I don't think the concrete slab is any different from the cherry tree photos, but they're difficult to compare because of the different size of detail. In the cherry tree pics, the softness is most evident in minute detail like the foreground grass. In the concrete slab pics, there's a bit more detail on the left edge than on the right edge if you look at the grains in the cement between the pebbles. Too bad there's no features of intermediate size in the slab.
What would be interesting, though, is a series of images like the cherry tree scene at different apertures. If lens centering is the issue, I'm pretty sure the lens would prodcuce more colour fringing aorund the branches in one orientation at small apertures.
Still wonder which lens this is. Wider than 24 still leaves a lot of options.
Jostein
----- Original Message ----- From: "Keith Whaley" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, March 19, 2005 2:16 PM
Subject: Re: Could anybody explain this?
Jostein wrote:
Just a hunch, I don't have any hard knowledge on this....
I think one issue with wide-angles is that the all optical elements have to be properly centered. I know one German photo journal used to test this when doing MTF tests. Maybe a slight misalignment of an element could cause what you observe?
Jostein
Okay, but... how do you account for Alan's comment:
* * *
"Now is the weird part. I did some careful test on a 2D subject (aligned with bubble
level and shooting straight down at very close distance, about 0.6m) but there is no
trace of blurry edge/corner at all. Both sides of the picture look equally sharp, or
at least I cannot tell the difference."
http://www3.telus.net/wlachan/f11.jpg (2.8MB)
* * *
If that's true, it doesn't happen all the time.
Just curious... keith whaley
