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I think I just discovered a hidden Pentax MX feature


david_barts2

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<p>No... not the mirror-lock-up one, that's quite commonly known. Multiple exposures.</p>

<p>Instead of advancing the film in a full lever stroke like you're supposed to, use lots of little baby strokes, until the shutter cocks. The film won't advance, and your next shot will be on precisely the same frame.</p>

<p>I discovered this quite by accident this weekend. I was doing a somewhat awkward macro shot, and part of the tripod got in the way of the film advance lever. It was starting to rain fairly hard, and I was in a hurry. Instead of removing the camera, I tried to advance using baby steps.</p>

<p>As I was walking back to the car I thought to myself "self, you probably shouldn't have done that". I was expecting overlapped frames. I was quite surprised to see the resulting perfect double exposure.</p>

<p>Disclaimer: I have no idea how healthy (or unhealthy) this is for the camera. The rest of the shots on the roll exhibited normal film advance.</p>

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<p>You maybe correct. Or, you may have discovered that your mechanism is showing its age and/or that it needs cleaning. Because of some funk, the baby steps may not have enough force to cause it to engage properly. Take it to a shop and have it looked at. I would think that after 40 years a hidden feature like that would be common knowledge. A CLA (clean, lube & adjustment) will run less than $100 and will ensure that it will continue to give many years of service. Good luck.</p>

<p>Mel</p>

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<p>I thought about it, and deleted what I wrote because I might be wrong about one of the springs in there. My main point is, though, that I think Mel is right. You need to have someone look at the camera. I think you will find as soon as the top cover is taken off that there is excessive wear where the film advance gear (driven by a large coil spring) meets the film advance drive sprocket (the sprocketed axle near the take up spool inside the film chamber is actually the outside covering of a long axle that runs the height of the Pentax SLR; that axle transfers spring loaded force to several parts)(The film advance lever assembly houses the powerful spring that holds the mechanical force that is sent to the other parts). [At least that is so on the Spotmatic-derivative bodies I've seen from Spotmatic to ME Super and K1000; I have been tinkering some lately.]</p>

<p>The mirror thing; that's just a synchronizing; those are easy to clear up. But, this type of failure that you're talking about, that's a failure in "the power train" of the camera's mechanics. I don't know about that model; but I have seen some similar problems in tinkering lately; I had a couple of cameras that had jams or wear in the film advance that I had to clear. There's a gap in my knowledge about the shutter trip and the film advance drive spring; but, I think you are seeing the beginnings of a mechanical failure that can lock up the camera to the point that it will not unlock without disassembly and possible replacement of parts.</p>

<p>It will get to the point that either the film will not advance; or that the shutter will not trip and the film will not advance; and, it won't be because of synching; it will be because of a broken part in or near the film advance and sprocket drive gears.</p>

<p>Have someone look at your camera. I got a camera from a guy who ruined his because he didn't maintenance the film advance. Some of those I've been able to fix; but, I have already seen one that will require a full replacement of the drive gears.</p>

<p>Get a repairman. The camera will bust if you keep that up. And, there are some failures and other forms of damage that can be caused by underwinding or overwinding repeatedly. Good news is that underwinding is less destructive than overwidning. Anyway, get a repairman, I think. J.</p>

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<p>Here's another reason to get it CLA'd. It's going to sound stupid, and like it's somebody else's problem, but it will affect your repair bills because of time spent working on a camera: stuck bolts. Yes, stuck bolts. Even though there are chemical contact release agents out there, the bolts that hold that whole thing together get rock hard solid because of anodizing and corrosion. More time will be spent getting the fixtures apart than the actual repairs. If your camera is getting to the point that it needs a repair; it's time to get it on a maintenance program of some sort. Getting the bolts unstuck and the covers off and the parts apart is the number one time consumer of the whole process. On a camera in good condition, all it takes it the right tool, and disassembly is easy. On a corroded unit, even if it appears otherwise fine, but there is corrosion about the threads of the bolts; take your jacket off and get set to sit awhile. It's going to take a bit to get that thing apart. That time will translate into increased repair bills, I bet. Good luck, though. J.</p>
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<p>The MX does have a multi exposure function.<br>

From the manual:<br>

 

<p >"For deliberate multiple exposures, make the first exposure in the normal way. Then tighten the film by turning the rewind knob, and keep hold of the rewind knob. Depress the film rewind release button and advance the rapid-wind lever. This cocks the shutter without advancing the film. Finally release the shutter to make the second exposure. Then make one blank exposure, before taking the next picture, to avoid overlapping. As the exposure counter continues to function each time the shutter is cocked, a double exposure will be counted as two frames."</p>

<br>

The MX is a truly wonderful camera, I've only just upgraded to the K20. Very exciting. So exciting in fact that when i first took the camera out of its box, i accidently drooled on it (i'm quite ashamed to say). Thank heavens for the weather sealing!</p>

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<p>I actually had it CLA'ed a few years ago (by Advance Camera in Beaverton, OR, an official Pentax service depot), it hasn't been used all that heavily since, and it exhibits no problems in normal use, so I really don't see the point in having it CLA'ed again.</p>
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<p>CLA is not necessarily indicated by amount of use. Time and it's environment are the larger enemies. Only your tech knows for sure. None of us can actually diagnose a problem via posts on a forum, but we can throw out some advice based upon our own experience. It's up to you to decide to take it or not. The point I was making and I'm sure John will agree, is that it sounds like the camera is not functioning correctly. Lack of cleaning is the most frequent cause. Just about any mechanical failure can be traced back to this. Lube dries out and gets full of pollutants (smoke, dust, etc). The lack of lubrication causes more friction and requires more force, more force leads to stripped gears or metal fatigue and broken parts,springs, etc. So, back to your camera, something is amiss. You should have it looked at sooner than later. It will be cheaper to have it looked at now. In fact, most shops have a diagnostic fee where they open it up and take a look and can tell you exactly what it is and how much to fix and if cleaning is needed. Cost is usually $10-$20. Thats cheap insurance for an old friend like your MX.</p>

<p>Mel</p>

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