Canon 24-70 f/4 IS Resolution Tests

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A lot of people have been waiting on the release of the Canon 24-70 f/4 IS, deciding which of the new lenses they wanted, or whether they wanted to upgrade at all. So, when the first batch arrived early this morning we were set up and waiting to do some resolution testing.

The Players

The Canon 24-70 f/4 IS fits in the 'standard zoom' lens category which is fairly crowded. The new Canon 24-70 f/2.8 Mk II and Tamron 24-70 f/2.8 VC lenses are already out. The Canon 24-70 f/2.8 Mk I is no longer produced but is in a lot of photographers' bags already. The Canon 24-105 f/4 IS already offers an f/4 image stabilized zoom with a greater range. It's a lot to choose from and the new lens is going to have to be impressive to sell well at its higher price.

Let's take a look at how this group prices out (these are today's retail prices, but I expect you can get $100 or so off each of them fairly soon).


Canon 24-70 f/2.8 Mk II$2,199
Canon 24-70 f/4 IS$1,499
Tamron 24-70 f/2.8 VC$1299
Canon 24-105 f/4 IS$1,091


We've previously compared the Mk and Mk II Canons in depth, and compared them to the Tamron f/2.8 VC. A couple of conclusions are already apparent:

  • If you want the best 24-70 f/2.8 zoom at any price, the Canon 24-70mm f/2.8 Mk II outresolves anything else, period.
  • If you want image stabilization with your 24-70 zoom, the Tamron is really very good, and while it doesn't quite resolve up to Mk II standards, it does outresolve the Mk I version (which is itself a pretty good lens, at least when you get a good copy).
  • The Canon 24-105 f/4 IS gives good quality and greater range at a lower price.

I try to identify my expectations going into an evaluation. In this case, given the price, the 24-70 f/4 IS will need to be a better lens than the Canon 24-105 and at least as good as the Tamron at f/4 to justify its price. I'll go further and say it should be better than the Canon 24-70 f/2.8 Mk I at f/4 as well. Anything less would be a failure.

The Usual Disclaimer

This isn’t a lens review. I am not a reviewer. I don’t spend days evaluating a single copy of a lens for all of its traits and characteristics, nor do I take hundreds of really great photos with it and describe how it works in the field. Several of the lenses I tested today are on the way to people who will do just that and their thorough reviews will be available in a week or so.

What I do is test multiple copies of the lens for resolution and other basic stuff. Multiple copies lets us take sample variation into account to some degree, which a thorough review of a single lens can't.

A Quick Comparison

Compared to the Canon and Tamron 24-70 f/2.8 lenses, the new one is a bit smaller at 3.7" long, 1.32 pounds, with a 77mm front filter ring.


Left to right Canon 24-70 f/2.8 Mk I, 24-70 f/4 IS, 24-70 f/2.8 Mk II


Left to right: Canon 24-105 f/4 IS, Canon 24-70 f/4 IS, Tamron 24-70 f/2.8 VC


And with barrels extended


It's also significantly shorter than the 24-105 f/4 IS - although they actually look quite alike. I'll add that I really, really, really like the pinch cap on the new lens, which makes it easy to remove the cap even with the hood mounted.

Macro Mode

Not really part of our usual testing here, but the 24-70 f/4 IS has a special switch that allows it to become a near macro (0.7x) at the expense of losing infinity focus. While I usually think of 'macro zoom' as a marketing gimmick (and I'm still not sure about this one), Canon did put their Hybrid IS unit in this lens, just like the one in the Canon 100mm f/2.8 IS L macro lens, so I'll give this one the benefit of the doubt.


Macro with 100mm f/2.8 IS L (center 50% of image, resized)


Macro mode with 24-70 f/4 IS (center 50% of image, resized)


I find the macro mode and small size nice differentiators that may make this lens a good choice for some photographers if the optics are excellent. I should mention, though, that the macro working distance is quite short -- about 2 inches from the front element. Getting it into macro mode is a bit clumsy as you have to hold the switch while rotating the zoom ring. But it's a nice feature.

Resolution Results

We tested 22 copies of the Canon 24-70 f/4 IS L at 24mm and 70mm using our Imatest lab. We had numbers from testing 100+ copies of the 24-105 f/4 IS already available. We had recently tested all of our 24-70 Mk I, Mk II and Tamron 24-70 f/2.8 VC lenses, but only at f/2.8, so we repeated those tests on 10 known good copies of each at f/4 so we would be able to compare how all the lenses performed at f/4. There was not time to test everything at f/5.6.

