Thanks, but of course I did that before I posted the link. The mfr. image shows it attached to a spotting scope, not a microscope. I was interested in assessing if there might be a balance problem due to the weight of the camera and appliance when attached to a mic.
so here's the adapter attached to the right occular of my scope:
here's the same with camera added:
and here's what is displayed by the camera screen (as you can see the image of the stone through the camera screen is so small that you cannot judge how the picture will be from looking at this screen): I tried to zoom with the camera but for some reason it didn't make the image bigger, and only greatly decreased the luminosity.
Could someone tell me if there's a way to get a full image on the camera screen (instead of getting the small circular image in the middle of a black field)?
Last edited by cascaillou on Wed Jan 18, 2012 2:08 pm, edited 1 time in total.
Joined: Fri Feb 24, 2006 1:20 am Posts: 2756 Location: Southern California, U.S.A.
cascaillou wrote:
Could someone tell me if there's a way to get a full image on the camera screen (instead of getting the small circular image in the middle of a black field)?
Thanks cascaillou, your images answer my questions about balance very nicely.
I've wondered the same thing about image size; I had the same problem when I rigged up a Rube Goldberg (anyone remember him?) trial contraption with a tripod for microscope shots. Maybe some of our optical gurus can ride to our rescue
Have you removed the ocular?? If you have put it back. You are not getting enough magnification. You also may not be focused on the eyepoint of the ocular. You should be able to make some Z axis(focal distance)adjustments and get the whole imaging chip covered.
The camera holder looks nice. There is a cheaper one made out of metal that will do about the same thing. Search Orion Telescopes dot com. The GemOro is a little small and light for that purpose but where there is a will there's a way.
You also might need to buy a 15x or even 20x ocular to fill your frame. Remember that the ocular lens diameter on the Gem Oro is 30.5mm . (Measure yours to make sure they didn't change anything when I wasn't looking. The last one I had in my loathesome clutches was a 30.5) http://www.ebay.com/sch/i.html?_trksid= ... 5&_sacat=0
You ARE on the right track though unless there is something weird or strange about your camera. It should be focus locked at infinity. Changing the Wide-Telephoto focal length ought to help. Usually the cameras own zoom lens will act as a relay lens and this has been widely exploited by microscope hobbyists. (notably with the Nikon Coolpixes)
The camera should NOT be set to macro mode. Like your eye when looking through any scope, it should be focused at infinity. It needs to be set to view a distant scene. The microscope is sort of acting like a macro lens the way Jamie meant it. But macro lenses are simple magnifiers stuck in front of the camera lens. With them you set the camera at some close usually closest setting and the macro lens actually makes it possible to focus closer. Exactly like on eye loupe. A scope is a compound magnifier and thus needs the camera focused at infinity. There is also a third category of macro lenses which are only useable on SLRs and on bellows and do not apply generally to point and shoot class cameras.
A way to see what the camera is seeing is to take the video output which most of these cameras have and feed it to a small screen on your work table. You can of course also try to look through the other ocular if the camera lets you get close enough. That is why "real" camera adapters were invented for scopes.
thanks for these guidelines. I'll have to experiment further until I find the trick. I'll report how it goes (and I'll try with another camera just in case there's something wrong with mine).
Joined: Fri Feb 24, 2006 1:20 am Posts: 2756 Location: Southern California, U.S.A.
G4Lab wrote:
Usually the cameras own zoom lens will act as a relay lens and this has been widely exploited by microscope hobbyists. (notably with the Nikon Coolpixes)
Thanks for responding to my shameless plea for help Gene.
I plan to use a Nikon Coolpix 4500 for this experiment. Would you be generous enough to translate what you mean by "relay lens" into layman's terms? My Coolpix features 4X optical and 4X digital zoom. How does one "exploit" the zoom feature in the microscope application? TIA.
Your 4500 should work just fine. Just lock it at infinity focus. Get the video cord and plug it into your TeeWee. Use any of the abovementioned adapters. The one cascaillou is using looks fine though Orion is closing one out for $20 and it may have better depth control.
You do the same thing you did on the Rube Goldberg setup. Focus at infinity and adjust the zoom to suit. The ends should be something like on the wide angle end there will be vignetting like above. On the Tele end you could end up with increased magnification (which could well be desireable) and not picking up the whole view as seen through the oculars.
