Thus, we decided to buy a new camera and suddenly I found out that there are a lot of companies which sell scientific cameras. I had no idea which criteria are important and where I should start searching, so I began talking to people who had bought cameras recently and that was unbelievable helpful!
So far, I have been interested in "normal" photography and I cared a lot about resolution, aperture width and imaging speed. Looking for scientific cameras is different, but I was still comparing resolution in terms of nanometer-per-pixel ratio and the number of frames per second (like 100 frames per second, unlike 0.5 or 1 second for touristic photos). In addition to that, the data transfer speed to the computer was important (plus: can we use USB 2.0 or 3.0?) and if we needed a frame grabber card (which is supporting the image transfer). Our computer is running the camera control software LabView which has to be compatible with the camera.
With this list of criteria, I found about six interesting cameras and we were able to find our "perfect" one - it arrived last week, yay!