ALPA (not Alpha) lenses on the A7

[f/otographer]

Does anyone have experience using Alpa bayonet lenses on the A7? Some wonderful and very esoteric lenses were made for this system back in the day. It has peaked my interest due to the fairly short flange to focal distance of the Alpa mount. At only 37.8mm the FTF is shorter then the shortest Japanese SLR system which is Konica at 40.5mm. A shorter adapter will help the overall A7 package stay nice and small.

My concern is that the mount registration distance is getting so short that it is very close to some of the longer rangefinder distances where we know all kinds of corner and smearing issues can show up. For instance, the Contax RF register is 34.5mm.

Im wondering though if the lens designs for the Alpa system were more SLR like then Rangefinder like so this might help prevent bad corners and such.

And advice would be appreciated.

 

[Ben Rubinstein]

Can you tell me about their lenses? I've only ever heard of them as a name.

 

[f/otographer]

Im not familiar with much of the line Ben. I know that the Kern Macro Switar is supposed to be the best 50mm lens ever, beating out even the Summilux. All that is subjective of course and up to an individuals tastes. Examples I have seen from the lens online look very nice.

Alpa made some of their own lenses but many famous makers also supplied glass. Angenieux and Schnieder to name just a couple. Prices for many of the lenses are now in the 'esoteric' bracket. How they actually perform in real life I would like to see for myself.

 

[Ben Rubinstein]

The prices are certainly 'exotic'!

 

[brianc1959]

My concern is that the mount registration distance is getting so short that it is very close to some of the longer rangefinder distances where we know all kinds of corner and smearing issues can show up. For instance, the Contax RF register is 34.5mm.

FWIW, the smearing issues are related to the exit pupil distance. Exit pupil distance is unrelated to mount registration distance or to the BFL.

 

[Michiel Schierbeek]

I think Klaus and Hakkalo are your men.
You can ask Klaus in the M4/3 bokeh thread where he posts almost dayly.

 

[f/otographer]

FWIW, the smearing issues are related to the exit pupil distance. Exit pupil distance is unrelated to mount registration distance or to the BFL.

You are, of course, entirely right Brian. I had learned this some time back and completely forgotten about it. My bad.

 

[f/otographer]

I think Klaus and Hakkalo are your men.
You can ask Klaus in the M4/3 bokeh thread where he posts almost dayly.

Thanks for the head up Michiel. But I have just decided to stay with my ML glass instead of diving into such deep waters as Alpa and such. The lenses are just more then I want to spend. There are to many other great lenses that are much more budget friendly.

But the Kern Marcro Switar......mmmmm

 

[agfa100]

I have a GXR with the M module and use my kern macro switar 50mm f 1.9 on it. I forgot what a nice lens it is. This coming weekend I am going to do a shoot out with a friend that has the new 50mm Apo. Summicron. We know that his lens has more contrast then my Switar, but my lens was made back in 1967 so there is going to be some difference just in the coatings plus whatever type of glass Leica is using. Most don't know that Leica purchased Kern back around the mid 1980's to get their binocular contracts with the Swiss military, and when we compared the lens diagrams of both lenses they are close. So did Leica use the old Kern design as a starting point, who knows.
wbill