Advice on trinocular port camera. Is this normal? What adaptors/camera? - Page 1
Forum section: electronics / general

author: KL27x
author_rank: Super Contributor
timestamp: February 15, 2019, 12:54:25 am
content: ()I want to buy a camera for my microscope. It has a trinocular port with the slider that blocks out the left eye.I believe this is what is called a "photo port." It has an aluminum cap that screws out which the threading is 25mm in diameter. Then there's a smaller tube below this, which is about 16mm in diameter (and it is also threaded?!)When the slider is pulled out all the way1. there is an obstruction in the view. You can see it in the linked picture. It covers a third of the view, towards the bottom and to the left. Is my microscope defective?2. When viewing by naked eye, the image doesn't come into focus until my eye is 16" away from the top of the photo port. Is this normal? This seems super excessive. I have to stand on a chair to see (the half of) the image.Assuming this is normal, do I just buy one of these?https://www.amazon.com/AmScope-CPC-Adapter-Converting-C-Mount/dp/B007LBDXAA/ref=sr_1_1?ie=UTF8&qid=1550191968&sr=8-1&keywords=photo+port+to+c+mountAnd screw in the c mount camera? How does the focal length get to 16"? I suppose the c mount camera takes care of that? I actually bought one, though, and there's no lens on it. It looks like there's just a sensor right on the end of the camera. I suppose the area of the sensor on the camera means that it will be able to be much closer, of course.*I think I figured it out. I'm guessing you need two adaptors. There's a photo tube adaptor that can extend up/down with a set screw,l which is just a hollow tube. And then there's another reducer with optics. Then the camera. So I think you need at least 3 things.

author: jfiresto
author_rank: Frequent Contributor
timestamp: March 16, 2019, 01:19:38 pm
content: I only recently stumbled onto this thread. Then I got distracted, documenting some issues with a pair of Zeiss eyepieces I won off ebay that were "optimistically" described. That, in itself, is kind of interesting, but grist for another thread.Not everyone has gotten good images out the Amscope photo ports. So I would suggest you first test yours to see if it is up to snuff.Install or use 10X eyepieces, if you have them, and place a contrasty specimen under the microscope that spans the field of view at minimum power. I use a bright white page with fine, black text.Make sure your microscope is parfocal. As a reminder, first fully open the microscope's apertures if it has them. Then zoom in to the highest magnification and focus on the specimen. Without disturbing the focus, zoom out to the lowest magnification and adjust the eyepiece diopters so that the specimen is in focus. Zoom all the way in, again, and confirm the specimen is still in focus.You may have to repeat the above to find the happy, parfocal medium.Now zoom all the way out, direct the image out the photo port and check the image. The photo port, if it is like the ones I know, projects a real image some millimeters to centimeters above the outlet. Hold a clear object with a matt surface above the outlet, move it up and down, and note where the image is in best focus. I found a magnifying visor, brighter light on the specimen, and a dimmer room, help.You could use a glass slide that has been sanded on one side, but what really works for me is a clear drafting stencil that is frosted and printed on one side:Remove an eyepiece and see if it has an external field diaphram, a clean aperture upstream of the lens glass whose diameter is exactly the eyepiece's field number (21mm for a 10X/21 eyepiece):If it does, hold the eyepiece over the photo port with the diaphram at the height that gave the sharpest image. If the diaphram is surrounded by glass, you may have to move the eyepiece a bit more. Look through the eyepiece, move it up and down around that height, and see if you are happy with the image.

author: KL27x
author_rank: Super Contributor
timestamp: March 18, 2019, 01:43:38 am
content: Thanks for the help.I don't understand most of what you wrote, but I have already made my microscope parfocal. My GF messes it up from time to time; it is pretty obvious she can't see through both eyes at the same time, because she prefers to focus the microscope by turning one of the eyepieces.When I hold an eyepiece 3-4 inches above the photo port, I can see a clear, focused image that has been reversed. And the FOV seems to cover a bit larger area than through the eyepiece, proper, so the artifact that is in the way doesn't appear to impinge over what can be seen in the microscope.This seems to confirm what I thought... I need some special adaptor made in China (the bundles with microscope plus camera seems to have a single adaptor), or I need a combo of two adapters including the adjustable length photo port (to C mount) adaptor. The only question then is do I need a Cmount with a reducing lens or not. I guess I just have to spend some money and find out.

