# Roger Cicala: Canon v. Nikon lenses on optical bench (no camera)



## ScottyP (Sep 7, 2014)

http://www.lensrentals.com/blog/2014/09/just-the-lenses-canon-vs-nikon-zooms-at-70mm

Roger at Lens Rentals is comparing 24-70's and 70-200's from Canon and Nikon. Interesting because it removes the huge variable of the different camera bodies you usually have.


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## privatebydesign (Sep 7, 2014)

And when we learn to take pictures without camera bodies the results might be relevant.

Yet more critical over analysis of a non relevant point. How a D810 and Nikon 24-70 f2.8 performs compared to a 5D MkIII and 24-70 f2.8 is all I, as an educated camera system buyer, want to know.


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## Jim Saunders (Sep 7, 2014)

privatebydesign said:


> And when we learn to take pictures without camera bodies the results might be relevant.



I agree; between the two skill matters more than kit.

Jim


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## Mt Spokane Photography (Sep 7, 2014)

privatebydesign said:


> And when we learn to take pictures without camera bodies the results might be relevant.
> 
> Yet more critical over analysis of a non relevant point. How a D810 and Nikon 24-70 f2.8 performs compared to a 5D MkIII and 24-70 f2.8 is all I, as an educated camera system buyer, want to know.



You mean uneducated?

Some people want to know how good a lens actually is. When you couple it with a body, that drags down the actual capabilities of a lens to that of the body.

I'd like to know the actual resolution of a lens regardless of body.


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## ScottyP (Sep 7, 2014)

privatebydesign said:


> And when we learn to take pictures without camera bodies the results might be relevant.
> 
> Yet more critical over analysis of a non relevant point. How a D810 and Nikon 24-70 f2.8 performs compared to a 5D MkIII and 24-70 f2.8 is all I, as an educated camera system buyer, want to know.



And yet another response from someone who somehow forgets that this is a gear site. An experiment that attempts to shed light on a question unanswerable in ordinary conditions is exactly the sort of thing that is of interest to some people on a gear site. And a test of Canon vs. Nikon gear, done in a way that isolates the lens capability from other variables is the sort of thing people are interested in, whether it has practical relevance or not.

Next thing will be the standard tired pat answer that someone always applies to every thread; "skill matters more than gear". Oh. No, wait that actually IS what the very next person did in fact regurgitate.


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## Mt Spokane Photography (Sep 7, 2014)

ScottyP said:


> privatebydesign said:
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> > And when we learn to take pictures without camera bodies the results might be relevant.
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I have no problem with users having their own opinion, even when I think its incorrect. Its only when they claim their opinion is the only correct one, is there a issue.

The post was meant for discussion, and we all have our own viewpoints and opinions, lets hear them.


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## tyger11 (Sep 7, 2014)

Another reason this is good information to have is because of the respective lifetimes of camera bodies compared to lenses. Expensive lenses typically go through multiple camera bodies because they aren't updated anywhere nearly as often. When CaNikon come out with their new bodies, for the most part, their lens lineup barely changes. It's good to know, and certainly doesn't hurt anything.


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## helpful (Sep 7, 2014)

Mt Spokane Photography said:


> I'd like to know the actual resolution of a lens regardless of body.



Hearty Amen.


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## Mt Spokane Photography (Sep 7, 2014)

For those that might not have actually read the report, there is some information on curvature of field that is not accessable using imatest with a lens / body combination. Knowing the limitations due to curvature of field could help select among lenses from the same manufacturer for a project. Would you use a 24-70 at 70mm, or a 70-200, or is there a difference? The answer is in the article.


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## unadog (Sep 7, 2014)

I shoot both Nikon and Canon.

I am a former pro with 20+ years of experience. I own the Canon 24-70 2.8 II and the 70-200 2.8 II. I absolutely love those lenses. I only shoot the beat glass after using versions I and II of those for 10+ years.

The article is directly relevant to me as I decide which system to shoot as full frame and which to keep as a crop. 

I have the Nikon D7100 and the Canon 6D right now for high ISO shooting. If I moved to the D610, D750, or D810, I would have to sell the Canon pair to buy the Nikon 24-70 and 70-200 II. 

Those are basic, "bread and butter" lenses for a pro kit. But I really can't justify $3,000 used for the Nikon and $3,500 used for the Canon glass. And I'm not willing to sell the Canon glass. Yet.

