Microstar IV Camera Setup

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BrianBurnes
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Microstar IV Camera Setup

#1 Post by BrianBurnes » Mon Jun 22, 2020 2:48 am

Hi all,

I've been trying to build a decent quality DSLR setup for my trinocular Reichert Microstar IV, and I could use some advice from the resident microscope experts on how to fix the problems I'm seeing (or - maybe these issues are expected with this microscope). I'm at a point now where I can capture images, but I'm disappointed with the quality I am getting: No matter what I do, the images seem blurry and contain chromatic aberrations.

I have a Reichert #1943 trinocular head, but I haven't been able to find much information about the intended camera adapter that fits onto the trinocular port (it is a 40mm male dovetail) and whether it contained any optics, so I am mostly guessing here. The head itself has a slider for a 100/0 split, where the slider moves a prism out of the way so that there are no optics between the trinocular port and the tube lens (other than a mysterious glass cylinder). The port itself is shaped like this:

Image

I am using a Canon EOS 7D, and I've been experimenting with two different setups for image capture: A direct projection setup, with the bare camera sensor located at the intermediate image plane and no optics between camera and tube lens; and an afocal setup, with a third eyepiece mounted in focus atop the trinocular port and the camera looking through the eyepiece (with a Canon 50mm f/1.8 lens) focused at infinity.

Pictures of the two setups are below: Direct projection (left), Afocal (right)
ImageImage

To mount the camera I'm using a DYI adapter tube, fixed to the microscope using a 3D printed adapter that replaces the original port:

Image

The adapter holds an M42 ring that leads into M42 macro extenders and a helicoid to fine-adjust the focus. For the afocal setup, I am mounting an eyepiece inside the macro extender tube closely in front of the camera lens. I designed a 3D printed eyepiece holder, but it was destroyed in the mail, and so for now I am testing using a makeshift wedge made out of cardstock that holds the eyepiece in the tube:

Image

In the end, the mechanical setup goes something like:
3D printed adapter -> M42 thread -> macro extension tubes -> helicoid -> M42-to-EF adapter -> camera (for direct projection)
3D printed adapter -> M42 thread -> extension tubes -> helicoid -> extension tubes -> eyepiece -> step-up ring -> Canon 50mm f/1.8 lens -> camera (for afocal)

I've been doing some comparisons to see whether either setup gives me satisfactory results, and I have been testing using a reticule from an eyepiece that I was able to remove.

Below I'm showing results from both direct projection and the afocal setup, at 40x/100x/400x magnification both at horizontal and vertical orientation of the reticule. There is no cover glass, just the glass reticule sitting on top of a microscope slide (so not optimal). Images were shot by focusing through the eyepieces, then adjusting the helicoid until the camera was parfocal with the eyepieces. For the afocal setup, I adjusted the helicoid without the camera attached until the image looked sharp through the eyepiece in the adapter tube. I then attached the camera, focused at infinity.
Results below:

Direct projection: 40x, 100x, 400x (click images for full-res)
ImageImageImage
ImageImageImage

Afocal: 40x, 100x, 400x (click images for full-res)
ImageImageImage
ImageImageImage

While I don't know what the quality ceiling is for this scope/camera combination, I can't say I'm fully satisfied with either of these. The direct projection setup is acceptable, but especially at lower magnification, the image looks a bit hazy. There is also a lot of chromatic aberration towards the edges, which is not great. These aberrations are not present when looking through the eyepieces, as far as I can tell.

The afocal setup is really not very good. The images are hazy and the chromatic aberrations are extreme. Aberrations are not symmetrical which is mysterious.

For now it seems the direct projection setup is just barely usable. Images shot under more realistic conditions look something like this (click for full res):
Image

The quality is disappointing however - even though the image looks very sharp in the eyepieces, the image from the camera just feels blurry even when shooting at the shortest exposure time. The 7D that I'm using has a low-pass filter which may be contributing, but overall it feels like the quality I'm getting out is less than it could be. For reference, here is an image of diatoms that I shot with a hand-held cell phone through the eyepieces (click for full-res):

Image

Even with a much cheaper phone camera held much less robustly (compared to the DSLR setup), the image is sharp and free of aberrations as I would expect.

I'm curious if anyone has any ideas on where these issues stem from and how I could possibly fix them. Maybe there's a glaring mistake I'm making?

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wporter
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Re: Microstar IV Camera Setup

#2 Post by wporter » Mon Jun 22, 2020 5:24 am

Maybe there's a glaring mistake I'm making?
Yes, perhaps. You are missing the shutter/photocell housing which goes on top of the trino head, and one of the various lens systems (1762, 1763, 1764, or 1768) that goes on top of the shutter housing. Not sure how much compensation or correction these latter would provide, but I suspect some. The shutter housing of course can be gutted and used just as a spacer, or you could make an equivalent.

See the manual "Reference Manual Photostar Automatic Camera System" off the internet, for details:

http://doclibrary.com/MSC167/DOC/PhotoS ... al0956.pdf

MichaelG.
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Re: Microstar IV Camera Setup

#3 Post by MichaelG. » Mon Jun 22, 2020 6:40 am

The afocal images are quite revealing

Chromatic Aberration is greater :
  • to the right side of the picture
and
  • to the top of the picture
Edit: and the direct-projection images [although less severe] are the other way

This would seem to indicate that the attachment is not axially aligned.
... Philosophical Question: Is 3D printing really up to this job ?

MichaelG.
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viktor j nilsson
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Re: Microstar IV Camera Setup

#4 Post by viktor j nilsson » Mon Jun 22, 2020 7:25 am

In fact, if I read the post right, the 3D printed part was destroyed in the mail, so the eyepiece is held by cardboard.

So there is one issue: the eyepiece may not be properly aligned.

However, I am still worried about the height of your afocal setup. Afocal setup are almost always more compact that setups with projection eyepiece. You said that it needed to be this high to be parfocal. This, however, to me suggests that you are missing some optics in your trinocular port. You really shouldn't need that amount of extension. So while your setup is parfocal, I highly doubt that it is working as intended with regards to optical corrections.

photomicro
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Re: Microstar IV Camera Setup

#5 Post by photomicro » Mon Jun 22, 2020 8:45 am

I can't find any reference to *what* eyepiece is being used in the afocal method...

MichaelG.
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Re: Microstar IV Camera Setup

#6 Post by MichaelG. » Mon Jun 22, 2020 9:03 am

viktor j nilsson wrote:
Mon Jun 22, 2020 7:25 am
In fact, if I read the post right, the 3D printed part was destroyed in the mail, so the eyepiece is held by cardboard.
Ah ... but:
.
To mount the camera I'm using a DYI adapter tube, fixed to the microscope using a 3D printed adapter that replaces the original port:
.
For the afocal setup, I am mounting an eyepiece inside the macro extender tube closely in front of the camera lens. I designed a 3D printed eyepiece holder, but it was destroyed in the mail, and so for now I am testing using a makeshift wedge made out of cardstock that holds the eyepiece in the tube:
.

So we seem to have both 3D printed and Cardboard components involved.

MichaelG.
Too many 'projects'

apochronaut
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Re: Microstar IV Camera Setup

#7 Post by apochronaut » Mon Jun 22, 2020 11:44 am

There are three main problems with your set ups, if I am reading you correctly.
1) Chromatic aberration. It is worse with the afocal set up.
2) The chromatic aberration is asymetrical.
3) The images suffer from a lack of resolution.

Solution.
----------------

1). Your direct projection to sensor system in theory makes sense, only if the sensor size is smaller than the image circle size of the objectives. You need to install a relay lens in the system . I use a #145 or 145P for projection to an APS-C sensor , which provides aberration free images corner to corner. Probably a 483 eyepiece would do as well or possibly better. You will have to increase your extension considerably to a full frame sensor. Likely close to 250 mm above the telan lens.
The shutter box from a Photostar system will work as wporter suggested. The original photo lenses provided in those do not project as much field to the sensor as one sees. I removed mine and use a 145 eyepiece instead.

