Filters on a Kinoptik Tegea 5.7mm?

January 29, 2005

I recently bought a 5.7mm Tegea wide angle lens off Ebay at a very good price from a seller who was closing out an estate. The lens is in an Arri standard mount and has a built-in slot for two-inch square filters. The lens came with an 85 filter in the internal filter holder.

Is it okay for me to leave this internal filter slot empty when I don't need the 85 filter, or do I need to obtain a special clear filter? In other words, is the filter part of the optical formula? The viewfinder image when looking through the lens mounted on my CP16R seems sharp whether the 85 filter is in the holder or not. I suppose this means that I can shoot with no internal filter, but I don't quite trust my tired old eyes. :blink:

Also, does anyone know of some kind of appropriately-sized clamp-on adapter which would allow me to position filters in front of the lens? (The front rim of the lens is not threaded.) I'm planning on using this lens outdoors, and I'd like to be able to protect the front element with a UV filter at the very least, and it would be great if I could get a polarizer too. Obviously they'd have to be pretty large filters to avoid vignetting - 4.5 inchers or something.

Any information from experienced users of this lens would be welcome!

Edited January 29, 2005 by Ian Marks

Sam Wells · February 1, 2005

I am NOT an experienced user of the 5.7 Tegea (disclaimer) but AFAIK the internal filter position is in collimated space so should not matter.

You could easily see for yourself if you are concerned on a test projector or bench.

-Sam

J. Lamar King IMPOSTOR · February 1, 2005

I used one for a POV shot once and did not use a filter. The shot was out of focus. I did take note that there was a clear glass filter as well as an 85 in the case. The clear glass filter struck me as odd but I didn't have time to think about it on a quick coverage shot. So I can't say for sure or not either, it'd be nice to know.