Also, from the comments at the article:

"This sounds like someone is tempted by the D810 to switch…heehee, is that right?
I am in the same shoe, owning the 5D3 and the 2 Canon you mentioned above. The quality of the lenses is what is stopping me at the moment. And your article kind of confirms that."


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## sagittariansrock (Sep 7, 2014)

The header might be somewhat misleading. The comparison between the Nikon and Canon zoom counterparts are somewhat academic (or for the show), with comparison only at a single focal length. The real comparison is between the standard vs tele zoom at the common focal length, i.e., 70mm. So one can always argue putting a camera into the equation might not have altered the results. Thing is, the cameras aren't there because the testing paradigm doesn't require them, not because Roger wanted to keep them out of the equation.


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## privatebydesign (Sep 7, 2014)

Mt Spokane Photography said:


> privatebydesign said:
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> > And when we learn to take pictures without camera bodies the results might be relevant.
> ...



Maybe.

Some might, I was just trying to head off the inevitable 'my ?? is better than your ??' because when taken out of context the result, however interesting and informative, has little practical application. 

Nobody in their right mind is going to have their buying decisions, or even their shooting choices, impacted by these results, and anybody with the gear crossover should already know what works better for them. Sure this lens might have fractionally less field curvature than that lens, put in the context of dof, framing, lens changing, exposure, focus, framing, subject, light, artistic merit, post processing etc etc the outcome is so minor as to not make any real world difference.

Say I had two 5D MkIII's and a 24-70 and a 70-200 and was shooting a wedding, I need 70mm, what camera/lens combo do I need? The one in my hand, the one I just shot 35mm with, the one I just shot 180mm with, the one I am going to use after the 70mm shot? On and on, my thought as to what lens is going to give me "more" doesn't factor into it.

Or, I want to shoot a landscape at 70mm, which do I use? Well again the miniscue differences in bench tested aberrations doesn't really matter because my dof is going to cover a mutitude of sins and post processing is going to cover the rest.

Sure this has an academic value, my point was, it is only academic.

To be sure, I really like Roger's blog, he writes some very interesting articles and gives seemingly unbiased views on pretty much everybody, I wish there were more like him, his testing seems very balanced, fair and consistent, his results posted with similar common sense and notes as to practical application. He is well aware of the furor taking these kinds of results out of context can create, how is calling for relevance and moderation a bad thing?


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## privatebydesign (Sep 7, 2014)

ScottyP said:


> privatebydesign said:
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> > And when we learn to take pictures without camera bodies the results might be relevant.
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Not at all, I was questioning the practical value of the question, I don't see why that brings about such negativity. If you can't take a picture without the camera then a test of the lens seems to be of limited value, to me.

Put another way, what difference does it make if I am shooting with a 24-70 and a 70-200 and want a 70mm shot which lens I use? The body free lens test can't tell me! Besides so many other factors impact the image far greater than the small measured body free lens tests differences that even if it did those other factors would almost certainly impact my decision making more.


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## privatebydesign (Sep 7, 2014)

helpful said:


> Mt Spokane Photography said:
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> > I'd like to know the actual resolution of a lens regardless of body.
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Why? Academia? Don't get me wrong, there is nothing wrong in and of itself that I can see, but seeing as how we pay thousands of dollars for these lenses that we can't use without bodies I question any results relevance.


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## LovePhotography (Sep 7, 2014)

privatebydesign said:


> And when we learn to take pictures without camera bodies the results might be relevant.
> 
> Yet more critical over analysis of a non relevant point. How a D810 and Nikon 24-70 f2.8 performs compared to a 5D MkIII and 24-70 f2.8 is all I, as an educated camera system buyer, want to know.



Science require control of the variables. Too many variables and you can conclude nothing.


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## privatebydesign (Sep 7, 2014)

LovePhotography said:


> privatebydesign said:
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> > And when we learn to take pictures without camera bodies the results might be relevant.
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Photography isn't a science. If you don't include all the variables you end up with purely academic test results that have extremely limited, if any, real world value.


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## LetTheRightLensIn (Sep 7, 2014)

Mt Spokane Photography said:


> For those that might not have actually read the report, there is some information on curvature of field that is not accessable using imatest with a lens / body combination. Knowing the limitations due to curvature of field could help select among lenses from the same manufacturer for a project. Would you use a 24-70 at 70mm, or a 70-200, or is there a difference? The answer is in the article.



