Homemade SLR Camera by Denis MO (in English!)

[denis MO]

I finished the new speed selection assembly:



I also made a new system to lock the winding drums axis in place. It will possible to tune these drum using screws on the top plate – I know, that’s eccentric! Two simple screws lock the axes in place. By the way I don’t need anymore the two large screw on the bottom plate, which were ugly but useful!



Don’t worry the speed sticker isn’t the definitive one, neither is the white plastic spring.

[denis MO]

I’m now working on the body itself.

The bottom plate is made of 4mm thick steel, but I did a fair amount of work: in some places there only 1mm left.
These two parts aren’t welded yet.



The whole casing is going to slide like a sock on a foot. There are grooves all over the reflex cage, in order for it to be lightproof.



There will be butterfly screws in the side holes, and a tripod socket in the central one.
On this picture you can also see prototypes of the mirror and focusing glass.

[denis MO]

I’m back! Don’t worry I didn’t drop this project.

I solved the mirror problem: it will be coupled with the shutter release.

There is a lever that is using the vertical movement of the shutter release. This lever has a set screw on its axis in order adjust the angle.



The lever that retains the mirror releases it by swithching forward.



I used a green leatherette – it could become my trade mark, who knows?



The image is of course reversed left-to-right, as you can see on this improvised cardboard finder.



More about the mirror: this isn’t an instant-return mirror. I do not know how to use a camera movement to return the mirror in the viewing position. If I don’t find a solution, I will use a manual lever to bring the mirror down. This isn’t the best solution, but at least I will be able to return the mirror into viewing position without cocking the shutter.

[denis MO]

I finally decided to make a small lever to return the mirror in its down position. The prototype is working; I need to work on a definitive one. This way the operating mechanisms are much simpler, plus I won’t be slowing the shutter operation. According to my testing, the noise is very limited and less metallic than a good old Zenit.

The handling of this lever is ok, one can press it while winding & cocking for the next view, so it doesn’t slow the camera operations. Of course, the mirror locks up automatically when the shutter release is pressed, which is a good idea!

[denis MO]

Today I tackled with the top of the camera. The finder will be a waist-level finder – just like looking a digital camera screen, only this one is reversed left-to-right.
I started with a aluminium block that I hollowed out. It’s only 2mm thick now, so it is quite light at 35grams.



So this is what the camera will look like, sort of a hybrid between a Zenit and an Exacta. I changed the knobs, they are now made of inox [stainless steel], I would have otherwise needed to nickel-plate the brass.



Here is the small lever that takes the mirror in the viewing position. It is not inconvenient, since you can press it while winding or even before winding, unlike some 1950s SLRs where you were “left in the dark” until you wound.



I will paint the bottom plate with the same green so that is it looks uniform. As you can see there is a tripod socket.

[denis MO]

I assembled the shutter and painted the whole thing with black paint to avoid light reflection, too bad this hides the “beautiful mechanisms”.

The main drum and the winding drums are now installed on the bottom plate. For the time being the winding drums’ tension is hold using two M3 screws. I also made a part that hide the instant-return mirror mechanism on regular camera; here it doesn’t hide anything at all but it nevertheless useful to protect from light leaks.



The top is ready for assembly:



Both parts assembled, everything needs to fit in.



I then tested the shutter speeds using 3 control points (right, middle, left) to make sure that curtains travel at a constant speed.



It’s not bad at all. Bulb is working, 1/30 is a tad fast, 1/60 is correct, 1/125 is to slow, and so is 1/250.
It really isn’t that bad in comparison with older production SLRs. Getting the exact shutter speed isn’t in my opinion as important as having a constant curtain travel speed, which I did achieve here (not so much for the 1/250).

Here is a video of the operation of the shutter & mirror: http://www.dailymotion.com/video/xbw0e3 ... e-slr_tech

[denis MO]

Today’s work: I finished all the stainless steel knobs; the shutter button even has a cable release thread. I didn’t have time for a conical thread like those on regular cameras, but a M3 thread will do just fine.
As I have neither the time nor the will to make myself an engraving machine, I printed transparent stickers on my computer. They really look good on polished steel, I fell like it gives a “pro” look.



