MicrobeHunter.com Microscopy Forum

1. How to get parfocality of an image from a camera with a microscope eyepiece? / 2. Image quality in OBS

I want to use the Olympus BHSU / BH-2 microscope for regular images/video shows (dark field and polarization) in schools.
The image will be presented on the projector screens.

Currently, my setting is an old APSC Nikon d3200 camera (trinocular head), an adapter from EBAY (it has an adjustable sleeve - it brings the mounted camera closer and away from the NFK eyepiece)
NFK 2.5 ND eyepiece

I lifted the NFK eyepiece up on two fabric elastics so that it was as close to the camera matrix as possible. Then I got a larger field of view. (But there's still something to improve here - I just don't know how anymore)
The NFK eyepiece sits in the adapter tube, shortened to the maximum.

I connected the HDMI mini - HDMI cable to the Nikon D3200, and the HDMI cable is connected to the video grabber from aliexpress (camlink equivalent for about PLN 25)
I watch the picture in the OBS program.

When I watch a super cool image in the eyepiece, unfortunately I do not have parfocality on the SLR screen or on the laptop screen.

I have to get up and looking at the lifeview camera screen to focus with the micrometric screw. At the same time, I zoom in on the "+" image on the camera's lifeView to focus as much as possible, but with living organisms that swim it misses the point.

When I would like to focus looking at the image transmitted on the screen of an old laptop (i3, 64bit processor), the image is of lower quality than on the SLR screen.

The lenses I use have a very shallow depth of field and focusing when looking at the screen is poor. After focusing it is still not quite clear. Only when I watch large organisms is the picture great because they are "fat". For example Bleuparisma japonicum. but Vorticella? < my setup is peaky..

What should I change / improve to make image quality on the screen better and to make the field of view from the camera larger?

How to get the parfocality of the image on the laptop screen with the image from the eyepiece?

Does buying / changing other lenses with greater depth of field make sense for faster sharpening? I have OLYMPUS SPlan Apo lenses.

Before writing this post, I read "Budget Friendly BH2 Video?" to which Mr. Tom Jones was responding. I also wanted to get an image in 4K. I wonder if my counterfeit camlink card is enough and what necessary purchases to make.

This (non recent) website contains a lot of photo micrography info including an article on achieving parfocality .

https://krebsmicro.com/

Alternative source is Alan Woods Olympus website and his article on photography using a BH2

http://www.alanwood.net/downloads/olymp ... camera.pdf

In short: parfocality requires the NFK eyepiece at the original position (no “rubber bands”) a tube length till sensor of 160 mm using the Olympus L photo tube.

Getting a full frame picture on an APS camera requires a NFK 1.67 eyepiece: unobtanium (ebay prices in 800-1000 range if you are lucky). For alternatives : refer to the Alan Wood publication.

Depth of field is a serious issue: requiring an optimal set-up: starting with coverglasses 1.5 of exact 0.170 mm thickness (the expensive Zeiss CG come to mind here), pond samples require a VERY thin fluid layer (so no debris in your sample). Alternatively I often use 1.0 coverglasses to compensate for a thicker fluid layer.

Closing the condenser diaphragm helps a bit, but reduces effective NA and thus resolution.

This may appear counter intuitive, but the cheaper less corrected Achromat objectives actually give you the largest depth of field.

On my scope used for watching pond samples I actually have BOTH a 20* Achromat (for depth of field) AND a 20* SPlanApo (for resolution).
The Olympus LB SPlanApo serie has wonderful image quality, but actually the worst D.O.F.

As a Nikon user for over 45 years Owning “the full artillery” I’m using a Canon APS camera 750 D on my microscope: with electronic first shutter curtain (EFSC) to reduce vibration and (relatively old) Canon Control software to link the camera to the PC via USB (remote control plus preview for focussing plus picture transfer to the PC using native camera resolution).

