400. 

However, if I was reach limited .... 600mm end of Sigma 100-600/6.3C at F6.3 is equivalent to 500 at F3.7 , 400 at F2.3 and 300 F1.35 

Go Sigma ? 

Cheap 600/6.3 DOF is shallower that 500/4 DOF


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## AlanF (Feb 24, 2020)

SecureGSM said:


> Measuring 25, 50, 100 meters to subject.
> DOF of 500 at F7.1 is equivalent to DOF of 400 at F4.6 approx. or 300 at F2.6
> 
> Meaning that at the 500mm Bokeh should be more pronounced than 400/5.6 but at 400 mm lens bokeh will be harsher being F6.3 vs F5.6 of the EF 100-400.
> ...


The dof calculator gives the dof of the whole field of view, when viewed at a particular distance, defined by the circle of confusion for the image. When you crop out some of the image taken by two lenses of different focal lengths, say of a bird in a bush, and view at the same output size, the relative depths of field change because the smaller image is enlarged more. For a 500mm lens vs 600mm lens, the dof of the smaller lens is reduced by a relative factor of 1.2x. The cropped image image from 600mm f/6.3 will have the same dof as the same view crop from a 500mm lens at f/5.25.


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## Pape (Feb 24, 2020)

AlanF said:


> Doubling the focal length does make a lot of difference to the depth of field. I am no expert in this area and may have it wrong. But, my understanding is the depth of field, all else being equal, increases linearly with f-number but decreases inversely with the focal length squared. So, if you double the focal length of the lens, the dof decreases by a factor of 4. Shooting a 1000mm lens at f/10 gives the same depth of field and subject separation as shooting a 500mm lens at f/2.5. Similarly, shooting a 400mm at f/5.6 gives the same depth of field as shooting a 500mm lens at f/8.75. But, it gets more complicated if you crop the shorter focal length image and view at the same size as for the longer. I think you then have to divide the dof by the crop factor. So, after cropping, the 1000mm lens at f/10 will give the dof of the 500mm shot at f/5. And the 500mm at f/7.1 will give the very close to the same dof and subject separation as a 400mm at f/5.6.
> 
> *Take home message is that the 500mm/7.1 gives us croppers the same subject separation from background as a 400/5.6.* Please correct me if I am wrong.
> 
> Edit SecureGSM posted just as I was posting and so it seems my maths is correct.


Hmm doesnt cropping give same dof ,unless you using lense what makes smaller image circle? =crop camera lense?


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## AlanF (Feb 24, 2020)

Pape said:


> Hmm doesnt cropping give same dof ,unless you using lense what makes smaller image circle? =crop camera lense?


Hi Pape
I am talking about using different focal length lenses on the same camera and sensor, cropping and then looking at the output image at the same size, just as we do for our bird portraits. The image from the shorter lens will before enlargement have greater depth of field, but this decreases on enlargement. For example, consider blowing up a 4mmx4mm image crop from the sensor with a 400mm lens to full screen size and comparing it with a 5mmx5mm crop from a 500mm lens blown up. The part of the image that is perfectly in focus in the focal plane of the image will still be tack sharp in both when enlarged. The out of focus regions will become more blurred when they are enlarged. The 4mmx4mm gets enlarged by 1.25x1.25 more so the blurring gets worse.
I worked this out in my head this morning and have now found, as I expected, it is well known to the experts. There is an image of a golf ball in the middle of this link that shows how the dof appears smaller as an image is enlarged.
See https://www.bhphotovideo.com/explora/photography/tips-and-solutions/depth-field-part-1


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## Pape (Feb 24, 2020)

AlanF said:


> Hi Pape
> I am talking about using different focal length lenses on the same camera and sensor, cropping and then looking at the output image at the same size, just as we do for our bird portraits. The image from the shorter lens will before enlargement have greater depth of field, but this decreases on enlargement. For example, consider blowing up a 4mmx4mm image crop from the sensor with a 400mm lens to full screen size and comparing it with a 5mmx5mm crop from a 500mm lens blown up. The part of the image that is perfectly in focus in the focal plane of the image will still be tack sharp in both when enlarged. The out of focus regions will become more blurred when they are enlarged. The 4mmx4mm gets enlarged by 1.25x1.25 more so the blurring gets worse.
> I worked this out in my head this morning and have now found, as I expected, it is well known to the experts. There is an image of a golf ball in the middle of this link that shows how the dof appears smaller as an image is enlarged.
> See https://www.bhphotovideo.com/explora/photography/tips-and-solutions/depth-field-part-1


Ah yeah i am again messing things on my head


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## AlanF (Feb 24, 2020)

Pape said:


> Ah yeah i am again messing things on my head


I've taught myself a lot from these discussions because I hadn't thought much about dof in the past. What's becoming more and more clear to me is that there are minimal disadvantages of a 500/7.1 vs a 400/5.6 and it puts more pixels on a kingfisher.


