Hello everyone. I just wanted to show this off--it's hopefully headed to a good home in the area soon. I got this gemolite base at a good price, intending to upgrade it for my own use (with some help from Timur (Energyos) when getting started). It is a gemolite deluxe and came with an American Optics 569 head rather than the equivalent Bausch and Lomb stereozoom. That meant that instead of the somewhat easier-to-source B&L Stereozoom 7, for a comparable zoom factor I had to get an AO (or Reichert) 580 head (baseline 1-6x zoom). These are quite a bit rarer than SZ7s, but if you wait long enough they do come up for sale. I only had to return one broken one in the process which isn't bad. I also got really lucky andgot to buy both a photoport attachment and a 2x auxiliary lens.
I had an earlier thread asking about tightening the focus mount on this microscope--the mount that came with the scope bows out at the center--when I tightened it it ended up with a good grip in the normal focal range no grip if the head was set much lower than that. That didn't matter...until I put a 2x aux lens and basically halved the working distance. Rather than fight that any more I just replaced the entire mount with the one from the base the 580 head came on and it works great, though that focus mount had two set screws that required a very small allen wrench to unscrew. Fortunately the AO parts are pretty compatible.
Also, the clip that holds the darkfield cup in place during tilted was broken, so I had to make one from a bit of spring steel. That part was actually kind of hard--turns out spring steel likes to flex rather than to bend. Who'd have thought.
Anyway, I just wanted to run through all the steps to make it seem harder than it was. Most of it was buying stuff on eBay and using screwdrivers. All that to say I'm excited to have finally sourced all the bells and whistles, with a whopping 120x zoom with 10x eyepieces. More if you want to cheat with the eyepieces. She's a beaut.
I have used Bausch and Lomb eyepieces are the right diameter and the 10x ones I have tried work just fine, but the 20x ones I got on eBay produce an unfortunate chromatic abberation. That said the 20x ones might not be the right type of eyepieces. That said, I did find a company that says they bought out AO's stock when they closed shop or something like that when I was looking for a 2x aux (they didn't have one, though they did have some 1.5x) They did say they had eyepieces too. http://www.imillermicroscopes.com
Post subject: Re: Finished up my AO Gemolite Mark V
Posted: Tue Apr 17, 2018 7:59 pm
Platinum Member
Joined: Tue Jan 02, 2007 8:20 pm Posts: 2659
Although I keep 20x oculars for all my scopes I hardly ever use them. 10x is the regular standard magnification for microscopes. GIA made that 15x for gemolites which is OK but if you want more mag use a 2x auxiliary.
The eye relief for the 20x oculars is so small that you have to have the interpupillary distance and the eyetube focus adjusted perfectly. If you move your head you may lose one image or the other. Doesn't mean anything wrong, just the more mag the ocular the more of a pain scope adjustment becomes.
I have a pair of 33x Bausch and Lombs that fell into my lap. I have never even stuck them in a scope. I don't know why they even made them.
Miller microscopes is a reputable old time scope store. I have found their prices on things remarkably reasonable.
AO and Bausch stereo oculars are completely interchangeable. If you had color fringing there may have been some other problem. This can happen if oculars are cleaned and not reassemled properly. (don't ask me how I know this) or there could be something wrong with your scope.
Well, I decided it wasn't really finished until it's adapted to accept a modern camera. With that in mind I asked around on the microbehunters forum--they recommended I get a dovetail adapter on eBay, which made sense. I picked up a 43mm to 42m thread adapter, along with an adjustable length 42m to 42m extender and a 42m to canon adapter to make a phototube I could attach. Unfortunately I a) measured wrong, picking up a dovetail that was a bit too wide and b) ended up with a dovetail that was about half as deep as the AO takes, meaning that even with the right diameter a good fit unmodified would be unlikely:
Fortunately I have access to a drill press and some free time, so I shaved the edges down a bit and carved out slots for the tabs with some dremel bits (pictured in progress):
I still have a few details to perfect and beautify on it, but I got it to the point that it is quite functional, with a nice tight fit and able to accept the set screw. So I put on an older canon EOS and snapped a few photos for a quick comparison. Unfortunately the camera adapter is designed for a polaroid camera so it has built-in magnification to deal with the larger format. Because of this you get a much smaller area in the camera than through the eyepiece. Here is a quick comparison of the two views, one shot with the EOS through the adapter and one shot freehand with my phone through the eyepiece (both stacks of 6 photos):
That's a pretty big difference!
However, cropping out the equivalent section of the phone picture shows that the canon did at least take a better picture of the small area (phone first, canon second):
That said, it's not entirely a fair comparison since with the phone I could actually zoom in on the subject more and probably get a much higher resolution image.
Anyway, this is kind of interesting. I'm not sure if it would be feasible to add some sort of reducing optics to the adapter to undo that excessive zoom (and whether it would have too bad an effect on the image) but I will be considering the options on that.
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