50mm 1.2L with FoCal accurate?

Started Apr 21, 2013 | Discussions thread
carnac Regular Member • Posts: 433
Re: 50mm 1.2L with FoCal accurate?

I have the Canon 50mm 1.2L. I have used FoCal on the lens with success.

The 50L has focus shift. It is inherent in the design. New or old, this lens design has focus shift. It has never been a problem for me because; the focus sift occurs between around f2 to f2.8 near min-focusing distance. Below f2 the aperture change is small enough that the focus does not shift and above 2.8 the depth of field gets large enough to make focus shift unnoticeable. I shoot wide open most of the time.

FoCal will help you set a good micro focus adjustment, and that makes a great lens even better. Plus if you are dead on with the focus, a slight shift may remain within the depth of field resulting in a still sharp photo.

If you use FoCal, make sure you follow the directions closely, set-up with LOTS of light, and use 50x the focal length as your adjustment distance (50 x 50mm = 2500mm (2.5 meters, or about 8.2 feet).

You can also try the "dot tune" method that is popular over on the Fred Miranda forum (free, no software needed):


They have a good video describing the procedure at the above link.

-- hide signature --

Jim 'Carnac' Carnahan

 carnac's gear list:carnac's gear list
Canon EOS 5D Mark II Canon EF 50mm f/1.2L USM Canon EF 16-35mm F2.8L II USM Canon EF 24-70mm f/2.8L USM Canon EF 100mm f/2.8L Macro IS USM +4 more
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow