Suggestions for clamping a camera to scope for afocal

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dragonblade
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Joined: Sat Oct 18, 2014 11:16 pm

Suggestions for clamping a camera to scope for afocal

Post by dragonblade »

For afocal imaging, Ive been using a tripod and a macro slide bar to get my camera lens positioned just right in relation to the microscope eyepiece. The results are good but it takes an incredibly long time to get the orientation right. Sometimes as much as 15 - 20 minutes and I'm getting really tired of it. I would really like a quicker setup or maybe even something semi-permanent. Can anyone suggest any systems where you can clamp a camera to a microscope? With some sort of rig clamped on there, I could just remove or add a camera when the need arises. And an extra bonus would be having enough clearance for my head when the camera is not attached so that I could use my own eye over the eyepiece when I simply want to view.

By the way, I'm using a Micro 4/3 camera so the rig / clamping system would have to support that kind of weight (heavier than a point and shoot but lighter than a DSLR.) And I'm also using a monocular microscope.

Pau
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Re: Suggestions for clamping a camera to scope for afocal

Post by Pau »

Here and in the links inside you have some ideas:
https://www.photomacrography.net/forum/ ... 265#p99265

Something like my third setup would work well and can be made with an old style camera adapter and some adapter rings.
If you post a picture of your microscope this would be useful. What's the external diameter of the tube, maybe 25mm?

Something like the adapters pictured at this auction can be useful
https://www.ebay.com/itm/UNITRON-PHASE- ... SwigpfmHNf

Pentax adapters are good and now inexpensive (although for afocal many of this style of adapters will need to drill the internal hole to slide over the 25mm tube)
Pau

dragonblade
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Re: Suggestions for clamping a camera to scope for afocal

Post by dragonblade »

Thank you for your reply. Yea that third setup in your link looks really attractive. I guess I'd screw the front of my lens on to that filter ring at the end of the assembly. And I assume the Zeiss camera adapter clamps directly to the tube rather than the eyepiece itself? I'm just not sure if I could source all of those parts.

Regarding the Pentax adapters, do they have a specific model name? Any other adapters that would need to be fitted to them?

Oh and is that Olympus lens you're using in your setup an old manual focus type? If so, I'm surprised that you can focus that lens to infinity on your Canon EOS DSLR. I keep hearing about the problems people having when focusing old film lenses at far distances on Canon DSLRs due to the difference in flange focal depth.

Regardless, I wish I could use an old manual focus lens on my M4/3 camera for afocal photography. It would make life considerably easier. I use a Sigma 30mm f2.8 for this kind of work. Although it's a really nice lens optically (including wide open) it's a nuisance to use for afocal because of the electronic focus design. I don't mind going outside and focusing on a far away subject to get infinity focus (if done just once.) Though I have to keep the camera turned on and active the whole time during the microscope shooting session. If the camera is not used for a certain period of time and turns itself off to save power, the focus setting is lost and I would have to detach the camera from the microscope and go outside and repeat the process again.

I note that you recommend using a 63mm lens if using a full frame sensor with a 10x eyepiece. I can think of a lens which could be a contender if one was using a full frame photography system. I also shoot medium format film and one of my MF cameras is a Koni Omega Rapid mechanical rangefinder camera which shoots 6 x 7cm film. This camera was produced during the 1960s and 1970s and was intended for press photographers. One of the Koni Omega's lenses is a wide angle with an approximate focal length of 60mm. Though I'm not sure how such a lens could be adapted to a digital camera successfully since there is no focusing ring on the lens itself.

dragonblade
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Re: Suggestions for clamping a camera to scope for afocal

Post by dragonblade »

So if I understand it correctly, the front of the lens is screwed on to that filter ring? I'm not sure if I would feel confident about a screw thread supporting the weight of a camera and lens in a diagonal orientation as in my case. The tube on my monocular microscope is diagonal so there would be a fair amount of weight hanging off it. No issue for your equipment since the tube and camera are vertical so they're directly on top of each other.

By the way, my microscope is an RM-600 which is available from an Indian company called Radical Scientific Equipments.

Pau
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Re: Suggestions for clamping a camera to scope for afocal

Post by Pau »

Thank you for your reply. Yea that third setup in your link looks really attractive. I guess I'd screw the front of my lens on to that filter ring at the end of the assembly. And I assume the Zeiss camera adapter clamps directly to the tube rather than the eyepiece itself? I'm just not sure if I could source all of those parts.
Yes, it clamps over the 25mm tube and in most cases you must fit it before putting the eyepiece back, the classic camera adapters like the Pentax also do.
They can be found, although separately and maybe a bit too expensive
- The Zeiss part (also can be found as part of different camera setups)
https://www.ebay.com/itm/Rare-Zeiss-Iko ... SwTmBfe~BM
https://www.ebay.com/itm/Zeiss-microsco ... SwwS9fjxe9
- A dovetail to M42 adapter
https://www.ebay.com/itm/43-5mm-microsc ... SwaeRfhwaj
- You also will need a M42x1 to your filter thread adapter
Regarding the Pentax adapters, do they have a specific model name? Any other adapters that would need to be fitted to them?
In place of the Zeiss and dovetail adapter at my setup you can use other parts like:
- The old Ihagee Exakta seems very nice (although I don't understand well how its clamps over the tube)
https://www.ebay.com/itm/tubus-adapter- ... SwyDFbFjE5
https://www.ebay.com/itm/tubus-adapter- ... SweVZeWC6z
- The Pentax with M42 screw mount (avoid the newer K bayonet model) like
https://www.ebay.com/itm/ASAHI-HONEYWEL ... SwdLpflH5h
Originally it was intended for eyepiece projection raising the eyepiece. For afocal it is too long, this is why you could need to drill or file a bit the internal hole to allow it fully sliding in the tube (I don't know its exact length nor your microscope 25mm tube part length)
Many other SLR camera makers made similar adapters, and also third party ones like Vivitar (avoid bayonet models, much more difficult to adapt for afocal)
Oh and is that Olympus lens you're using in your setup an old manual focus type? If so, I'm surprised that you can focus that lens to infinity on your Canon EOS DSLR. I keep hearing about the problems people having when focusing old film lenses at far distances on Canon DSLRs due to the difference in flange focal depth
No issues here, the flange focal distance of the EOS EF bayonet is a bit smaller that the OM (and also of Nikon and many others) so the adapters allow infinite focus at the right position.
I use a Sigma 30mm f2.8 for this kind of work. Although it's a really nice lens optically (including wide open) it's a nuisance to use for afocal because of the electronic focus design. I don't mind going outside and focusing on a far away subject to get infinity focus (if done just once.) Though I have to keep the camera turned on and active the whole time during the microscope shooting session. If the camera is not used for a certain period of time and turns itself off to save power, the focus setting is lost and I would have to detach the camera from the microscope and go outside and repeat the process again.
This seems annoying!
Can't you set it to infinite in manual focus mode?
Enrico Savazzi, a forum member, uses this lens and didn't report any issues, you can ask him
http://savazzi.net/photography/zeissadapter.html
I note that you recommend using a 63mm lens if using a full frame sensor with a 10x eyepiece. I can think of a lens which could be a contender if one was using a full frame photography system. I also shoot medium format film and one of my MF cameras is a Koni Omega Rapid mechanical rangefinder camera which shoots 6 x 7cm film. This camera was produced during the 1960s and 1970s and was intended for press photographers. One of the Koni Omega's lenses is a wide angle with an approximate focal length of 60mm. Though I'm not sure how such a lens could be adapted to a digital camera successfully since there is no focusing ring on the lens itself.
I can't give you advice on that equipment, although I don't think that a big heavy wide angle lens would be convenient
Pau

viktor j nilsson
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Re: Suggestions for clamping a camera to scope for afocal

Post by viktor j nilsson »

Pau wrote:
Tue Nov 03, 2020 2:53 am
In place of the Zeiss and dovetail adapter at my setup you can use other parts like:
- The old Ihagee Exakta seems very nice (although I don't understand well how its clamps over the tube)
https://www.ebay.com/itm/tubus-adapter- ... SwyDFbFjE5
https://www.ebay.com/itm/tubus-adapter- ... SweVZeWC6z
- The Pentax with M42 screw mount (avoid the newer K bayonet model) like
https://www.ebay.com/itm/ASAHI-HONEYWEL ... SwdLpflH5h
Originally it was intended for eyepiece projection raising the eyepiece. For afocal it is too long, this is why you could need to drill or file a bit the internal hole to allow it fully sliding in the tube (I don't know its exact length nor your microscope 25mm tube part length)
AHA! This explains something I've thought about for quite some time, and discussed it a bit on microbehunter a couple of years ago: http://www.microbehunter.com/microscopy ... 009#p61009

