9 replies to this topic

[gina]

Hi. I have a Canon 16-35mm lens that I previously used on a 5D and am now using on a 5D MkII. I've noticed that a lot of the photos I take with it seem to have a bit of a "soft" focus. They're not all out of focus--I have taken some that are good and clear--but too many of them are not sharp. I don't think it's user error because my photos taken with other lenses (15mm fisheye and 100mm macro) seem to have a better ratio of sharp photos, and many fewer pics that aren't quite in focus.

Before I take it in for what might be an expensive servicing I was wondering if anyone else has experienced this, i.e., is it common or do I have a defective lens?

Thanks,
Gina

[blibecap]

Hi Gina

What type of dome and housing are you using?

Are your pictures in focus in the center and softer around the edges?

Can you post some pictures and tell us more about your equipment.

Edited by blibecap, 25 March 2012 - 12:48 PM.

[Drew]

Try shooting topside to see if there is an issue. Also use the 5D2 micro adjust to make sure the lens is calibrated to the camera.

[Cary Dean]

Try shooting topside to see if there is an issue. Also use the 5D2 micro adjust to make sure the lens is calibrated to the camera.

I agree w/ Drew. Try this.
There was some tests that said the first version of
that lens was not as sharp as the newer version.
Could come into play with the 5DII.
Are you using a diopter on the lens with a dome port?
I also found that you need to stop down about 3 stops
for optimal sharpness. Made many mistakes wide open

[gina]

Hi Gina

What type of dome and housing are you using?

Are your pictures in focus in the center and softer around the edges?

Can you post some pictures and tell us more about your equipment.

I was previously using a 5D in an Ikelite housing with an 8" dome, now I'm using a 5D MkII in an Aquatica housing with an 8" dome and a diopter on the front of the lens. (I don't have it in front of me but it is the diopter that was recommended by the people at Backscatter.)

Here is a photo taken with the new MkII setup:

surprise! by g-na, on Flickr

This was shot at 1/100sec, f/7.1, iso400, no strobe. While the fuzziness might be explained by the relatively slow shutter speed, it is typical of many other photos I have taken with this lens, even with strobes and higher shutter speeds.

I had completely forgotten about the micro adjust. I can give that a try and see if it helps.

Thanks,
Gina

Are your pictures in focus in the center and softer around the edges?

Oh, also, they seem to be evenly out of focus (not in focus at the center).

-Gina

[Ryan]

I've shot grid charts with and without Schneider 82mm +2 Diopter, and the lens without a diopter has much better overall and corner sharpness. This is counter to common logic...

[gina]

I've shot grid charts with and without Schneider 82mm +2 Diopter, and the lens without a diopter has much better overall and corner sharpness. This is counter to common logic...

The thing is, my lens has taken fuzzy photos both with and without the diopter, and on two different cameras. And I have taken some crystal-clear photos with the diopter. Which is why I was wondering if others have had this problem, or if it's just my lens ... and I now think it's the latter.

-Gina

[loftus]

The thing is, my lens has taken fuzzy photos both with and without the diopter, and on two different cameras. And I have taken some crystal-clear photos with the diopter. Which is why I was wondering if others have had this problem, or if it's just my lens ... and I now think it's the latter.

-Gina

Have you tried some topside test shots? It's possible the lens needs to be focus calibrated back at the Canon shop

Edited by loftus, 28 March 2012 - 07:04 AM.

[Drew]

Is this version I or II of the 16-35?

Ginga, it's going to be pretty hard to help diagnose unless you post some 100% of the issues you are talking about. The pic you posted shows a tad of motion blur and some depth of field issues in the tail, which is distinctively different from focus blur. I'm not sure if you cropped the pic but the lack of distortion puts it in the 30+mm range? I assume you were using less than f8?
Judging from that angelfish, I'd say your shark is about 5ft? @ 35mm f8 DOF is just under 5ft overall. Furthermore DOF doesn't mean that whatever is within will be tack sharp. There is a bit of tapering of sharpness as one approaches the limits. COmbined with motion blur, it can look OOF.

[gina]

Hi. Just thought I'd report back. I sent the lens in to Canon for repair. They confirmed "Adjustment of the lens assembly was incorrect causing the focus to operate improperly." It's now fixed and (hopefully) happy. This just goes to show that when you think something may not be quite right, trust your gut and get it checked out.

Looking forward to using it on Bonaire reefs in a couple of weeks.

-Gina