Hello CS gurus out there,
Sorry if this topic has been discussed to death, but I hope you'll indulge me... =P Already did a search but couldn't find what I was looking for...
I'm trying to evaluate the sharpness of my new Sigma 10-20mm f/4-5.6 EX DC HSM. I tried it at the shop and it seemed OK, but testing in the shop was sub-optimal: poor lighting + small camera LCD. I've now shot some test pics, but I'm still not sure how sharp is 'sharp'. My concern is that the edges (esp the top and bottom) always seem to be sharper than the centre of the image! Please help me to evaluate... would like to know if the lens is 'ok', or if there might be a QC issue, or even a back-focusing problem.
Thanks in advance!
All pics shot on a Nikon D80 at f/8, ISO100. In-camera sharpening: Medium High, tone compensation: Normal.
10mm, full FOV, scaled down
Centre 100% crop:
Left 100% crop:
Right 100% crop:
Bottom 100% crop:
Sorry if this topic has been discussed to death, but I hope you'll indulge me... =P Already did a search but couldn't find what I was looking for...
I'm trying to evaluate the sharpness of my new Sigma 10-20mm f/4-5.6 EX DC HSM. I tried it at the shop and it seemed OK, but testing in the shop was sub-optimal: poor lighting + small camera LCD. I've now shot some test pics, but I'm still not sure how sharp is 'sharp'. My concern is that the edges (esp the top and bottom) always seem to be sharper than the centre of the image! Please help me to evaluate... would like to know if the lens is 'ok', or if there might be a QC issue, or even a back-focusing problem.
Thanks in advance!
All pics shot on a Nikon D80 at f/8, ISO100. In-camera sharpening: Medium High, tone compensation: Normal.
10mm, full FOV, scaled down
Centre 100% crop:
Left 100% crop:
Right 100% crop:
Bottom 100% crop: