Hi everyone.
wilper, your design looks very interesting; the one thing I'm not sure about is the focusing system, as I'd like to shoot portraits at larger apertures, thus needing to have a precise focusing system.
Even having a fixed focus camera should not preclude sharp portraits with large apertures.
Have a model sit for you when you install the spacers for the "film holder". Compose a picture by observing the projected image and fasten your spacers accordingly.
Then fasten a chain to the front of the camera and light a candle in front of the camera. Move the candle back and forth until the projection is sharp. Stretch the chain to the candle and cut/mark it at the correct length.
Now you can get the right distance to the subject by checking against the chain.
Not very fancy, but it should give you pretty good control of the focus.
hi diegoV
i have made simple cameras with a way to focus them.
what you need to do is make a "friction mount" for you lens or the board
your lens will be mounted on. you will slide the lens ( or board) in and out of the camera
and you will be able to focus. you can also make it so the lens board tilts and shifts because it is friction mounted
you can have it at an angle and do your own bit of distortion.
so the back end of your camera remains stationary, ( allowing you to have a film back &c that is standard
and use standard film holders &c ) the camera will be a fixed box, but the lens moves.
you can put marks inside the box to correspond to pre measured strings with knots on them &c if you want ...
know where infinity is, know were 3.5 meters is &c .. and it makes it easy for you. stopping your lens down a little bit
will also make sure your subject is in focus ( if you want that, that is ).
good luck with your project ! ( i liked your video too)
john
what's a GG holder? It's like a...film holder? :confused: I'm feeling really dumb now, sorry.
Not at all dumb, really and seriously! A "ground glass" holder, i.e. the focus screen. If you make film/paper holders, it is handy to make a GG holder that puts the front plane of the focus screen ( ground glass or other ) exactly where the front plane of the film will be.
Your English is incredibly good; I would not have guessed it is a second language. The way you use idioms is smooth and natural and normal, and that is often the giveaway.Have fun building your camera!
So yes, I'll build a GG holder and figure out a way to place the paper/film exactly where the focus plane is. It's gonna be fun haha
Have a look at how Dean Jones did the GG screen on his Razzledog conversions - Unfortunately, his site no longer exists, so here is an archived copy:
http://web.archive.org/web/20120914...es.ihug.com.au/~razzle/Razzlok_/razzlok_.html
If you look at the first image, it is a standard 5x4 film holder with the insides removed and the ground glass dropped in. The idea will scale up for 10x8 or larger.
For a sliding box camera velvet ribbon can work as both a light trap and friction for the focusing box. It does come in different widths.
Depending on the size of the moving box you could use two 15mm strips on each side. that would reduce the tendency to droop when it focused closer.
Mine focuses fairly smoothly and stays in place well ( my film and GG holders drop into a slot from above, so they do not require attaching to the rear ). But as soon as the camera warms up ( black foamcore in the sun! ) the focus starts to stick and get difficult. You'd think when the sun hit it, the outer box would expand and make them slide easier, but that's not what happens. If it gets hot enough it really seizes up. I think all such cameras suffer from their simplicity in some way... I think Joe VanCleave uses stick-on felt sheets on the sliding surfaces and that might solve both of these problems.
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