Results at f/2.8

The f/2.8 numbers are posted elsewhere, but I'll repeat them here.  If you're going to pay more money for an f/2.8 lens, but mostly will shoot at f/4, it's worthwhile knowing how much resolution you give up at f/2.8. The numbers are Imatest MTF50 values at the cener, averaged at 13 points over the entire lens, and the average of the 4 corner numbers.

Lensfocal lengthCenterMTF50AverageMTF50Avg. CornerMTF50
Canon 24-70 f/2.8 Mk I70mm710580360
Canon 24-70 f/2.8 Mk II70mm940810480
Tamron 24-70 f2.8 VC70mm740660420
Canon 24-70 f/2.8 Mk I24mm730610380
Canon 24-70 f/2.8 Mk II24mm950820510
Tamron 24-70 f2.8 VC24mm815765430


The three 24-70 f/2.8 zoons are all good lenses, but it's obvious from a resolution standpoint the Canon Mk II is the best and the Tamron between the Mk I and Mk II results.

Results at f/4

We have 5 lenses to compare at f/4 and I've added corner resolution, distortion, and chromatic aberration numberes. To keep all that data organized I'l make separate tables for results at 24mm and 70mm.

We'll look at 24mm first.

LensCenterMTF50AverageMTF50AvgCornerMTF50Barrel Dist.CA%
Canon 24-70 f/2.8 Mk I8607354702.0%.05%
Canon 24-70 f/2.8 Mk II10109106152.1%.05%
Tamron 24-70 f/2.8 VC9408155002.8%.04%
Canon 24-70 f/4 IS9508255601.7%.05
Canon 24-105 f/4 IS8907304805%.06%

The f/2.8 lenses, which are all good at f/2.8, sharpen up even further when stopped down to f/4. The Canon 24-105 f/4 IS accounts itself well here, resolving just as well as the original Canon 24-70 f/2.8 lens, although it does show more barrel distortion than the others. The new 24-70 f/4 IS isn't quite what I'd hoped (I was hoping it would match the Mk II f/2.8 lens at f/4), but it's better than the 24-105 or the original 24-70 f/2.8. It's probably a bit better in the far corners than the Tamron 24-70 f/2.8 VC, but otherwise they're about dead even.

One thing that is very good on the new lens is the lower barrel distortion, just under 2%. This probably is most noticeable when compared to the 24-105 f/4 IS, which has pretty bad barrel distortion right at 24mm.

Here is the same data when the lenses are shot lenses at 70mm

LensCenter MNTF50AverageMTF50Avg.CornerMTF50Pinc. Dist.CA%
Canon 24-70 f/2.8 Mk I8056454301.3%.04%
Canon 24-70 f/2.8 Mk II9758205801.4%.05%
Tamron 24-70 f/2.8 VC8907355101.5%.04%
Canon 24-70 f/4 IS9207505251%.05
Canon 24-105 f/4 IS8406804701.2%.05%


None of the f/2.8 zooms are quite as sharp at 70mm as they were at 24mm, but the difference is pretty minimal. The 24-105 f/4 IS still does quite well, perhaps a bit better than the original 24-70, although that's splitting hairs. It should be mentioned, though, that the 24-105 starts to get a tiny bit softer after 80mm - at 70mm we're in its sweet spot.

The new 24-70 f/4 IS stays in proportion -- it's about the same as the Tamron, not as good as the Canon 24-70 f/2.8 Mk II, but better than the original Canon 24-70 and the 24-105 f/4 IS.

Sample Variation

I've graphed the center and average resolution for all 22 copies below.


Center (horizontal) and average (vertical) MTF50


That's a nice, tight pattern at 24mm, but at 70mm things are a bit more spread out. There are two outliers at 70mm. Further testing on the worst one shows it is clearly decentered. The not-quite-as-bad one seems to be a bit decentered as well. I will note that I took these two values out when I calculated the averages above since I want those to reflect good copies of the lens.

Twenty-two lenses is a pretty small sample to make further comments. I'll have more to say when we have seen 60 or 70 copies.

Addendum, January 14: 

After a head's up from our friends at SLRgear.com and a couple of other users, who saw lower resolution in their copies at 50mm, we went back and retested a couple of dozen 24-70 f/4 IS at 3 focal lengths (24, 50, 70mm) instead of our usual two. (Most, but not all, zooms have lowest resolution at one extreme or the other, so we focus our testing there.)

