Test shots with Canon EF 17-40mm f4 lens

Ron Metz · #1 10-10-2007, 07:29 PM

I just received a new Canon EF 17-40mm f4 lens from B&H and I have read that some of you are having difficulty with the sharpness or lack thereof with this lens. I have taken some test shots and I would like to ask for feedback on whether the pictures reflect a correctly calibrated lens. Thanks to Don Lashier, the link to my test shote is a link to your gallery All shots were taken with a Canon 30D at f4, 17mm - wide open. Any assistance would be appreciated.

Ron

DonLashier · #2 10-10-2007, 07:47 PM

Ron, here's a link to your gallery. What I did was go to your gallery, ctrl-c the address, then type the first sentence here, select the text I wanted to link, then clicked the link button on the toolbar and pasted the url.

It's hard to say without knowing the focus point, f stop etc., as DOF issues are subtle with WA lenses and easy to confuse with lens issues themselves. I don't have this lens but have a 17-35L and taking a cursory look would say that your's isn't terrible but isn't spectacular either, but bear in mind that imo none of Canon's WA zooms tend towards the spectacular.

- DL

Ron Metz · #3 10-10-2007, 08:16 PM

Thanks Don. I have included the link to my pictures. I am fairly new to digital (old Canon FD user) and never had to test any of my FD lenses. They all came from Canon perfectly aligned. This Canon quality control issue is new with me.

Ron

DonLashier · #4 10-10-2007, 08:49 PM

Ron, with an UWA like this the issue usually isn't "calibration" (focus related), but rather issues with the optics themselves and sample variation. Like I said yours looks in the ballpark but bear in mind that you're on a 1.6 crop sensor and this will minimize any "corner" issues which are often the points of concern. A lot of the first version of the 16-35f2.8L had left/right issues where one side was noticibly sharper than the other.

In any case it's difficult to do optics evals based on shots with lots of depth like these because as I mentioned earlier DOF issues are easily confused. At 17mm DOF is quite great but unless you place your focus point appropriately parts of the scene may appear slightly unfocused. If you want to get anal about this I'd suggest the classic brick wall shot, on a tripod, and bracket your focus slightly. For comparision there are a number of brick wall shots floating around the net taken with this or similar lenses. I'll see if I can round up one.

- DL

Ron Metz · #5 10-10-2007, 09:20 PM

Don,

I appreciate your help. I am a bit anal retentive. I have read about folks going through three and four of these lenses before getting one that functions the way it is suppose to. I also have the Canon EF 24-70mm f2.8 and that one works great. My EF 70-200mm f2.8 IS does also. As you mentioned, with the wide angle I am somewhat at a loss on what to look for.

Ron

Noel_Carboni · #6 10-10-2007, 09:55 PM

I see a fair bit of CA (color fringing) in the corners, but not beyond what I might expect from the 17-40. I see the same thing with my 17-40. If you shoot raw the CA correction functions in the Photoshop Camera Raw converter fixes it up very nicely.

Actually, as it turns out I've come to use my 17-40 very little since picking up the Canon 10-22. I haven't tested it at all yet on my new 40D.

-Noel

Ron Metz · #7 10-11-2007, 08:53 AM

Noel,

Actually, I looked very seriously at the Canon 10-22mm but went with the 17-40mm because it is an "L" lens. I do not really need the additional stretch that the 10mm gives. Thanks to you guys, I feel that my 17-40mm is accurate and a keeper.

This is a GREAT site - extremely professional.

Ron