Greetings, i'm using a Nikon F5 film SLR body with brand new Sigma 50mm 1.4 Art.
The problem is autofocus - in AF-S mode the autofocus is quite slow, loud, and a gentle vibration comes from the lens with a slight scratching sound, in the end it usually nails the focus but it takes it's time with quite a lot of searching. AF-C is virtually unusable, it searches in long slow steps, and when it locks it re-searches often, rendering this function completely useless. So at first i thought perhaps the lens is faulty, but when I tried it with my D3100, the lens worked perfectly, AF is quiet, fast and accurate, both in AF-S and AF-C modes. So i turned my attention to F5 camera body, however when i mounted practically any Nikkor lens AF function was also perfect in all AF modes. Then i thought perhaps the problem is the fact that F5 is an old camera while the lens is brand new so this difference in age is somehow making this combo incompatible - i went to look on Sigmas official web page where it clearly states: "...Sigma's HSM lenses have full compatibility with F5, F4 series, F100, F90/N90, F90X/N90S, F80/N80 F70/N70, u/F65/N65,Pronea 600 and Pronea S..." ( http://www.sigma-imaging-uk.com/index.php route=information/information&information_id=21).
I also tried another Sigma lens (the 24-105 HSM) and that lens too works perfectly. Then i went to local Sigma distributer and asked to try another sample of Sigma 50 Art, and that other sample also had AF issues of the exactly same type. So, it seems that my F5 works with almost any lens except Sigma 50 Art, and i cannot for the love of God figure out what is going on. If any of you have had simmilar issues or have any idea what might be the cause of my problems, i would GREATLY appreciate your help. The lens is apart from this problem optically flawless, and i would hate to be forced to sell it.
Thank you !
The problem is autofocus - in AF-S mode the autofocus is quite slow, loud, and a gentle vibration comes from the lens with a slight scratching sound, in the end it usually nails the focus but it takes it's time with quite a lot of searching. AF-C is virtually unusable, it searches in long slow steps, and when it locks it re-searches often, rendering this function completely useless. So at first i thought perhaps the lens is faulty, but when I tried it with my D3100, the lens worked perfectly, AF is quiet, fast and accurate, both in AF-S and AF-C modes. So i turned my attention to F5 camera body, however when i mounted practically any Nikkor lens AF function was also perfect in all AF modes. Then i thought perhaps the problem is the fact that F5 is an old camera while the lens is brand new so this difference in age is somehow making this combo incompatible - i went to look on Sigmas official web page where it clearly states: "...Sigma's HSM lenses have full compatibility with F5, F4 series, F100, F90/N90, F90X/N90S, F80/N80 F70/N70, u/F65/N65,Pronea 600 and Pronea S..." ( http://www.sigma-imaging-uk.com/index.php route=information/information&information_id=21).
I also tried another Sigma lens (the 24-105 HSM) and that lens too works perfectly. Then i went to local Sigma distributer and asked to try another sample of Sigma 50 Art, and that other sample also had AF issues of the exactly same type. So, it seems that my F5 works with almost any lens except Sigma 50 Art, and i cannot for the love of God figure out what is going on. If any of you have had simmilar issues or have any idea what might be the cause of my problems, i would GREATLY appreciate your help. The lens is apart from this problem optically flawless, and i would hate to be forced to sell it.
Thank you !