I'd use the 70-200 II or 70-300L if I cared about FF edges/corners at 70mm.

All I can say is that having used many copies, the weak spot of all 24-70 II I've tried is 70mm edges/corners on FF, especially in real world scenes.

Maybe the field curvature of the other lenses actually helps them fit many real world scenes better? I don't know what to say. I've seen others find this too, that the 24-70 II is amazing and better than most, except at or near 70mm and FF outer edges and corners.


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## LetTheRightLensIn (Sep 7, 2014)

privatebydesign said:


> And when we learn to take pictures without camera bodies the results might be relevant.
> 
> Yet more critical over analysis of a non relevant point. How a D810 and Nikon 24-70 f2.8 performs compared to a 5D MkIII and 24-70 f2.8 is all I, as an educated camera system buyer, want to know.



But what about the future? Unless Canon has utterly lost the plot they will have a D810 res sensor out soon. With this test we know how the Canon lenses would compare vs. Nikon with all sensors.


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## privatebydesign (Sep 7, 2014)

LetTheRightLensIn said:


> privatebydesign said:
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> > And when we learn to take pictures without camera bodies the results might be relevant.
> ...



NO WE WILL NOT.

Without a camera body behind it a camera lenses capabilities are entirely irrelevant.

To quote Roger himself _"But hey, I usually find the opportunity to do a meaningless test hard to resist."_, he fully understands the very limited practical value of this as a "comparison". Indeed it seems even a standard Imatest, that measures an actual image output, gives the 24-70 MkII the narrow edge over the 70-200 MkII, whereas this decoupled result gives it to the 70-200; so if we take a photo with our lenses we should use the 24-70, if we want to test some esoteric value we should shine a light through the 70-200! 

Call me dumb but I'd use the 24-70 unless I had the 70-200 on my camera, it is that close.


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## eml58 (Sep 7, 2014)

LetTheRightLensIn said:


> But what about the future? Unless Canon has utterly lost the plot they will have a D810 res sensor out soon. With this test we know how the Canon lenses would compare vs. Nikon with all sensors.



And this is where I believe this sort of testing is beneficial, at some point one of the manufactures other than Sony (a7r) will develop a +/- 50 MP Body with an interchangeable Lens arrangement, giving Photographers the opportunity to use the Lens line up that best suits their work at any given Lens Length, you may well find you have a collection of Canon, Nikon, Zeiss etc lenses that just do the job better than say all Canon, or all Nikon.

On wether or not Canon have lost the plot ?? seems to me they may have, perhaps they missed the need for a an a7r/D800/Pentax 645z type sensor in the Market, also seems to me enough people out there are buying into this MF DSLR arrangement, perhaps just not enough to convince Canon to get on the Hay Cart, in the meantime I'm sure Sony, Nikon, Pentax etc are quite happy with the status quo, unfortunately, I'm not, but then I'm not unhappy enough to seriously consider a switch, for now.


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## ULFULFSEN (Sep 7, 2014)

Mt Spokane Photography said:


> For those that might not have actually read the report, there is some information on curvature of field that is not accessable using imatest with a lens / body combination. Knowing the limitations due to curvature of field could help select among lenses from the same manufacturer for a project.



you think someone who actually makes money with photography looks at such data before he chooses a lens for a job?

i guess thats only interesting for gearheads and in very rare cases when this really matters (what would that be?).


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## infared (Sep 8, 2014)

As far as I am concerned...ANYTHING that comes from Roger is in an effort for himself and all of us to learn and understand more. He just "Gets IT"!


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## jrista (Sep 8, 2014)

Mt Spokane Photography said:


> privatebydesign said:
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> > And when we learn to take pictures without camera bodies the results might be relevant.
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Ditto!


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## TeT (Sep 8, 2014)

Great read, do more comparatives across brand...


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## RogerCicala (Sep 8, 2014)

I kind of agree with everything - I found it a fun test with limited practical value. As the database grows, though, I think it will help answer questions.

BUT there are always some real-world points. For example, I have some major customers who shoot magazine spreads on RED Dragons. They changes mounts and lenses like most of us just change lenses. Last shoot one of them had a Zeiss 135 f/2, Canon 85 f/1.2 and Sigma 35mm f/1.4 in Canon mount, along with a Zeiss ZF.2 21mm and Nikon 14-24 f/2.8. He changed camera mounts when he went to the wide angles, using a Nikon mount on the RED. 

