Saving Pentax-M

I’ve just spent pretty much the entire day restoring a Pentax-M 50mm f/1.7.

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Fungus-free!
I not able to do much moving about at the moment and so, rather than mope around and feel sorry for myself all weekend, I thought I’d spend an hour or two doing this. Lesson number one: estimate the time required to clean and restore a lens as bad as this was and then multiply it by three.

The lens arrived this morning from a well-known auction site and my expectations were fairly low from the start; it was at a buy-now price which was about half that of most others, with no real description to speak of and no way to see close detail from pictures. This was a cheap gamble and I was expecting to do some work on it, but I wasn’t quite prepared for the state of the thing when I examined it. Not that it needed close examination to see that it was completely infested with fungus – the worst I’d ever seen.

The outside barrel wasn’t too bad; a little grubby but easily cleaned. The elements, though, looked completely stuffed. Just about every glass surface inside and out was covered in masses of threads and patches of mould. Nasty! I’ve had success at cleaning fungus from elements before but I have to say I was close to giving up on this as it was so badly affected throughout. Pretty much unusable, optically.

OK, so it may take more than an hour, I thought. More than two, even. All in all, it took about six hours! Was it worth all that time, considering price difference between this one and a good one? Well, yes and no but I favour the “yes” because it gave me a project to do whilst unable to go out and, more importantly, I have saved a now-decent lens from the scrapheap. Make do and mend!

Often, it’s said that fungal infestation of lens elements is the end for them: the fungus etches into the coatings and, sometimes, the glass itself, causing irreparable damage. Up to now, though, I’ve been lucky as I’ve been able eliminate fungus on a few old lenses without leaving much permanent damage, if any at all. This lens turned out to be no exception but it’s been the most laborious lens-fix I’ve ever done, without any mechanical fixes, even, as everything mechanical worked perfectly. It was necessary to separate all of the individual elements and clean all surfaces which is very, very difficult to do because, even with fungus all gone, getting truly crystal-clear cleaning results on internal surfaces, without any smears whatsoever, takes a lot of time and patience. Still, time is what I’ve had and it did pay off in the end. Lesson number two: do not use a blower bulb with a metal end too close to an internal surface because one small slip could result in a permanent coating mark. Doh! Thankfully tiny and won’t affect anything but still, a swear-inducing moment.

I wish I’d taken a “before” picture but I honesly didn’t think I could salvage it so didn’t bother. Believe me, it was horrendous! Here it is again, in its fully restored state (I restored the filter, too, which was also in a very sorry, mouldy state but it’s a nice Hoya one so worth saving. I had to take the glass out of the frame to clean everything but all’s well and clear with that now, too):

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When elements and groups are taken apart and re-assembled it’s always a good idea to check for any misplacement or decentring as a tiny amount of misplacement of any individual element can have profound optical consequences. I’m glad to say all is well, wide-open and at high magnification (digital test). I replaced the front name ring and cleaned the barrel exterior thoroughly.

One clean and clear lens to add to the collection, and a very good one at that. I could now sell it for twice the amount I paid but it’s definitely a keeper.

The Praktica BCX project

IMG_0082.JPGAs if I needed another camera, not least one from 1983. I found myself staring at this one a few days ago, in what can only be described as a film camera and photography museum which also happens to be a shop. Wall to wall cameras, lenses, darkroom equipment, accessories – everything from Rollei to Zenith, large format to miniature, most things being decades old. So, what’s so special about the Praktica BCX 35mm SLR?

I almost owned one back in 1984/85. At the time I was using a Praktica MTL3, which I was happy with, yet I secretly longed for something more sophisticated. Alas, I was still at school and such things seemed to be out of my reach. That was, until I saw a fellow pupil come in one day to take some pics of us preparing for the school play – and he was holding one of these. It was the first time I’d seen, or even been aware of, the Praktica B series and it immediately grabbed my attention. Nice camera, I thought: aperture priority as well as manual control, better handling, considerably smaller than my tank-like MTL3 (it really is small, even by today’s standards) and, relatively speaking, affordable. These were the days of pre-unified Germany, of course; Prakticas, made in what was then East Germany (DDR), were generally cheaper than their Japanese equivalents – if not apparently as reliable.

I needed one. I needed to have aperture priority auto, not to mention the word “electronic” stamped onto the front. My mission was to sell the MTL3 with all its lenses and get one of these with just a 50mm prime. I ended up with a close relative of the BCX, in black, as the BCX was no longer available new. I was really happy until the shutter jammed some time later, whereupon it went back for a refund and I switched brands. How fickle.

So, the BCX, in chrome, is the subject of a very vivid recollection from my youth even though I have never actually owned this model. B series cameras in chrome finish were and still are relatively rare and so I had to have a look at it in the shop; it turned out to be so cheap that I bought it, figuring that it’d be an interesting project with nothing to lose if it ended up as useful as a paperweight.

