I know that if you put a 10-stop filter on a lens, you won't be able to see anything through the viewfinder, so the proper way to use it is compose and then attach the filter. I would like to use a 10-stop filter on an 18-55 lens on my D5100, whose filter thread rotates as it focuses. Will the D5100 with 18-55 be able to autofocus through the 10-stop filter? If not, how would I be able to attach the filter after focusing without changing the focus? (Note that the focus lock on the 18-55 is not very secure and can still shift slightly.)
#1. "RE: AF with 10-stop ND filter" | In response to Reply # 0jec6613 Registered since 12th Feb 2013Mon 18-Feb-13 07:01 PM
It would have to be very bright light for AF to work through a 10 stop filter, and I'm sure it would only work with the center point and probably not lock. You should also use the AF-On function for AF in either case.
I see two easy options here: (1) first, stop the lens down some so if you knock it off focus slightly, it won't matter as much. Since you're using a 10 stop ND filter on a D5100 with kit lens, you should be stopped down to at about f/7.1 anyway (I you wanted DoF isolation, you need a faster lens anyway, and beyond about f/7.1 or f/8 you may run into diffraction). (2) Second, there are filter adapters that you screw into the lens, and allow you to snap your filter onto the lens magnetically, rather than screwing it on.
#2. "RE: AF with 10-stop ND filter" | In response to Reply # 0briantilley Nikonian since 26th Jan 2003Mon 18-Feb-13 07:49 PM | edited Mon 18-Feb-13 07:50 PM by briantilley
I think it's very unlikely that you'd get AF through a 10-stop filter.
One solution would be to use something like the HiTech Pro Stopper 10 filter, which is designed to fit the Cokin square filter holders. Then you can leave the holder attached to the lens and slide the filter in and out without disturbing focus
#3. "RE: AF with 10-stop ND filter" | In response to Reply # 0JonK Nikonian since 03rd Jul 2004Mon 18-Feb-13 11:02 PM
You could also get a variable neutral density filter. After you focus, you dial in the amount of neutral density desired. Two drawbacks: I don't think they do to ten stops (mine does eight) and they are pricy.
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