This is a video of jonni's short and cheap DOF adapter for the Casio EX-F1 (and every other camera). It works with M42 and Canon EF lenses.
If you're interested in one of these, feel free to contact me.
Check jonnionhd.com for more information.
music: Fat Boys - Fat Boys Are Back
cam: Casio EX-F1
Because I got so many questions:
The distance between the lens and the ground glass (GG) is the most important thing and has to be absolutely correct. It is called "flange focal distance (ffd)". I recommend to screw on a Canon Tube #2 first and then the #3 (not like I did in my video). It is much easier to position the GG in tube #3. (The only advantage of screwing on tube #3 first is that you can disassemble the adapter and clean every single part of it.) The ffd has to be exactly 44mm for Canon EF lenses and 45.46mm for M42 lenses. Don't forget that the GG also has a specific thickness.
Next thing is the quality of your GG. You will loose less light if it is thinner. It also has to be very fine if you don't want to see a lot of grain.
3rd: the condenser lens. It will improve the image quality a lot if you buy a good one (less vignetting). If it is coated or not depends on how much money you want to spend.
Last but not least, if you screw on a cheap macro lens the quality will get worse (chromatic aberration). So it's better to spend some more money here.
If you think this is to complicated - let me know, I can build one for you.
Hope this helps.