I do think a day may come when there are cameras all of us can use with interchangeable mounts. 

In the meantime, I find this kind of stuff very interesting, if esoteric. For example, I've got another dozen similar comparisons done with primes. From what I see, there are actually some interesting differences in design philosophy between the companies. In many lenses Nikon has lower resolution but less astigmatism and flatter fields. Canon seems to push resolution and are willing to use some field curvature and odd astigmatism patterns to get it. 

Assuming that's the case, then when Canon inevitably has a similar pixel density I suspect we'll see different 'looks' to the lenses more clearly. I think that's interesting stuff and of practical value to know. Or what if Canon's 36 Mpix camera comes out and the corners seem softer (or better) than Nikon's? Is that a difference in lenses or in the sensor's microlenses, or something else? Without knowing the way the lenses function by themselves, we can't answer that question. 

But even I agree, this kind of thing isn't something I'd pick a lens or a system over. 

Roger Cicala


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## ScottyP (Sep 9, 2014)

Well, I don't know nearly as much as Privatebydesign does about everything, but I do think Roger of Lens Rentals may be an educated lens buyer almost on the same level as Privates. 

Privatebydesign: how many lenses have you purchased? Just round it over to the nearest hundred lenses to keep it simple.


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## privatebydesign (Sep 9, 2014)

ScottyP said:


> Well, I don't know nearly as much as Privatebydesign does about everything, but I do think Roger may be an educated lens buyer just like Privates.
> 
> Privates: how many lenses have you purchased? Just round it over to the nearest hundred lenses to keep it simple, so we can compare your totals and see if Roger at Lens Rentals is as educated as you are.



Scotty,

Personally less than 100, over the years probably closer to 1,000 that involved work for other people too, though I never tested one of them to the extent Roger and Lens Rentals have. 

So what?

As I already said I have the utmost respect for Roger, his blog, his testing and his considered comments.

Now in his own comment on this thread he stated many of the same sentiments I did, 
Roger: _"I found it a fun test with limited practical value"_, 
Me: _"the result, however interesting and informative, has little practical application." 
_

Roger: _"even I agree, this kind of thing isn't something I'd pick a lens or a system over"_
Me: _"Nobody in their right mind is going to have their buying decisions, or even their shooting choices, impacted by these results,"_

Roger: _"I find this kind of stuff very interesting, if esoteric."_
Me: _"if we want to test some esoteric value"_

Now it seems to me I am the one more in tune with his position than you. However, whereas I saw _"test results that have extremely limited, if any, real world value"_ Roger did point out that he does have a couple of clients that use interchangeable mounts, and in time he believes others might. So do you use interchangeable mounts? Does anybody here? If, as he believes, one day many of us will be using interchangeable mounts then his database will have a lot more practical value, personally I don't see interchangeable mounts in my professional lifetime (probably another ten to fifteen years), I think the manufacturers will push back against it if it ever happens in serious numbers, heck we have seen how petty they can be over simple things like third party batteries, what do you think they would do to protect their lens lineups!

Sorry, but the Dragon stills shooters are the highest high end, they are the guys (and girls) that have H5D 200's outright and use them for test shots and "personal projects", and they will always find the next thing long long before anybody else because that is the market they move in, they have the time, money and assistants to cull RAW video to stills, who of us ever will?

So you go ahead and devalue the conversation to antagonistic, petty, and mean spirited insults and personal digs, that makes far more sense to people like you. I'm happy to discuss the relevance of the tests, along the same lines as the tester does, with anybody with a more interesting thing to say.


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## jdramirez (Sep 9, 2014)

privatebydesign said:


> helpful said:
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Why is it wrong to want to know. I want to know regardless of the practical application of the results. I will say I earned a bachelor's of science so I've been asking why for a long time... why... didn't I pick a better major.


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## privatebydesign (Sep 9, 2014)

jdramirez said:


> privatebydesign said:
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I am seriously starting to worry about peoples reading comprehension.

Did I say it was wrong? NO, if you look at the words I wrote and you quoted you will see this _" Don't get me wrong, there is nothing wrong in and of itself"_ See? I actually said there is *"nothing wrong"*!

On the flip side of that however, even if you are 100% wrong about my point of view, what is wrong with me asking why people are interested in the result, other than it is what it is, when even the tester says _"I found it a fun test with limited practical value"_ and _"But even I agree, this kind of thing isn't something I'd pick a lens or a system over. "_?


