direct projection with an Optiphot?

[Lomonaut]

I'm still pondering what would be the best photography setup for my Optiphot.

It has a trinocular head with ultrawide eyepieces. I would need a CF PL2.5x projection eyepiece and preferrably a full frame sensor camera to use that optimally. Plus adapter, helical focuser and what not. Expensive.

On the other hand, for photography: why not remove that trino head altogether and somehow place the sensor at the primary image plane. Nikon CF objectives allow this, they don't need compensating eyepieces.
My home made PVC adapter happened to have just the right length to be parfocal, it was hand-held and resting on the bare POL part that was exposed by the removal of the trino head.
So here's a direct projection test shot taken with a M4/3 sensor (Olympus E-500), 20x/0.40 Plan DIC.

The area at the right is a bit unsharp, probably some misalignment - but no lateral CA

A modern APS-C mirrorless camera with live view would be an interesting and relatively cheap photography upgrade option. Who needs a trino when you have a HD live screen..

[imkap]

A modern APS-C mirrorless camera with live view would be an interesting and relatively cheap photography upgrade option. Who needs a trino when you have a HD live screen..

I have this kind of camera connected to a TV with HDMI, it is fun especially when observing in company. But still I like the views the best through the binocular... As for your Optiphot setup, I can't help.

[PeteM]

Direct projection works - though it ends up a bit soft in the corners even with a Nikon full frame set to cover APS-C. Your MFT sensor is just about right.

One way to have half your cake and consumer the other is to use a Nikon teaching head. Binoculars get 50% of light. Then put the direct adapter on the back part. I recently made up and tested one. It ends up sitting a bit more than two inches above the scope or teaching head.

A Nikon teleconverter (1.4, 1.6, 2x) can also be inserted.

[blekenbleu]

This fellow did Optiphot direct projection with the trino head,
by substituting a lens in the bottom of its photo chimney:
http://www.photomacrography.net/forum/v ... 25&t=33471

I have a notion to remove that chimney and lens, allowing the prism's infinity space
to extend up to a telephoto camera lens focused at infinity...

[Scarodactyl]

You need the lens to be as low inside the head as possible or you'll get vignetting. Plus side you can finely resize the image however you want by changing the focal length. A simple achromatic doublet does work fairly well.

[Lomonaut]

Thanks for the feedback everybody!

I think I'll just try Nikon's projection eyepiece CF PL2.5x (A) and see how it goes with my current M4/3 camera (even though I don't like the crop), they are readily available and not too expensive. I'm aware (and grateful!) of your test Scarodactyl, apparently it's not perfect. If the corners are fuzzy on this small sensor a full frame would make little sense... it would be interesting to visually inspect the image (with a piece of frosted glass and a small loupe).

Also, I tried some shots through the left UW eyepiece with my new smartphone and it was much better than expected, even when just handheld! Ridiculously sharp considering the circumstances. See attachment, but it's too small to really see it.
I'm an absolute noob with phones but don't they heavily process photos: sharpening, trying to make artificial bokeh, etc? That could be a disadvantage.
But afocal is interesting, I may have been prejudiced about it.

[Phill Brown]

I'm at a similar fork in the crossroads with image capture.
Taking cues from nature bigger sensors are only an advantage in lower light.
If you are cranking up the lumens on crystals,unless the heat distorts the results it's not a great advantage to use full frame from a cost perspective?
The moment can get lost so quickly that live view recording can be a good compromise.
RGB isn't all it's cracked up to be.
Heavily reliant on the average retina and its optics and embedded firmware

[blekenbleu]

My understanding for recent camera sensors is that dominant noise in lower light is photon statistics;
spreading the same photons over more sensor area does not help...

I have been experimenting with an RGBW LED pin spotlight:
https://www.amazon.com/dp/B07QGJRCT7
...for microscope illumination:

RGBWpin.jpg (33.24 KiB) Viewed 3750 times

Extending provided optic beyond supported distance further concentrates the beam.
Potential advantages:

• replacing obsolete/hard to get proprietary replacement lamps

• isolate heat and vibration from microscope stands

• separately illuminate R, G, B, then focus stack to mitigate chromatic aberrations

[Lomonaut]

Small update: I never got the projection piece but went for direct projection. Last week I bit the bullet and bought a Lumix G9!

Like PeteM said, the M4/3 sensor is just about right size for direct projection with this system.

Other reasons:
- I get a piercing pain in the neck after 10 minutes looking through the trino, so why not ditch it altogether and look at a screen (HDMI output from the G9).
- the Nikon CF objectives don't require compensation, so they are ideal for direct projection!
- lower cost; the G9 is not cheap but the full frame option would be much more expensive
- full frame would offer no advantage image-wise in this situation. The G9's M4/3 sensor in direct projection receives much more light per mm2 than a full frame sensor would (on top of the trino with a PL2.5 projection eyepiece), this compensates the FF's low light advantage. Pixel density of the G9 at 21 megapixel is overkill.
- a clean image, no chance for in-between optics to ruin the image

I improvised a no-cost adapter (goodbye body cap ) and did some tests. Promising!

Can't wait to film some ritifers with this camera

[ADi]

Congratulations on buying a great new camera!
BTW, very nice photo!

[Lomonaut]

Thanks, so much to learn about this great camera! I'll post more pictures soon.

[Sure Squintsalot]

How did you avoid getting a diffuse bright central spot in your image capture?

[Phill Brown]

.

[Lomonaut]

How did you avoid getting a diffuse bright central spot in your image capture?

Reflections from tubes and other internal parts? Never had that problem, but I'll have to make the inside of the PVC pipe adapter matte black anyway, and add a diaphragm to avoid reflections and improve contrast.

Here are some more pictures. I notice some residual CA but hey, they are planachromats

[Phill Brown]

Edited.
Internal surfaces should all be matt black.
No grease spots or joints that could be reflective or allowing light in.
Lenses need to be clean around the edges, residue at the edge can make a bright spot.
Image capture can be a lot more sensitive to subject illumination also.

[MichaelG.]

Very impressive results, Lomonaut … Thanks for sharing them.

This should be the go-to reference for anyone wondering about direct projection !

MichaelG.

[Lomonaut]

Thank you so much MichaelG!
And thanks for the tips Phill Brown. I'm thinking of buying a sheet of hmm, how to call it... self-adhesive black velvet (Dutch: 'plakvelours') which is often used by DIY telescope builders.

I haven't even blacked the inside yet, and have so much to learn about the camera - things can only get better

Loads of free time this week, I'll post more in the Pictures and videos section.