Thank you DeBult

this is my setup

It should still be possible to achieve parfocality with the eyepiece raised. The position required doesn't change when you change objectives. But what's counterintuitive is that your lower mag objectives are more sensitive to the position of the camera than your high mag ones. So the typical procedure is just like getting eyepieces parfocal--focus on a flat, stationary sample at high mag using your focus knob, then switch to your lowest mag objective and adjust the camera dostance until that detail is in sharp focus. Repeat as needed. That is assuming you have your eyepieces parfocal--if not, just focus on the detail with your lowest mag objective and adjust the camera position to matching focus.
Note that raising the eyepiece is going to have a detrimental effect on image quality, a fairly noticeable one with the nfks.

Scarodactyl wrote: ↑

Tue Mar 01, 2022 7:14 pm

It should still be possible to achieve parfocality with the eyepiece raised……

Scarodactyl wrote: ↑

Tue Mar 01, 2022 7:14 pm

Note that raising the eyepiece is going to have a detrimental effect on image quality, a fairly noticeable one with the nfks.

Fair refrased: In short: parfocality COMBINED WITH OPTIMAL IMAGE requires the NFK eyepiece at the original position (no “rubber bands”) a tube length till sensor of 160 mm using the Olympus L photo tube.

Your D3200 is limited to Full HD per Nikon's website, 4K is not possible. You'll need a camera that will output 4K video to clean HDMI. Your computer screen will need to be 4K as well. That's not happening with an old laptop. Your cam-link clone is probably not 4K either. 4K takes a high-throughput system. Also, the projector, unless it's really new and pricey probably doesn't do 4K, and may not do Full HD either. Most stop at 720p.

In short, 4K requires a whole new system.

APSC needs the lower magnification projection lens NFK 1.67x ($$$$) for optimal image size. The NFK 2.5x gives a cropped image just like you get with 35mm lenses on the APSC sensor. Live with the image size. If you move the projection lens up away from its intended position you will degrade the image. How much depends on how far you move it. Just use a lower magnification objective if you don't like the zoom. Yes, there may be empty magnification. No, you can't really do anything about it.

Ditch the laptop and get a TV or separate monitor with an HDMI input. Go straight from the camera to the monitor and focus using the monitor. When you use the projector instead of the monitor, focus using that image. You only need parfocality if you are going to use the microscope eyepieces and the monitor at more-or-less the same time.

That looks like a pretty short straight through adapter without a lens. Parfocality, and optimal image quality, will take the appropriate length adapter to go with the NFK projection lens. If you cheat on the proper dimensions, your image quality may be really bad to unusable.

SPlanApos are the nicest lenses you can get for your BH-2.

From the price/performance point, the M43 camera (Panasonic GH4) + NFK3.3 + U-PMTVC adapter (catalog number U-V210, 037151) provides perfect access to 4K images and videos. The cost is about 2000 + 150 + 600 = 2750RMB. The above are the experience summaries of the forum leaders, and I would like to express my gratitude.

What woyjwjl said:

From the price/performance point, the M43 camera (Panasonic GH4) + NFK3.3 + U-PMTVC adapter (catalog number U-V210, 037151) provides perfect access to 4K images and videos.

That combination, along with DIC on my BHS, is what I used to shoot the 2018 Nikon Small World in Motion Honorable Mention video: https://www.nikonsmallworld.com/galleri ... er-feeding

The full video is on my YouTube channel here: https://www.youtube.com/watch?v=mqZns4wo0AQ

Tom

Wow Tom, nice video

Clear i need to practice, practice, practice to approach this quality level.

Scarodactyl wrote: ↑

Tue Mar 01, 2022 7:14 pm

… But what's counterintuitive is that your lower mag objectives are more sensitive to the position of the camera than your high mag ones. …

I think the necessary intuition comes more easily to those who have done a lot of close-up photography … it’s basically a matter of appreciating the difference between ‘depth of field’ and ‘depth of focus’

MichaelG.

Tom Jones wrote: ↑

Wed Mar 02, 2022 2:09 am

The full video is on my YouTube channel here: https://www.youtube.com/watch?v=mqZns4wo0AQ

That is really beautiful, Tom !!

MichaelG.

