Resolution Tests

Roger Buys a Camera System: A 24-70mm System Comparison

Published January 29, 2013

Note: I’m going to bore people for a week or two while I decide on a new camera system for myself. To alert those who are going to be bored by posts about “Roger Buys a Camera System”; I’ll put that in the title for the rest of this series. 

I don’t own an SLR – I go check one out for ‘testing’ when I need one. But I’ve moved out to the country and I want a camera at the house. I can’t really justify to management that I need to test a camera and some lenses for a year or two.

I know what I want: the Canon T4i‘s touch screen, the Canon 6D‘s Wi-Fi, and the Canon 5D Mk III‘s autofocus built around the Nikon D800E sensor, Nikon’s flash systemPentax’s user interface (I’d take their sensor too, if I went crop frame), and be able to mount lenses from all manufacturers. But given a far-less-than-unlimited budget, I’ll be making some compromises, like everyone else. In order to make comparisons, I want to take a look at exactly how some systems differ.

Most of that doesn’t involve geek stuff like this, but geek stuff is what I know best so that’s where I’ll start. Resolution isn’t the end-all point for deciding on a camera system. It isn’t even the most important point in my decision about a camera system, and I’m a resolution nut. But it is a thing I want to know about.

A Resolution Comparison

One of the things I constantly harp on is that people should not compare Imatest or DxO results on two different cameras. You can’t look at the results of a lens on a crop sensor and a full-frame, for example. You can’t look at results of a lens test on a Canon 5D and make good predictions of how it will behave on a Canon 5D Mk III. We’ve even found lately that you can’t take the results on a Sony NEX-7 and extrapolate to a Sony NEX-6.

But there is one thing you can do fairly reasonably. You can compare two systems (camera and lens) to each other and determine the overall resolution of each system. I had some pretty self-centered reasons for doing just that. I, the ultimate camera system commitophobe, am going to have to buy, with my own money, a camera system. I hate when that happens., 2013

One of the first compromise questions I had involves shooting with 24-70mm f/2.8 lenses; this is my most commonly used lens. The highest resolving 24-70mm f/2.8 lens is the Canon 24-70 f/2.8L II. The highest resolving camera is the Nikon D800E. Since I can’t mount the best lens to the best camera, I thought I’d look into how the two systems compare in final resolution.

I was fairly certain the D800E with a good Nikon lens is going to be better than the 5D Mk III with the great Canon lens. But I wasn’t sure by how much. The other nice thing about working at this focal length is we have a similar lens we can mount to either camera, the Tamron 24-70 f/2.8 VC, to get a little further comparison.

Let’s Look at Just the Lenses

Before we begin, I know there are some Fanboys somewhere who have stopped payment on their reality check and are stabbing pins in their Roger Effigy Doll because I said the Canon 24-70 II is the highest resolving f/2.8 lens. So let’s take the camera out of the equation and compare just the lenses on our Well’s Optical Bench. This means no camera mount, just evaluating the lens itself.

The following are MTF vs frequency plots for the center of the lenses in question – again, this is not Imatest data using camera images, this is purely assessment of the lenses (at infinity focus). The separation of the two graph lines shows the astigmatism of the lens. Almost all lenses have some; the Canon is truly unique in having so little. (These graphs courtesy of Aaron Closz who still gets nervous when I play with the optical bench. It’s nice and predictable, though. If I want him to run some tests all I have to do is sit down and say, “where’s that 70 micron reticle?” and here’s there like magic.)


MTF (vertical) versus frequency (horizontal) of Canon 24-70 f/2.8 Mk II @ 50mm


MTF (vertical) versus frequency (horizontal) of Nikon 24-70 f/2.8 @ 50mm


MTF (vertical) versus frequency (horizontal) of Tamron 24-70 f/2.8 VC @ 50mm


From direct comparisons we’ve known the Canon 24-70 II had a higher MTF 50 than the Tamron on Canon cameras, and that the Tamron was nearly as good as the Nikon on Nikon cameras. The optical bench shows a bit more differentiation between the Nikon and the Tamron than I expected, but otherwise clearly demonstrates what we already knew. I should mention we tested 2 copies of each, all of which had already been tested using Imatest and shown to be good copies.

System Testing

Now let’s add the camera systems into the mix, something Imatest is perfectly set up to do. We’re going to measure Imatest MTF in line pairs / image height, as always. Since the D800E has 4912 pixels of image height compared to the Canon 5D III’s 3840 pixels the Nikon should resolve somewhere around 1.2 to 1.3 X the Canon’s resolution if the lenses were equal. (Several other factors, including that the Nikon does not have an AA filter, lenses aren’t perfect, and the math is more complex than a simple ratio, make this a very rough estimate.)

