Making one's own filters?

[One_DaveT]

I have a 8mm Peleng fisheye lens that I'd like to use for some infrared photography. It has a big bubble front element, so filters are meant to go on the end. Unfortunately, it didn't come with a red (25) or R87 filter. It did come with what appears to be a clear filter ?holder?, a UV filter (as well as green and orange), that screw on the end.

Having never dealt with a rear element filter, I was hoping for some advice. Short of this, I'm thinking about finding some red celophane from and sandwhiching it between the rear elemant and the clear filter. For the R87, I'm not sure what I'm going to do there...short of perhaps sacrificing the orange filter, cutting up an R87 filter, and gluing it into where the orange glass was.

Any ideas will be much appreciated.

Thanks,
Dave

 

[One_DaveT]

So, what exactly is a gelatin filter? Is this a flexible celophane-like material? or is it hard solid plasticky, like a cokin filter, or is it glass coated with something?


Thanks,
Dave

 

[richard ide]

Hi Dave,
Gelatine filters are excellent optically. Made of a sheet of dyed gelatin about .005" thick. It is like a piece of clear plastic such as acetate, but more fragile and don't get it wet. If you treat them with respect, they will last a long time. I have some that I have been using for 30 years and still scratch free. Mine all were made by Kodak and I think they still sell them. They can be cut to size with a sharp knife or scissors best done between a couple of sheets of paper.

 

[ehparis]

You might want to find out a bit more about your lens. Some lenses require a filter and make it part of their optical formula meaning that dimensions and materials may be critical.

 

[One_DaveT]

Thanks Richard. gelatine filters sound perfect.

Ehparis, thanks for the caveat. This Belarus lens came with all the instruction in Russian. The clear filter that came screwed in may very well be what you say. It looks like it may do well to sandwich a small thin ~1cm round piece of gelatine. I think I'll give it a try. Too bad it only comes in such large expensive pieces.

Thanks for taking the time,
Dave