01-15-2012, 01:21 PM
[quote name='Xastoul' timestamp='1326378423' post='14810']
Both picture were take a 50mm f8, the camera on manual, Wb in manual. They were take will the camera was stable on a desk. If this can help.
[/quote]
that sounds more like the sigma lens has some miscalibration or even hardware issue, the f-stop not closing down to f8 as it should, maybe only to f5.6.
If you increase ISO, so that you can use faster shutter speeds, does the effect get worse?? (In case the mechanical shutter of the Sigma does not close fast enough - an unlikely scenario, but the above test is easy).
Both picture were take a 50mm f8, the camera on manual, Wb in manual. They were take will the camera was stable on a desk. If this can help.
[/quote]
that sounds more like the sigma lens has some miscalibration or even hardware issue, the f-stop not closing down to f8 as it should, maybe only to f5.6.
If you increase ISO, so that you can use faster shutter speeds, does the effect get worse?? (In case the mechanical shutter of the Sigma does not close fast enough - an unlikely scenario, but the above test is easy).