Same thing for the logo:



Now I just need to finish the top and some small details as well.

[denis MO]

It’s almost finished now; I still need to work on some details, but nothing big.







With the finder open, it looks a little bit like an Exacta.






You can see that this homemade is no bigger than a Zenit B.

[denis MO]

[Reply to someone asking about the time & money investment in this project]

I don’t calculate the financial cost: this is a hobby and like any other hobby you spend some money, but not that much when you look at the “annual cost”.

As for the time, it is difficult to calculate. I spent roughly:

1/3 of the time on the blueprints & engineering
1/3 of the time actually making stuff
1/3 of the time adjusting and fine-tuning
It doesn’t take me that long to make the parts, because I think & design them in such a way that they will be easy to make. I also know my tools very well, and I know a lot of tips to save time.

All in all, I’d say maybe 500 hours.

[denis MO]

One thing for sure, I will have used a lot of M2 taps & dies, these are really brittle! And when they do break it is very difficult to take them out without damaging the part you are working on. I know where to find good quality taps & dies, but they are expensive.

I finished working on the last details.

I cut the pressure plate from 3mm thick brown Plexiglass (I would have used black if I had some). The legs of the pressure plate are 0.2mm higher than the plate, so that the film can slide without scratching.

I also finished the two locking screws. It is harder than it looks, because the mobile part is 2.5mm thick and it is attached through a 1mm axis. Just imagine, drilling 1mm holes in stainless steel!
These are not quick-release locks, but rather disguised butterfly screws



The pressure plate in place: two pieces of foam act like a spring – by any means this is sufficient since there almost no room between the back of the pressure plate & the camera body.
I also added a foam light seal at the bottom of the top plate.



Bottom view with the locking screws in position:

[denis MO]

Here are the first pictures!

Yesterday morning the sun was shining bright, so I left with some Russian lenses and an Ikophot [lightmeter] and loaded an expired 100iso film from Super-U [a department store].
The pictures were taken between 9 and 11am, and then I dropped the film at a local 1-hour place.

When I came back one hour later I was shocked by what the clerk gave me back! No light leaks, no scratches, no unwanted reflection… well nothing that could give away this was taken with a homemade camera! By looking closer, I can see a small darker strip on the right side of the picture, maybe cause by a curtain. I don’t really know what causes this strip at the moment.

I scanned the prints on my Lide25 scanner; I didn’t crop or adjust anything. It’s only a test roll so don’t go looking for something artistic here, I took what the countryside had to offer in a two-hour time lap.

Now let’s see the picture you have been waiting for!



4)helios44-2_60-8


7)helios44-2_60-5.6


8)helios44-2_125-8


12)jupiter11_60-11


15)mir1b_125-11

[denis MO]

17)helios44-2_60-8


19)industar50_60-16


21)industar50_60-16


22)industar50_60-8


23)industar50_60-5.6


DM-flex and Russian lenses : Industar 50-2, Helios 44-2, Mir 1b, Jupiter 11

[Stephen G]

Brilliant work Denis!
And thanks for translating Pierre-Yves!

[denis MO]

Thanks Stephen,
You can see my new chanlenge here : Homemade rangefinder camera body

[denis MO]

Film roll number 3

Pentacon50-125-11

Pentacon29-125-11

Pentacon29-125-11

Pentacon29-125-11

[denis MO]

Roll film number 4

Mir20m-125-11

Pentacon29-125-8

Pentacon29-125-8

Pentacon29-125-8

Pentacon135-125-11

[denis MO]

Roll film number 6

Bye bye darker strip on the right

Porst 50 1.4 125-11

Industar 61LZ 125-8

Porst 50 1.4 60-11

Porst24 60-11

Porst50 1.4 60-5.6

Porst 50 1.4 60-5.6

[denis MO]

Roll film number 8

Oreston 50/1.8

[denis MO]

Roll film number

Flektogon 35 2.4