I have the Asahi Pentax Microscope adapter on my Wild M20. I tried, and I can't fit a Nikon CFW 10x eyepiece in there, but I have been using it with a 2.5x CF PL eyepiece. But even with the 2.5x CF PL haven't been getting the magnification I've expected, and have been wondering if this is because the adapter raises the eyepiece a mm or so. I have been meaning to file off the inner ledge, but I haven't had the courage to do so. I haven't been sure whether the adapter was designed differently from the Zeiss adapters.

It was very good to get your confirmation that filing it off is the way to go.

dragonblade
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Re: Suggestions for clamping a camera to scope for afocal

Post by dragonblade »

Pau wrote:
Tue Nov 03, 2020 2:53 am
This seems annoying!
Can't you set it to infinite in manual focus mode?
If only I could! It's not that easy. There is no stop point for the focus ring. It just rotates around and around continuously. When you are manually focusing, a display appears in the EVF which shows mountain peaks for distant subjects and flowers for close subjects. And as you rotate the focus ring, there's this cursor thing that moves between these two icons. Logically, you would think that moving the cursor on to the mountain peak icon would focus the lens on infinity. Not so! I did exactly that with another M4/3 lens with the same silly wire focus system when I was shooting a lightning storm a number of years ago. All the lightning photos were out of focus. Previously, I used to shoot lightning on film with old manual 35mm SLRs. And achieving infinity focus with that equipment was dead easy - just rotate the focus ring all the way until you hit the infinity mark.

So later on, whenever I shot lightning with an M4/3 lens, I would always seek out distant subjects to focus on to get infinity focus. It was the only way. And sometimes I mount old manual focus lenses on my M4/3 cameras with adapters and that makes infinity focus very straightforward.

Though yea when I was first researching my lens options for afocal photography, I was interested in using old film lenses via an adapter. Though I couldn't find any lenses in the 35mm film format that were suitable for M4/3 and a 10x eyepiece.

Though in more recent times, I discovered some very cheap Chinese 35mm lenses which can be mounted on M4/3 cameras. And they are fully manual lenses which is a nice bonus. I'm not exactly sure if they're designed specifically for mirrorless cameras though if they are, they are unlikely to be retrocus design so probably a low chance of vignetting. Regardless, they're probably optically inferior to the Sigma 30mm, especially wide open.

And today, I discovered a Minolta 30mm enlarging lens online. That could be another option. And looking at photos of this lens, it looks like it has a focus ring. I haven't used an enlarger for a long time though I assume a lot of the lenses intended for them wouldn't have focusing rings since there would be little need for them.

Pau
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Re: Suggestions for clamping a camera to scope for afocal

Post by Pau »

viktor j nilsson wrote:
Tue Nov 03, 2020 6:37 am

AHA! This explains something I've thought about for quite some time, and discussed it a bit on microbehunter a couple of years ago: http://www.microbehunter.com/microscopy ... 009#p61009

I have the Asahi Pentax Microscope adapter on my Wild M20. I tried, and I can't fit a Nikon CFW 10x eyepiece in there, but I have been using it with a 2.5x CF PL eyepiece. But even with the 2.5x CF PL haven't been getting the magnification I've expected, and have been wondering if this is because the adapter raises the eyepiece a mm or so. I have been meaning to file off the inner ledge, but I haven't had the courage to do so. I haven't been sure whether the adapter was designed differently from the Zeiss adapters.

It was very good to get your confirmation that filing it off is the way to go.
Well, I don't think that "a mm or so" would have much impact in magnification. Is parfocality good? The distance between the projective and sensor is more important.
Right now I'm experimenting with Nikon PLI 2.5x and 2x photoeyepieces in my AZ100 and I'm getting higher magnification than expected (about 10-15% higher) I'm still investigating it but I'm confident of having them at the right position because parfocality is good and it is very sensitive to length mismatch

The idea of filing the Pentax or similar adapter to allow sliding more on the tube is because in an afocal setup the camera lens must be very close to the eyepiece upper lens and using the adapter as designed this will not be possible.
Pau

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