corner softness of EF-S 17-55mm


#1
Hi guys, I noticed an issue. I'm currently shooting with canon 17-55mm, while shooting at 17mm I notice the object at the corners are pretty soft. I understand that to a certain extend, there will be some softness at the corners at wide angle, however what I dont understand is that the "softness" is much worse especially when taking pictures under strong sunlight, I cant remember what my aperture is but it should be around f11-f16.

under circumstances when the lights is not not extreme, shooting at wide angle is not really and issue, the softness at the cornet is still acceptable. Anyone know the reason why? is there is any explanation or it might be faulty lens?

I'll try to find picture to post up tonight. Thanks!
 

Kit

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Jan 19, 2002
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#2
Improper lighting or exposure will lead to lack of local contrast, which in turn affect your perception of sharpness. I'm guessing this might be the cause.
 

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#3
may i know why you are using such a high f number?

perhaps the corner softness is because you were too close to the subject and using the recomposing technique. In such cases the sharpness might be slightly off.

I recommend using f4-f5.6 and test again. U can use the corner AF points instead if you were not using them previously.
 

shidenx

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#4
Could be stray light entering the lens since you mentioned strong sunlight? Using any lens hood?
 

shidenx

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#5
may i know why you are using such a high f number?

perhaps the corner softness is because you were too close to the subject and using the recomposing technique. In such cases the sharpness might be slightly off.

I recommend using f4-f5.6 and test again. U can use the corner AF points instead if you were not using them previously.
My guess is he is doing landscape shots. Using a low f number will be kind of weird for landscape shots as there is no need for depth of field.

Well for corner softness, there is still sharpness for the subject/s but one can observe softness around the edges. Dont think its related to focusing issue.
 

#6
may i know why you are using such a high f number?

perhaps the corner softness is because you were too close to the subject and using the recomposing technique. In such cases the sharpness might be slightly off.

I recommend using f4-f5.6 and test again. U can use the corner AF points instead if you were not using them previously.

Hi, I was doing an outdoor shoot and using flash for filling in. I use high f number so that I can keep my shutter speed at 250. using 4-5.6 with high speed sync results in very high shutter speed which is too fast for the flash. Pls guide me if im doing it wrongly, thank you. :)
 

#7
Improper lighting or exposure will lead to lack of local contrast, which in turn affect your perception of sharpness. I'm guessing this might be the cause.
Hello, When I zoom in 100%, the subject at the corner isn't sharp compared to those at the centre, which usually isnt so bad when the light wasnt so strong and harsh. There were only twice I notice this and both happen to be under very strong sunlight.
 

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