sigma lens

[wmchauncey]

Using canon xti with sigma 55-200 mm lens, shooting 200 mm in RAW at a cell phone tower 1/2 mile away to check for clarity in Colorado.  There is no haze and no adjustments were made in ACR.

Should my image be burry at 200% magnification in ACR?  I'm just trying to determine what to expect from my lens and if a better lens would give more clarity at that distance.

[mahleu]

Do you have a UV filter on? Are you steady when you shoot?

[larsrc]

Using canon xti with sigma 55-200 mm lens, shooting 200 mm in RAW at a cell phone tower 1/2 mile away to check for clarity in Colorado.  There is no haze and no adjustments were made in ACR.

Should my image be burry at 200% magnification in ACR?  I'm just trying to determine what to expect from my lens and if a better lens would give more clarity at that distance.
[{POST_SNAPBACK}][/a]

Did you have the camera on a tripod and use shutter-lockup with delay?  What aperture did you use it at?  Photozone does indicate that the lens is capable of very good sharpness: [a href=\"http://www.photozone.de/8Reviews/lenses/sigma_55200_456/index.htm]http://www.photozone.de/8Reviews/lenses/si...0_456/index.htm[/url]

-Lars

[:Ollivr]

how blurry is blurry? could you post a crop?
a cheap lens like that at such a focal length and an AA'ed bayer sensor AND 200% on-screen interpolation can get you soft images. If it looks good at 50% it should be fine.

O.

[wmchauncey]

I have takn this shot several times over several days at different settings always using tripod and remote without mirror lockup and without polarizing lens. The results are the same.
I just want to know if I'm expecting to much from the lens at 1/2 mile and 200% magnification in ACR.  Looks good at 50%.

[mahleu]

Ok, you have 2 possibilties.
1, the camera is either front or rear focussing
2, the lens has a problem
3, you picked a murky/hazy etc day
4, You're being too critical. If its sharp at 100% then it's probably fine