no focus shift on the rollei 40?

[back alley]

common thought is that sonnars, all sonnars, have some focus shift...but i have never heard any comment to that point being made about the rollei 40/2.8 lens.
i have that lens and have never experienced any noticable focus shift...am i missing it or is there no focus shift?

anyone know for sure?

 

[maddoc]

I don`t know for sure but the Rollei Sonnar 40/2.8 has a maximum aperture of f/2.8 at 40 mm focal length and then I would expect that any focus shift (if existent) is already covered by the depth-of-field.

I had this lens and have never detected any focus shift with my copy of the lens and on film.

 

[Palaeoboy]

The lens at first was suspected of having focus shift when it came out however it turned out a number of examples had their focus adjusted wrong in the factory. (They were front focusing if I remember correctly). My example was one of them. It was noticeable at shorter focusing distances. There was some discussion about this when they first come out but not sure if it was this forum or not. Once adjusted it focuses fine.

 

[back alley]

so would the rollei be an atypical sonnar?

 

[Palaeoboy]

I haven't tried alot of different Sonnars to say for sure, they do share a smooth look that's hard to quantify but the ones I have tried each had a character all their own. So apart from all being good lenses they are all atypical to me LOL Strangely though in my 40mm collection the 40mm Sonnar is the lens I have most of because of all the Rollei 35's. Interestingly to me early and late 40mm Sonnar seem to have a different character to them as well and technically they are virtually the same lens. It shows the influence of new glass types and coatings can help a lens evolve.

 

[Richard G]

I got one off the auction site. It back focusses by a couple of centimetres rather than has focus shift. And it might do this more with my Leitz 50mm adapter than with the supplied 35mm adapter, if there's any sense in that. I have only tested this at minimum focus distance. I'm used to the C Sonnar focus shift so this is not a deal-breaker, but it is annoying. As is the rough focus in what looks like an unused lens.

 

[zuikologist]

I agree about the rough focus, it feels like some of the CV lenses when their lubrication has dried out.

In my experience, the maxim7m aperture is small enough and the lens wide enough that focus shift (if any) is nothing to worry about in normal use.