six portraits of Copepods

Franz Neidl · Post by **Franz Neidl** » Mon Sep 09, 2013 2:03 pm

As I have in this period many copepods in my plankton net I show you six portraits of them. You can see: everyone has it's own "personality".

brightfield, objective 4x, nocturnal seaplankton

Franz

1.

2.

3.

4.

5.

6.

carlos.uruguay · Post by **carlos.uruguay** » Mon Sep 09, 2013 8:26 pm

Great details

Charles Krebs · Post by **Charles Krebs** » Thu Sep 12, 2013 9:28 pm

Franz,

You've done really well with these. They are trickier to photograph than would be expected. (Are these stacks or single frames?)

Franz Neidl · Post by **Franz Neidl** » Fri Sep 13, 2013 2:51 am

They are trickier to photograph than would be expected. (Are these stacks or single frames?)

Thank you Charles. These are not stacks but single frames. My method: I take only very big copepods, more than 1 mm long (which I find in the nocturnal plankton), so I can use the objective 4x, but only in brightfield.

In the future I want to photograph the copepods also with DIC. But DIC is starting only with objective 10x. Therefore I will have to reduce the magnification. The unique possibility which I have is to reduce the magnification of the camera. The Pentax D20 wich I currently use has a focal lenght multiplier of 1,5x. So I am waiting for the Pentax full frame (24x36) which should have a focal lenght multiplier 1x. But Pentax is such a boring company: Up to now the FF did'nt came and I have to wait and wait. Somebody knows when this camera is coming? I know that Nikon and Canon have FF
cameras, but I dont want to change my hole system.

Franz

Pau · Post by **Pau** » Fri Sep 13, 2013 3:35 am

Franz, I allways love your plancton images

Franz Neidl wrote:
Therefore I will have to reduce the magnification. The unique possibility which I have is to reduce the magnification of the camera.
I don't know about your equipment, but in some cases there are other approaches.
- If you use an eyepiece in your camera setup (both as projective or as part of an afocal system) you can look for a lower magnification one. For exemple in my afocal system I have (approx) the same magnification with a 6.3X eyepiece in APSC as with a 10X with FF, and Charles do the same with a 1.67 projective with APSC as equivalent to 2.5X on FF.
- In an afocal system you can switch to a camera lens of shorter focal lengh
- In some microscopes with fully corrected objectives (or objective +tube lens combo) you can make a direct projection setup (1X magnification on sensor)
- some microscopes have a magnification changer with negative magnification like 0.8X

...but I guess you already had studied those possibilities

Franz Neidl · Post by **Franz Neidl** » Sat Sep 14, 2013 8:21 am

Hello Pau,

thank you for your kind answer. Unfortunately I can not act on your suggestions, because I am working with a Nikon Eclipse 600 microscope.
- Nikon does'nt have a 1,67 projective. (Currently I work with the 2,5x projective, but I have also the 2,0x projective)
- Nikon does'nt have a magnification changer with a negative magnification.

If I am wrong I would be happy if somebody correct me.

Franz

Pau · Post by **Pau** » Sat Sep 14, 2013 9:18 am

I don't know for sure, but if the phototube is detachable from the trinocular head as it seems from some images I've seen googling, the direct projection system will be doable (and great!), a similar case as with the Olympus BX series that some members use. It would be as simple as an empty tube to place the camera sensor at the same height of the primary image inside your photoeyepiece.

Franz Neidl · Post by **Franz Neidl** » Sat Sep 14, 2013 1:30 pm

Pau wrote "It would be as simple as an empty tube to place the camera sensor at the same height of the primary image inside your photoeyepiece."

Hello Pau,

I was trying also this solution, but the quality of the picture was not convincing for me. I think the infinite objectives from Nikon (together with the fieldlens) are not perfectly corrected, otherwise I can not explain why Nikon is selling projection eyepieces for photography. Why they dont sell (additionally) also "an empty tube" (to use together with the fieldlens!) as you wright? Maybe one should ask Nikon itself?

Is somebody in the Forum who made experiments with this solution? I know people who made experiments with the microscopes from Olympus, but from the Nikon-Users I dont know anybody.

Franz

Pau · Post by **Pau** » Tue Sep 17, 2013 9:58 am

Franz, I'm really curious about what went wrong, as the image emerging from a CFI objective, with original (or not) tube lens, must be in principle fully corrected. As you know people use those optics for macro with photo lenses and without eyepieces.
The photoeyepieces are intended to expand the primary image to fill the 24X36 camera sensor but without it, apart of posible vignette issues no correction problems are to be expected IMO, but (sadly) I don't have experience with Nikon Eclipse scopes

If you're interested in following this discussion, please post images of your results and setup (better at the Equipment forum)