Trying Raynox DCR-250, DCR-150 and 6X as tube lens on NEX-5N

[cmagno]

Thanks for sharing your interesting tests.

M42 male to 52 male>52 female to 49 male>Raynox reversed>43 female to 52 male>52 female to M42 male> M42 female to M42 female>M42 Iris>Nikon objective

I got the M42 female-female from one T2 to M42 adapter like this one on ebay (150666501698)

You can found a direct M42 female-female adapter on eBay, item number 290861230439.

Regards

Carlos Magno

[eurythyrea]

Seeing the photos about the attached objectives/Raynox/adapters I found a question. When we firstly used the iris diaphragm made by jinfinance, the length between the morfanon and the Mitutoyos was a question. As far as I remember it was important to be as close as it can be.
So, what about the Raynox tubes? It looks it is much far due to using the adapters. Then doesn't count the length between them?

Nikola

[seta666]

Thank you Javier, 150 (normal way round) + Nikon 10x on APSC worked well for me, which I tried because of this post. I had longer distance though between Raynox and objective, I used a focusing helicoid. I havn't done anything for a while so a nice thing to come back to. Excuse the dust, I hadn't planned on posting this but it was purdy so I thought what the heck...
r

Great!! I am happy it works good for you too. The image does look very nice (you have to fix the link here though)

You can found a direct M42 female-female adapter on eBay, item number 290861230439.

Thank you for the info, but I find it is way too thick.

Seeing the photos about the attached objectives/Raynox/adapters I found a question. When we firstly used the iris diaphragm made by jinfinance, the length between the morfanon and the Mitutoyos was a question. As far as I remember it was important to be as close as it can be.
So, what about the Raynox tubes? It looks it is much far due to using the adapters. Then doesn't count the length between them?

Nikola

This could also be true, but with 3D subjects normally I would use the M42 iris. The oly time I do not use the iris is for flat-tish things like butterfly wings. So I need to know how they do behave with the Iris on place.

With the Iris on place there is a 25mm gap between the back of the objective and the Raynox front glass, which I thing is within reasonable limits.

I this this you say may affect more the Raynox 6X (28mm wide glass) than the DCR's (36mm wide glass), noirmally you want to use the central part of the tube lens, specially if it is low quality.

I have an Olympus U-TLU tubelens I got cheap wainting to be modded to M42, I tried it at infinity and it had good image from center to corner with good contrast. better than anything I am using now.

Regards
Javier

[johan]

Fixed, thanks

[crayfish74]

in all case the raynox works bettter in reverse? mean for example a lens 150mm + reverse raynox? will be better than normal?
best

[papilio]

Sunset Moth by Johan J.Ingles-Le Nobel, on Flickr

Johan, this is brilliant work!! I've got a Sunset Moth in my collection but wouldn't have a clue as to how you got those hues to show up the way you do!

[papilio]

Thanks guys for the tip on removing the barrel ... mine came free easily when I held the threads looooosely with vice-grips. Amazing how fat that barrel is!

Now I still need to blacken the front of the objective, it really shines when shooting with cross-polarization.

[lolhonk]

After I saw your thread on the MT-1 http://www.photomacrography.net/forum/v ... hlight=mt1

I thought to myself " eveness is more important than central performance"; the Raynox shown very crappy results but the good thing is that image was very even and there was no CAs so I thought it was worth a try.

To mount the Raynox in mormal position
The tricky part was to mount it reversed; I neded a female to female at some point but at the end I got it ;-)

Again from bellows to lens:

M42 male to 52 male>52 female to 49 male>Raynox reversed>43 female to 52 male>52 female to M42 male> M42 female to M42 female>M42 Iris>Nikon objective

I got the M42 female-female from one T2 to M42 adapter like this one on ebay (150666501698)

Regards
Javier

Hi Javier,

i cant find any 42 to 42 female to female adapter. Could you help me Please?

[Saul]

...i cant find any 42 to 42 female to female adapter...

