Here is my attempt at the repair of a interesting German twin lens reflex (TLR) from the 1930s. The Mentorett was made by Mentor Goltz & Breutmann. With all mentorett cameras found to have a serial number of 53XXX, this one has a quite early number of 53034.
The Mentorett camera has a few features not found in many other TLRs :
1) an aperture mechanism in the viewing lens to preview depth of field. The aperture is also linked to the taking lens and can't be moved independently.
Only a few other TLRs have this feature - the Primoflex Va, and the 105mm DS lens for the mamiya TLRs.
2) it uses a focal plane shutter (Bulb, 1/15-1/600sec) instead of the more common leaf shutter. The only other commonly found focal plane shuttered TLR is the German Foth-flex.
The lever on the right side of the camera has three functions, it advances the film, cocks the shutter, and also acts as the shutter release. It also has a shutter lock switch built into it.
On the left of the lever is a switch that disengages the shutter to the film advance. This allows you to wind the film without triggering the shutter, useful at the start of a roll of film. This lever is absent on the later models of this camera. On the right of the advance lever is a small knob that starts the automatic frame counter. The frame counter doesn't automatically reset, it just stops at frame 12 and needs to be started again using the knob.
Unlike almost all TLRs with a metal waist leve finder, the viewing hood is made of leather, similar to large format SLRs. And a small knob can be turned at the top of the finder to pop up a small magnifier.
On the left of the camera is the focusing lever. This lever was replaced by a knob on later models, and an extra retractable viewfinder was also added beside it.
When I received the camera it was in very poor condition, it hand a brown substance covering everything, including the lenses. And this was hard to remove, only slightly dissolving when acetone or alcohol was used. The main problem as the shutter. The shutter curtains were hard and crunchy after from being more than 80 years old. I removed the seized curtains from their rollers, measured them and made a new set using light proof material from an old film changing bag. One benefit of this shutter is that once installed, their position can be easily adjusted by changing the position of the gears on the top roller.
I was also able to clean the brown substance off the lenses, while they are still scratched it is in much better condition now. Under the lens panel can also see the very short bellows used for the taking lens. The internal body of the camera is actually made of wood. I also replaced the mirror and ground glass, and put new leather on the top, back, bottom and a small section on the front.
When cleaned up the Mentorett is a quirky but handsome camera. Compared to other TLRs it is quite bulky being larger in every dimension. I hope to test it out soon with some film.
