Does anyone know the backfocal distance of the Swift M10T microscope?

[Topcode]

While the tube length is 160mm, I don't know how much of that length might be folded. Before I purchase a c mount adapter, I need to figure out the back focal distance I need, does anyone know what the back focal distance is, or know a method to find out the correct optimal back focal distance?

[Tom Jones]

https://wp.optics.arizona.edu/optomech/ ... Sophie.pdf

[Topcode]

https://wp.optics.arizona.edu/optomech/ ... Sophie.pdf

This article seems to measure the back focal distance of a single lens, with light at infinity focus entering it. Maybe there is some way to apply it to a microscope system, but I don't see it, maybe you could try to explain what you meant?

[Tom Jones]

I actually didn't mean anything. It was just the first item in a quick Google search...

[crb5]

By back focal distance, do you mean the position of the primary image? In a 160 mm tube length microscope this would be 10 mm in from the eyepiece shoulder i.e. a USB cameras designed to fit in an eyepiece port has its sensor 10 mm into the port. So hold an eyepiece above the camera port and adjust the height until it is parfocal with the regular eyepiece, then measure 10 mm from the eyepiece shoulder to find the primary image plane. A C-mount would need to be closer to the objective lens, since C-mount cameras have their sensors 17.5 mm from the C mount thread. The back focal plane of the objective lens is different parameter - that's where light is focused when parallel light enters from the front of the objective, as shown in the link in an earlier post to your question.

[Topcode]

By back focal distance, do you mean the position of the primary image?

Yeah, by by backfocus I mean the distance you have to travel backwards from the camera port to reach ideal focus.

So hold an eyepiece above the camera port and adjust the height until it is parfocal with the regular eyepiece, then measure 10 mm from the eyepiece shoulder to find the primary image plane.

That could work, ill have to try and maybe 3d print something to be able to hold it steady and try that.