Iris Cleaning - The final chapter (I hope)

First Thanks to all who offered advise on my previous topic "Iris Cleaning".
I've now stripped and rebuilt the lens and am moderately happy with the results. The blades are not as "snappy" as I expected but moving freely at least. I suspect the return spring is a bit soft- not surpising after 40 odd years I suppose.

Despite Hefty's warnings about removing the blades this was imposed upon me when they all fell out so I simply picked them up with tweezers, put them into a small dish of surcical spirits whils I attended to the rest of the lens assy. After picking them out and leaving to dry on kitchen paper I found re-assembly fiddly but not too onerous, just as well because they fell out several times further. [Method-Set the aperture to 2.8 and proceed clockwise, gently easing the last one into place].

I was unable to disassemble the front and middle lens or the aperture setting ring, but they looked clean anyway (curiously there is a small red fibre between the lenses but it stayed at the edge no matter what I did.)

Because of the multistart thread I had to try several times to realign the scales (each time manging to dislodge the iris blades) but eventually everything went back together with a deligtful bonus - no bits left over.

Not wanting to wait for prints to come back I set the lens into a 7mm extention tube, using a 40mmx30mm brass washer to depress the auto pin and mounted the lens via a M42/K adapter on my K10D and took the following shots, the first at f2.8 and the 2nd at f8. :-

[IMG]http://i1236.photobucket.com/albums/ff444/Frogherder/IMGP5517a.jpg[/IMG]

[IMG]http://i1236.photobucket.com/albums/ff444/Frogherder/IMGP5518a.jpg[/IMG]

On my 15x12 screen they don't look the best in the world but I suppose good enough for 6x4 prints

Bernard

It sounds like a success to me! Domiplans always did have a very poor reputation for IQ (hence them being so cheap) so I think your results are very much in line with how the lens performed when it was new.

I bet your friend will be chuffed anyway.

Thanks again Hefty - At least it is actually working now. Not as well as I had hoped, but as you said I was a little puzzled by the tapered image particulary as I spent ages squaring everything up - I wonder if it's because I dropped out the back lens and haven't quite got it aligned - it fits in a hole about 1mm bigger than its mount and there's adjustment in the grub screws. I simply tried to centralise it

regards
Bernard

That is a possibility, but I wouldn't waste too much time trying to make a silk purse from a sow's ear if I were you - a Domiplan is never going to be winning awards for fidelity.

Assuming your friend's camera is an M42 mount then there are a couple of other lenses out there, that can be had for around £10, that would give much better IQ than the Domiplan. The first that springs to mind is the Helios-44 (Russian Biotar copy, supplied with various Zenit SLRs, 58mm f/2), the other is the Carl Zeiss Jena Tessar 50mm f/2.8 (usually one of the "budget" lenses on Praktica SLRs). For slightly more money (£15-20) he could have a Takumar 55mm f/1.8 or a Pentacon 50mm f/1.8.

If you're wondering what to buy him for Christmas this year then any of the above would work with his current body and offer a serious upgrade on the Domiplan.

That was the lens fitted to one of my first SLRs (a Pentax, but I can't remember the model). It was second hand in the early 70's as I recall and I took it everywhere. I only gave it away some years ago when I had a DSLR for my 60th as it was only collecting dust. I didn't think it was worth anything - little did I know.

I'll be taking the Domiplan back tonight - I'm reasonably sure he'll be happy with it - I'm equally sure that he would be most offended if I gave him a replacement lens, even for Christmas.

He has photos he took in Malaya (B&W - or rather faded brown and yelow). How he did it in a POW camp I'll never know as it's a subject he'll never discuss and Japanese cameras /lenses are an abhorance to him.

Sorry I'm getting maudlin.

regards
Bernard