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## LovePhotography (Sep 9, 2014)

privatebydesign said:


> LovePhotography said:
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In my opinion, the picture on the page is photography, but the benchmark performance of different optics is optical lens science. http://www.answers.com/topic/lens-1 There is no objective way to measure photography. But, there is, (and needs to be) a way to objectively measure lens performance. And, like all science, the best testing measurements require the best scientific method, which includes limiting variables to (hopefully)- one. Pax.


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## jdramirez (Sep 9, 2014)

privatebydesign said:


> jdramirez said:
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You know what... it's probably me. I'm reading a good deal of disdain in what I perceive to be the subtext of your comment. But if you say it isn't there... I won't argue that.

But in regards to knowing... I think there is some merit in knowing which lens set is "better" than the other. Bodies can be changed every 3 years, but you can keep a lens for 20 years and while they may replace it after a decade, the practical benefit of the successor may be marginal or merely show up on tests but have less real world value. 

And if you are prone to replace your body with any frequency, knowing which lens system is better equipped to handle in increases in resolution and... let's just say micro contrast, would be worthwhile. 

Now is this the point of the study... probably not... I'd say it's a d!ck measuring contest... but content with my girth and length... I'm going to go to bed.


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## privatebydesign (Sep 9, 2014)

LovePhotography said:


> privatebydesign said:
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Why?

The logical conclusion from that train of thought is that the "best" tested lens will give the "best" photograph, when that is patently false. Even if you totally discount the photographer from the photograph making equation your fundamental point is flawed.

For example, you have an assignment to photograph Usain Bolt crossing the line of the 100m at the next Olympics, you can use any camera system, just get *the* image. For arguments sake the Canon 400 f2.8 tests better than the Nikon 400 2.8, but the Nikon has more MP and more DR, however the Canon has better AF, but the Nikon system can resolve more even though it doesn't test as well. Hm, the Canon can do more fps. Now which do you choose? The lens that esoterically "tests better" or the the other system that scores much better for more meaningful metrics; or the system that "wins" your test but for reasons other than that...........


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## jdramirez (Sep 9, 2014)

privatebydesign said:


> Why?
> 
> The logical conclusion from that train of thought is that the "best" tested lens will give the "best" photograph, when that is patently false. Even if you totally discount the photographer from the photograph making equation your fundamental point is flawed.
> 
> For example, you have an assignment to photograph Usain Bolt crossing the line of the 100m at the next Olympics, you can use any camera system, just get *the* image. For arguments sake the Canon 400 f2.8 tests better than the Nikon 400 2.8, but the Nikon has more MP and more DR, however the Canon has better AF, but the Nikon system can resolve more even though it doesn't test as well. Hm, the Canon can do more fps. Now which do you choose? The lens that esoterically "tests better" or the the other system that scores much better for more meaningful metrics; or the system that "wins" your test but for reasons other than that...........



I'm the biggest offender of refreshing my gear... I buy something with the expectation of selling it at some point in the future. I've had gear, that I wanted, for less than a week because someone made me an offer. I tend to think I'm atypical. I tend to think that some people who buy gear (and I'm not only referring to high end lenses) that they are satisfied with have the intention of keeping it well past the freshness date on the milk expires. So if you have a few thousand bucks, and you know that the half-life of a body is significantly shorter than that of a lens, you might take that into consideration. 

Getting the shot now is short sided. Polaroid instamatics allowed us to get the shot now... and that really worked out well for them.


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## privatebydesign (Sep 9, 2014)

jdramirez said:


> Getting the shot now is short sided.



Really? If you didn't forget the irony tags then I'd have to take issue with that.

What use is a "better" lens for which there might never be a "better than the other guys" body? Any new body will give better results, even with a current lens; and any new lens will give better results with current or yet to be announced bodies, and the differences will be minute and be easily covered in post. If you need a 14-24 you need a Nikon, if you need a 17 TS-E you need a Canon, if you need a 400 f2.8 other factors will impact the differences far more than these esoteric test results.

That has to be the weakest point of view yet, I'll get the "best " lens now because the next generation or two of bodies might be better than the other guys, of course they might not, and the differences these tests show are unlikely to be visible anyway, but I'll have the "best" lens.

