Hi Al. Welcome to RPF. You could always make a new one!! I have a 10x8 / 5x4 Sinar but mainly shoot 5x4 on large format. And it's certainly a lot cheaper shooting paper than film although the image quality isn't quite up to the Sinar! Yet!!
Although the Mk II screen was much brighter than the Mk I, it was not possible to use a loupe so I made the Mk III. Again based on a piece of glass from a clip frame, the screen was made using a second sheet of glass and grinding paste. I used oil-based, medium-grade, valve grinding paste (as that was all that was to hand) but fine would have been slightly better. I added water and washing-up liquid to form a thinner emulsion and it only took about 10 minutes of grinding by hand to get a uniformly matte screen. Focus is much, much easier and is now accurate as can be seen in this test print (ca 6 seconds exposure) - the focus point was the larger seed pod in the bowl.
I stripped the print dryer down and cleaned it and re-shot the image. This time I scanned at 600 ppi (rather than 300) and inverted the image in PS.
I have just modified the base of the camera to improve its stability when mounted on a tripod. I originally intended to screw a sheet of ply into the recess below the camera but then realised this would cause problems with the fitment of the lens box. So instead I have added a second layer of plastic around the tripod boss and reinforced the front section and an area towards the back.
This shows the internal bracing of the rear reinforcement.
And this is the completed modification with the plate of a large ball and socket head mounted to the tripod boss.
It is not perfect but certainly more rigid and should give the extra stability I was after.
While flipping through the manual for the DIY camera, I discovered it had a macro mode so I thought I'd better try it out!
This is just about the limit of the extension possible with the camera before the lens unit falls out! It also means that there is not enough overlap to stop light sneaking through the gap and so for the actual shot I draped the focusing cloth over the camera to block any light.
This is the Mk III screen in place and for normal shooting inside it doesn't need shading...
A quick experiment from late this afternoon to try out the idea. The lily was lit the same way as the ones taken with the Cambo but this time the image was made using the DIY camera. An aperture of f/11 was used and the exposure was for 2 minutes. The paper negative was solarised using a small flash during development and was then scanned after fixing, washing and drying. The image was inverted in LR and edited for tone etc in SilverFX Pro 2. Definitely worth exploring further tomorrow I think...
Just for interest, here is a walk-through of the process I'm using to create solarised negatives of a Cala Lily.
The images are taken using the DIY camera onto paper negatives. The advantage of this is that this gives a negative with very low sensitivity that allows it to be solarised without totally over-exposing the negative (modern sheet material is just too sensitive).
This is the setup used to take the image - two minutes at f/22.
The manufacturers of the DIY LF Camera (http://www.realphotographersforum.c...format-paper-negative-diy-camera-project.html) are pleased to announce a long awaited Firmware update. This update introduces the new ultra slow focusing system plus a reinforced lens board that should significantly reduce the number of premature shutter closures. The new enhancements are illustrated below.
An overview showing the ultra slow focusing system fitted.