Whilst obviously anything introduced into the light path is going to affect the image to a certain extent, is there anything particularly special about internal filters compared to those positioned on the front of the lens? - or are they just the same material?
In the past I've been able to sucessfully cut resin filters then glue them into mounts I've machined to fit non-standard threads on older cameras. Potentially I could easily make a 2x2 filter & mount the same way, but there's no point wasting my time if the material needs to be something special to be positioned between the lens elements.
Finding 2x2 filters commercially here in the UK doesn't seem all that straight forward, hence why I'm considering cutting something larger down and mounting it myself.
Sorry, just seen I've posted this in the 'Cameras' section, not the 'Lenses' section where I'd intended.
Although I can edit the post, I can't now delete it to post again in the more appropriate section of the forum.
Edited by Ian Cooper, 17 December 2009 - 04:29 PM.