Raynox with Mitutoyo Objective

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GreenSugar
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Raynox with Mitutoyo Objective

Post by GreenSugar »

I have reviewed some of the other posts on this topic but remain a bit confused. Currently, I am using a Mitutoyo 10X M Plan APO Objective with a vintage Nikkor 200 mm as a tube lens. I have seen others mention the use of a Raynox 250 with a bellows in place of the Nikkor 200 mm, and would like to get feedback if this is a viable configuration, pros, cons, or any additional details on the specifics of the set up. Thanks
PaulF209

rjlittlefield
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Post by rjlittlefield »

Most commonly used is the Raynox DCR-150, which has nominal 208 mm focal length. The DCR-250 is shorter, nominal 125 mm focal length, so it gives lower magnification.

The main advantages of Raynox DCR-150 compared to various telephotos are that 1) the DCR-150 is completely free of vignetting on all sizes of sensors up to full frame 24x36mm, 2) it gives good image quality corner to corner, and 3) it is inexpensive and is still being manufactured, so it is simple to buy.

You can see a typical setup with discussion at http://www.photomacrography.net/forum/v ... hp?t=35350 . Note that the Raynox is "reversed" in that setup, with the Raynox male threads facing the objective. Current recommendation would put it the other way 'round, in the "normal" orientation with male threads facing the camera. Optically the DCR-150 works well in either direction, but it is simpler to mount in the "normal" orientation and some people have reported slightly better image quality that way.

If you are currently getting good results from your vintage Nikkor 200 mm, I don't know any good reason to switch. But if the corners of your images are darkened or soft, then switching could make things better.

--Rik

lonepal
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Post by lonepal »

FYI.
You can also use a Sigma Life Size Adapter which is +5 diopter and equal to 200mm FL tube lens.
Regards.
Omer

GreenSugar
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Post by GreenSugar »

The results with the old Nikkor are ok. I do see a little vignetting but it is not a major issue since I usually crop. Overall, I am trying to generally improved the sharpness and clarity of the images. I have heard of many in the micro mineral microcosm using the Raynox and Bellows, hence, came to the belief it was superior to the Nikkor.
PaulF209

JH
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Post by JH »

As you probably already know the objective is much more important than the tube lens. What you probably also know is that a 200mm tube lens (at infinity) gives you 10x magnification and a good quality image circle of aprox. 30 mm with the 10x mitutoyo. If you change the tube lens you change the magnification and the image circle.

I use a short empty tube with my nikon 200mm on a FF Canon. This helps with the corners.

Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

mawyatt
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Post by mawyatt »

JH wrote:As you probably already know the objective is much more important than the tube lens. What you probably also know is that a 200mm tube lens (at infinity) gives you 10x magnification and a good quality image circle of aprox. 30 mm with the 10x mitutoyo. If you change the tube lens you change the magnification and the image circle.

I use a short empty tube with my nikon 200mm on a FF Canon. This helps with the corners.

Best regards
Jörgen Hellberg
Hi JH,

So you are operating the 200mm Nikon beyond 200mm? Can you still achieve infinity focus on the 200mm, and is the IQ affected?

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

JH
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Post by JH »

There is a lot of variables at play here so I can not say for sure that the image quality is not affected. In the few ocassions when I used a short empty tube with a Nikon 200 mm the quality looked the same with and without the empty tube - even though the focus was not at infinity. At least in the center of the picture you can probably be off by a few centimeters with a 200 mm tube lens before you see disturbing degradation with the Canon cameras I use.

Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

GreenSugar
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Joined: Sat Nov 25, 2017 11:03 am
Location: California

Post by GreenSugar »

Thanks for you comments JH, the 200 mm Nikkor is focused at infinity. What is the length of the short tube you are using?

I am confused regarding your mention of a 30mm image circle. With the Mitu 10x, my full fov is just a bit over 3 mm.

Thanks

Paul
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Pau
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Post by Pau »

GreenSugar wrote:I am confused regarding your mention of a 30mm image circle. With the Mitu 10x, my full fov is just a bit over 3 mm.l
3mm x 10 = 30mm
Image circle is at the sensor side while FOV at the subject side. Am I losing anything?
Pau

GreenSugar
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Post by GreenSugar »

Ah ha... eyes opened to 30 mm! Thank you
PaulF209

JH
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Post by JH »

GreenSugar wrote:Thanks for you comments JH, the 200 mm Nikkor is focused at infinity. What is the length of the short tube you are using?
Hi Paul
Short answer approx. 1 cm. Longer answere here:
https://www.photomacrography.net/forum/ ... 114#237114

My conclusion is that if you already have a Nikkor 200mm and want to use a FF camera you should test the Nikkor before you buy another tube lens.

Have a small distance between the microscope objective and the Nikkor. If you still have problems with dark corners focus closer than infinity or use a short extention tube. Make sure that the extension tube does not add vignetting.

Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

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