Archived posting to the Leica Users Group, 2014/03/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]It, like most lenses, is not noted for having any ;-) john ________________________________________ Hi Peter, I don't have the CV 1.2/35mm anymore. My main lens on the M8 is the 2.5/35mm Leica, and I have not noticed any focus shift with it. But as I said, maybe I am just not looking for it. I don't doubt that the phenomenon exist; I am just saying that it does not seem to be relevant for the kind of photography I do. Cheers, Nathan Nathan Wajsman On Mar 13, 2014, at 9:36 PM, Peter Klein wrote: > 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 >