Portrait taking problems

[Johnny Rasmussen]

It is difficult to say what the problem is but you can try to sort the problems one by one.


1. You mentioned that the lens is sharp in most other cases and that you never had a problem in any other shots. Does this count for all focal lenghts?


2. You used a tripod and the IS was left on. In Bryan´s review of this lens he says:


This IS version is tripod sensing to prevent feedback loops between the IS sensor and stabilizer motor vibrations. The manual recommends turning IS off when tripod-mounting the lens (to save battery life) or when panning (panning mode IS is not available).


This could be the problem. I do not think movements from the tripod itself is the problem.


3. You said "when i shoot portraits at the wide end of the 17-55 2.8, I'm getting horribly unsharp pictures". Is this a problem only when shooting portraits or in general?


4. Is this a crop from the center of the image or from the side? If it is from the left or right side is the center sharp/in focus?


5. You were using a flash. Have you tried shooting the same portraits without the flash?





These are only a few thoughts. It is difficult to guess. I would have performed a few test with the camera on the tripod, no flash, IS off, plenty of light, using center focus point only and using different focal lengths. That will give you a clue if it is the lens or not.





- Johnny

[Oren]

If this was shot with a flash, I doubt the tripod or any other kind of shaking is the problem.


What program/mode is the camera set to (M, Av, Tv, Portrait etc.)??

[gbc]

The camera was in AV mode.


I'm going to try more shots using manual focus and then compare them to the AF shots. I'm beginning to worry it's the AF with either the camera or the lens.

[Oren]

Well it's not just AF IMO. The noise is too strong for ISO 400 on a 7D!

[Sean Setters]

Keep in mind that it's not terribly uncommon for a certain lens/body combination to need a microfocus adjustment (that's why the option is included on newer cameras). I have a 70-200 f/2.8 L IS that requires a heavy MF adjustment on my 50D, yet no adjustment is required on my 7D.


When you set up a controlled test, make sure to do it at 100 ISO--you don't want noise (and itsautomatic removal) to skew your sharpness results.

[gbc]

Thanks for the tip, Sean. Is microfocusing adjustment particularly difficult/involved? Any way I could seriously screw up the lens? I have almost no familiarity with it beyond a vague understanding of what it is.


And thanks for all the suggestions. These forums have been invaluable for me the past year.

[Sean Setters]

Thanks for the tip, Sean. Is microfocusing adjustment particularly difficult/involved? Any way I could seriously screw up the lens? I have almost no familiarity with it beyond a vague understanding of what it is.


And thanks for all the suggestions. These forums have been invaluable for me the past year.
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I'm sure there are optimal ways to do a MF adjustment and not-so-optimal ways. If you do it incorrectly, as far as I know, there's no risk of doing any damage to your lens and every adjustment is reversible (there might be damage to your reputation if you miss focus on every shot of a photographic session, however).


To dial in the MF adjustment on my 70-200, I set my camera on a tripod on one end of the largest room in my house (including a few feet of a hallway). I focused on my camera bag logo at an average portrait focal length and distance, and dialed in the MF adjustment until it was sharpest. After that, my keeper rate for the lens improved significantly. I haven't accessed the MF adjustment since.

[neuroanatomist]

It's not particularly hard, it seems. Before I got my fancy LensAlign tool, I used a [url="http://www.focustestchart.com/focus12.pdf]cut-out paper chart[/url]. With my T1i body (which lacks the microadjustment feature) and that chart, it seemed myEF 100mm f/2.8<span style="color: red;"]LMacro IS USM was front-focusing a bit, while all my other lenses were ok. But, there was nothing I could do about that myself - lens and body would have had to go to Canon Service. Now, with my 7D andLensAlign Pro, I just tested my100mm f/2.8<span style="color: red;"]LMacro, and pretty close (though I may adjust it a bit). The only other lens I've tested so far - my EF 85mm f/1.8 USM - seems to be back-focusing a bit. These are only single test shots, as well. I really need to shoot 3-5 shots, obviously. I haven't done adjustments yet (having a 2 year-old daughter means not having long blocks of time!), but the procedure seems to be simple.

[gbc]

Thanks for the help, guys. I tried a little microadjusting, and I think it may have solved the problem. Didn't have a whole lot of time to set up proper lighting or anything, but just from a quick test, the problem was apparent.


This is the lens prior to adjusting, at 18mm, from about 8 feet away:


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This is the adjustment at +10:


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(Glad I finally found a use for the bizarre, shiny string my girlfriend has lying around)


The problem is only apparent at wider focal lengths. Is that normal for this kind of problem? I've had this lens for a while, but most of my shots are around 40-55mm, so it took me a while to really notice the focusing problems. I also bought this lens refurbished. I figured that a refurbished lens would've been put through its paces, since it had to be repaired anyway, but I guess I should've checked it out better.


Anyway, thanks again everyone for the suggestions. I'll have to do more tweaking, but I think this is the right track. I can't thank you guys enough. I was really going crazy over this.