Re: Pre-order: Sigma 100-400/5-6.3 DG DN OS FE ($949!)
j4nu wrote: GartenMoorriem wrote:
I suspect atmospheric disturbance. At 400 mm it is significant. Cars, heating between you and your subject. You have to judge the different lenses with pictures taken under identical conditions.
Yes, that's of course true. That is also why testing this is not that easy on the long end at far away subjects.
From what I've seen so far, I'm leaning towards AF being at fault, but of course that can be a wrong impression...
MF on tripod test tomorrow hopefully .
Maybe this helps. I received my replacement Sigma 100-400 last week. Tested it and was not getting sharp shots at 400mm. Not nearly as bad as the first copy, but just not very sharp. It occurred to me that maybe it was atmospheric issues. The first two tests were on 90 degree days in the heat of the sunshine with subjects 150-200 yds away.
So I took some "macro" shots a couple of days ago near mfd. f/6.3 - f/11 at 400 mm, All handheld. You could see the little "hairs" on the little miniscule stem in the middle of the flower bud at f/6.3. Opened up, the increased dof affect overwhelmed any diff in sharpness.
For medium range: I took it outside yesterday, a cold drizzly day, and took a bunch of shots of a building 30-40 yds away. All at 1/400 sec. ranging from f/6.3 to f/11 at 100, 200, 300 & 400 mm. auto ISO. All handheld
After doing a little exposure adj to get them all the same, and a little LR NR scaled to the ISO (5,000 - 12,800), I couldn't tell the f/6.3 from the f/8 or f/11 even at 200%. The ever so slight diff at f/11 could have been due to ISO, NR, Diffraction impacts. It was so slight nobody would notice unless told to look for a difference, and even then I'm not sure one would be judged sharper than the other.
After taking one of those 400mm f/6.3 shots through Denoise and AI Sharpen (moderate settings), it was sharp as a tack - I could feel the rough edges on the little dribble in the brick's mortar.
May 30, 2021 at 12:02 PM
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