Pentax MX Users

Hello there,

I'm new on here, but was intrigued by your MX battery-drain problem. I've used, with great pleasure, a Pentax MX since 1981, and never encountered this problem, however...

I recently (middle of last year) had my camera serviced and they (Harrow Technical) did a first-class job. I'm guessing they fitted a couple of new button-cells, but could be wrong. Anyway, I picked up my MX just before Xmas to take a few outdoor shots, and was dismayed to find the cells not only flat, but one had started leaking! I replaced both cells with a 3V lithium cell and all appears OK.

Bearing in mind the possibility of a fault, I measured the current to be 750 - 780uA, dependent on which LED was illuminated in the viewfinder - not sufficient, I wouldn't have thought, to drain the battery.

So... Is this Pentax MX battery-drain problem intermittent? What is the cause? I always lock off the shutter-cock when not in use, to prevent inadvertent battery drain. All advice appreciated.

According to Pentax instructions, Lithium cells are not suitable for the MX. As always of course they don't say why, but it could be either too high a voltage or heat generation problems.

The best option for the M series are Silver Oxide cells, and Alkaline ones if you can accept the shorter life span. 1 year at least for Silver, 6 months for alkaline.

Thanks for that, John. Perhaps the fault-current of a lithium cell is too great in the event of a short-cct, and might cause damage? I shall replace with the traditional silver-oxide cells soon. The lithium is 3V so I guess it isn't a voltage issue, as I believe the MX meter is regulated such that a change from 2.7 to 2.6V shouldn't affect the metering (gleaned from a quick glance through the service manual).

The bloke in the camera shop put me on to this lithium job; didn't mention anything about not being suitable, so I took him at his word!

Hi Neil! I have received from my Aunt-in-law the same Rig you have. How does it work? do you have any pictures you have taken with that MX?

Chris

The battery drain problem (as I understand it) is simply a mechanical linkage which occasionally jams and means the meter doesn't turn off. This will drain the batteries in about three days. There is a website which shows how to repair this (the link is on ths site somewhere).

If you aren't going to use an older camera for a while it is worth removing the batteries. Perhaps the most common problem with 'classic' cameras is corrosion in the battery compartment.

K.

The MX is an easy camera to use. It is all manual, the only thing the battery powers is the lightmeter. You simply adjust the aperture / shutter speed until you have a green light in the viewfinder. Amber lights are +/- 1/2 stop, red lights > +/- 1 stop. The meter has a centre-weighted lightmeter which is fine with print film, but will tend to under-expose a little bit with slide film if you are photographing a scene with sunny skies. Meter off the grass in those cases.

Best wishes, K.

Of course, one of the neatest parts of the MX is the fact that you can see aperture and shutter speed in the viewfinder.

I'm guessing that you already understand depth of field, as that's fairly crucial here (and will improve photos taken on any camera). I tend to use the scale on the lens rather than the preview lever, then set a suitable shutter speed (until you get a green light) and shoot.

If you need a manual for your MX (it'll help you find some of the less obvious things like the depth of field preview lever) then they are online as a .pdf.

That's a useful heads-up on the slide film, I just bought three rolls to use this summer and one will most likely go in my MX. I'll remember to meter for the ground rather than including the sky in bright weather.

Grass works very well! K.

Yep, but if you don't have any grass to hand...

I'm planning to shoot some slide film in my SF7 too, as I still haven't tried that marvellous old beast. It's a bit of nostalgia really - I always remember family holidays including a few rolls of the stuff that Dad would use in his K2 and I've been scanning some of the better results from those years of late. As I've now run a roll of black and white through the MX I know it works well, I've got another roll in there at the moment awaiting something worth photographing.

I had an MX back in the 1980s and it was a lovely camera. I shot mainly slide film then and it did slightly under expose if you had too much sky area in the frame so tilting down slightly to take a reading before clicking is a good idea as Kris says. I found it was more prone to under expose with wide angle lenses than telephotos. Once you knew the camera's habits it wasn't a problem, you just did mental adjustments automatically.
david

I picked up one of those as part of a job lot a couple of weeks back. Currently loaded with Delta 100 but haven't had a chance to use it yet. On first inspection it looks a but fiddly compared to the MX or LX I used most of the time.

K.

It's not too bad if you read the manual - you just need to learn what all the little pictograms on the LCD mean. As it has a proper KAF mount you can put any K mount lens on and it'll work in at least aperture-priority mode. What I do expect to find difficult is that it gives no indication of what aperture it has chosen in Program AE mode, so I've no idea whether it's suitable for what I'm trying to photograph or not.

I'm currently fiddling about with mine, trying to put it into the various auto modes and metered manual. I'd rather learn now before I've put a film in!

Weirdly I actually find depth of field much easier with A series or earlier lenses, as they have a printed scale. The MX is definitely less complicated and the lack of any automation doesn't slow me down all that much.