DSLR Adapter for Stereo Microscopes

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len
Posts: 43
Joined: Sat Dec 26, 2009 5:51 am

DSLR Adapter for Stereo Microscopes

Post by len »

Hi,

I would like to take photos with canon dslr through ocular tube of my non trinocular Stereo Microscopes with objective 1X-4X .

I read somewhere that dslr are not always perfect with ocular tube. Does anyone has experience with that kind of photo or maybe can recommend the following ebay Adapters:


1. http://cgi.ebay.com/CANON-DSLR-SLR-CAME ... 3ca5e269af
or
2. http://cgi.ebay.com/Microscope-Adapter- ... 27ae0a8b45

g4lab
Posts: 1434
Joined: Fri May 23, 2008 11:07 am

Post by g4lab »

There are two aspects to fitting a DSLR or film camera to a microscope.
The mechanical and the optical. You have found the reasonably priced sellers on ebay for adaptations.

You need something that fits your camera properly.

You also need a piece the fits the ocular tube. These have IDs of 23.2 30 and occasionally 30.5mm so measure before you buy.

The brand specific bayonet or screw mount is usually pretty sturdy. But you need to make sure the scope stand and eyepiece tube is sturdy enough to hold the camera without falling over.


The scope adapter has a projective lens in it. This needs to be the correct magnification to throw an image circle onto the sensor of your camera. It can be a circle wherein the sensor is smaller which uses all the camera pixels or it can be smaller which gives you everything seen in the microscope but wastes some of the camera resolution instead wasting microscope field of view (and possibly resolution) This usually results in projective lenses from 1.67 to 3.5. You have to tell either of those sellers what size chip your camera has.

Then there is also the issue of parfocality. You want to try and adjust the location of the projective so the camera is in focus say when the other eyepiece is so that you can use it to focus and help frame. An LCD screen hooked to the Live View output of the camera is a really useful and necessary thing to do if you have the budget and room on you work space.

The only inherently non perfect thing about a setup like that is that stereo microscopes don't look straight down on their objects. Your view will be at an angle of a few degrees from one side or the other. Depending on the scope you might get better optical performance using one of the macro lens techniques described here on this site.

HTH.

Gene

len
Posts: 43
Joined: Sat Dec 26, 2009 5:51 am

Post by len »

Many thanks g4lab for you thorough reply,
g4lab wrote: You also need a piece the fits the ocular tube. These have IDs of 23.2 30 and occasionally 30.5mm so measure before you buy.
Yes, I notice that one of the seller give also a 23-30mm adapter sleev so it's a bonus.
g4lab wrote: The scope adapter has a projective lens in it. This needs to be the correct magnification to throw an image circle onto the sensor of your camera. It can be a circle wherein the sensor is smaller which uses all the camera pixels or it can be smaller which gives you everything seen in the microscope but wastes some of the camera resolution instead wasting microscope field of view (and possibly resolution) This usually results in projective lenses from 1.67 to 3.5. You have to tell either of those sellers what size chip your camera has.
The adapter is for canon EOS so I hope cheap size and optics are compatible.
g4lab wrote: Then there is also the issue of parfocality. You want to try and adjust the location of the projective so the camera is in focus say when the other eyepiece is so that you can use it to focus and help frame. An LCD screen hooked to the Live View output of the camera is a really useful and necessary thing to do if you have the budget and room on you work space.
Good point, The other eyepiece may not be in focus when the camera is but I'm not sure why to use an extra Live view when I can use the camera live view. In my camera 50D I can also zoom the live view for fine focus checking.
g4lab wrote: The only inherently non perfect thing about a setup like that is that stereo microscopes don't look straight down on their objects. Your view will be at an angle of a few degrees from one side or the other.
Yes you are absolutely right, I guess I'll have to find a way to tilt the object to get perfect dorsal view.
g4lab wrote: Depending on the scope you might get better optical performance using one of the macro lens techniques described here on this site.
Which macro lens techniques are you referring? use a copy stand, bellows etc... ?

Thanks

rjlittlefield
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Post by rjlittlefield »

I see this thread has been hanging for quite a while with an unanswered question. Sorry about not noticing that!
g4lab wrote: Depending on the scope you might get better optical performance using one of the macro lens techniques described here on this site.
Which macro lens techniques are you referring? use a copy stand, bellows etc... ?
Macro lens or reversed enlarger lens on bellows, typically focused with either a screw slide or a microscope focus block. For 1-5X, a reversed EL Nikkor 50 mm f/2.8 enlarging lens focused with a Proxxon screw table would be a good inexpensive choice. Most stereo microscopes have long working distance and relatively small apertures that limit resolution even if there are no other problems. A good macro lens will give the same resolution, typically over a wider and flatter field, and there is less to go wrong with macro lens on bellows than trying to shoot through a scope.

--Rik

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