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## Pape (Feb 24, 2020)

AlanF said:


> I've taught myself a lot from these discussions because I hadn't thought much about dof in the past. What's becoming more and more clear to me is that there are minimal disadvantages of a 500/7.1 vs a 400/5.6 and it puts more pixels on a kingfisher.


I doubt losing one stop never decrease resolution more than what extra 100mm gives more.And all bright days are just pure advantage. 
Ok i guess there is one disadvantage ,birds looks bit more fat with 500mm ,but i doubt they come complain


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## dcm (Feb 24, 2020)

This makes a lot of sense when you consider it from the intended M series user’s perspective (small/light) rather the a D/R series user wanting the same from an M series, but cheaper. Something has to give. 

Could be an interesting compact lens when compared to the EF-M 55-200 f4.5-6.3 IS STM that I have, as long as they are able to incorporate IS (say in group L3). I’d definitely carry this over my EF 100-400 L or 70-300L when hiking with the M6II just for the size and weight savings. If I want to bring the big lens as I sometimes do, I’ll bring a bigger camera to go with it (D or R series).


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## Dragon (Feb 25, 2020)

SecureGSM said:


> here is Sigma 100 400 5 -6.3 at 400/F6.3.. 500 at F7.1 should give a similar look. see if you like it:
> 
> 
> 
> ...


Note that those first two links were shot with a 1.4 TC, so at least f/9. Just look at your third link and scroll down to find the pics with the mention of the 1.4 TC.


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## Dragon (Feb 25, 2020)

dcm said:


> This makes a lot of sense when you consider it from the intended M series user’s perspective (small/light) rather the a D/R series user wanting the same from an M series, but cheaper. Something has to give.
> 
> Could be an interesting compact lens when compared to the EF-M 55-200 f4.5-6.3 IS STM that I have, as long as they are able to incorporate IS (say in group L3). I’d definitely carry this over my EF 100-400 L or 70-300L when hiking with the M6II just for the size and weight savings. If I want to bring the big lens as I sometimes do, I’ll bring a bigger camera to go with it (D or R series).


I just ordered a Kenko HD 1.4 TC (that works with EF-s lenses) to put behind an EF-s 55-250m and in front of an EF-M adapter. That results in 98-350 with f/8 max, so pretty close to the discussed lens and the 55-250 is very sharp at the long end, so that combo should give a pretty good feel for the new lens. Given that the Kenko TC also works with standard EF lenses, it should produce almost a FF image circle, so the 55-250 with TC may work well on a FF body as well. At a minimum, it will be an interesting experiment for not very much investment.


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## Daner (Feb 26, 2020)

Thinking of this as an EF-M 120-360 mounted on an M5 MkII (with IBIS, please!) would make it a compelling small and light long-reach companion to an EOS R with the RF 24-105L. That combination would hit a pretty sweet spot when it comes to price/weight/volume/IQ for travel and landscape work, especially for those of us who prefer to minimize the need to check bags when flying whenever possible.

I have demoed the 1DXIII and the EF 200-400 f/4 + 1.4x lens and loved them both. While that combination would be wonderful for riding around in a Land Rover on safari to shoot wildlife, I would not look forward to lugging it through airports or on any kind of extended hike.


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## SecureGSM (Feb 26, 2020)

Dragon said:


> Note that those first two links were shot with a 1.4 TC, so at least f/9. Just look at your third link and scroll down to find the pics with the mention of the 1.4 TC.


I have noticed that. however, at F7.3 depth of field is not much wider than at F9.0


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## Dragon (Feb 26, 2020)

Dragon said:


> I just ordered a Kenko HD 1.4 TC (that works with EF-s lenses) to put behind an EF-s 55-250m and in front of an EF-M adapter. That results in 98-350 with f/8 max, so pretty close to the discussed lens and the 55-250 is very sharp at the long end, so that combo should give a pretty good feel for the new lens. Given that the Kenko TC also works with standard EF lenses, it should produce almost a FF image circle, so the 55-250 with TC may work well on a FF body as well. At a minimum, it will be an interesting experiment for not very much investment.


Follow up. I just tested the 55-250 with the new Kenko TC on a 90D and the result is not bad at all. The center is not quite as sharp as a 70-300L, but with a TC, that is no surprise. It is, however, quite decent even on the 90D. The edges have some CA, but that seems to clean up pretty well in LR. Magnification is only a little more than the 70-300L (maybe 320mm), so the 55-250 looks like it really tops out at about 225. Also just checked it on the 5DSr and it seems to provide almost a full image circle with a bit of vignetting in the very corners. I will try the combo out on an M5, but no reason to believe it won't work well and as a proof of concept for the lens under discussion, the answer is basically, I would buy the new lens in a heartbeat for my M kit.


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