I'm looking to get a Pentax MZ-50 (or ZX-50, if you're in the 'States) and will mainly be using it for ultra-low light work - like ISO 6400 low light. Since my fastest lenses are all K's, I need to know if it can meter with it.
I was wondering if it's as easy to use M or K lenses on the MZ-50 as it is with my K100D. In other words, I understand it's a crippled mount, but can you stop-down to meter by pressing the AE-Lock button in Manual mode, like with the K100D?
Also, how hard is it to set the ISO manually? DX coding only goes to 3200, so there's a problem. Manually underexposing each shot by a stop is just too much effort for me

(I will be using Delta 3200 in it.)
I know, I know, I should get an MZ-S, MZ-7, MZ-6, PZ-1p, but I know where I can get an MZ-50 for cheap now...
Thanks.