Let’s start by comparing the Tamron 24-70 f/2.8 VC on the two different cameras. We shot two copies on two bodies and averaged the results (which, btw, were nearly identical) to show MTF 50 in the center, averaged across the entire lens, and averaged in the 4 corners at f/2.8 and f/4.

These tests are all done at 50mm. I just didn’t have time to set up at multiple focal lengths and 50mm is a strong area for all 3 lenses. I wanted to compare them at their best.


Tamron 24-70mm f/2.8 VC on Both Cameras

 Center MTF50Average MTF50Corner Avg. MTF50
Canon 5DIII f/2.8810665350
Nikon D800e f/2.81085855445
Canon 5DIII f/4940710445
Nikon D800e f/41225955560


The MTF50 difference between the two cameras shooting the same lens is quite apparent. The difference is a bit greater in the center and a bit smaller in the corners but it is quite significant – as we knew it would be.

Canon 24-70mm f/2.8 II vs. Nikon 24-70mm f/2.8

Now let’s compare the Canon camera with the Canon 24-70 f/2.8 Mk II to the Nikon camera with the Nikon 24-70 f/2.8 AF-S. The better Canon lens should offset some of the Nikon camera’s superior resolution. That is exactly what happened.

 Center MTF50Average MTF50Avg. Corner MTF50
Canon @ f/2.81000860450
Nikon @ f/2.81170945500
Canon @ f/41060910505
Nikon @ f/412401000570


The higher resolution of the D800E makes the resolution of the Nikon system superior to the Canon system, although the difference isn’t as great as it was when we compared identical Tamron lenses. No real surprise here. Also not surprising, the Nikon lens is slightly better than the Tamron, although this is fairly close.

The real bottom line here is that there are no losers. The resolution numbers all of these combinations show are nothing short of amazing. For example, all three zooms are equal to, or slightly better than, the superb Zeiss 50mm f/2 Makro Planar at equal apertures on the same camera.

I’ll show the f/2.8 data as our usual graph with center resolution on the horizontal axis, average on thevertical, all in line pairs / image height. I think this shows fairly well the actual resolution difference between the cameras (compare the two Tamron results) and the degree to which a better lens closes the gap.


MTF50 (LP/IH) at f/2.8


There’s one other aside that is probably worth mentioning; the test fairly well confirms common wisdom. If we run SQF numbers on these resolution differences, it suggests we’d need a print size of about 11 X 16 to detect this resolution difference. At that print size we should be able to tell the Tamron mounted to 5DIII (worst performer) from the Nikon 24-70 f/2.8 on D800E (best performer) pretty clearly. We might detect the difference between the Canon 24-70 Mk II on the 5DIII and the Nikon on the D800e. On a 16 X 20 print the Canon – Nikon difference would probably be clearly apparent.

So What Did I Learn Today?

Not too much. Like everyone else I already knew the D800E with a good lens was going to out-resolve the 5D III with a great lens, but that I’d need a reasonably large print to see the difference.

It also demonstrates another thing I mention a lot: the value of any third party lens varies according to what camera you shoot. The resolution difference between the Canon and Tamron 24-70 lenses is greater than that  between the Nikon and Tamron. Right now, the price difference reflects that: the Nikon costs $600 more than the Tamron, the Canon $900.

But if you want to look at it another way, the Tamron on a D800E is about the resolution equal of a Canon Mk II on a 5DIII — a bit sharper in the center, not quite as sharp in the corners, but pretty even. The Tamron-Nikon combination (for a guy like me looking at shelling out some major bucks soon) is $1,000 cheaper than the Canon-Canon system.

Of course, all of those prices are going to settle a bit differently in a couple of months. This is just where they are right now. And resolution is just one factor that goes in to choosing a piece of kit.

As to my ongoing search for which camera system I’m buying into, this just answers one tiny question. I’ve got a lot more research to do. I expect you’ll be reading more about that soon.


Roger Cicala and Aaron Closz

January, 2013





Author: Roger Cicala

I’m Roger and I am the founder of Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

Posted in Resolution Tests
  • Fernando

    Very interesting. What about testing this at f/8? I always wondered if diffraction at this sensor resolution levels do make a difference at this aperture.

  • Jamie

    I would love to see how the Micro four thirds standard (like the Lumix GH3) stacks up against the competition.

  • Roger Cicala


    My feeling was the Sony lens isn’t better than the Nikon or probably the Tamron, being a much older design (and from separate testing) and the Sony sensor doesn’t have the huge jump in Mpix that the Nikon does to pull the resolution up. But so many people have asked me to do so that I will, just to double check my assumptions.

