RF24-70 & RF15-35 Reviews

Digital Camera world have just posted reviews. Seems both are good but edge sharpness could be better ...


 
Feb 19, 2016
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I think we might really be now well into the law of diminishing returns. The EF 24-70 2.8L II was such an amazing lens, the equal of a whole range of f/2.8 primes that to expect a big step forward in terms of sharpness was unlikely. Consider that since it was released Nikon released the 24-70/2.8VR, the (mirrorless) 24-70/2.8S and Sony released the (mirrorless) 24-70GM, while Tamron and Sigma both put out highly regarded 24-70 2.8s... And not a single one of them is as sharp as the EF Canon lens. SLR or mirrorless, it doesn't seem to make much difference with the size/quality of 24-70s.

Then when one considers that the new lens has IS and how that must complicate lens design and layout then perhaps hoping for more was unrealistic. I have the EF 24-70 2.8L II on the adapter to my R and it works flawlessly so given that it seems there won't be any huge optical improvements (though the closer minimum focus distance would be nice) I will likely wait a while for prices on the RF to fall. If you need IS then I think buying the RF lens you would be unlikely to be disappointed especially as the appearance now of an entire holy trinity with IS make me wonder if Canon will bring IBIS anytime soon. If they were planning to then I would expect the 15-35 and 24-70 to both be without IS.

As for the RF 15-35L, that will be the more investing one to see as more tests come in. The very low distortion at 15mm is welcome. Probably the key question for many will be, given it is a sharp lens, what is the vignetting like? That was the achilles' heel of the EF 16-35 2.8L III and in particular the area where the Sony 16-35GM beat it. If the RF 15-35L is much better in that regard it may well be a good choice for astro use, the larger size being a reasonable trade off for the extra millimetre in focal length.

One final thing I'll add is that Canon clearly regards 2.8 zooms as their professional bread and butter. Things like autofocus performance, build quality, repairability etc will all factor as high as image quality but don't tend to feature in the same way in most reviews. I am confident they will get such lenses right.
 
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AlP

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I wouldn't take the two reviews cited above as a reference for judging the performance of these lenses. There isn't a lot of information about the methodology used for sharpness measurements, so it could well be that the results depend on image processing. It might also well be that vignetting affects the measurement. It is surprising that center sharpness reaches its maximum at f/4, while edge sharpness reaches its maximum at f/11 (!) for the 15-35 at 15 mm. Most recent Canon designs (or maybe even all of them) didn't need that much stopping down to reach peak performance even in the corners, and it would be very surprising if that changed with the RF lenses. Something is a bit off in my opinion.

Also, the TDP results for the 15-35 do not look disappointing to me. The comparison with the EF lenses tested on a 5 DSR is difficult, as confirmed by Bryan Carnathan in his comments to the review. He also suggests comparing it to the RF 85 tested on the EOS R. The comparison is then between a UWA zoom lens and a 85 prime (possibly the best one available), and that doesn't look too bad.

Another aspect is distortion: The 15-35 has significantly lower distortion than all EF 16-35 designs, and it has also lower distortion than the EF 24-70 in the overlapping focal range. Software algorithms are getting better and better, but I'd argue that having slightly less edge sharpness but significantly lower distortion might still lead to better detail in the corners than with a lens requiring a significant amount of distortion correction in post.

There is a video "review" of the 15-35 here:
It's not a scientific test, but it compares the RF and EF lenses in real-world situations and there are some interesting aspects: The 15-35 seems to be only slightly less sharp at 15 mm than the EF 16-35 III at 16 mm, but at 15 mm there will be "fewer pixels available for the same amount of information", meaning that with identical sharpness a 15 mm lens would look worse than a 16 mm one on the same sensor, if the 15 mm image is cropped such that it covers the same fov. So, it's possible that the two lenses would have the same sharpness at 16 mm.
What also seems to be good is coma performance. There's just one image, so again not a scientific test, but the corner performance of the RF lens at 15 mm looks at least as good as the EF 16-35 at 16 mm if not better. If that turns out to be true it would be great!
Vignetting is difficult to judge, but it doesn't seem to be worse than the EF lens. That one is rather bad concerning vignetting though, so this might be a less than optimal result. But then, the 15-35 lens allows the use of front filters and has a not so critically exposes front element while other <16 mm f/2.8 UWA zooms with less vignetting wouldn't.
 
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SecureGSM

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I think we might really be now well into the law of diminishing returns. The EF 24-70 2.8L II was such an amazing lens, the equal of a whole range of f/2.8 primes that to expect a big step forward in terms of sharpness was unlikely. Consider that since it was released Nikon released the 24-70/2.8VR, the (mirrorless) 24-70/2.8S and Sony released the (mirrorless) 24-70GM, while Tamron and Sigma both put out highly regarded 24-70 2.8s... And not a single one of them is as sharp as the EF Canon lens. SLR or mirrorless, it doesn't seem to make much difference with the size/quality of 24-70s.

