there was enough of a break in the rain to run out and do a quick and dirty
set of photos with 6 lenses: Sigma 12-24/4.5-5.6, DA 14/2.8, DA 16-45/4,
31/1.8 Limited, FA* 24/2, and FA* 28-70/2.8. if i had time, i should have
tried the FA 24-90/3.5-4.5 too. it's too late now. you can see selected 100%
crops of portions of the images at
http://users.bestweb.net/~hchong/LensTests/. the first image shows the
overall scene as taken with my Sigma 12-24. the rest of the files are named
with lens name, focal length used, location of crop from image, and the
shooting aperture. i used autofocus with the center AF point aimed at the
trees in the far distance. i didn't wait for the light wind to stop before
exposing each image, so there is a chance of slight amounts of wind blur at
the smallest apertures as the shutter speeds were down to about 1/6 second
or so. i also didn't apply any exposure compensation as i should have to not
burn out the trees against the clouds. i was dodging rain showers and didn't
feel i had the time. as it was, i had to reshoot the FA* 24 images in a
shower.
there's good news and there's bad news. the good news is that the best lens
in terms of sharpness wide open on this quick and not very controlled test
was a zoom lens. the bad news is that it wasn't a Pentax. anyway, take a
look. some of the apparent chromatic abberation of the tree branches against
the sky is because of overexposure. backing off about 1/2 to 2/3 stop would
have prevented clipping in one of the color channels and reduced the purple
fringes.
Herb...
