Size of Nikon Eyepiece Diopters?

[jgoody]

I am trying to make a neat installation of an eyepiece diopter on my Canon 7 rangefinder camera. I am hoping to remove the threaded eyepiece lens mount (which unscrews) and replace the lens. The Nikon diopter for FM3A, FM2 etc is too large. Nikon makes other round eyepiece diopters for various models - for example the N008s have a model as do the D800s. Does anyone know the diameter of these? The obvious thing would be to have the optician make me a lens of the correct diameter, but their equipment will not cut anything that small, so I am hoping to find something that will fit with a little modification.

 

[bdial]

My 8008 eyepiece is 22mm in diameter. I think Nikon has only used a couple of sizes for all their cameras. I think the F's through the F3 are slightly smaller, but not by very much.

 

[ronnies]

Nikon have two sizes of round eyepiece. As already mentioned they use 22mm for their 'high eyepoint' finders. Their older finders on Nikkormats, FMs etc are 19mm.

Ronnei

 

[jgoody]

Thank you for the information -- I need something like a 13mm diameter -- so I guess it's back to the drawing board....

 

[jgoody]

In case anyone is interested this is what I have come up with -- it's a modified Nikon rectangular diopter which normally slides on the eyepiece. I removed the lens and cut off the tabs (on the side and top of the mount) with a hacksaw blade, making it much thinner, reinstalled the diopter lens, and put on a few strip of removable thin foam tape near the edges, and stuck it to the camera. So far it works well and all the framelines are visible - unlike with my eyeglasses on. We'll see if it stays in place - if so I'll clean it up.

 

[emacs]

I might have to steal that idea since it's a pain seeing the 35mm lines with my glasses. Boggles the mind why Canon never incorporated diopters in the first place.

 

[jgoody]

Had the camera out today -- eyepiece seems to be holding on fine. Be aware that the Nikon eyepiece diopters are not the value they are marked - I believe the minus 3 is really minus 2 as the Nikon eyepiece has a correction in it and they factor that in. To add to the confusion some of the original Canon 7 eyepieces have a small minus correction, but some don't. The rectangular Nikon eyepiece diopter (DK-20C) is $15 so it's not a huge deal if you get the wrong power and need another.