MichaelG. wrote: ↑

Wed Mar 02, 2022 7:52 am

Scarodactyl wrote: ↑

Tue Mar 01, 2022 7:14 pm

… But what's counterintuitive is that your lower mag objectives are more sensitive to the position of the camera than your high mag ones. …

I think the necessary intuition comes more easily to those who have done a lot of close-up photography … it’s basically a matter of appreciating the difference between ‘depth of field’ and ‘depth of focus’

MichaelG.

Thank you All for your Professionalism.
Could you please explain the difference?

Tom Jones wrote: ↑

Tue Mar 01, 2022 11:10 pm

Your D3200 is limited to Full HD per Nikon's website, 4K is not possible. You'll need a camera that will output 4K video to clean HDMI. Your computer screen will need to be 4K as well. That's not happening with an old laptop. Your cam-link clone is probably not 4K either. 4K takes a high-throughput system. Also, the projector, unless it's really new and pricey probably doesn't do 4K, and may not do Full HD either. Most stop at 720p.

In short, 4K requires a whole new system.

Thank you, how to deal with Old schools projectors when my image is 4k or even full HD? ? Should I connect via a laptop with a full HD 1920x1080px and somehow change the picture settings? How to show a sharp image on the projector assuming the projector's resolution of 720?

Anything you output to a 720p system will be limited to 720. The original resolution doesn't matter. Even 8K to 720 still gives 720, and that's pretty low-res when blown up to projection scale. 720 looks pretty good on a laptop screen. If you double the size vertically and horizontally (essentially the same as having 4 screens, two vertically and two horizontally) you will see half of the resolution vertically and horizontally, as on the original screen. The same number of pixels spread across twice the horizontal and vertical space. If you back up your viewing position to the point the 4 screens appear to be the same size as the original screen, the view will be very close to the same.

There are no "spare pixels" that can be used for higher resolution images. Unfortunately there is no free lunch here! The bigger the image you want to show, the more pixels you will need to have the same visual resolution. And the maximum number of pixels is a physical limit of the system.

I shoot in 4K, edit in 4K and display 4K using a 4K monitor. I deal with the classroom issue using my own 43" 4K monitor, not their projectors. There is no getting around the limitations of low-res monitors or projectors. Projectors that give nice image quality in lighted rooms are hard to find and not cheap. I just picked up a Canon R5 and will be shooting as much as 8K in the future. It will be down-sampled to 4K simply because no one has 8K monitors. Very few folks even have 4K monitors, so the best they can see is limited to whatever their screen resolution is. The original images will be higher resolution to future-proof them.

Tom

That’s an excellent summary of the situation, Tom

… a proper ‘Reality-Check’

MichaelG.

ewieckow wrote: ↑

Tue Mar 08, 2022 7:40 pm

MichaelG. wrote: ↑

Wed Mar 02, 2022 7:52 am

… it’s basically a matter of appreciating the difference between ‘depth of field’ and ‘depth of focus’

Could you please explain the difference?

.
Apologies … I have only just noticed your question

Please have a look at this discussion: viewtopic.php?f=5&t=13415
… and, for enlightenment, follow the links that I gave there, in Post #7

MichaelG.

Thanks Michael!

Good luck in this quest. I struggled for a long time, then bought a new scope, then struggled for a long time. Some times it just is what it is. Have patience.

MichaelG. wrote: ↑

Wed Mar 09, 2022 6:49 am

ewieckow wrote: ↑

Tue Mar 08, 2022 7:40 pm

MichaelG. wrote: ↑

Wed Mar 02, 2022 7:52 am

… it’s basically a matter of appreciating the difference between ‘depth of field’ and ‘depth of focus’

Could you please explain the difference?

.
Apologies … I have only just noticed your question

Please have a look at this discussion: viewtopic.php?f=5&t=13415
… and, for enlightenment, follow the links that I gave there, in Post #7

MichaelG.

THANK YOU!

Greg Howald wrote: ↑

Wed Mar 09, 2022 10:11 pm

Good luck in this quest. I struggled for a long time, then bought a new scope, then struggled for a long time. Some times it just is what it is. Have patience.

Thank you!