How to mount a microscope objective on a bellows?

arlon · Post by **arlon** » Fri Jan 11, 2008 5:48 am

Or is there even any point in trying? I just have a 10x objective from an old microscope and thought it would be fun to try getting to focus through a bellows on my D200. I have nikon and t mount bellows to play with.

Tony T · Post by **Tony T** » Fri Jan 11, 2008 7:52 am

Certainly worth trying. For a 'quick and dirty' trial just stick a piece of card (black on inside) to bellows opening, punch hole in card, screw in objective:

to see some results click HERE top of 2nd page

waltknapp · Post by **waltknapp** » Fri Jan 11, 2008 11:23 pm

For a slightly less quick and dirty method, use a body cap. Preferably black and soft plastic. Drill a hole through the center just slightly under the screw thread diameter so the threads will bite. Screw the objective into that and attach it to your bellows.

augusthouse · Post by **augusthouse** » Sat Jan 12, 2008 12:33 am

Definitely worth trying...

I managed to find a Nikon to RMS adapter on the net when I was looking for a solution.

They are usually expensive as far as adapters go; but they are out there.

Here is an example. For this particular one you would also need a Nikon to M42 adapter.

http://cgi.ebay.com/Carl-Zeiss-Luminar- ... dZViewItem

patience · Post by **patience** » Sat Jan 12, 2008 1:10 am

Another not very inexpensive way is an adapter sold by Edmund Scientific that adapts a microscope objective to a T-mount. It costs $27.50 plus about $10.00 for UPS to deliver it. Take a look here:

http://www.edmundoptics.com/onlinecatal ... uctID=1968

Their description is:
"Ring mount with an interior thread (20.1mm / 0.7965" Dia. 36 TPI, 55° Whitworth) that accepts all DIN standard microscope objectives. Front face has male external T-thread and back face has female internal T-thread. Adds 11.5mm to system length."

Mine arrived a few days ago but I haven't tried it since I forgot to order a T-mount to Nikon adapter.

Thanks to all of you for the brilliant discussions that have inspired me to buy a bellows and start taking some pictures. Maybe I will have some results by the end of the Summer.

Roy

Charles Krebs · Post by **Charles Krebs** » Sat Jan 12, 2008 1:01 pm

Greetings Roy...

Maybe I will have some results by the end of the Summer.

It would seem that your screen name is well chosen!

But I suspect you'll have some results long before then.

arlon · Post by **arlon** » Sat Jan 12, 2008 1:28 pm

Thanks for the replies. I think I'll give a go at some home brewed adapter to start with. If I can get anythig at all out of it, I'll spring fore the Edmunds adapter...

Harold Gough · Post by **Harold Gough** » Wed Mar 12, 2008 4:10 am

Whilst it must be possible to use a microscope lens for such a purpose what is gained e.g. over the characteristics of a 20mm bellows macro lens?

It would be an unusual microsope lens that had a diaphragm, that normally being located below the microsope stage.

Are there any linear or colour abberations which might be corrected by the microsope eyepiece in normal use?

augusthouse · Post by **augusthouse** » Wed Mar 12, 2008 4:33 am

Hi Harold,
In reference to your third question; this topic has been discussed in some detail recently. The link below should provide some relevant info.

I'm just a little fish, but I am sure the big guns on the forum will be able to offer additional information.

http://www.photomacrography.net/forum/v ... 21&start=0

Craig

rjlittlefield · Post by **rjlittlefield** » Wed Mar 12, 2008 7:34 am

Harold Gough wrote:Whilst it must be possible to use a microscope lens for such a purpose what is gained e.g. over the characteristics of a 20mm bellows macro lens?

Significantly higher resolution. See http://www.photomacrography.net/forum/v ... .php?t=424 for head-to-head comparisons including 10X NA 0.25 microscope objective versus Olympus 20 mm f/2 bellows macro and Luminar 16 mm f/2.5.

--Rik

Charles Krebs · Post by **Charles Krebs** » Wed Mar 12, 2008 8:55 am

Harold,
Some additional thoughts to Rik's reply...

The use of a microscope objective is likely not an option if the image is to be made in a "single shot" (unless your subject is extremely flat!).
For a "single shot" image it is usually necessary to arrive at a compromise between acceptable DOF and resolution through use of the lens diaphragm.

Those of us who have pressed microscope objectives into service on bellows inevitably are using "stacking" software like Helicon Focus or CombineZ to process multiple images taken at different focus points into a single image.
The increase in resolution (and apparent DOF) made possible by working in this manner is quite significant at higher magnifications.

There are some caveats...

You are pretty much limited to subjects that are completely stationary.

A microscope objective projects a much smaller image than most macro lenses, so adequate "coverage" on the camera sensor can sometimes be an issue. Most would not cover a "full frame" 35mm area when used at the designed magnification, but are very usable on the digital SLR's with sensors smaller than 24x36mm.

Many of the "finite" microscope objectives will not be fully corrected for chromatic aberrations (by design... this was intended to be accomplished by eyepieces with addition optical corrections). With some it is so noticeable that they are really not too useful for this purpose. If the CA is mild it can often be corrected in a digital image with software. But it can be avoided. The best objectives I have found for this use are Nikon "CF" objectives, particularly the 10/0.30 CF N Plan Achro, and several of the CF M-Plan series. These were designed with full chromatic corrections in the objective itself. (And they also seem to have a very flat field as well).

Working distances can be very small. With many objectives it is too small to be practical. So that is a specification that must be considered.

Harold Gough · Post by **Harold Gough** » Wed Mar 12, 2008 9:03 am

Charles,

You have covered the general flavour of why this is way down on my list of priorities. Most important is that most of my subjects are active, getting them in the field of view and in focus being challenging.

It's just that the lenses are at hand....

Harold

Charles Krebs · Post by **Charles Krebs** » Wed Mar 12, 2008 9:23 am

Harold,

Like many techniques, it has it's weak and strong points. I find myself using "conventional" macro optics up to about 10X. Beyond that, the loss in resolution due to diffraction with these "conventional" lenses is too great for my tastes, especially on SLR cameras... the "effective apertures" simply become too small. This is where the objective/bellows technique really starts to becomes useful.

(Back in the days of 4x5" sheet film, the Luminars -and similar optics - were perfect for the job. They were able to "cover" the large film area, and the effects of diffraction were less noticeable when the subsequent enlargement was only 1X-3X)

Harold Gough · Post by **Harold Gough** » Wed Mar 12, 2008 9:30 am

That lets me off the hook nicely, in that I am strictly 35mm.