the mega battle of 24-xx

I have a copy of 24-105, 24-70 f4IS, 24-70 2.8 IS II, and good copy of Tamron 24-70 2.8 VC in my possession, and shot some detailed brick wall today, at 24, 28, 35, 50, 70, 105, 2.8-f11, where applicable.
all shots were taken on a tripod, live view 10x contrast detect autofocus in the center, remote release, iso 200 raw. Default LR sharpening and removal of CA by LR.
summary of findings
1. 24-105 meters 1/3 of stop darker than the other 3 at all focal lengths. That is consistent with its T value.
2. Wide open performance, corner to corner is the best on the 24-70 II no surprise there.
3. The best stopped down performance (f8-f11) corner to corner is achieved by the tamron 24-70. at 50mm and 70mm it does better in the corners than the other 3. at 24, not quite as good as 24-70II, but very close at f8 and f11

Now by lens.
canon 24-70II. excellent center, very good corners wide open. lens is strongest at 24mm, weakest at 50mm, where in the corners, wide open performance is good, but stopped down, it never gets excellent. same is true at 70

24-105, a lot of distortion at 24. Center very good to excellent through out lens does the best in mid range, esp at 50. at 24mm, needs f8-f11 for a very good corner. I do have a stellar copy of the lens though.

Tamron 24-70. wide open sharpness excellent in center 24-50. very good at 70. corner sharpness good, but lags canon at all focal lenghts. at 70mm it has field curvature if best center sharpness is achieved (focus at 10x in center) corners are mushy However, if contrast detect sharpness done at center without 10x, the center is a little softer, but corners are a lot better. turns in excellent performance stopped down at all focal lenghts, where it easily does better than both canon 24-70 at 5.6 and f8 in the corners at 50 and 70 mm

Canon 24-70 f4 IS. well, interesting lens. Its small and light If you get it for after rebate price of 800, it has strengths. Low distortion, good corner to corner sharpness at all focal lenghts. its is not as sharp at 2.8 II in the corners at the wide end, about same (may be a touch better) than tamron. at f11, they are all pretty close.
Its bit of a dog at 50 wide open, but stopped down, actually does better in the corners than 24-70II.

So what is the gist of it? First off, none of these lenses are perfect, and a clear cut winner.
If you are shooting wide open, canon 24-70 2.8 is easily the best for overall sharpness. It is also very fast and accurate focusing. In ballance however, it is not the best midrange landscape lens, b/c of its weakness in the corners at 50, and some at 70.
There still does not remain much justification buying the 24-70 f4IS over 24-105. You loose range, and money. Gain size and macro. You gain better 24, with much less distortion, and every so slightly sharper stopped down. However, you get worse performance at 50, wide open.
Tamron 24-70, has very good and even performance stopped down. It also has excellent performance in the center wide open, except for at 70, where it is still very good, at least for portraits, and sharpens well at f4. For me, its biggest weakness remains, as I have posted many times, its slower AF, and focus consistency issues, esp at 70 mm.
If I get the time, I will try to put some comparison shots
edited for typos

note to self... never sell my tamron 24-70.... it is flawless. /endnote

It's funny I just read this. I was using my 24-70 f/2.8 II just the other day at f/8 and 35mm and I was noticing some of the detail was lacking in the landscapes I was photographing that I was expecting to be there.

The real test would have been to compare it to the 24mm f/3.5 II tilt shift and see how much of a difference there was I could discern at 24mm.

It's very interesting that you noticed the same thing. It's very rare I use it for landscapes and I'm usually using it at f/2.8 so it's not a big deal for me but I am interested that you discovered this too.

subscribing for the eventual chest beating.

adharr, I do have the 24 tse II, as well as 24 1.4II. the 24-70 II is simply beyond reproach at 24mm. its exceptionally good corner to corner. at 24 2.8 its as good as 24-70 f4 and tamy at f8 in the corners, and at f 5.6, super crisp. Not saying tse is not marginally sharper, but it would be academic. however, at 35 5.6, it has some wavy performance and zone B sharpness is worse than 24-105, even though the extreme corners are slightly better. some of the results may be due to field curvature, but even at 35 f5.6, with a wall 30 feet away, its surprising.

