2nd copy of 17-40mm F4L, edge to edge inconsistency.

I think this is really sad. Canon lenses are getting so very expensive these days. There is absolutely no excuse for Canon to be sloppy about their quality assurance.

I have to say it hasn't been the most joyous introduction to Canon L glass thus far! Although from reading other posts around various forums it would seem the 17-40mm is more prone to this copy variation than some of the other L lenses (perhaps).

Anyway I have pretty much decided to return this copy also, albeit at the risk of getting another soft one. At least this one is sharp for half of the image!

gcams wrote:
I have to say it hasn't been the most joyous introduction to Canon L glass thus far! Although from reading other posts around various forums it would seem the 17-40mm is more prone to this copy variation than some of the other L lenses (perhaps).

Anyway I have pretty much decided to return this copy also, albeit at the risk of getting another soft one. At least this one is sharp for half of the image!

Well, good luck with the replacement! At the price of 'L' lenses, it's your right to have a good one - tho' the bummer is that we often end up out of pocket for the postage, apart from the hassle

You should change another copy until you get one that you like. After all you paid good price for the lens. In some states, the dealer cannot sell the returned items as new. If we all do this, Canon will notice this.

MDJAK wrote:
I own this lens and have been very happy with it, until reading this thread and taking a group shot this weekend. The right side of the photo was considerably softer than the left, though I chalked it up to not having the camera square to the group I was shooting. Now, I'm not so sure.

http://i.pbase.com …2/1/53440323._I​1A5291.JPG

The little boy on the right is considerably softer than the others, though I know I wasn't square and it's possible he moved.

One more tidbit: My camera is FF so it shows corner softness more readily.

Should have gotten the 16-35 f2.8.

Why do you feel the 16-35 would be better in this respect, its MTF shows softer than the 17-40?

Is there generally perceived to be a difference in quality between the 16-35 and 17-40?

I've tried 2 x 17-40 f4L and 2 x 16-35 F2.8L lenses with my EOS 1Ds MkII, the result were horrible, I returned all 4. My existing 20-35mm F3.5-4.5 was much better at the edges in all cases. The center results from the best 17-40 were about equally sharp, the color was possibly a little better than the 20-35.

One of the 16-35mms was so bad at 35mm F4 it was not sharp anywhere on the frame, Canon rebuilt the lens, before I decided to return it. None of the L lenses I tried gave an image that I felt I could sell. I'm sure there are some good samples out there, but I don't know what it says about Canon's manufacturing process and QA.

I think if you buy a pro lens for several times the price you are entittled to expect a better perfomance.

I'm thinking of an 24-105 F4L, but I will be taking test shots and examining them carefully before I part with any money for the lens.

If I still have my test shots I will post an example later.

Hi Joncl,

Very interesting to hear you had poor results with both the wide angle L zoom offerings. It would be very interesting to see your samples so please feel free to post them into this thread.

With your 17-40mm F4L's, was it mainly edge softness you had issues with as you commented your centre sharpness was OK on the better of the 2 copies? Was the edge softness consistent or did you encounter something similar to my problem above whereby one side is sharp whilst the other is on the soft side?

Now this IS interesting stuff, particularly as it is full frame.

The 16-35 looks like a handy lens but the MTF curves are not that good. I wonder why people give the lens such good reports. Is all this variation down to the individual or process variation on the lens I wonder??

Hi,

Unfortunately all 4 of the lenses were blured at both edges of the frame, I don't remember one side being worse than the other. But I do still have some of the test shots, so I will try to post some samples 2nite. Then U can see for yourselves and make up your own minds.

I can tell you when I got the first 16-35 onto my camera I was really shocked at how awful it was, I couldn't beleive it. I was in Glacier National Park with a Milk Bottle bottom, luckiliy I still had the 20-35mm with me.

I think there must be quite a variation between samples as some people seem to have good examples.

All the individual elements in the lens have to individually created, then the whole thing has to be assembled. I expect that their consistency needs to be improved.

Maybe these lenses were designed before the days of high res digital SLRs and people just didn't see the problems when they were using 35mm?

gcams wrote:
Hi folks,

Well this is my second copy of the 17-40mm F4L after returning the first one I had (thread https://photography-on-the.net/forum/showthre​ad.php?t=115418 refers). The new lens is much better than the last one I had and centre sharpness is excellent. In fact, so is edge sharpness, but only on one side. I did some tests this morning outdoors and started to notice that the right hand side of the frame is always softer than the left. This is particularly noticeable when shooting close up.

I did some newspaper tests under daylight and these are the results (all shot off tripod at F4 with mirror lockup, 100% crops):

Top Left:

Hosted photo: posted by gcams in
./showthread.php?p=989​421&i=i205353219
forum: Canon Lenses

Top Right:

Hosted photo: posted by gcams in
./showthread.php?p=989​421&i=i28169445
forum: Canon Lenses

I know the consistency of lighting across this shot is not ideal, but I have a number of other examples under different lighting conditions. Regardless of the situation, the results are the left is always sharp and the right is always soft.

My real question is, bearing in mind this is on a 1.6x crop factor camera (350d), is this inconsistency acceptible or should I be sending back my second copy and trying for a third??

I guess I'm a little hesitant to return this copy also, as at least it is sharper than the first, although the right hand edge of frame is getting quite soft. I'm not sure how it would look on a full frame camera which I hope to one day own.

Thoughts, comments?? Am I being too picky??

Nope QC is dodgy on these lenses

I did the same tests because I noticed one edge was OOF all the time

My THIRD 17-40 was fine but the first two must have been from the same batch as they both had exactlty the saame problem , OOF down one edge

Thanks for the further comments guys. I've just returned the lens for exchange. I'll post the results in this thread. Here's hoping the third copy does the trick!

I have a 17-40mm that I'm very dissatisfied with. For me the upper left quadrant is softer than the balance of the image and does exhibit a bit of CA at 40mm but only in the upper left. At first assumed it was my fault. After using it for a bit now I really seem to think there's something going on with this lens.

Sorry to hear that Vixeh. It would be worth trying to get it repaired by Canon or even better, replaced by the supplier if you can (still under warranty I assume?). If you've had it a while, you might not have much luck with an exchange and I've heard of folk having mixed success with repairs but I guess it's better than being stuck with a lens you're dissatisfied with.

I hate to hear this sort of thing because it makes me even more nervous about buying lenses over the internet. The problem is that I really don't have access to a decent camera store. If I drive 2 hours each direction, I can get to one that has a rather poor selection and seems to charge at least 20% more than B&H. Your post reminds me to carefully evaluate return policies before buying.

I can appreciate your concerns vjack.. I can't speak about American suppliers but I have been really fortunate to be dealing with AJ Purdy here in the UK. They have been exceptionally helpful in helping me through these bad copies. Obviously the return postage does add up (I've spent £10 on the two returns) but I think it's money well spent if I do end up with a decent copy of what can be a great lens. I guess the trick is to deal with an Internet supplier who are willing to do the right thing by you with returns.