Reversed Raynox Tube (my version)

bobfriedman · Post by **bobfriedman** » Fri Jun 12, 2015 5:51 am

Based on numerous discussions with Rik Littlefield I finally have my Raynox DCR-150 working and will probably not use the Nikkor 200/4 Ai'd lens as a relay any further with the Mitutoyo objectives..

this version provides infinity focus at aprox. 220mm camera side with the Nikon D800E.. based on Rik's advice i have placed the objective as close to the reversed Raynox as possible..

The PK-13's provide greater structural integrity than the 52mm tubes and i can place a Nikon PN-11 within the group if i wish a tripod collar on the tube. I have flocked the M52 tube length between the Raynox and the PK-13's.

I am now able to attempt non-spec magnifications by adjusting the length of the bellows extension by eliminating a PK-13 or two.. realizing there will be image quality consequences.. so far results have been good.

rjlittlefield · Post by **rjlittlefield** » Fri Jun 12, 2015 11:15 am

Bob, this looks good.

To clarify for others, the motivation for mounting the objective close to the Raynox in this case is to give maximum ability to adjust magnification by changing the rear extension. The system focal length of a combo can be calculated as 1/f = 1/f1 + 1/f2 - d/(f1*f2) [ref]. Increasing the separation d also increases the combo focal length f, and that reduces the available change of magnification which is delta_mag = delta_extension / combo_focal_length.

There is further discussion of this effect at http://www.photomacrography.net/forum/v ... 703#169703 and in the surrounding thread, where another member noted that "However, tube length seems to have only a small effect on magnification: with a 10x objective (an Olympus UPlanFL UIS2) I get roughly 9x for 100 mm tube length and 11x for 250 mm tube length". The lack of adjustability in that case traced to a large separation -- about 100 mm -- between the objective and tube lens.

--Rik

Peter De Smidt · Post by **Peter De Smidt** » Sun Jun 14, 2015 3:35 pm

Thanks for the post! I see the PK-13s (of course), and the Nikon K set, but what's the adapter right before the Raynox?

ChrisR · Post by **ChrisR** » Sun Jun 14, 2015 4:56 pm

That would depend which way round the K rings are. Both would be possible!

The Raynox is 43mm at the normally camera end, and 49mm at the normally front/filter end.

Other than Step rings and a Coupling ring,
a common set of parts needs a 52mm female to female (something like a 62 - 52mm through-threaded step down has to be used) , but Bob seems to have avoided the need for that.

RobertOToole · Post by **RobertOToole** » Sun Jun 14, 2015 5:20 pm

rjlittlefield wrote:Bob, this looks good.

To clarify for others, the motivation for mounting the objective close to the Raynox in this case is to give maximum ability to adjust magnification by changing the rear extension. The system focal length of a combo can be calculated as 1/f = 1/f1 + 1/f2 - d/(f1*f2) [ref]. Increasing the separation d also increases the combo focal length f, and that reduces the available change of magnification which is delta_mag = delta_extension / combo_focal_length.

There is further discussion of this effect at http://www.photomacrography.net/forum/v ... 703#169703 and in the surrounding thread, where another member noted that "However, tube length seems to have only a small effect on magnification: with a 10x objective (an Olympus UPlanFL UIS2) I get roughly 9x for 100 mm tube length and 11x for 250 mm tube length". The lack of adjustability in that case traced to a large separation -- about 100 mm -- between the objective and tube lens.

--Rik

Excellent, thanks for the clarification Rik!

Robert

bobfriedman · Post by **bobfriedman** » Tue Jun 16, 2015 2:33 pm

Peter De Smidt wrote:Thanks for the post! I see the PK-13s (of course), and the Nikon K set, but what's the adapter right before the Raynox?

i am sorry i didn't answer earlier.. just noticed

PK-13, K2 (F mount-M52), M52 Male-Male, K rings female-male K4+K5+K4, M49-M52 step up, RAYNOX reversed, M52-M43 Step-down, M52-M52 Female-Female, M52-M26 step down.

ChrisR · Post by **ChrisR** » Tue Jun 16, 2015 3:05 pm

M52-M52 Female-Female

That's the one with print - is that "OM"?

bobfriedman · Post by **bobfriedman** » Tue Jun 16, 2015 3:13 pm

ChrisR wrote:
M52-M52 Female-Female
That's the one with print - is that "OM"?

not sure what the OM means.. but it is a Kenko 52mm to 52mm F-F with the print

the set

http://www.kenko-tokina.co.jp/imaging/e ... 00034.html

ChrisR · Post by **ChrisR** » Tue Jun 16, 2015 3:45 pm

Your linked site says ~$16, other oriental sites $12, Ebay $31 (+ shipping)!
http://www.ebay.com/itm/Kenko-OM-Ring-S ... 33a1c33fb9

It's neater than these, but...
Ebay item 261448691981 (UK) referred to here

bobfriedman · Post by **bobfriedman** » Tue Jun 16, 2015 3:50 pm

ChrisR wrote:Your linked site says ~$16, other oriental sites $12, Ebay $31 (+ shipping)!
http://www.ebay.com/itm/Kenko-OM-Ring-S ... 33a1c33fb9

i bought mine at Yodabashi Camera in Shinjuku, Tokyo... i guess i need another trip back there!