Then when one considers that the new lens has IS and how that must complicate lens design and layout then perhaps hoping for more was unrealistic. I have the EF 24-70 2.8L II on the adapter to my R and it works flawlessly so given that it seems there won't be any huge optical improvements (though the closer minimum focus distance would be nice) I will likely wait a while for prices on the RF to fall. If you need IS then I think buying the RF lens you would be unlikely to be disappointed especially as the appearance now of an entire holy trinity with IS make me wonder if Canon will bring IBIS anytime soon. If they were planning to then I would expect the 15-35 and 24-70 to both be without IS.

As for the RF 15-35L, that will be the more investing one to see as more tests come in. The very low distortion at 15mm is welcome. Probably the key question for many will be, given it is a sharp lens, what is the vignetting like? That was the achilles' heel of the EF 16-35 2.8L III and in particular the area where the Sony 16-35GM beat it. If the RF 15-35L is much better in that regard it may well be a good choice for astro use, the larger size being a reasonable trade off for the extra millimetre in focal length.

One final thing I'll add is that Canon clearly regards 2.8 zooms as their professional bread and butter. Things like autofocus performance, build quality, repairability etc will all factor as high as image quality but don't tend to feature in the same way in most reviews. I am confident they will get such lenses right.
A slight correction: Sigma 24-70 Art isn’t all that hot. CA levels are excessive to say the least. Tamron 24-70 G2 and 70-200 G2 are a very compelling proposition though.
 
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Maximilian

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Do engineering changes needed to accommodate IS affect image quality?
I suppose yes.
At least the additional optical elements of the IS are additional glass in the path of light.
So more possibilities to lower the IQ.

Do I remenber right that this was an argument from Canon to release the EF24-70/2.8 II and not an IS version?
Or was this just forum talk?
 
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YuengLinger

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I suppose yes.
At least the additional optical elements of the IS are additional glass in the path of light.
So more possibilities to lower the IQ.

Do I remenber right that this was an argument from Canon to release the EF24-70/2.8 II and not an IS version?
Or was this just forum talk?

It gets harder for me to track down things I think I remember...
 
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Do engineering changes needed to accommodate IS affect image quality?
IS usually requires a couple of seconds to kick in. So it has negative effect if shooting before IS settles down. :)
From what I know, the IS mechanism may cause a slight blur due to added elements bending the light but it is much lesser than what is caused by the motion of camera and lens for longer focal lengths. So it reduces the "overall" blur.
 
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koenkooi

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IS usually requires a couple of seconds to kick in. So it has negative effect if shooting before IS settles down. :)
From what I know, the IS mechanism may cause a slight blur due to added elements bending the light but it is much lesser than what is caused by the motion of camera and lens for longer focal lengths. So it reduces the "overall" blur.

On R and M cameras IS is always running in live view, it only shuts down during playback and entering the menus.
 
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I suppose yes.
At least the additional optical elements of the IS are additional glass in the path of light.
So more possibilities to lower the IQ.

Do I remenber right that this was an argument from Canon to release the EF24-70/2.8 II and not an IS version?
Or was this just forum talk?
I do remember something about Canon saying IS wasn't a high priority for 24-70 when they did an assessment of likely users, compared to resolution, weight and I don't know what else, but that would have been a while ago now. It is true that IS doesn't help a lot if you have moving subjects or the camera is on a tripod.
 
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YuengLinger

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IS usually requires a couple of seconds to kick in. So it has negative effect if shooting before IS settles down. :)
From what I know, the IS mechanism may cause a slight blur due to added elements bending the light but it is much lesser than what is caused by the motion of camera and lens for longer focal lengths. So it reduces the "overall" blur.

This does make sense; it's complex. I wonder if some focal lengths might be more problematic, or if implementation and tolerances might make for better or worse IS.

Just from my limited experience, on the ef 70-200mm's, and on the ef 100-400mm II, the IS seems amazing. And I'm really impressed by the older ef 100mm f/2.8L IS. Maybe it's just my copy, but the IS on the ef 85mm 1.4L helps, but sometimes seems to make the AF miss in odd ways. (Looking through the OVF when IS engages, I see the smoothing and steadying right away, but the pics never quite live up to expectations.)

The ef 16-35mm f/4L IS works great too, but the focal-lengths, for still photos, don't really need all that much help.

Interestingly, the RF 50mm f/1.2, combined with the EOS R's Servo AF, produce astounding results with no IS in the mix, even at slower shutter speeds. My theory here is that the Servo AF is so good it acts almost like IS for the slight forward and backward swaying or shaking that would otherwise cause havoc with the shallow DoF, but of course it does nothing for lateral movement. The balance of the lens and camera also have something to do with it, and it helps that the lens is so sharp to begin with. But I am getting better results with Servo AF than with One Shot.
 
