MicrobeHunter.com Microscopy Forum

Every time I use this industrial camera I see glare.

Left side: when there is an adapter; Right when the camera directly sit on camera port.

Left: camera with adaptor Right: camera without adaptor

This is how this camera looks like. I suspect it's because the filter in front of the CMOS sensor caused the problem， probably there is no anti-reflective coating.

Do you see similar issue?

A couple of thoughts:

1. Check your kohler alignment and make sure the field stop is opened sufficiently. This looks like a "hot spot" from a mis-aligned condenser. Kohler alignment can change with cameras, as the adaptors (or lack thereof) that you add to the optical path can change the focal length of your system.
2. Check to make sure that you have a light-tight seal where the camera meets the scope. While I've never seen it with a setup like yours, flares like the one you have are common when there is a gap between the camera and scope (e.g. cell phone adaptors), allowing room light into the system where it can then reflect and cause glare.
3. Related to the previous point, check to see if the glare goes away if you use the camera with the room lights off. If it is room lights entering the system, this will make the glare go away. If its an issue like mis-alignemnt of the condenser, turning off the room lights will not help.

SuiGenerisBrewing wrote: ↑

Wed Feb 07, 2024 1:03 pm

A couple of thoughts:

1. Check your kohler alignment and make sure the field stop is opened sufficiently. This looks like a "hot spot" from a mis-aligned condenser. Kohler alignment can change with cameras, as the adaptors (or lack thereof) that you add to the optical path can change the focal length of your system.
2. Check to make sure that you have a light-tight seal where the camera meets the scope. While I've never seen it with a setup like yours, flares like the one you have are common when there is a gap between the camera and scope (e.g. cell phone adaptors), allowing room light into the system where it can then reflect and cause glare.
3. Related to the previous point, check to see if the glare goes away if you use the camera with the room lights off. If it is room lights entering the system, this will make the glare go away. If its an issue like mis-alignemnt of the condenser, turning off the room lights will not help.

Thanks SuiGenerisBrewing. I turned off room light, it does not help. Then I removed the condenser, the glare is still there.

Then I put a tissue on the scope, there is no hotspot. When I replaced it with a glass, a bright spot appears. I think the problem is on the side of anti-reflective coating of the lens or CMOS sensor.

Hi all

I finally found a solution. It turned out to be the reflection in the adaptor tube. 3D printed adaptor ( ABS ) naturally brings some reflection. I tried to use other black material, like black paint for car, dark ink, etc., none of them helps. The ultimate solution is light-absorbing matte flocking paper, it's quite working and widely used on Telescope as well.

This is how it looks

The knockoff AO photo tubes beiing sold on ebay have the same problem but it doesn't look exactly like that. I thought about it in your case but decided not to bring it up in order not to lead you away from the real cause, which did seem to be a focal point problem. Glad you found that solution.
In the case of the AO tubes, the problem induces mostly a huge loss of contrast. In the factory tube, there is a lip machined at the bottom which acts similarly to the diaphragm at the rear of an objective. The knockoff tubes don't have that lip and the light is allowed to glance off of the interior tube opening edge, which is painted flat black. It doesn't matter though, there is a big circular flash of light at that point, easily fixed by a 1/2" ring of flocking right there. The flocking must be very thin though, otherwise it will vignette the tube.

Stick them into your tube.