Hi Adam,adampembs wrote:. . . My main reason for a dedicated camera is for size measurements of spores. . . .
If you were to use Micam software (possibly other scope software would work in a similar manner), provided that you can hold the camera such that you are pretty constant in the field of view you get, then you don't actually need a dedicated camera, or indeed, any camera that's physically attached to the scope.
All you would need to do would be to photograph a stage graticule using each of the objectives. - Put those photos in a folder, then open them in Micam. You can then calibrate Micam for your scope/camera, from each photo (for each objective) in the series.
To calibrate (for each objective), you open the photo, type in the lens magnification, draw a measurement line between two known points, tell Micam the length of the line in microns. store the settings - job done.
Once that's done, you can simply take photos as you have been doing, store them in a folder, open them from your selected folder in the "Measuring Window" in Micam, and add any measurements, scale-bar, etc.
Micam has now been calibrated, so now knows the length of any measurement line it draws, and automatically shows the length in figures, at the end of each measured line. The only thing you have to remember, is to tell it which objective has been used to take the photo.
NB: The above photo is one of the shots that I did to check the calibration. I simply drew a line between the two points on the photo, and Micam said that the distance was 100µ - which was correct, and thus confirmed that Micam was correctly calibrated for the lens in question.
Provided that you can keep the camera in a reasonably constant position relative to the scope, for every photo you take, (and obviously don't alter the zoom etc, etc.), then your measurements will be reasonably accurate.
Might be worth a try in the meantime, until you decide which route you want to take in getting a scope camera?