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This does make sense; it's complex. I wonder if some focal lengths might be more problematic, or if implementation and tolerances might make for better or worse IS.

Just from my limited experience, on the ef 70-200mm's, and on the ef 100-400mm II, the IS seems amazing. And I'm really impressed by the older ef 100mm f/2.8L IS. Maybe it's just my copy, but the IS on the ef 85mm 1.4L helps, but sometimes seems to make the AF miss in odd ways. (Looking through the OVF when IS engages, I see the smoothing and steadying right away, but the pics never quite live up to expectations.)

The 85 experience you're describing... is that on the DSLR or the R?
 
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YuengLinger

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The 85 experience you're describing... is that on the DSLR or the R?

On both. Same results, 5DIV and R. AFMA is fine on the dSLR, seems to work just fine on the R, but just never get the expected IQ at any shutter speed. Maybe just my expectations and not the IS, but, like I said, I don't think the IS is as good as on other lenses. We are talking one copy here, one photographer.

Yes, my keeper rate was a slightly higher than on the 85 1.2L II which I sold, but I think my technique was pretty good with the older lens. (Wish I could say the same about my technique with the 135mm f/2!)

Maybe I should have sent it to CPS for a check, but they seem to have a fairly easy going attitude about what is "in spec."
 
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A slight correction: Sigma 24-70 Art isn’t all that hot. CA levels are excessive to say the least. Tamron 24-70 G2 and 70-200 G2 are a very compelling proposition though.

Well that is true, though a few people, notably Dustin Abbott, have praised its rendering you're quite right it falls short in measurable terms. Which again I feel re-inforces that the EF 24-70 2.8L II was just one of those lenses that set a new standard and somehow found something special previously missed. I don't say it as a Canon fanboy either. Probably the best example from recent years of such a lens was Nikon's 14-24. I wasn't alone in using it adapted to a Canon SLR back when Canon offered very little with high quality in the wide angle arena. All these years later and Sigma brings out a 14-24 2.8 Art that isn't really that much different. Canon never did bring one out a 14-24 2.8 and Tamron only got to 15mm.

Every now and then you get those kind of lenses that it takes years for others to catch up and I think the EF 24-70 2.8L II was just such a lens.
 
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The Nikon 14-24 is a dogs breakfast of a lens, at the time the Canon option was the 15mm 2.8 fisheye defished, it has better image quality and a wider fov. Now the 11-24 at 11 comfortably outperforms the Nikon at 14. The poor Nikon always made far to many compromises to be an f2.8 at which it is basically unusable if anything is outside the center of the image.

Well that is true, though a few people, notably Dustin Abbott, have praised its rendering you're quite right it falls short in measurable terms. Which again I feel re-inforces that the EF 24-70 2.8L II was just one of those lenses that set a new standard and somehow found something special previously missed. I don't say it as a Canon fanboy either. Probably the best example from recent years of such a lens was Nikon's 14-24. I wasn't alone in using it adapted to a Canon SLR back when Canon offered very little with high quality in the wide angle arena. All these years later and Sigma brings out a 14-24 2.8 Art that isn't really that much different. Canon never did bring one out a 14-24 2.8 and Tamron only got to 15mm.

Every now and then you get those kind of lenses that it takes years for others to catch up and I think the EF 24-70 2.8L II was just such a lens.
 
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Del Paso

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This does make sense; it's complex. I wonder if some focal lengths might be more problematic, or if implementation and tolerances might make for better or worse IS.

Just from my limited experience, on the ef 70-200mm's, and on the ef 100-400mm II, the IS seems amazing. And I'm really impressed by the older ef 100mm f/2.8L IS. Maybe it's just my copy, but the IS on the ef 85mm 1.4L helps, but sometimes seems to make the AF miss in odd ways. (Looking through the OVF when IS engages, I see the smoothing and steadying right away, but the pics never quite live up to expectations.)

The ef 16-35mm f/4L IS works great too, but the focal-lengths, for still photos, don't really need all that much help.

Interestingly, the RF 50mm f/1.2, combined with the EOS R's Servo AF, produce astounding results with no IS in the mix, even at slower shutter speeds. My theory here is that the Servo AF is so good it acts almost like IS for the slight forward and backward swaying or shaking that would otherwise cause havoc with the shallow DoF, but of course it does nothing for lateral movement. The balance of the lens and camera also have something to do with it, and it helps that the lens is so sharp to begin with. But I am getting better results with Servo AF than with One Shot.

I can only confirm!
I've been using the 100-400 quite often at speeds like 1/30th sec. at 400 mm with success! (and some failures, of course...)
Canon's IS works extremely well, and, as you wrote, servo AF is indeed a great help, also for "windy" macro shots, not speaking of hurricanes, obviously!;)
PS: I'm in love with the 100-400 :love:, it's become along with the 35 mm Leica M my most used lens!
 
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