author: jfiresto
author_rank: Frequent Contributor
timestamp: March 18, 2019, 09:17:01 am
content: I did not mean to be unclear. I have a bad cold and am a little groggy.What you report is very encouraging.Are you happy with how the eyepiece frames the image out of the photo port? If you are, what is the eyepiece's field of view in millimeters (the second number of e.g., 10X/22)?How many millimeters above the photo port is the focused image?With those numbers, I can make some suggestions to reduce the trial and error that I often experience with incompletely documented, low cost adapters.

author: KL27x
author_rank: Super Contributor
timestamp: March 18, 2019, 09:36:25 am
content: Jfiresto, I really appreciate the help so far. If you can make any other suggestion, I'm all ears.The eyepiece says 10x/20The framing looks good, but it is hard to say what it will be when the camera is fixed. I mean, I can move the eyepiece around a little bit to center it on what I'm looking at. There's a little bit of excess border that I can't see if i keep the eyepiece in one spot.If I measure from the top of the photo port to the top of the eyepiece* where it is in focus, the distance is 100.8mm +- a couple mm, maybe, lol.... when the scope is zoomed in. And I can see just about exactly the same FOV as thru the normal eyepiece.But if i zoom out, the distance is still 100.8mm, which I take it that is good. But the FOV decreases a bit compared to the normal view.*The top of the eyepiece is without any rubber cushion on it. The top of the lens is maybe a mm or 2 below the top of the eyepiece.

author: jfiresto
author_rank: Frequent Contributor
timestamp: March 19, 2019, 05:03:21 pm
content: Quote from: KL27x on March 18, 2019, 09:36:25 amWell, I would really like to see what sort of pictures you can get out of your microscope. Are you after stills or movies or both?I suspect it uses the same lenses to project an image out the photo port that it uses for one of the eyepiece tubes. Does the microscope let you use view through both eyepieces and the camera, simultaneously, or does one eyepiece go dark when you direct the view to the camera port?QuoteThat all seems cool. I am trying to encourage the idea that you want to know the height of the sharp, projected image above the photo port, and the diameter of the image. Those two numbers will suggest how best to capture it with a camera. They will also suggest whether the adapter(s) you will consider are going to work. (There can be a bit of trial and error in all this).QuoteThat all seems o.k. You need to know, however, the height from camera port flange to the eyepiece's focal point. Do you see the collar inside the above eyepiece, about 10mm above the bottom? A broader white flash bounces off of it. Does your eyepiece have a similar collar, that in your case, narrows to a 20mm opening? That opening is the focal point. You want to know the height from the camera port to there.You can also get the image height and diameter by holding a matt target above the camera port, as I describe earlier. I like this method because you see the actual image that you want to capture and photograph. The above, drafting template makes a good target as you can directly read off the image diameter.In both cases, you want to find and measure the image with the microscopeat its lowest magnification, fully zoomed out. (No need to repeat a mistake I once made.)

author: KL27x
author_rank: Super Contributor
timestamp: March 19, 2019, 08:53:18 pm
content: Thanks, again. I'll try doing the paper test when it gets darker. Fully zoomed out. I still don't know what you mean by the underside of the eye piece. It looks like there just a single lens in it, and the ID of the aluminum tube appears to be 20mm, extending about 3/4" (or maybe less) below the lens before it flares out to a larger diameter. I don't want to scratch the lens, so I'm just eyeballing the distance.I'm not sure why it would matter: Photos are probably more important, but I also want to take video. My microscope is not "simulfocus." The left eyepiece is blocked out when using the photo port.

author: jfiresto
author_rank: Frequent Contributor
timestamp: March 20, 2019, 12:49:31 pm
content: Quote from: KL27x on March 19, 2019, 08:53:18 pmI bet tracing paper would be good. I see a nice image through every drafting template I have tried, parchment paper, and "clear" polyethylene bags that are actually a little cloudy.QuoteI don't think I have every seen an eyepiece like that. Could you post a picture of the inside, like the one earlier? All mine are thicker near the eyeball (from en.wikipedia.org/wiki/Eyepiece):Here1is the image from the microscope, captured by the eyepiece, and2is the 20mm collar ("eyepiece diaphram") I am thinking about.QuoteTaking still pictures tend to be more demanding, or rather, people seem to be less demanding if the picture moves. What microscope do you have?QuoteMore light for the camera.