Topic – Aires Penta 35

Phew! This 1959 camera is  really  an odd piece of work. In my collection there already is an Aires, the Aires 35-III rangefinder. I real like the sturdiness of the 35-III and its sharp Coral f/1.9 45 mm lens so when a Penta 35 was on the auction site it was a simple decision.

The Penta sure looks like an SLR: The pentaprism is there, the flapping mirror, it is there. But when you look through the finder – it is dark! And that is not a malfunction it turns out. Opening it one quickly notices the absence of curtains or shutter blades. This camera is an odd mix between SLR looks and some rangefinder technology. I have never seen this type before, still it must be some sort of logical (missing) link between older and newer cameras.

The shutter (which comes to be the real problem in this post) is still a central leaf shutter. The Seikosha-SLV is an ordinary shutter, albeit with an extended time setting from ‘B’ to ‘500’. This is how the camera works: In ‘rest’ the shutter blades are closed

penta35-10

and from the film compartment this still looks like any ordinary view- or rangefinder.

But activate the film transport lever one through and the most unexpected happens:penta35-11

Bang! The floor of the lens chamber rises and blocks the film. Behind the now vertical floor, a mirror is also lowered from the bottom of the pentaprism  in the ceiling and the shutter is set wide open. Now the light path from the scene to the finder is open and you  compose the picture and focus as on any modern SLR.

A press on the shutter button closes the lens, slaps the mirror up, the floor back down into place and when the floor is firmly out of the way the mechanism gives the Seikosha trigger lever a nudge and the picture is taken. The finder is of course of no use as the mirror is removed from the path.

This is cool from a mechanical perspective and, I imagine, actually not that difficult to implement as the only addition, apart from the rising floor/mirror/pentaprism, is an extra sliding ring behind the shutter unit.

As it turned out there were two faults with the camera I bought: the timer scale rotated freely and the shutter times did not work. I guessed the faults were interlinked somehow but alas that was not so. After disassembling the shutter (more than necessary…) it turned out that the shutter was always very, very quick. It ran at 1/500 s no matter the setting. It took an excessive amount of time to find out why and repair it but it ended up in that a pinion with cogs did not stick to a cogged wheel. From factory they relied on press matching the pinion into the wheel, but during the years they had loosened and there was no grip at all. This all meant that the gear train leading to the slower speeds was broken.

Unfortunately I have no photo documentation of the wheels, by then I was not sure I would be able to get it back together,  but I cannot take such macro pictures anyway. The pinion was some 2-3 mm largest diameter and, say, 1 mm smallest. The hole in the cogged wheel was something like 1.5 mm. Not having a replacement part I bruised the contact areas for better mechanical grip, squeezed them together and used tiny amounts of cyanoacrylate glue administered with the point of a needle. Amazingly this seemed to do the trick, for now anyway.

This is the first time I actually have mended an escapement mechanism and I am sort of proud it worked afterwards:)

Putting everything back in place was a chore though. Reassembly had to be done in strict order or there was always something that did not work. First the actual shutter never opened. This was due to a screw in the mechanism that by some reason had unscrewed itself to the degree that a fork-shaped piece was dislocated. Took some time to fathom that one out! Second the mechanical logic behind the film transport lever, mirror and fully open shutter had to be reassembled in a certain order. Here a jamming tooth pick came in handy before inserting the shutter body into the camera. This also took a few turns to get correct…

As the free moving timer scale is common (read: I have seen it mentioned on the internet somewhere. In no way is this camera “common”.) here are the steps leading from the broken pin which has to be replaced to full assembly.

Notice the little hole at 12 o’clock. This is the place for a pin! The front parts of the lens stop on this and if it is broken (or, as in my case, completely vanished, disintegrated and gone) a new one must be put there. The pin must not protrude beyond the thickness of the metal, there is some other stuff behind it that must not get jammed:penta35-1

Here I used a piece of metal from a toy helicopter in my junk box. One end was already lettered and had a tight fit so this piece was used. The exact length was correct on the first try so I didn’t have to go out in the snow to the little tool shop more than once! Success!

Too much cyanoacrylate glue holds the newly fabricated pin in place as in the picture below. Due to the tight fit there are no forces sideways on the glue, it is there only to keep the pin from falling in or out of the hole, not to take sideways torques:penta35-4

Next the front assembly is screwed into place. Nothing special here except that one must make sure the pin fits the recess on the reverse side of the assembly. The two small yellow craters in the brass look “not professional” so I assume I was not the first one here:penta35-5

Then the front lens is plopped back into place. The curved side towards the viewer in this picture:penta35-7

And finally the cover is screwed back:penta35-9

I would never have managed this without a camera spanner wrench. So don’t even try without one. Especially the brass part was almost impossible to remove.

One can always tell if the operation was successful by the amount of left over parts. This time it qualifies as “pretty good” as there was only one washer left. I have an idea where it came from but there is no way I’m putting it back!penta35-8

End result is a ho-hum working Penta. The escapement never really recovered but it runs on a few selected speeds around 1/250-1/60. Good enough for hobby use. Apart from the missing shutter times it sounds, feels and acts as one would expect. penta35-12

So “Phew!” again. It took the better part of one evening to get this into shape. Worth it? Well, its a hobby…

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