How long should the tube of darkness be?
A friend recently gave me this to help with my ttv experiments.
Pretty cool huh? Some girls want diamonds but me you can make happy with a piece of PVC pipe. I especially like the black rubber that fits nicely around the lens of my Canon 300D.
The point of the “tube of darkness” is to block out light between the lens of the operational camera and the viewfinder of the viewing camera. This piece of pipe works a treat. But it does need some refinement. I’m taken with Karri’s idea of an old sock.
But what I do need to know is, what is the optimum length for the tube? Mine is obviously too long. I say obviously because I end up with tiny files once I’ve cropped down to the viewfinder itself in the final photo. I say obviously because it looks like this:
But before I hack into it with a saw what have people found to be the optimum length for them? How do I make sure it will work well on all settings on both cameras, the Argus 75 and the Kodak Duaflex IV, and even my old box brownie? Or am I making this too complicated?
Mike Emmett
What is the minimum focus distance of your lens? That would also be the minimum length of the tube.
Faith Hunter replied
wow! so simple? .........knowledge really is power. Thanks heaps you technical whizz you!
Mike Emmett
Actually, I think I answered my own question… if this is your lens, then the minimum focus distance is 28cm. The tube should be no shorter than that. If you really want to fill more of the frame with the viewfinder, a macro lens or set of macro tubes will let you focus a lot closer.
Faith Hunter replied
Yup, that the one. And the 300D’s macro function HATES the viewfinders so a macro lens is looking like a contender for the christmas lis.! Thanks heaps Mike.
Mike Emmett
Actually, I just realised I was a little bit out of whack with that measurement. the 28cm is taken from the shutter plane, so from the front of the lens-front it would be roughly 13cm. YOu could work this out by simply seeing how close you can focus to something, then cutting the tube to fit the gap…
Duncan Waldron
The “Tube of Darkness” ... I had to look. Sounds like a good title for a gritty novel or film noir project!
Faith Hunter replied
hehehe… ttv could probably do film noir quite well….......... if I ever get the hang of the tube of darkness.........
Duncan Waldron
Get to grips with the Tube of Darkness, before it grips you … mwahahahahaaa…
Faith Hunter replied
shot of screaming flailing victim as they fall spinning into the black center of the tube of darkness.............