  • klw10

    Just curious… Why did you not compare those two with the Sony a99 and the Sony Zeiss 24-70? I would love to know where that combo stands in comparison to the other two. Thanks

  • Thanks for the great article at relevant time. I have been considering switching to a Nikon system, specifically the D800E, from my aging Canon 5DII. One of my biggest hesitations has been the belief that Nikon is lacking in the pro-grade f4 department. Almost all my work is done in the field, so weight and size take precedence over brightness and depth of field. I often photograph in remote areas where it’s possible to bring only one lens. The Nikon 24-70 f2.8 is a big, heavy lens. I had considered, contrary to your advice, getting a D800E paired with a 24-120 f4. After reading this and other of your resolution tests, I was able to get a rough extrapolation to compare a Nikon D800E with a 24-120 f4 to my current Canon 5DII with the new Canon 24-70 f2.8 II. It appears that the Nikon combination would be little improvement over simply upgrading my Canon lens. Your article was posted the same day I was going to buy the Nikon system. The long and short of it is that I pulled the plug on the Nikon idea for now. Thanks again for the posts. Very informative!

  • Roger Cicala

    MacLek = when I add an adapter I have another set of lens-mount interfaces and an increased chance of decentering or tilt – which probably wouldn’t be significant, but would put another variable into the comparison.

  • Very good comparison. Those are all great lenses, although IMHO the Sony/Zeiss 24-70/2.8 is a bit superior. Looks like you really want either Canon or Nikon, but wouldn’t it be wothwhile to also try a Sony A99/Zeiss 24-70/2.8 combo for a change…? Even if it’s just to boldly challenge the status quo!

  • Roger Cicala

    Christian, the Canon 5DIII with the 24-70 II should out-resolve the Nikon 24-70 f/2.8 on a D600. Of course there’s a lot of other factors that may make you prefer the look of one lens over the other and the resolution difference isn’t going to be huge.

  • Maciek

    The truth is – you CAN use Canon lens on Nikon body 😀 but not other way around. Wonder what results would it show?!!

  • cdubman

    Roger – great article and site, thank you!

    How do you think the Nikon D600 and Canon 5DMIII compare with these lenses? Since they are about the same resolution, would the Canon have an advantage/better performance?

    Thanks in advance

  • Great tests Roger – brilliant stuff.

    Now about Nikon AF….. 🙂

  • Bob B.

    GREAT info.
    I am very happy with my 5DIII and my Canon 24-70 f.2.8L II.
    I really don’t need the huge Nikon files and unless you are doing some ridiculously serious pixel peeping…my 16″x20″ prints look just fine!
    Thanks for taking the time and presenting such precise organized information…really great!!!!!

  • Rene

    Resolution of a lens is just a small part of it. There are many other factors like colour and types of distortion. There’re even things that cannot be measured but adds to give different types of “look”.
    If all you care about is resolution then this is a good research but to decide on which system to buy it is far from enough.

  • Im working in Architecture and Landscape where resolution at the focus point is as important as resolution in the depth of field. When I compare the 24-70 Canon (the old one which was already exellent to me) on a 5d II with the 24-70 Nikon on the D800E (I tried 3 copies of the Nikon 24-70)I find that in the Nikon solution resolution decreases very quickly in the depth of the field. The Nikon solution has not at all the depth of field resolution at 24 as a 24 should have (everythig quite sharp from 3 meters to infinity at f8). The Canon 24-70 has this quality on the 5d II.
    In adition the Nikons 24-70 that I tested had no reliable autofocus.

    A lens that realy shines in terms of resolution, depth of fiel resolution and autofocus on the D800E ist the 14-24.

    It would be extremely interesting to see your test with the test-chart located two meters or more in front and in the back of the focus plane.

  • Thanks Roger, as always, for a sane and logical discussion and test of the toys we so like to play with! We are spoiled for choice at the moment, but this article proves once again that lenses play a huge part in in overall image quality…that’s probably why the Leica’s do so well but its also nice to see that Canon is pulling out all the stops with their new lenses even though their new cameras are somewhat unexciting compared to the competition…so now we all wait to see what they can come up with to equal or beat the mighty D800.

  • Your analysis raises a bigger question for me. With all the cameras and lens available to you, why are you looking at shelling out big bucks for a camera system? It is right there in the warehouse, ha ha.

  • Rick Knepper

    Since I own the 5D2/24-70 II combo and the Nikon D800E/24-70G combo, I have a pretty good idea regarding performance so I skipped to your conclusion which kind of left me hanging. Here’s what I think for a guy in a similar position to your own sans the ability to pick any equipment he wants. Since all 3 lenses are relatively new and updates probably are very far in the future, buying the sharpest lens today and waiting for the Canon response to the D800E might be a good strategy.

  • Roger Cicala

    Peter, I’m definitely looking outside Canon and Nikon and outside of full-frame.

