I recently purchased a 2-year old Master Techinka. Great camera, but the one thing I don't particularly like about the camera is the fresnel lens that is installed in it. I find it somewhat difficult to focus, due to the ridges on the fresnel. So, I'm thinking of replacing it.

I'm a touch concerned about the fresnel focus shift that I've seen discussed here. If I remove the fresnel/glass protector and replace it with a plain ground glass (or a Boss screen, or a Maxwell Bright screen, or a ... ) do I have to do anything (send it away for servicing?) to adjust the back? Or, am I worrying to much about it?

What I also found interesting is that the fresnel doubles as the ground glass - the user-side of the fresnel is frosted; I had initially thought that the fresnel butted up against the 'ground' glass, but when I took the glass off I was surpised to find that the 'ground' glass wasn't - it's clear!

My guess is that to replace the fresnel/protector combination with a plain ground glass, you would need the ground glass to be exactly the same thickness as the fresnel, and you would install it with the ground side towards the user, instead of towards the lens - this would insure that the ground side of the glass would be in the same plane as the 'ground' side of the fresnel. I would therefore still need a protector glass to ensure that the ground side of the glass didn't get damaged.

Anyone care to comment?