Depending on your camcorder lens, you will need an achromatic diopter to focus on your 35mm lens adapters' ground glass. I used an old Tasco 10x50 binocular with coated front lenses from ebay for $15. For camcorders with small lens (Sony HC1, Panasonic NV-GS400/500…) this set of binoculars with Ø 50mm is ok. If you want to shoot HDV/HD (with Sony FX/Z1, Panasonic HVX200) you will need binoculars with bigger front lenses Ø 60mm or more so that you use only the "sweet spot" of the lens.
Technical data for these 10x50 Tasco binoculars:
Achromatic front lenses Ø 50mm
Magnification 10x
(focal length for one achromat is 1 / 0.265m = +3.77 diopters)
If you put both front lenses together you get a very cheap coated achromat with +7.5 diopters for your 35mm adapter.
If you need a more powerful diopter, try binoculars that are 7x50. The focal length of these lenses vary from manufacturer to manufacturer so you may have to look up the individual manufacturer and/or just experiment.
1. Get yourself a cheap binocular (i.e. from ebay)
Search for a cheap of binoculars (I used a Tasco 10x50 for my little camcorder) at online auction places like ebay. The old binoculars from Zeiss, Tasco… are far better because they have coated lenses that can be unscrewed. The very cheap, noname brand binoculars mostly use glued-on lenses and you will need to saw them off. Open the binoculars and take out the front lenses. Use a screwdriver to open the threads. Be careful not to scratch the lenses!
2. Search for a holder for your achromat lenses
For the 50mm Achromats you will need two 58mm Filters to hold the lenses. If you don't have a 58mm Filter, try to use a piece of PVC pipe. Use silicone or hot glue to fix the lens in the filters or pipe. To avoid barrel distortion, face each lens as seen in the illustration below. That's all, have fun with your new achromatic diopter.
Here is my self-made Achromat with +7.5
I made a lens holder on my CNC-machine to fit exactly my adapter.
DIY-Achromat +7.5 (Made of two front lenses from old Tasco binoculars.)
