Archived posting to the Leica Users Group, 2012/02/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hmmm. Sounds like the 90AA needed a custom cam grind. I'm thinking that it would be an expensive custom operation. Vick On 2/2/2012 9:11 PM, Henning Wulff wrote: > Marty, > > This is not a focus shift issue as in - it shifts plane of focus as it is > stopped down. This is an issue as in - it focusses accurately at one > distance, but not at another, all at the same aperture. The 90AA exhibits > very little focus shift, as stopping it down doesn't change the plane of > focus much at all, at any distance. > > The problem with mine, and I believe Howard's, was that the cam did not > follow the focus properly. If the lens focussed properly at infinity, it > was off at 10m and then on again at 3m. Not very user friendly. I too now > have some other 90 options which work better. > > In a related vein, the 75 Summilux exhibits focus shift in the traditional > manner, but at f/2.8 it is off the intended focus plane by the same > proportional amount at every distance, and I have learned to compensate. I > can use it very well, and have a high degree of confidence in it. > > Henning > >