Why the rear door?

[Asim]

Maybe a dumb question but I've had my MP for about 10 years and never needed to open the back door/hatch. What is it meant for?

Before anyone says that it's to make sure that the film is aligned properly, keep in mind that the bottom plate is designed to align the film. No one needs to ever fiddle with the film from the back as this risks ruining the curtain. Locking the bottom plate ensures the film is running straight.

So why the back door. I'm just curious.

 

[Mackinaw]

To help with loading film. I always open the back door when loading film in my MP and M3. Helps me make sure the film is properly threaded on the take-up spool.

Jim B.

 

[Ko.Fe.]

M3 was made first, door was helping with film loading. And so was with M2.
MP is just an iteration of those cameras bodies. Even if Leica figured out how to get rid of the spool by M4.
Also, it is easy to collimate lenses and test shutter. With door removed and camera on the tripod.
It is easy to check if curtain was burned as well.

 

[nickthetasmaniac]

Where there any accessories that require removing the back?

For myself, I find it handy to make sure the film is aligned...

 

[Rob-F]

I always check that the film is aligned on its rails and the sprocket is engaging the sprocket holes before closing the back. I like the rear flap.

 

[jsrockit]

You knew the answer before you made the thread... 😉

 

[Pál_K]

...
Also, it is easy to collimate lenses and test shutter. With door removed and camera on the tripod.

It is easy to check if curtain was burned as well.

Good reasons!

 

[Rayt]

If you follow the film loading diagram exactly as depicted on the inside of the bottom plate there is no need to look at the guide rails at all. I suspect the back door design since the M3 was because Leitz was a visionary and predicted someone in the future will someday market a digital back in place of that removable back door. And there will be a crop sensor 1.33x to be exact to fit between the guide rails.

 

[xayraa33]

The removable back of the 1930s Contax cameras were perceived as a plus for film loading, cleaning and shutter inspection and for cassette to cassette film with no need to rewind film by pros back then. Leitz was aware of this and incorporated the back door on the M3 to have some of these lauded qualities of their competitor.

 

[kshapero]

If you follow the film loading diagram exactly as depicted on the inside of the bottom plate there is no need to look at the guide rails at all. I suspect the back door design since the M3 was because Leitz was a visionary and predicted someone in the future will someday market a digital back in place of that removable back door. And there will be a crop sensor 1.33x to be exact to fit between the guide rails.

Great, very creative.

 

[raydm6]

My guess would be that the film pressure plate and take-up chamber pressure rails would interfere with loading film onto the track. Thus, pulling away the door flap allows initial easy access for the film.


https://pentax-manuals.com/manuals/service/leica%20basic%20repair.pdf

 

[thawkins]

I always open the rear door of my M3 when loading a film cartridge. I take the opportunity to look over the innards before use.

 

[Phil_F_NM]

It's a distracting flap, put there to appeal to obsessive camera collectors and ensure that they have a better chance of sticking their thumb into the shutter to allow Leica to may make some additional money off of during the 3 month repair.

Phil Forrest

 

[Richard G]

You only have to load a Barnack to see the genius of the swing up door. I can load my M6 in about 3s.

 

[Sarcophilus Harrisii]

Designing a conventional detachable or hinged door would have been an unthinkable admission that they were wrong with the layout of their screw mount cameras, and everyone else was right. The lift up trap door made loading Ms easier (not to mention checking the curtains and film gate) without losing too much face. Or getting screw mount owners too far offside, perhaps? Cynical? Maybe. But they eventually went to a conventional opening back with the Leicaflex, didn't they? Why else did it take them so long to see reason? And don't tell me design strength. The F has a detachable back. Enough said.

 

[Ko.Fe.]

Where there any accessories that require removing the back?

For myself, I find it handy to make sure the film is aligned...

It require a finger. Next time you load, check how it is done 🙂 .

 

[Benjamin Marks]

The back door was, I imagine, a reaction to what the IIIg was not: a solid cast casing for the camera body. Don't need it? Don't use it.

 

[sjones]

As early as 1934, Leica experimented with an open back on a Leica II prototype and then a year later with the never released Leica IV prototype. With the Barnacks, it was often hit or miss if the film aligned properly; I know this first hand. As such, access to the back helped facilitate or at least ensure proper alignment before putting back on the bottom plate. And having moved from a iiif to an M2, I’m glad the option exists.

 

[Pál_K]

You only have to load a Barnack to see the genius of the swing up door. I can load my M6 in about 3s.

That’s good. For my III or IIIf, it takes about 20 to 30 seconds. The way to help ensure a Barnack Leica is loaded properly is (1) trim the leader as shown in the diagram and (2) when the whole cassette-film-take up-spool assemblage is inserted into the camera, just ensure that a tooth on the sprocket cylinder has indeed engaged a sprocket hole in the film. From that point on, you can be certain film will advance. Watching the rewind knob move while winding will confirm it. In many years I have yet to mis-load a Barnack Leica.