CANON EOS 6D & RAYNOX DCR-250 & NIKON BE PLAN 10x

[Adalbert]

Hello everyone,

This time I would like to use the DCR-250 as a tube lens (up to now I have used the CANON EF 70-200L and CANON EF 100L Macro).
Does anybody know the optimal distances between the sensor and the DCR-250 and between the DCR-250 and the microscope-lens?
I only have found something about the original tube lens from NIKON:



Does this distance depend on the lens used?
http://extreme-macro.co.uk/raynox-tube-lenses/

BTW, and what about the adapters 43mm->M42 and 49mm-> M42 ?

Thank you in advance.
Best regards,
Adi

[etalon]

Hi Adi,

the DCR250 have 125mm or 8 dioptr fl. The distance DCR-->objective depend on the needed vignetting free image circle on the sensor side. If the distance is too close you get maybe some reflections from the backside of the objective. Some trouble through stray light caused by the lens rim of the DCR maybe occur, because they are not blackened. Here would help a stop in front of the DCR...

Cheers Markus

[Lou Jost]

There is a huge amount of information and experimental data on Raynox lenses in this Forum. Search for DCR150 (most often used). The lens-to-sensor distance should be the one that focuses an infinitely-far subject on the sensor. This distance can be found by moving the lens relative to the sensor (add or subtract tubes and filter rings to get the distance just right).

[Charles Krebs]

You are using a full-frame camera.

Out of curiosity... you say you have used the Canon 100mm as a tube lens... were you really able to get a good quality image away from the center, and no vignetting?

I just wonder if you will get an acceptable image over the entire frame using the DCR-250 with a full-frame camera (probably fine with an APS-C).

[Ichthyophthirius]

Does anybody know the optimal distances between the sensor and the DCR-250 and between the DCR-250 and the microscope-lens?

Hi Adi,

I just got this information on the flange focal distance of the DCR-250: http://www.photomacrography.net/forum/v ... hp?t=29906

[ChrisR]

I was hoping someone else would find the reference - I haven't! Rik did some tests, finding that it was best to have some space between the Raynox and the objective, for corner performance if I remember correctly, though it matters whether you reverse it or not.
Try 50mm. More may be better if you can avoid vignetting.

[rjlittlefield]

Rik did some tests, finding that it was best to have some space between the Raynox and the objective, for corner performance if I remember correctly, though it matters whether you reverse it or not.

That was with a DCR-150. I don't recall ever rigorously testing a DCR-250, and I have no reason to think it would be the same.

--Rik

[Adalbert]

Hello Markus,

“The distance DCR-->objective depend on the needed vignetting free image circle on the sensor side”

Yes, I have already found some information about that. Probably I would have to assemble a variable construction between the sensor of the camera and the DCR.
BR, Adi

[Adalbert]

Hello Lou Jost, Ichthyophthirius, ChrisR, Rik,
Thank you for the hints and the links!
BR, Adi

[Adalbert]

Hello Charles,
1.) Yes, I’m using a full-frame camera.
2.) Yes, I have tested with a CANON EF 100L macro too.
Please take a look at the table with the results of my test:
https://mikroskopie-forum.at/index.php/ ... unendlich/
3.) Yes, vignetting is visible but it is much better with the extender 1,5x
4.) Yes, I have already seen some really good stacks taken with a full-frame,
DCR-250 and microscope lens from Mitutoyo
BR, Adi