We did find that 50mm resolution was slightly lower than 70mm for every copy. The center / weighted average at 50mm for the 24-70 f/4 IS was 875 / 700, compared to 920 / 750 at 70mm. Not a huge drop, but it was consistent. This is a bit surprising, but not a total shock. Some wide angle zooms exhibit similar behavior and the dip in resolution isn't extreme.

One thing that may be important to those of you who shoot around 50mm a lot, though, is that we also tested the Canon 24-70 f/2.8 Mk II and the Tamron 24-70 f/2.8 VR at 50mm. Both of these lenses were as sharp at 50mm as they were at 70mm, at both f/2.8 and f/4.


Obviously this hasn't told us a thing about autofocus accuracy, bokeh, or a dozen other things that have to be considered when choosing a lens. Just like you, I'll be waiting for more complete reviews to tell us about that.

On the basis of this information, though, I'm . . .  well, I don't know what I am. This is a good lens, but I at the price point I'd probably prefer the f/2.8 of the Tamron VC to the new Canon's f/4. The macro feature is nice and will certainly pull some people towards the Canon.

This is only a sample of 22 copies, but the sample variation at 70mm is a bit bothersome. I don't feel comfortable making any statements about it, though, until we've seen another 40 or 50 copies. This might just be a couple of bad lenses in a small sample.

My bottom line is I sit here thinking the prices need to settle down a bit. If I was considering upgrading to one of these lenses I'd probably hold off a few months and see how the prices change.


Roger Cicala


January, 2013

54 Responses to “Canon 24-70 f/4 IS Resolution Tests”

L.P.O. said:

Once again, Roger, thank you so much for this little piece of insight! Even though you are "not a reviewer", and do not "take hundreds of really great photos with it and describe how it works in the field".

Nevertheless, I do have one question. You say: "It should be mentioned, though, that the 24-105 starts to get a tiny bit softer after 80mm – at 70mm we’re in it’s sweet spot."

(The pedantic in me says that you should've said "its", not "it's", but I'll never mention it.... Or did I???)

Still, I've seen several reviews saying that the 24-105/4L is at its unsharpest (is that even a word in English?) at 70 mm and gets better again at 105 mm. One example is PhotoZone: http://www.photozone.de/canon_eos_ff/420-canon_24105_4_5d?start=1
Also, my own findings, which are definitely indefinite, seem to support this assumption.

I know this is a lot to ask, but do you have any comment on this?

Kind regards,
- L.P.O.

PS. I shoot the 24-105 almost exclusively wide open on my 5D2, and I've never been worried about its sharpness. Its blurring capability and bokeh is really pretty unique for a standard zoom, and at its longest focal length doesn't really lose much to the two 24-70's, particularly the first one (even though primes like the 135/2L is obviously from a different planet).

CarVac said:

Is the background blur from the new lens in the macro photo consistent with the Sigma 70mm at the same magnification and stopped down one stop? It is a good deal less blurred than the 100L shot...

webtv said:

I watched the video on the "Traumflieger" site and read a bit of the background of the people behind this site. I'm german and understand quite a bit of photography. If you ask me: I trust Rogers tests much, much more. Traumflieger does the usual - they test one sample and draw "important" conclusions. In Germany the media (photo or computer magazines for example) usually get their tests done by specialized labs (http://www.image-engineering.de/ for example), but they test usually also only one sample, as far as I know.

@ Roger. Thank you for giving everyone insight into your testings and repair experiences. Your blog is the best source for things like that. Unfortunately you don't have a branch in Germany. And – I enjoy your writing.


Håkon K. Olafsen said:

Roger, do you know if the f/4 IS benefits from the "new" Canon focus system? Which gives better phase-detection autofocus performance.

george said:

They are obviously all high quality optics. I use the 24-105 on a very regular basis and the only drawback is the distortion. The sharpness is at a point where my camera can not see any loss of resolution at 100% when shot between f 5.6 & f 11. Note, that I am working between ISO 800 & 1600 in most cases, with a 6D. Also, sometimes I have to blur areas where people look a little too much like reality (accurate images are not what everybody wants).

I would love to see a 24-135 f4 L IS lens, that was as sharp as my 24-105. This would make my job many times easier at corporate events.

Conclusion, use the zoom range you need for you style of work, and think about if you really need f2.8. At the end of a 8 hour day, a camera that weighs less, is sometimes more practical.

Wphotog said:

I own a 24-70/2.8L Mark I and a 70-200/f4L IS (5D2 body). My gripe with the 24-70 is that it was never as sharp as the 70-200. It just seems like it should be sharper. I am thinking about selling the 24-70/2.8 and getting the new 24-70/f4 to replace it. Thinking the IS and better resolution would be nice and I wouldn't really miss the 2.8. I would wait for the price to drop a bit however. I also thought about sending in the 24-70 for calibration, but frankly I fear the lens may come back the same or worse.

