Using a digital camara on an Axioskop which has operated successfully in the past, I get an intense sphere of light. Th camera is mounted on an adapter, as before, but I wonder if there is a lens missing somewhere? I don't have a manual with which to check operating requirements. Billo Shaw ( Darrin Freshwater Institure, (Rensselaer Polytechnic Institute)

Generally speaking, without knowing much exactly what you have, there is a possibility that you could be missing a lens. It is hard to say though without asking you a 100 questions. The lens cell in front of the camera is designed to shrink down the square sensor of the camera, so that it can fit with in the round hole of the optics. Most adapters Will have several lens, which will depend greatly on the size of the sensor or how much it need to reduce it by. If there are no lenses then it would look like the camera is looking down a tube, and there will be shadowing or darkness all the way around your image.

If a single lens is missing then you would most likely get a sphere on light or very intense hot spot in the center of the field of view. It is really hard to describe what this would look like, but if you where able to see an image through it, it would appear to be bowed. With a photo, I could tell you for sure.

There are also other variables unrelated to the camera and adapter that might causes this, such has the position of the condenser (try adjusting the height), or you can also control this a bit by adjusting your iris. If this only occurs on the higher magnification, do you notice any changes in through the eyepieces. Sometimes if immersion old gets inside of one, it can act like an additional lens, and do all sort of crazy things.

When trouble shooting you need to determine which variables are at play. For instance do you only see it on one magnification, or is it only on low and not high. Is the hot spot seen through only the camera, or can you see if through the eyepieces as well? Each one of those question will help you start to isolate down where the problem is.

For instance if you know that it occurs on all magnifications, then you know you can rule out the objectives as the problems. If you can see it through both the eyepieces and camera, then you can rule out the camera and the adapter. If seen at higher magnification and not lower, than it is most likely not a condenser problem.

If you see it at lower magnifications then it could be several problems, but try to eliminate some of the variables at play. If you can answer some of the above questions for me, I might be able to guide you in a bit better direction.

Good luck!