Conversation interspersed. ----- Original Message ----- From: Dr E D F Williams Subject: Re: Advice for a microscope for photog. purpose?
> A binocular stereo microscope has two separate objectives. A transmission > light microscope a 'compound microscope' has one objective, but may have a > binocular head, or even a head with a binocular and a vertical photo tube. > The beam is split and 50% goes to each ocular. But both eyes see the same > view. In a stereo microscope the eyes are seeing a true stereo picture > through two separate objectives spaced some centimetres apart and focussed > (angled) at the same spot in the centre of the stage. I figured that out, even as I hit send. > > The magnifications obtainable with a good compound microscope approach the > theoretical limit of about 1250X for visible light. Stereo microscopes work > between 5X and 200X although some go higher. Anything about 150X is > impractical. This is a very good instrument, I think. My father in law used it at the cancer lab he managed, and when he retired, they gave it to him as a going away present. It is called a Leitz Wetzlar, and would have been produced in the late 1970's, or thereabouts, possibly into the 1980s. > > By putting a camera on one of the oculars (eyepieces) of your microscope you > got 50% of the available light, but also added noise to your picture > from reflections inside the unused side of the optical system and the beam > splitter and prism. There are at least ten glass surfaces that would have > been bouncing light up and down the tube. The only way to take decent > pictures > with a compound microscope is through a vertical phototube without any extra > glass surfaces to degrade the image. This makes me question the usability of any microscope of this type for any purpose at all. The act of putting the camera onto the instrument isn't going to have any effect, either good or bad, on the quality of the image, or the degree of flare from stray light. I can only presume that what you are telling me is that this type of microscope is fatally flawed. I have been seeking a phototube for it, but alas, with no luck as of yet. If as you say, the design is flawed to the point of being unusable, I will stop looking. It does surprise me that a company with Leitz Wetzlar's reputation would put crap onto the market, especially the medical research lab market. > > I've just had a look at Microscopes from Nightingales in Florida. They have > a number of beautiful instruments for sale. Many have solid stands that > would support a camera perfectly well. There is even one, a Leitz Ortholux, > with an automatic camera included. I think it was about $3500 and quite > reasonable at that. Perfect for an amateur who is really serious about the > job. The objectives and eyepieces included were Planachromats, specially > made for photomicrography. There were a few others like the fine Zeiss GFL > ( I had two of those) but they don't support cameras very well, an external > stand is always needed. For that kind of money, I would forgo anything that would be a 35mm accessory, in favour of a bigger format. > > Quite a few of the instruments offered are modern enough so that it would be > possible to buy a vertical phototube to which the Pentax K adaptor could be > fitted. An LX would be the ideal camera for the job. That it is. William Robb