Excellent review. Thanks.

kevindar wrote in post #16808428
So what is the gist of it? First off, none of these lenses are perfect, and a clear cut winner.
If you are shooting wide open, canon 24-70 2.8 is easily the best for overall sharpness. It is also very fast and accurate focusing. In ballance however, it is not the best midrange landscape lens, b/c of its weakness in the corners at 50, and some at 70.
There still does not remain much justification buying the 24-70 f4IS over 24-105. You loose range, and money. Gain size and macro. You gain better 24, with much less distortion, and every so slightly sharper stopped down. However, you get worse performance at 50, wide open.
Tamron 24-70, has very good and even performance stopped down. It also has excellent performance in the center wide open, except for at 70, where it is still very good, at least for portraits, and sharpens well at f4. For me, its biggest weakness remains, as I have posted many times, its slower AF, and focus consistency issues, esp at 70 mm.

edited for typos

Awesome run down! Thanks for taking the time to do this and sharing your results. Based on my recollection, your testing sounds pretty consistent with the general consensus... were there any surprises in your view?

I know it's a lot of work, but that would be great... it would be interesting to see some actual 100% crops of corners from all four at some select settings that show some differences and a comparison of distortion at 24mm amongst the lot. After all, sometimes a picture is worth a thousand words

the surprise was 24-70II performance in the corners on the long end.
here it is at 50 5.6 compared to 24-105. these are 200% crops, but reduced size since I got a 27 inch monitor, and these are screen captures.
center

Kevindar.
Thanks for reviewing the 24-70 Foursome.
Having purchased a 5D Mark III at Christmas, I have been looking to possibly upgrading my 24-105 f/4 L IS. Distortion is noticeable compared to when I had it mounted to my 7D smaller sensor as is the case. Virtual may recall I have been looking at both the 24-70 f/2.8 and the f/4 L IS. The lack of IS has me hesitant on purchasing the f/2.8 Has the lack of IS on the 2.8 ever come into play for you?
If I go for the f/4 L IS I control distortion better from my 24-105, however is the softness at noticeable at 50 compared to my 24-105?
I think we all can agree on this. Canon should introduce a 24-70 f/2.8 L IS. If Tamron can, why can't Canon?

Nick, the distortion is much better on the 24-70 f4L. at 50 mm, side by side, yes its a touch softer in center, a definitely softer in zone B and C. I does sharpen up stopped down however. It all depends on your use I suppose. I expressed its strengths are size, distortion, over all stopped down performance, and macro ability.
How much do I care about IS at this range, I dont. the only time its of use to me is shooting video. I am either shooting people or landscape. People, I need fast enough shutter speed, to prevent their blur, and landscape I use tripod. the VC on the Tamron has shown to cause some softeness of image, in the 1/60 to 1/125 speed range.
The VC can certainly provide for some nice city photography/night shots, allowing for some dragging of shutter. depends on your style of photography

Thanks for the mini comparison, much appreciated. Can you supply crops for the 24mm comparison of the 24-70 II vs 24-105? This is relevant to another discussion and I'm curious.

Thanks!

Thanks kevindar,

It makes one feel like getting a lens of a different focal length might be a better place to spend some of your lens budget than upgrading one of the 24-70s.

I own two of the lenses you tested and at this point in time am inclined to keep them both.

Truly one of the benefits of these forums is this type of information especially prior to purchasing.

somehow I missed 24, on 24-105, but I have it from another test. will post

kevindar wrote in post #16808428
Now by lens.

canon 24-70II. excellent center, very good corners wide open. lens is strongest at 24mm, weakest at 50mm, where in the corners, wide open performance is good, but stopped down, it never gets excellent. same is true at 70

Another reason I had a hard time pressing the buy button was because of this. After reading several peoples remarks that between 50 to 70 you are usually shooting people or other isolated objects so corners were not as critical. This of course depends on what type of work you do. When shooting landscapes I don't normally go that far so I decided to go for it. Of course I would have preferred excellent as I do shoot doors, etc when I'm travelling.

Good reviews. Thanks.

Nice write-up, and it is pretty consistent with other reviews.

I had two copies of the 24-105, but also bought the 24-70 f/4 IS recently from Adorama when they had the rebate ($800). I think the weakest point of the 24-105 is the performance at 24mm, as confirmed by your test -- excessive vignetting and distortion. The 24-70 f/4's weakest point is its performance at 50mm, but I don't consider it to be that much of a problem for the following reasons:

1. It is not THAT bad, as confirmed by your testing also -- that it gets better stopped down. So really you just need to make a mental note not to use it wide open at 50mm unless you have to.
2. Actually I tend to use my zooms at the extreme ends, so this is even a less issue for me.
3. I also have the 50mm f/1.4

So I think it is a keeper.

Howard