  • Denny


    Do you think color rendering should be the number one factor to differentiate between camera systems?


  • Dave M

    The differences between Canon and Nikon in terms of resolution, focus speed and accuracy, low light performance, frame rate, exposure accuracy, and whatnot are small. For me, those differences are too small to be the basis of making a choice. To me, price, reliability, durability, and ergonomics are the deciding factors. What does it feel like to hold and use the camera? Are the buttons and controls well placed? Are the menus easy to use?

  • Thomas

    Peter, what “equivalent aperture” are you talking about? Your math is only correct when talking about DOF and nothing else. An f1.4 lens is an f1.4 lens, regardless of sensor size. Did handheld exposure meters have dials for f5.6@135, f5.6@6×6, f5.6@4×5″ and so on? Can’t remember ever having seen these and my remaining three meters definitely don’t have them…

  • Peter

    Hi Trevor,

    Your math is wrong. Converting to equivalent aperture (m-stop), your 30mm f/1.4 is m/2.2, so acts like an expensive 50mm f/2.2 on FF. Your 17-50mm is m/4.5, so acts like an expensive kit lens on FF. Your f/4 is m/6.4, so acts like — well, no one makes lenses that slow for FF that I know of.

  • Peter

    Would you consider comparing outside of Canon+Nikon? I’d be curious about e.g. the Sony-Zeiss and others.

  • ZiZi

    OK, I see the advantage Nikon lens on D800E has @2.8. But am I interpreting this data correctly if I say that difference practically disappears @F4?

  • Roger Cicala

    Hi Trevor,

    I’ve lately been shooting with an Olympus OM-D and fairly happy with it (even with 16 X 20 prints made with it) but it can’t quite fill my everyday needs. I shoot a lot with both of the Canon and Nikon cameras I’ve just tested. I’m going to look at cost to value ratio a lot with my decision, so I’ll be looking at a lot of APS-C cameras too.

    Should be fun for a while!


  • Roger Cicala

    My rough guess is I’d have to expand the scale of the graph a bit. I may be off on this supposition but I’m thinking something like this: Canon on Canon outresolves Tamron on Canon by 200 Lp / ih in the center, roughly, 100 lp/ih in the corner. The Nikon on Nikon outresolves the Tamron on Nikon by about 100 lp/ih, so the Canon could be 100 lp/ih better. That’s a very simplistic thought, there’s a lot more to it than that. But it can never be, we can’t adapt a Canon lens to shoot on Nikon.

    So the interesting question might be how much better with the Nikon Version 2 24-70 f/2.8 be?

  • Trevor

    Great article!

    I have been debating something similar for a while and I am really, REALLY interested in following your blog as you work through this. You are so lucky to be able to these side-by-side comparisons and really find what you like when most of us simply get into a circle-jerk on DPReview or the like because we can’t get our hands on hardware.

    So far I am happy with my Canon 7D but it’s low light performance has been tempting me to move up to a FF option. Problem is that I like this APS-C camera! My 30mm F1.4 Sigma acts like a cheap 50mm F1.4 on FF. My 50mm F1.8 acts like a cheap 85mm F1.8 on FF and my 17-55 F2.8 VC Tamron acts like a cheap 24-70 2.8 on FF. Then my 70-200 F4 L IS lets me reach out cheaply to a 320mm equivalent on FF.

    The cost for me to buy FF, and a 50 F1.4 and a 85 F1.8 and a 24-70 2.8 IS and a 300mm F4 is WAY up there and I would loose my 8 FPS as well.

    I know you have given up on hope but I am holding out (and hoping) for a 7D MkII.

    All that aside. It really comes down to the images. I have never seen side by side image comparisons of “equivalent” lenses on the FF vs APS-C systems. Eg. A 30mm F1.4 on APS-C vs a 50mm F1.4 on FF, A 50 mm F1.4 on APS-C vs a 85 mm F1.4 on FF. I wonder if you ever thought about looking at that (hint, hint).

    Anyways, I am looking forward to following this along with you.

  • Roger Cicala

    Norman, 16 X 20 is where I live and breath given my usual display areas and subject matter. I occasionally will go to a 20 X 30 but that’s rare. My subject matters tend to be detailed, though, macros often, which make people want to look at them closely, so I probably want a bit more resolution than most people.

  • NormSchulttze

    What is your idea of a “reasonably sized print”? Mine is 16×20.

  • fabio

    As you state, sharpness only matters up to a certain point. Chromatic aberration is to me the most annoying issue with any lens, and it usually determines my purchase choice. Whenever you process images in any way, CA is the first thing that sticks out like a sore thumb.

    I don’t buy Canon/Nikon because it is sharper than Tamron, but really because it usually has a lot less CA.

Follow on Feedly