Ebay:
One pcs of 251028341384
Two pcs of 391548937716

[rjlittlefield]

M42 male to 52 male>52 female to 49 male>Raynox reversed>43 female to 52 male>52 female to M42 male> M42 female to M42 female>M42 Iris>Nikon objective

I got the M42 female-female from one T2 to M42 adapter like this one on ebay (150666501698)

Regards
Javier

i cant find any 42 to 42 female to female adapter. Could you help me Please?

I believe that the "T2 to M42" adapter that Javier mentions is now eBay part number 121167154476. Its inner section looks removable to yield a fairly long section of M42 female thread that could accept shorter male threads on both ends.

That's also the idea used by Saul's three-piece assembly. eBay 251028341384 is a 55-to-52 step-down ring that is threaded 52mm female all the way through. You screw the other two parts into that, leaving the outer 55mm section of the ring unused.

--Rik

[lolhonk]

M42 male to 52 male>52 female to 49 male>Raynox reversed>43 female to 52 male>52 female to M42 male> M42 female to M42 female>M42 Iris>Nikon objective

I got the M42 female-female from one T2 to M42 adapter like this one on ebay (150666501698)

Regards
Javier

i cant find any 42 to 42 female to female adapter. Could you help me Please?

I believe that the "T2 to M42" adapter that Javier mentions is now eBay part number 121167154476. Its inner section looks removable to yield a fairly long section of M42 female thread that could accept shorter male threads on both ends.

That's also the idea used by Saul's three-piece assembly. eBay 251028341384 is a 55-to-52 step-down ring that is threaded 52mm female all the way through. You screw the other two parts into that, leaving the outer 55mm section of the ring unused.

--Rik

thank you @Saul & Rik that helped me a lot !! ;-)

[harisA]

Thank you for the testing.

This illustrates the importance of testing a lens as it will actually be used.

By itself, the Raynox DCR-250 is about f/3.6. But when used with the CFI 10/0.25, the objective stops down the Raynox to about f/12.5. The wavefront error due to spherical aberration goes as the fourth power of the aperture size, so there is a whopping 150X difference between these two cases.


--Rik

Although this is an old thread it did'nt catch my attention.Rik can you please explain more analytically why the objective stops down the Raynox to F/12.5?
Also can you give an explanation why Raynox is so brilliant as a tube lens despite the fact is pretty unusable wide open (as telephoto lens focused on infinitty)?

[rjlittlefield]

Rik can you please explain more analytically why the objective stops down the Raynox to F/12.5?

When using an infinity objective as designed, each point on the subject turns into a beam of parallel light rays coming out the back of the objective. The diameter of those beams is limited by the rear aperture of the objective, just the same way that diameter of incoming beams would be limited by the aperture of the rear lens if it had one.

Physically, the rear aperture of the objective is 10 mm diameter. The focal length of the Raynox is 125 mm, and 10/125 = f/12.5 .

Mathematically, the following relationships are handy to know:

1. NA = 1/(2*effective_f_number), where NA and effective_f_number are both measured on the same side of the lens

2. NA_at_subject = actual_magnification*NA_at_camera

3. actual_magnification = objective_rated_magnification*(tube_lens_focal_length/200), for an objective designed to work with 200 mm tube lens

Then slogging through the arithmetic, actual magnification = 10*(125/200) = 6.25, NA__at_camera = 0.25/6.25 = 0.04, and effective_f_number_at_camera = 1/(2*0.04) = 12.5 .

Also can you give an explanation why Raynox is so brilliant as a tube lens despite the fact is pretty unusable wide open (as telephoto lens focused on infinitty)?

Sorry, I cannot.

I think that any such explanation either would be hand-waving or would rely on such deep analysis of the lens design that it would give no useful insight.

It's clear that stopping down is a powerful way of reducing many kinds of lens aberration.

But it's not at all clear why stopping down a Raynox DCR-150 reduces aberrations enough to give good corners on full frame, while stopping down other apparently similar lenses such as the Nikon, Mitutoyo, and Thorlabs tube lenses does not. (See experimental results at http://www.photomacrography.net/forum/v ... hp?t=23898.)

No doubt all this would be "explained" by analyses like ray-tracing, given sufficiently detailed models of all the lenses. But I don't know any way to predict it from simpler aspects of the lenses.

--Rik

[harisA]

Rik many thanks for your accurate answers to my questions.