That’s the justification out of the way – now for the list of problems. It had:

  • a very loose flash hot-shoe
  • a loose self-timer lever
  • a sticking wind-on making it impossible to fire the shutter sometimes
  • masses of dust inside the viewfinder
  • a dirty mirror
  • a mirror foam buffer that had disintegrated into powder and sticky goo

and it was generally a bit grubby. What’s more, the lens had some haze on an internal element which needed to be cleaned, otherwise it would flare horribly and contrast would be unacceptably low.

I’ve replaced mirror foam buffers in other cameras so that was relatively easy. The hard part was cleaning the mirror of general dirt but also sticky, decomposed foam from the original buffer. The mirror in every SLR, film or digital, is extremely fragile and I have found the best thing to do, if it’s absolutely necessary to clean it by contact, is to treat it a little like a digital camera sensor and use sensor swabs with light breathing – no fluid! – and very light, full downward swipes. It’s now looking as good as new.

The sticking wind-on meant removal of the base plate. It’s just four tiny screws. It took me some time to figure out what was sticking and, finally, some light grease saved the day, applied to and around the semi-toothed wheel which is attached to the motor drive coupling. Now the mechanism will spring back, as it should, following wind-on so that the shutter can be fired.

The dust inside the viewfinder meant taking off the top plate. I could have left it but it bugged me so much that I had to give it a go. It’s not too difficult but I’ll make it a bit easier, for anyone with a B series who might be contemplating this, by outlining the steps here (for my own benefit, too!). Firstly, unscrew the film rewind lever by holding the rewind arm still from within the film chamber and rotating the lever anti-clockwise. Then, remove the slotted collar which goes around the rewind arm from the top but do not undo the two screws either side. (The slotted collar is meant to be undone with a special tool but I used small screwdrivers and a small hammer to gently tap and loosen it.) The film speed unit will then lift out, leaving the empty housing ring which is attached with three small screws. Undo these and lift off the ring. Moving on to the wind-on lever now, remove the plastic cover by turning the camera upside-down and undoing the screw which holds it in place. The metal lever itself can now be removed by undoing the small nut; lift the lever off and keep the nut and washer safe together. There is another slotted collar to remove here, around the wind-on (mine was actually already loose!). Next, remove the flash shoe by first lifting the sprung “x” plate at the front, using a small screwdriver, and sliding off to reveal four screws; undo only the rear two screws since the front two secure the flash shoe to the top plate but not the plate to the camera *. Finally, remove the four screws directly holding the plate to the body and it should be possible to lift the plate up and away. In particular, note that the shutter speed dial and shutter button remain attached as part of the top plate – but watch out for the remote release pin which may fall out of the shutter button assembly from underneath.

Getting inside the viewfinder is then a case of removing the four screws holding on the outer eyepiece unit. I have no idea how quite so much crud had found its way inside there but it was a very satisfying job cleaning it all out.

Refitting is the reverse procedure, making sure the shutter speed dial is set to the same as it was when the plate was taken off, so that the pin underneath is in the right place to register.

Tightening the flash hot-shoe and the self-timer lever is a case of tightening the screws and another slotted collar, respectively. Testing shows the camera to be mechanically and electronically sound.

All that was left was the lens: a third version (I believe) PB mount Pentacon 50mm f/1.8. It was cheap enough to be almost disposable, so I set to work not really knowing how to open it up. I have dismantled and cleaned/fixed several Nikon lenses in the past but, unfortunately, this one had no visibly obvious means of getting inside. Once I’d popped off the plastic collar surrounding the rear element, though, it all became clear: screws to hold on the metal mount, then screws to hold the aperture ring assembly to the main housing, then more screws holding the two halves (separated by the aperture blades) of the optical set together. I could already see from the outside that the haze was on just the surface directly in front of the aperture blades and, luckily, the optical set came apart pretty easily to reveal this surface. The haze came away without too much of a problem but getting it all dust-free after cleaning was another matter, especially as each time I went near it I risked trashing the loose, flimsy aperture blades. I’ve been there before, though, and so, with the required patience, the result is a lens that’s now crystal clear right through. If the aperture blades had been sticking (a problem that’s not uncommon in older lenses) then it’d be the same procedure to get at them to clean.

There. I have a “new”, fully working, clean camera with a standard lens for peanuts; a vintage but totally functional compact SLR from a time when the Berlin Wall was very much intact and the thought of The Hoff singing his freedom song, as the wall fell, would have been completely ludicrous. I guess it still is.

* I’ve since taken apart a BC1 which I won for virtually nothing on eBay because it came with a lens I was after. The BC1 is slightly different in that all four screws of the flash shoe must be removed in order to release the top plate (which is plastic – as opposed to the BCX’s metal** top plate!).

** Metal? It certainly appears to be so but may not be, after all – well, not completely, anyway. There’s evidence to suggest it may be a plastic shell with metal coating. See comments for details.