Not sure I agree with that, I would have thought, I'll get what I can now and use it would be a more solid foundation for taking photographs, but maybe that is where I am going wrong, maybe taking photographs isn't the goal of many measurbators here. 

Besides, the cost of "jumping ship" is always overestimated, like for like via the secondhand market it costs very little to move manufacturers.


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## tolusina (Sep 9, 2014)

privatebydesign said:


> .....
> Besides, the cost of "jumping ship" is always overestimated, like for like via the secondhand market it costs very little to move manufacturers.


For some, that's sure enough true.

For many others, the second hand market is a place to unload unwanted items, new is the preferred way to purchase. Cost to change camp is then quite significant.

I'll buy someone's used car and deal with its issues, but only after picking and choosing through what's on the market at the time. 
When I buy camera gear, I pretty much want new.


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## jdramirez (Sep 9, 2014)

I'm trying to think of how many twenty year old lenses are still in heavy use... the 50 f1.4 usm comes to mind. I know it's long in the tooth.

Ok... now let's move backwards twenty years to which bodies were in use in 1994. Film obviously, but in the digital realm there was.... assuming I believe Wikipedia, the Canon eos dcs 1.

I'm kinda thinking the lens outlived the generations of bodies. 

That's not a fair comparison... but I don't feel like being fair.


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## Lee Jay (Sep 9, 2014)

privatebydesign said:


> helpful said:
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Convolution.

Ask yourself this question. Why, when DPReview tests a body, do they use a quality prime at an optimal aperture, mounted to a heavy studio tripod, with careful focus bracketing and remote release?

The answer is, so that the lens so dramatically out-resolves the body that the results you get are almost entirely limited by the body itself.

Why do you want that? So that you can estimate how the body will perform with other lenses.

Same thing with lenses. How does the lens perform by itself? You want to know that so you can estimate how it will perform with any body.

If you don't do that, you're left testing every possible lens/body combination and retesting every lens every time a new body is released.

Convolution allows you to avoid that.

1/R^2 = 1/Rs^2 + 1/Rl^2, where R is system resolution, Rs is sensor resolution, and Rl is lens resolution.

If you know Rs and Rl independently, you can find R.


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## LovePhotography (Sep 14, 2014)

privatebydesign said:


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I'm sorry, sir, but you simply cannot conduct science in the way you have described here.  Once again, there are way too many variables. The fact is, that if you photographed Usain Bolt crossing the finish line with two identical situations except, one, with a good lens, and, the other with a great lens, the photo with the better lens will be better. That is simply a fact. About that there can be no rationale doubt or conflict.


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## LovePhotography (Sep 14, 2014)

Lee Jay said:


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Precisely.


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## ChristopherMarkPerez (Sep 14, 2014)

This is the very equation that the theoretical physicist I spoke with pointed out was wrong. The equation _only_ applies if you consider light as photons, which they are not. At least they don't behave that way when it comes to optics, sensors, and photography.

HOWEVER, the good news is that the entire exercise in understanding resolution performance of an imaging system can be simplified in a meaningful and useful manner. It's been hinted at in this thread, in fact. 

Calculate the sensor resolution and you'll have the right answer.

This holds true to the cross-over point where optical diffraction effects take over. For current sensor technologies that aperture is f/16. Everything from wide open down thru f/11 is "good to go." This will hold true with Sony's soon to be announced 46mpixel FF sensor and their current 50mpixel medium format sensor.

Go over to Nikon's US website and look at their D800E/D800 technical recommendations (it's a PDF file). Scroll down to where they talk about resolution and aperture selection. Note they recommend not stopping down below f/11 (they give examples). You'll find no discussion of the 1/r equation as Nikon has figured out that it doesn't apply in the way we all too often think it does.

On the other hand, if you still believe in 1/r, go to Fuji's website where you'll still find support for your claims.



Lee Jay said:


> ...
> 1/R^2 = 1/Rs^2 + 1/Rl^2, where R is system resolution, Rs is sensor resolution, and Rl is lens resolution.
> 
> If you know Rs and Rl independently, you can find R.


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## ChristopherMarkPerez (Sep 14, 2014)

That would be great, except MTF is _not_ a measure of resolution. It's a measure of how much contrast a lens will transfer from the original scene to the film/sensor/imaging system.

MTF can give hints as to how humans will see resolution, but only at certain resolution frequencies that are determined by image size and viewing distance. 

Contrast can be easily modified in processing. So it's never just about the lens.