Your tests are very helpful in trying to "figure this out".
Do these resolution tests represent one focusing distance (infinity?)?
Is it possible that say if the lenses are focused at 5 or 10 feet, things may change significantly in their relative resolutions?


Joachim / CH said:

Thank you for the link, NoiseJammer. I was just flipping through the video. They went outside with an EOS 6D to check the lense's macro abilities. Honestly, I don't take their "testing" very seriously, a lot of balbla and the 6D ability to connect with a smartphone (which is nice, but the way they used it, could also be done with a swivel screen). Sorry for not recapping, I simply ran away of their "wannabe professional" attitude. But that was only first impression...

Ron said:

I'm with Steven. I had this preordered as well, but cancelled last week (apparently just in time) and then ordered the 2.8 II. I used the 2.8 II last fall and was very impressed with it.

GR said:

The results so far are about what I expected. I won't be buying this lens since I already own the 24-70 L 2.8 II. But, I will probably rent this lens with a 100-400 L to take on a trip.

richard said:

thanks for the info Roger!

I suspected even by MTF that it would fare better than the 24-70 I and less than the II and better than 24-105 .. seems like real life confirms it.

one thing to also note especially over the Tamron is the weight difference of nearly 225g's .. which isn't exactly insignificant. So it's really lighter, smaller and even a bit sharper. A stop slower - however it's a lens that I would be more inclined to be considering for it's portability or you might as well get the 24-70II.

LensRentals Employee

Roger Cicala said:

Thank you Simon and NoiseJammer. I was assuming there were resolution tests I was missing. If he's testing on a crop sensor it would make corner performance different, but I can't see center and average resolution being hugely different.
Couple of thoughts: Imatest numbers like mine may be different than infinity focus performance, so I look forward to more non-Imatest reviews.

But I also wonder, given the 2 bad copies I've already gotten, if this is going to be one of those lenses that will have very 'copy dependent' reviews. For example the two copies we had that are both way off at 70 don't really look that bad. I wouldn't have picked them up as decentered if I didn't have comparison data.

We have a couple of reviewers we work with who wait and get pre-tested copies from us just so they know they're getting a representative lens. I think that's a good thing theses days.


simon said:

that isn't the first time traumflieger comes to very different conclusions than everybody else. I don't know weather that is a good thing, make up your own opinion about that.

NoiseJammer said:

This link may take you to the Traumflieger site http://tinyurl.com/a9a9czf .

Unfortunately, it seems the reports are in German video and my command of the language isn't good enough to extract the detail. (Perhaps a more fluent speaker could chip in here.)

From scanning the site, it's apparent that the test was performed on a crop sensor, so edge sharpness and illumination fall-off may be quite different from your results.

Regards etc.

A said:

Another interesting article; thankyou Roger!

As a matter of interest, did all the new lenses arrive in one batch from one supplier, or were the sourced from different suppliers and/or in multiple batches?

I'm just wondering how the de-centered lens came to be de-centered... Was it poor QC at the factory, or did one shipment get dropped. Or...? Any thoughts?

I've seen parcels being mishandled (in one case even watched horrified as they kicked parcels labelled fragile from one train to another, accompanied by the sound of breaking glass), and I've taken delivery of had a pallet load of very dropped computers. I know that bad things can happen in transit. Do you think the packing you received them in was up to the job?

Do some companies pack things better than the others?

I also know that sometimes QC isn't all it could be, even in best companies...

Just trying to get a feel for where the problems might be coming from; but maybe that's content for another article ;)

abi74 said:

looks pretty good need to rent it first to see how it performs on the field. barrel distortion figures seem very good. Never really like the 24-105L and the 17zoomL, sold those two for a mint used still 8 months warranty 14mmL version II. The only grip I have is the F4, zooming with my feet, I might get the 35mm I.S f2 instead.

Ben said:

*your blog.

Sorry for the reposts.

Ben said:

Thanks for the info. PS if you don't hear it enough, you're blog is terrific. I especially love the historical articles. Have a great weekend.

LensRentals Employee

Roger Cicala said:


One thing - when I'm writing I'm considering purchase price since most of my readers are considering purchase. Rental prices get a little strange because things like resale value, durability, repair rate, repair costs, etc. all figure in. For example a Canon 300 f/2.8 IS lens rented for about the same price as a Sigma 120-300 f/2.8 IS even though the Canon costs twice as much to buy.

