Pentacon MC Prakticar 2.8/135 Nikon conversion

[iangreenhalgh1]

I happened to have a spare copy of this lens so I converted it to Nikon F mount, which was pretty easy, hits infinity and works very well.

Dull, gray day, just some mundane test pics on my D50 to check it works, No PP.

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[Lloydy]

I thin you might be liking this lens ?

[skida]

Impressive!

[iangreenhalgh1]

Yeah, I like this one, it's a good copy, I've had three or four of these PB mount ones and they vary in quality, I kept this one because it was good, although as all my Praktica bodies bit the dust, it never got used. Conversion was rather simple, required a little bit of work with the bench grinder and some epoxy, looks pretty neat when done. Nikon-M42 adapter to form the new mount cost 1.08ukp on a slow boat from China. Being a pauper it was preferable to repurpose this old lens than buy a Nikkor 135.

I've converted a Pentacon 2.8/28 in the same way but it's proving a little problematic to get it to hit infinity, I might have failed on this one by just a fraction.

[Basilisk]

Nice idea. These lenses can be excellent with plenty of smooth bokeh. Mine has a sticky aperture and still finds service on my Spotmatic F, otherwise I might give it a go!
Can we see your conversion?

[iangreenhalgh1]

Sure, I'll take some pics of it, looks quite neat I think.

[iangreenhalgh1]

Here she is:

[Basilisk]

[iangreenhalgh1]

It would work, I tried it on my 35mm film Nikon and it clears the mirror. That back part is just a hollow metal tube so I could shorten it to be flush anyways.

That's the advantage of that long 46.5mm register on a Nikon - loads of space for crap to hang out the back of the lens without hitting the mirror.

I have also converted a Pentacon 2.8/28 but at infinity, the rear does hit the mirror, so today I ground it down on the bench grinder tomorrow I'll see if I removed enough metal.

I'm not a fan of DIY lens hacking as it's easy to destroy the lens, but I had a Nikon I needed to use, no lenses to fit it, no money to buy any and a bunch of spare lenses of low value so I gave it a go.

Next I need to convert a 50 to fit, a Helios 44-2 is looking a likely candidate.

[Basilisk]

[iangreenhalgh1]

I'll let you know how I get n with the 44-2 conversion. There's plenty of spare room at the back to remove metal so it should be possible.

[philslizzy]

The 44-2 should be simple enough. Plenty to take away at the back end and you can take out the whole optical block while yer doing the job.

[iangreenhalgh1]

I decided to convert an Exakta Tessar 2.8/50 instead. Took a couple of hours with the hacksaw and emery paper, worked out nicely, I'll post some samples tomorrow as it's raining now.

Sadly, the Pentacon 2.8/28 conversion has been a failure, I removed the rear optical block and ground down the metal protrusion at the back so it missed the mirror, that was successful, mirror clears it, but now the images are distinctly soft at all distances, so it's ruined. Oh well, it was a junk copy anyways so no loss.

Now I have 24, 28, 35, 50 and 135mm lenses for the D50. That should be all I need, and my total cost was about a fiver.

[Orio]

Seems good Ian, clever conversion work.

[iangreenhalgh1]

Cheers Orio. It was a really simple conversion, and I knew I really liked this lens before I started, so I'm pleased to be able to use it. Of course, I could use it on my NEX, but I must have another ten 135mms that will fit my NEX.

What it boils down to is a poor man has to use his head rather than his wallet.

[Basilisk]

[Pancolart]

Splendid work Ian. And it truly seems good copy, no Chroma aberrations to be noticed.

[iangreenhalgh1]

Cheers. I have had two other copies that were less good.

There is a tiny, tiny bit of CA present on out of focus areas, the usual green behind the focus plane and red in front of it, but you have to look hard for it. These shots were taken in very dull, very flat gray light, so in strong direct sunlight there may be a little more CA visible, but it doesn't worry me, the strengths of the lens will outshine any such issues.