Rollei 35 SLR mounts

[xjjohnno]

What kind of butchery is required if any to make a Rollei bayonet mount lens usable on a Pentax mount?

[ryan s]

Seems like the Rolleiflex SL35 is the series?

If so...you would have to make a really thin adapter since its register length is 44mm vs 45.46 of Pentax otherwise you won't have infinity focus.

Converting lenses really depends on the lens itself. Some have a mount screwed on to a tube...some mounts ARE the tube and can't be removed. Then others require the aperture to be held open by the mount so you'd have to work around that.

Get a cheap lens, a cheap flanged M42 adapter or a cheap K bayonet and try it out.

[xjjohnno]

Cheap flanged adapters I have already. It looks like I'll need to use the depth gauge on my verniers before I do any disassembly so I know what shimming I'll need to compensate for the different registers.

[ryan s]

I've heard some say that certain Minolta lenses just have a really thin mount on them and can be converted easily and then have the focus adjusted with no real pain involved...you might be able to get lucky with these (I can hope).

Keep us posted...I'm curious to see what happens

[georgweb]

John,
which lens do you want to convert?
Onto which camera?

Here's a Rollei on Pentax:

stolen from here: Adaptation d'objectifs via des bagues [Topic Unique] - Page : 10 - Objectifs - Photo numérique - FORUM HardWare.fr

French text says it's hard to convert, cause the backplate is one single milled piece.

You gotta make up for 0.9mm less for Pentax to reach infinity (Lens mount - Wikipedia, the free encyclopedia)

Most Rollei mount lenses have also been produced in M42.

Best, Georg (the other)

[xjjohnno]

It's the Planar 50mm f1.8, yet to be bought George. It's a bayonet mount as seen in it's ad. Naturally before I commit myself to a buy I'm doing the research for converting it. From the photos if I remember correctly the bayonet section is held on by three screws and might be a seperate plate and a little different to the mount you pictured here.

[georgweb]

Aha, good to know. The mount you see on the lensback of the separate lens is not the Rollei mount. Looks like a flanged-adapter PK conversion.

FWIW, the Rollei HFT Planar 1.8/50 should be something like 10 dollars really. It is the same lens as the older 'Carl Zeiss' version like on the camera on the photo, same lens as 'Voigtländer Color Ultron'. The latter two are available also in M42 mount. Then they are suddenly valued 100 dollars (speaking strictly market prices here and only 'made in Singapore' versions).

The Y/C Contax Planar 1.7/50 is something like the follow-up of this lens, behaves very similar, better coating probably. I'd go with this one, rather easy conversion. But hey, the 1.8/55 S-M-C Takumar can do magic too.

More on the different conversions here, Converting 'other' lenses to Pentax
Best, Georg (the other)

[xjjohnno]

Thanks for the extra info George, the price you mentioned is about what I was looking at paying. The super Takumar 55mm f1.8s here tend to usually come with Spotmatics.