andrewaaa5
5th of August 2006 (Sat), 06:12
sigma 17-70mm
i got this lens the other day. happy with it so far and it performs just as I expected it to : )
this is my problem though.
Either: i am not sure what 'infinity' is 'meant' to do on a camera focus ring, OR, the 'infinity' lens is not doing what I expect it to. I thought instead of assuming, I would ask the helpful people on this forum.
well, i know what 'infinity' does, but what if you turn the ring slightly passed the 'infinity' mark? is it meant to keep distant objects in sharp focus still or blur them slightly?
the best thing to do is to illustrate with a few pictures (all taken AV at f8.0):
1st picture is taken at 70mm and on 'auto' focus, with the background building set to be target for focus lock. Note the position of the fosus ring to the right of the picture:
http://www.butterpeanut.com/canong3/01_70mm_autoSM.jpg
Nest I took a shot at 70mm and 'manually' focussed, but i pushed the focus ring all the way as far as it would go, again see the photo of the lens on the right. I expected distant objects to be in focus, and they are not. Is this a problem, or expected?
http://www.butterpeanut.com/canong3/02_70mm_manSM.jpg
I thought I could try the same at 17mm and this shot was taken in auto focus, with the distant buildings as the focus point, and again, notice the position of the focus ring.
http://www.butterpeanut.com/canong3/03_17mm_autoSM.jpg
Last example, taken at 17mm and manually focussed, but again I pushed the fucus ring all the way as far as it would go. Again the distant buildings are slightly out of focus or soft. Expected or not?
http://www.butterpeanut.com/canong3/04_17mm_manSM.jpg
Is this normal and expected to have distant objects go out of focus when you push the focus ring as far as it will go, i.e. passed the infinity marking? My expectation was that distant structures etc. would still be sharp.
Please note that I am in no way 'bad mouthing' or critising this lens, I am just curious if it is meant to be blurred after you push the focus ring past infinity. Maybe it is a normality of all lenses that I just did not know about. You kind reponses and sympathy for my lack of 'hands on' knowledge appreciated : )
Andrew
i got this lens the other day. happy with it so far and it performs just as I expected it to : )
this is my problem though.
Either: i am not sure what 'infinity' is 'meant' to do on a camera focus ring, OR, the 'infinity' lens is not doing what I expect it to. I thought instead of assuming, I would ask the helpful people on this forum.
well, i know what 'infinity' does, but what if you turn the ring slightly passed the 'infinity' mark? is it meant to keep distant objects in sharp focus still or blur them slightly?
the best thing to do is to illustrate with a few pictures (all taken AV at f8.0):
1st picture is taken at 70mm and on 'auto' focus, with the background building set to be target for focus lock. Note the position of the fosus ring to the right of the picture:
http://www.butterpeanut.com/canong3/01_70mm_autoSM.jpg
Nest I took a shot at 70mm and 'manually' focussed, but i pushed the focus ring all the way as far as it would go, again see the photo of the lens on the right. I expected distant objects to be in focus, and they are not. Is this a problem, or expected?
http://www.butterpeanut.com/canong3/02_70mm_manSM.jpg
I thought I could try the same at 17mm and this shot was taken in auto focus, with the distant buildings as the focus point, and again, notice the position of the focus ring.
http://www.butterpeanut.com/canong3/03_17mm_autoSM.jpg
Last example, taken at 17mm and manually focussed, but again I pushed the fucus ring all the way as far as it would go. Again the distant buildings are slightly out of focus or soft. Expected or not?
http://www.butterpeanut.com/canong3/04_17mm_manSM.jpg
Is this normal and expected to have distant objects go out of focus when you push the focus ring as far as it will go, i.e. passed the infinity marking? My expectation was that distant structures etc. would still be sharp.
Please note that I am in no way 'bad mouthing' or critising this lens, I am just curious if it is meant to be blurred after you push the focus ring past infinity. Maybe it is a normality of all lenses that I just did not know about. You kind reponses and sympathy for my lack of 'hands on' knowledge appreciated : )
Andrew