Quote:
Originally Posted by multiweb
Great shots Roger.  I sarted playing with a Pentax 18-35 (67mm dia) last night and I found a fair bit of coma and field curvature on the edges. Do you stop the lens and make a mask in front? Or do I need to zoom in more. It goes from 18, 25 to 32.Last night I tried 25.  |
Thanks
I just stop it down in focal ratio, so from F/1.4 to F/2.8 on the camera settings. I don't stop down the actual apperture of the lens, I think that would only make the situation worse but haven't tested it to have proof
Stopping the focal ratio to F/2.8 has a dramatic effect on the picture quality, the corners go from swan shaped stars to circular stars, and F/2.8 is still quite fast
Zooming in/out will change the distortions evident from your lens but I think it's a case of trial and error. I've tried different zooms with my 17-40 and 70-200 and find it's not necessarily the long end (40mm and 200mm) that has less distortions, but there's always a best place, if keen to minimie the distortions.