A relay lens is just one or more lenses to relay the image from the back of the objective lens to the film or sensor plane. Sometime you use an ocular and a separate lens (like when you use a Wild 10x ocular and then a 0.32x relay lens.) other times just a photo ocular (like if you just stuck a 2.5x or 4x photo ocular instead of a 10x times 0.32x equals 3.2x) Then there is the afocal technique where you don't use an eyepiece at all and possibly no camera lens either. The microscope objective just focuses on the film or sensor.
You should get fine results with your Coolpix and I think cascaillou will too when he figures out what isn't quite set right.
however it's not impossible that I uncalibrated the objective settings as I often manualy help the objective to spring out of the casing since dust from the mines has made its way into the mechanism and it would often refuse to spring out unless I pull it out myself...underground mines are not the best place to make digital cameras fully happy, but hey, that's where I do feel happy
I checked with a friend who knows more than I about these matters.
His replies:
Quote:
Gene,
All the posters in that thread are running into the standard problem where the entrance pupil of the lens is too far back to match up with the eyepiece's exit pupil, so they're getting serious vignetting. Unfortunately there's no real cure short of replacing the eyepiece and/or the camera. It helps to make sure the camera is set to leave the aperture wide open (aperture-priority mode with smallest available f-number). You should play around with various zoom settings to see which setting vignettes the least. The best place can be anywhere -- full wide, full telephoto, or anyplace in between. Sometimes the best place will be quite good, sometimes pretty bad. The problem depends heavily on gory details of the camera lens that are never published, so try-it-and-see is the only way to know. It also depends on details of the eyepiece. An eyepiece with a "high eyepoint" (exit pupil far back from the eyepiece) generally works better.
With some cameras, especially cell phones, you have the opposite problem that the entrance pupil of the camera is far forward so you get vignetting when the camera is very close to the eyepiece. But in that case the cure is easy -- just move the camera farther away.
Quote:
Quote:
I was under the misteaken misapprehension, that any point and shoot, could do the shoot into the ocular trick.
I suspect that's a pretty common misconception.
But here's a simple experiment that shows the basic problem. Close one of your eyes and position the other one at the microscope eyepiece so that you get a perfect view of the full field. Now slowly move your eyeball away from the eyepiece. As you do that, you'll notice that you see less and less of the full field. Light rays from the periphery of the field, diverging as they leave the eyepiece, just never enter the pupil of your eye. The same thing happens with many cameras, because the camera's pupil is buried deep inside the lens and can't get close enough to the eyepiece to see the full field.
Last edited by G4Lab on Sun Jan 22, 2012 4:44 pm, edited 1 time in total.
All the posters in that thread are running into the standard problem where the entrance pupil of the lens is too far back to match up with the eyepiece's exit pupil,
I hope this is not my case, because I can't get the objective of my camera closer to the scope eyepiece (all pics I posted were made with cam objective right against scope ocular) I've 10X, 15X and 20X eyepieces for my scope (the bigger the magnification, the smaller diameter the lense), which do you suggest me to use?
Your output image darkens when you zoom. Try manual setting, follow above guidelines as to aperture and focus. Because you are shooting a stationary object, you can use a long exposure (won't work very well hand held). Doing so will compensate for dimness.
ALSO, manually set your ISO or Din to a higher #. You may find a balance where there is no appreciable introduction of artefacts in your images. Some cameras (like mine) will not allow disabling of noise reduction features on longer exposures. Try disabling if you can. I have posted several pics here where NR was enabled with fine results in spite of it.
Joined: Sat Jul 11, 2009 10:29 am Posts: 928 Location: USA
I can't add much more info. Once you get camera proper distance to eye piece it won't be like this. Zoom should help, it does on all my cameras. You shouldn't be in macro mode, but, some cameras in my experience do work better with it. On my one camera I get a tiny bit of vignetting but I just crop it out. But it gets that way because the adapter won't let the camera get far enough away to use a high enough zoom.
I finally succeeded in getting a full screen view on the camera screen, thanks to the camera zoom. This allows me to set F=4 (the smallest F my cam can do is 3.5 but that doesn't allow me to zoom enough to get a full screen view, and maximum F is 10)
I could also set focus to infinity.
Now, in manual mode, I have to choose ISO and speed.
here are the ISO my camera features: iso automatic, iso100, iso200, iso400, iso 800, iso1600, iso 3200
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