Microscope RMS objectives to camera bellows

[hansz]

Is it feasable to attach a RMS (Royal Microscope Society) threaded lens to a digital camera (Nex3), and how to proceed?
I know the Zeiss Luminars (or the DDR equivalent Mikrotar) do a perfect job, only they are far to expensive for my budget.
Also a M42-to-RMS adapter exists. But can it be done in the first place (as there is no ocular).
Hans

[Stephen]

With a microscope lens it can be used as the prime lens, and the digital camera looks "lens less" into a tube adaptor in place of the eyepiece. The position from lens to the sensor depends on the power of the objective lens.

But you can also rig it to keep the eyepiece in place and look through the eyepiece with the camera lens in place, both work, but at different magnifications.

The best image quality will be with just the main microscope lens. It should be possible to use just the lens on a digital camera, but you then lack any focusing, which the body on the microscope provides.

Stephen.

[hansz]

I'll try it out, Stephen, the focusing can be done by a bellows. It needs to be steady and I reckon the exposure time will be substantial.
Hans

[Stephen]

A bellows should be the easiest way, focusing and the tube in one.

First thing though, is to determine the basic focal length of the lens to give an idea of the distance from the back of the lens to the sensor. With weaker lens, the distance may be usable, but short focal length objectives may need to be deeply recessed into the bellows, so much so the bellow will get in the way!

It is certain the exposure times will be many seconds, the "T" stop value will be very low indeed, even if a calculated "F" stop indicates a large figure. Sunlight or ring light flash may be needed. Home made LED ring lights are easy to make.

Some very short focal length objectives may need to be mounted direct to an adaptor for the mirrorless reflex, perhaps a modified "C" mount, the focusing achieved by moving the whole camera. Very cheap black aluminium "C" mount extension tubes are made, which could be modified to take the microscope objective lens, and leave the C mount screw to attach to the adaptor mount.

Stephen.