Raynox Tube Lens

by Johan J Ingles-Le Nobel
Last updated May 13, 2017

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Besides being most excellent macro diopter lenses, a Raynox can also be used as a tube lens for an infinite objective.

Mounting A Raynox Tube Lens

For best IQ, the Raynox must be mounted at one of its own focal lengths from the sensor, so that it focuses at infinity. The separation between objective and Raynox that may change the image circle but not the IQ.

The Raynox DCR-150 is (250mm) and the Raynox DCR-250 is (125mm) -- the equation is 1000/diopter to get the mm. So ideally, a Raynox DCR-250 should be located 125mm from the sensor, with the CFI60 10X positioned somewhere between 140 and 200mm (maybe more) from sensor plane. It seems to play well in this region.

Raynox Reversed?

my image quality seems to improve if I have the Raynox very close to the front element of the microscope objective

Tests at PM.net show that the image quality does appear to be improve if the Raynox is mounted in reverse. The Nikon MicroscopyU site recommends distance between lenses for better optical performance and in at least one setup the 150mm distance range seems to work well, which is in the middle of the Nikon recommendations (100-200mm).

That said I've personally found that my image quality seems to improve if I have the Raynox very close to the front element of the microscope objective so there is possibly some more empirical testing to be done with respect to these apparently contradictory conclusions.

The DCR-150 at 208 mm will give very close to rated magnification with the tube lens focused at infinity; the DCR-250 at 125 mm will give about 62% of rated magnification, with a correspondingly wider field.

Raynox As Closeup Lenses

Besides making a fine tube lens, Raynoxes are of course intended as macro diopter lenses and I must mention this here, as their quality is excellent.

For Canon folk, the Raynox DCR-150 is a good choice to start with a kit 18-135 IS lens. It is a +4.8 diopter lens, focal length about 210 mm. Used in front of a 18-135 IS lens, it will go up to about 0.65X, so a field width of about 35mm on a 550D.

Should you seek higher magnification, you might go up to the DCR-250 at +8 diopters, which will get you to a little more than 1:1, about 21 mm field width.

A nice, but discontinued diopter set from Raynox, is the Raynox CM-3500 set. The most powerful of the three is identical to the excellent MSN-202 diopter. The +12 lens in that set works well in combination with a 100/105mm macro lens and an APSC sized sensor.

Comments (3)

Article: Raynox Tube Lens
Max Rockbin says...
Thanks for the detailed info! I was looking for measurements and suggestions for mounting a Nikon objective on my bellows. It seems like the really hard part with this Raynox setup is the adapters! 49mm female on the front of the Raynox, 43mm male on the back. The Front is pretty easy since they RMS adapter can be purchased as RMS > 58mm and you can work your way down from 58-49 with nothing exotic.

But how about connecting to the bellows (or tubes)? It seems like you have to use an adapter from M42 to whatever your bellows brand is, which gives you Female m42. Then you have to get from there down to 43mm Female. There are 42-43mm step up rings on ebay, but I'm not sure if they're M42 (1mm thread) or filter size 42mm (0.75mm thread). Probably the latter... I ordered one anyway since it was $2, so I guess I'll find out.
10th December 2014 12:50am
Johan says...
This can be tricky, yes. I use a Pentax bellows which has a detachable front, and the Raynox fits inside that.
10th December 2014 5:36am
Harold Gough says...
I have a Raynox MSN-202. It does not have a hood as part of the kit and I feel that one is important, for minimising flare and for protection for the front of the glass. I measured the front of the mount and decided that a 43mm push fit might do nicely. I have just received a "Vintage 43mm Chrome/Alloy Lens Hood - Push fit" and it fits like it was made for it. The hood is one of the not-very-deep types, thus helping with access for lighting, but will still use about 21mm of working distance. Such hoods are available cheaply on Ebay, often for Kodak, and cost just a few pounds.
4th December 2013 11:43am
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