Zooms in the M42 era weren't very commonplace and those that were made tended to be telephoto rather than wide / normal lengths. There are a couple out there but they tend to be rather bulky so I'm not sure you'll find one that fits inside his case I'm afraid.

The closest thing to matching your needs that I'm aware of would be one of these: link which, by the time the auction finishes, I'd expect to fetch around the £20-mark.

Good luck!

That's because you live in Manchester.

That's because you live in Manchester.

Actually, one of the advantages of the UK / Northern European climate is that fungal infections in lenses are quite rare. I have all sorts of old lenses pass through my hands, some of which are 40, 50 (or more) years old and kept in appalling conditions yet very few have any sign of fungus in them. Those that do often have other signs of water damage suggesting they've been used in the rain (or dunked in a puddle) before being sealed in a dark stuffy camera bag and allowed to fester.

You are correct.

You'll need to set the ISO and aperture values on the camera manually to match those on the flash, then let the flash do the light measurement. If you want to have the camera take care of the exposure then you'll need to invest in a more modern gun capable of P-TTL operation.

I think the idea's sound but the pricing a little on the high side. Still, if it's anything like my Ricoh GR-D then it will be a well thought out design with superb ergonomics and top-notch glass. I'd quite like to try one with the 50mm lens and the APS-C sensor, I'm betting it would be a pretty sweet set-up.

Remove the cap and expose them to bright sun if you can. Just be careful what's behind the lens as it will focus the rays like a magnifying glass and if there's paper / dry leaves / etc behind then you could easily have a fire on your hands.

Exposure to direct sunlight is only bad for lenses if you're trying to take a picture at the time as it leads to flare, it shouldn't cause any damage to them though.

Some excellent tips above, I'll just add:

It's very sensible. Sunlight contains UV rays which, as pointed out, will kill the spores. Regular blasts of sun will do your lenses many favours.

It shouldn't damage the K100D but you'll be restricted to Auto or Manual use as the K100D doesn't support TTL (just P-TTL).

I don't have either at the moment, but many such things pass through my hands so I'll keep you in mind if either filter or cap turn up.

I use two 1.5v LR44 batteries and haven't tried it with a single 3v (and I don't have one to hand), but I'd imagine the results are more-or-less the same.

As for the angle of the meter, again I don't know for sure but the results are broadly comparable to my K10D when set to centre-weighted. I've never felt the need for a seperate meter with my MX and I've had excellent results from slide film, hence I don't tend to think about it - just trust the camera and it usually gets it right.

Somewhere dry, well aired and not too hot or too cold. Preferably with occasional exposure to daylight too.

In fact lenses like the same sorts of conditions humans do, which makes sensible storage quite easy.