Archived posting to the Leica Users Group, 2014/03/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Nathan: All lenses have focus shift, but some more than others. The original 35/1.4 ASPH without the floating elements is one, and it is my principal lens on my M8. At f/1.4 and f/2, the RF is accurate. At f/2.8-5.6, the actual point of focus is a bit behind where the RF says it is. At f/8 and smaller, the DOF covers things. I confirmed this with testing, but it was pretty apparent without testing. So if I want to shoot it at f/2.8-5.6, I focus a little closer than I actually want. It bothers me to have to do it, but the lens is so good otherwise that I put up with it. IIRC, you are using the Voigtlander 35/1.2 on your M8. That lens handles focus shift in a very sneaky way. As you stop down, the actual focus point oscillates back and forth around the point the RF is focused on, but only very slightly. You can see it if you pixel peep, but not in real life. When I first tested my 35/1.2 on the M8, I did pixel peep, and I couldn't believe my eyes. I repeated the tests, same results. So I asked Erwin Puts about it. He confirmed my observations. Erwin said that what the Cosina designers did is a less expensive way of minimizing focus shift, but that Leica would never do it that way, because there are some other optical drawbacks to it (I think involving contrast). So for all practical purposes, your normal M8 lens doesn't have focus shift. So you don't notice it. :-) --Peter > I have never seen any focus shift on my M8 with any of my lenses. Perhaps I > don't know what to look for. Heck, I just take pictures. > > Cheers, > Nathan > > Nathan Wajsman > Alicante, Spain > http://www.frozenlight.eu > http://www.greatpix.eu > PICTURE OF THE WEEK: http://www.fotocycle.dk/paws > Blog: http://nathansmusings.wordpress.com/ > > YNWA