You need to turn the aperture ring all the way to the right (smallest aperture), then press the button next to the A and turn it a little further. You have to press the button before you can put it into or out of A mode.

Mine came from the states and cost £15, most of which was postage!

Currently attached to the bottom of my mint MZ-50, which I plan to hang onto as I suspect really nice examples may become rare.

I just managed to bag a K 85-210mm f4.5, looks mint in the photos and has original case!

Hope it's as good as it looks, will post photos and sample images when it turns up.

Regarding the Battery Grip FG, there is currently a brand new one listed in the UK for £9 with free postage, I'd suggest pouncing if you can spare the cash and definitely plan to buy an MZ-series body.

I've also had blots that look like tiny spiders on internal elements - I wasn't sure whether these were dust or fungus, but as I suspected the latter the lens is currently being professionally cleaned.

I also think that the single-digit MZ series have the contacts for Power Zoom? However, they only seem to support two of the power zoom modes - using the motor to zoom and retracting the lens when you switch off.

I'm actually quite tempted to buy a Z series body and a power zoom lens, as I fancy having a play with the system. Just keeping my eye on ebay for a cheap one.

AFAIK the single-digit MZ series (as in MZ-5, MZ-7) are higher spec than the double digit ones (as in MZ-50). The MZ-M is manual focus.

Keep an eye on MZ-60s, some of them were sold with a 28-90mm zoom which is a pretty handy performer and the camera was intended as a premium amateur model.

Try not to buy the 35-80mm lens (F or FA versions - same lens with different casing) as it's not especially well regarded. I have one but it hasn't seen much use as it just doesn't match the colours and contrast of my other lenses. I paid £10 for it attached to a mint MZ-50, any more and I wouldn't have been happy!

MZ-50s can expire with a cracked drive cog, usual symptom is that the thing just whirrs when you put batteries in and switch on, it also ignores any buttons.

My lenses all live in Lowepro lens cases with a bag of silica gel each, they do come out fairly often so air does circulate. Then again, it's a fairly steady temperature in my house and also pretty dry.

If I've taken gear out in damp or cold weather I do let it warm up and dry out first - for example, after photographing the moon recently I left my camera on the tripod in the living room for an hour or so to make sure any condensation had cleared.

Your 50mm shouldn't be too hard to clean, I've dealt with two f2s and an f1.7 with the same problem. All you need are cotton buds, vinegar, lens cleaning fluid, a microfibre cloth and obviously the tools to open the lens with. After finding the mould, dip a cotton bud in vinegar and use it to clean the element. When that dries, clean with lens cleaner on a clean bud and brush away any dust with the cloth before reassembling.

The main location for mould in 50mm lenses seems to be on the rear element of the front group or the front element of the rear group, so you don't need to take much apart to get to it. Simply unscrew the finishing ring and then unscrew the front element group. When replacing them, just do it up slightly more than finger tight.

I mainly bought the HP5 because it was cheap for a 36 exposure roll! I've since bought more because it works very well and seems to tolerate my home processing using the kitchen clock to time the various stages.

I buy Ilford HP5 400 for my black and white needs, it seems to be decent stuff and not too grainy.