Hi Rik. Seems you still have a soft spot for these little critters.
Getting to your technical question. I have a long winded answer with photos to guide you.
My Ortholux dates back to the early 1960’s. Leitz introduced the 35mm Leica camera to its microscope line at that time through the use of a Micro Camera Attachment. See photo of device off the microscope. The early units came with a 2x conical adaptor that matched the image in the 90 degree eyepiece to the film plane of the Leica camera. This was done with a 1/2x reflex lens that was placed above the prism used by the focusing eyepiece. The attachment came with a 10x Periplan projection eyepiece. I call the reflex lens a relay lens. This camera attachment provides quite a magnification factor.
At some point, my historical records are sketchy, an additional setup was offered with a 1/3x Special Reflex lens. Also called a 32:1 Reflex lens. This attachment had a shorter conical adaptor (see first photo again) and had less magnification which is now a important issue.
I use one of these Micro Camera Attachments on my Ortholux that has the conical adaptor removed. The 10x Periplan has been replaced with a rare 4x projection eyepiece and the lack of a conical adaptor allows me to lower the 50D as close to the 32:1 reflex/relay lens as possible. All this allows me to combat the problem of having too much magnification applied above the objective. All this stuff was made for a 35mm format and with the smaller sensor in my 10D and 50D there is way too much empty magnification. Mr. Charles Krebs has explained all this very well on his web site.
Walt
