RMS micrscope objective 52 mm adapter

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vocci
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Joined: Sat Jan 07, 2017 7:13 am
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RMS micrscope objective 52 mm adapter

Post by vocci »

Greetings all-

My first posting on this forum. I have been doing macro for years - using many different systems - but I want to try a microscope objective on one of my conventional Nikon lenses.

As I understand it, I need an RMS (0.8 diamx36) adapter with a 52 mm thread on the lens side.

I believe there are two varieties: a "flat" one and a cone-shaped one. Would anyone be able to enlighten me on the advantages/disadvantages of each?

Thanks-
Vocci

Pau
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Location: Valencia, Spain

Post by Pau »

Hi Vocci, welcome aboard!

- To mount on a lens you need an infinite corrected objective

- some infinite objectives have RMS mount, but there are several wider ones, so better first select the objective

In general flat adapters are better:
- because they have less flare issues due fo internal reflection
- if you want to mount the objective on a photo tele lens to put them as close as possible

Cone adapters could have some advantage for illumination because the narrower angle and could provide the adequate distance between objective and tube lens when using an original TL or a close up lens like the Raynox, but they need to be flocked to avoid glare.

Lots of info at http://www.photomacrography.net/forum/v ... hp?t=12147 and at much others posts at the forum
Pau

vocci
Posts: 6
Joined: Sat Jan 07, 2017 7:13 am
Contact:

Post by vocci »

Thank you, Pau - truly appreciate it!

vocci
Posts: 6
Joined: Sat Jan 07, 2017 7:13 am
Contact:

flat (non-cone) RMA objective adapter

Post by vocci »

Greetings Folks-

So I just received my flat 52 mm to RMS objective adapter and hooked it up to my 50 mm macro. I have a 4x infinity lens mounted on the adapter.

I looked through the viewfinder and I can see my subject, but most of the viewfinder is black with only the subject visible through that small circle.

Is that normal?

Thanks-

Vocci

Pau
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Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

Yes, the normal lens to work with an infinite corrected objective is about 200mm
Pau

vocci
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Joined: Sat Jan 07, 2017 7:13 am
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Post by vocci »

Thanks so much, Pau. I have an entire collection of objectives from 4 to 100. Would any work on the 50 mm lens? Or is there a calculator on your web site that I can use to figure the best objective/lens/distance?

Thanks-

Jim

Pau
Site Admin
Posts: 6051
Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

First take a look at:
http://www.photomacrography.net/forum/v ... hp?t=12147

also search at the forum for "tube lens", be aware that you will get hundreds of results.

In short, infinite objectives are designed to work with a converging lens called "tube lens" to project a real image at a finite distance. The focal length determines together with the objective the magnification but because the image circle is limited you will get vignette if you use a too short FL lens as you're doing.

Most microscope manufacturers use 18Omm to 200mm tube lenses. Usually camera lenses of that focal work quite well, in some cases you can use lower FL down to 100mm and still get a good image at reduced magnification, but not a 50mm!
Coverage of different objectives can vary but not up to this point.
Pau

vocci
Posts: 6
Joined: Sat Jan 07, 2017 7:13 am
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Post by vocci »

wow, thanks Pau. I just slapped on the 105 macro. Much better!

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