cyberstudio 寫:
I was looking at the white sign "Quali Walk" "6=>" on the lamp post, at the top left corner of your pictures. Clearly, both Canon 17-40 and 24-70 were sharper than VS24-85 at the top left corner, so I wondered if that was what you were focusing on... and asked you that question.
Also, you would notice that the lamp post was suddenly very sharp for the two Canons. The rest of the frame was less sharp. I was not sure if that was indeed the focus plane, or whether it was because of field curvature. (I thought the lamp post on the left was indeed the focus plane, judging from the scrub in the center.)
To sum up, from the two Canon pictures, what you focused on was less sharp than what you don't focused on!
Strange.
First of all thanks for reading the pictures in detail!
As a long-term manual focus user, sometimes I would use hyper-focal distance (or DOF) for shooting landscape or street snap shoot, especially for a rather wide angle lens (say 24mm this time) and moderately small aperture (such as f/8 or f/11), while the result on film usually won't let me down..........
Considering the setting for the test this time, i.e. 24mm and at f/8, would the DOF for all these 3 lenses still not enough to cover all the ranges from near and far as in the picture? (even a mis-focus did happen on the lamp post on the left hand side) I had been trying to figure out the answer also before I decided to post these pictures on the forum.............at lease what I can see are the lamp posts far away on the winding walkpath tend to be in focus in 3 of the pictures.
I add another 100% crop from the centre here:
Canon 17-40L
Contax 24-85 T*
Canon 24-70L
Should it be the problem because I had used ISO 1600? or should I say the AF system is not 100% trustful? That I dunno also.....