Actual numbers are proprietary a bit, but no question the 24-70 f/2.8 Mk I was our second most popular lens behind the 70-200 f/2.8 IS. At the moment the MkI and the Mk II are about even in rentals. With the 24-105 about 2/3 as many copies as those. We have far fewer Tamrons in general, but the 24-70 f/2.8 VC is the most popular of all Tamron lenses. We rent very few of the Sigma 24-70, most of those to people who want to decide if it's 'good enough'for their purposes.

Howard said:

Thanks for the testing. My impression is the same as RBR and others: this lens looks pretty darn good, except two things:

1. Price. It needs to come down a bit, and I am sure it will (the prices of all lenses, except for the super-teles maybe, eventually come down, look at the 24-105 for example). $1,200 would be my entry point.
2. Vignetting? My biggest gripe about the 24-105 is the severe vignetting at 24mm. If this new lens can solve this problem, I would definitely add it to my kit.

Ben said:

Roger, looking at the rental prices I would tend to think people would fall into three buckets: 24-105, the Tamron, or the Mk II depending on their needs and budget. I can't see why anyone would choose the Mk I, f4 IS, or Sigma given the prices.

This discussion makes me curious about which lenses are your most popular rentees. If the actual numbers are proprietary, maybe just a top 10 list. Hell, you could even keep a list of trending lenses to help draw customer attention to those models.

LensRentals Employee

Roger Cicala said:


We've been debating that all day: not only how many of these, but how will these affect the others. If it had sucked we'd have bought all the 24-105s we could get. If it was sharper than the 70-200 f/2.8 Mk II, we'd have bought 200 of these.

Now we're just clueless. To tell you the truth, we're largely following my suggestion -- buying just a minimum (maybe 50) for now hoping the price will drop by March or April when we have to increase stock on all of them.

RBR said:

Thanks for taking the time to do this. So far from what I can see, the lens looks good except for the price. What I would most be interested in is how the lenses compare at around f5.6 and f8. Nobody is going to buy this lens for its speed, but it could be a great landscape lens with its small size well suited for hiking and travel. Corner sharpness when stopped down a bit at 24mm is where I'm most interested in seeing the results.

Ben said:

Roger, thanks for the initial impression. I'm curious about how many you guys will stock vs. the other 24-(70|105)s. How do you all forecast demand for a brand new lens, especially when it is introduced into a crowded market?

Aaron said:

I'm still quite drawn towards the Tamron as it gives me f/2.8, although the increase in resolution over the 24-105 of the 24-70 f/4 is nice, but I find I need to have f/2.8 available often enough. It also can give me some extra high-accuracy AF points available to me on my 5d3, which may make a difference at times.

Again, thanks for all your work with this! I keep coming back because of it.

Patrice Troost said:

Thanks for all the efforts for getting and putting this first review ever online (I am getting the Tamron as a new tool)..
have a nice day,

LensRentals Employee

Roger Cicala said:


I couldn't follow the link - other than the summaries the actual testing information is apparently members only?

Given Canon's MTF published charts I find it very surprising. But then I'm never too shocked when any test of one copy shows a lens to be soft. That happens.

Bruce A. said:

For me there are two huge factors worth considering when deciding whether to purchase the new 24-70 f4 IS lens. The lens is smaller and lighter. This lens may be the perfect match for the smaller Canon 6D. In any case, for backpacking, smaller and lighter is generally always better. Also, IS is a great benefit with the f4 maximum aperture. Bottom line: there are always trade-offs to consider. Looks like a good travel/backpacking lens to me.

Steve Justad said:

It would be interesting to see if the figures for the 24-70 F4 IS lens improve one stop down at 5.6 as much as the 2.8 lenses did going to F4. If it made a similar jump in quality as those lenses it would seem a quite fine lens to me. Of course, the 2.8 lenses are also likely to increase in quality at 5.6 but the increase may well not be as great as the increase seen stopping down to F4. Perhaps at 5.6 the little 24-70 F4 IS will be pretty much the optical equal of the 24-70 F2.8 ii.

A little research into this might keep Roger out of trouble for the weekend. And thanks for the work up.

Steven D. said:

Still undecided on this lens. I had it preordered, but then cancelled at the last minute. Having image quality similar to the Tamron in a smaller package with a macro mode is appealing, but the price just seems too high; specially since I already have the 24-105 that came with my 5D3. I ideally I would like to have the lens before my trip in Feb, but I doubt the price will much, if any, by then.

I eagerly await full reviews as well.

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