Fortunately the authors of the site bring up other optical effects, such as field curvature. Chromatic aberrations and coma also effect optical performance.

There's a lot to this subject that is easy to get lost in the wrong or unimportant details. One has to be careful when attempting to understand what's really going on.

Fortunately, very little of any of this matters as commercially available optics and imaging systems are more than "good enough" when making very large, very sharp, very pleasing prints.



ScottyP said:


> http://www.lensrentals.com/blog/2014/09/just-the-lenses-canon-vs-nikon-zooms-at-70mm
> 
> Roger at Lens Rentals is comparing 24-70's and 70-200's from Canon and Nikon. Interesting because it removes the huge variable of the different camera bodies you usually have.


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## Rudeofus (Sep 14, 2014)

After reading yet another hatefest aimed at DxOLabs just recently, I am a bit surprised about the criticism aimed at Roger Cicala and his latest test report. DxOLabs got slammed hard because they measured lens performance together with the camera, and go figure, Canon didn't look good. Now Roger measured lens performance alone, Canon again didn't look stellar, and people throw another tantrum.

The only type of test, however contrived, which would find common acceptance here, would be one that yields results saying "Canon is better, pictures shot with Canon gear are automatically better, and people using Canon are a smart, attractive bunch, unlike users of other equipment."


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## privatebydesign (Sep 15, 2014)

Lee Jay said:


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Convolution does not allow for lens variation, it can only give you a figure for the lens or lenses tested. 

Convolution does not allow for factors most commonly used in actual photography, like auto focus.

Convolution is of limited value in telling you what you will actually get image wise. 

Photography, despite the best efforts of many here, is still about images, not equations. Nothing will truthfully tell you what you will get out of your camera until you take an image with your camera and your lens in your shooting situation.


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## privatebydesign (Sep 15, 2014)

LovePhotography said:


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Were I a Knight you could call me sir, as I am not you can't. 

Were photography a science you might have a point, as it isn't you don't.

If you assume the AF, the AA filter, the demosaicing algorithm, etc etc have no impact on the image output your example might be valid, as they do, it is not.


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## privatebydesign (Sep 15, 2014)

LovePhotography said:


> Lee Jay said:
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Precisely virtually zero practical value.


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## privatebydesign (Sep 15, 2014)

Rudeofus said:


> After reading yet another hatefest aimed at DxOLabs just recently, I am a bit surprised about the criticism aimed at Roger Cicala and his latest test report. DxOLabs got slammed hard because they measured lens performance together with the camera, and go figure, Canon didn't look good. Now Roger measured lens performance alone, Canon again didn't look stellar, and people throw another tantrum.
> 
> The only type of test, however contrived, which would find common acceptance here, would be one that yields results saying "Canon is better, pictures shot with Canon gear are automatically better, and people using Canon are a smart, attractive bunch, unlike users of other equipment."



I hope you are not including me as a criticizer of Roger, several times I have written of my respect for him, his work, his results and conclusions.

I don't care what gear anybody uses, I use my selection because I felt it was the right thing for me to get, and I might point out that Roger is a 6D Canon system owner. I don't care how my gear "tests" I care how it works.

If your comment is directed in part at me I would also ask what is wrong in questioning the value in such a test, especially given that the tester himself has replied that he agrees it is of extremely limited, nay "pointless", value.


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## Lee Jay (Sep 15, 2014)

privatebydesign said:


> LovePhotography said:
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Just because you don't understand it doesn't mean it's of no value to people who do.


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## Rudeofus (Sep 15, 2014)

privatebydesign said:


> I hope you are not including me as a criticizer of Roger, several times I have written of my respect for him, his work, his results and conclusions.



I most definitely don't try to act as Roger Cicala Defense Force here, first off all I had my own stern exchanges with Roger in the past, second I can confirm from personal experience that Roger doesn't need anyone as RCDF because he is quite capable of standing up for himself.



privatebydesign said:


> I don't care what gear anybody uses, I use my selection because I felt it was the right thing for me to get, and I might point out that Roger is a 6D Canon system owner. I don't care how my gear "tests" I care how it works.



In this case the DxOLab tests are for you, and luckily CR will continue to link to them as they appear. Roger's tests can be used as complementary tests for all those, who fit Nikon lenses to their Canon cameras, or who fit Canon lenses to their Sony A7R, or as some have pointed out, for those who upgrade their cameras more often than their lenses.


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