The CA with your afocal set up is being caused by your camera lens. There is an assumption often , that camera lenses are really good lenses. Usually they are adequate for photographs but they are not usually apos, so can easily contradict what the eyepiece is projecting, always at the periphery where they struggle to compensate for conditions caused by extremely bent light. A different , perhaps shorter focal length lens might solve the problem , or a different photo eyepiece that magically introduces the opposite types of distortion to that of your camera lens.
2) This is possibly caused by some asymetry in your extension system. Any cardboard pieces would be suspect. Alternately, perhaps the objective is not perfectly aligned. You might not see asymetry with your eyes but the sensor would record it.
3) Large bulky cameras are notorious for creating vibration due to mirror slap. Your set up, with many disparate components may be weak enough to allow that to affect it and be recorded. Mirrorless bodies are more user friendly for lighter bodied tubes than DSLRs but you should be able to find any weakness in your system. It is possible that there is an optical cause but the source of that isn't obvious to me right now.
Last edited by apochronaut on Mon Jun 22, 2020 3:16 pm, edited 1 time in total.

apochronaut
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Re: Microstar IV Camera Setup

#8 Post by apochronaut » Mon Jun 22, 2020 11:46 am

Regarding 3) above, if you haven't already you might just check the insides of your trino. I found a nice thick spider web inside one once. It didn't exactly perform as intended.

BrianBurnes
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Re: Microstar IV Camera Setup

#9 Post by BrianBurnes » Tue Jun 23, 2020 4:55 am

Thank you all for your replies!

I'm very much aware of the ad hoc-ness of my setup, and for sure would prefer to do without cardstock or 3D printing. With no access to a machine shop they sadly happen to be what can be easily accessed at the moment (and within budget!). I have been on the lookout for the photostar camera system but have not had much luck on ebay. There is an adapter tube that very rarely pops up but I'm unclear what eyepiece is supposed to go with it.

From your replies there seem to be three problems with my current setup: Centering of the eyepiece (for afocal), alignment of the optical tube, and mechanical stability. The eyepiece is visibly not centered at the moment, but it may be a while before a more reliable way of mounting it can be produced. That being said, it seems less desirable to add more glass between the objective and the sensor (the lens does add its own CA as apochronaut points out), and I prefer the direct projection setup, so the eyepiece may become less of an issue. Afocal was tried only because of the aberrations in the direct projection setup, which I assumed was because the microscope used corrective eyepieces (is this the case for this model?). I used the same #181 eyepiece as the head to (hopefully) achieve the same corrections.

As far as alignment goes, I am not sure whether the tube itself is responsible. Loosening its alignment screws and moving the tube side to side (and even tilting it) seems to have little effect on the chromatic aberrations. However, through a Bertrand lens I did notice something that I found unusual in the microscope itself: Even when the condenser is adjusted so that the field diaphragm is centered within the view, the condenser aperture does not appear centered when using the Bertrand lens to view the objective rear focal plane. I don't know enough to tell whether this is benign, or perhaps something is out of alignment in the rest of the scope (but what? the objective turret?) and contributes to asymmetric aberrations.

Finally, mechanical stability could certainly be an issue - my setup is far from solid - but what leads me to believe other factors are at play is that even in live view (with no shutter movement) the images still appear blurry to me (I have also been using EFCS to reduce vibrations in the posted images, though that may not bee enough).

That being said, I don't have enough experience to know what the quality ceiling of this microscope/camera combination is. With achromats I'm sure some CA is expected, and the image through the eye pieces appearing sharper may just be my eyes playing tricks on me (they do have higher dynamic range after all), so perhaps these images are about what can be expected?
I use a #145 or 145P for projection to an APS-C sensor , which provides aberration free images corner to corner. Probably a 483 eyepiece would do as well or possibly better.
This is very helpful, thank you! The #145 seem to be easy to come by, the #145P less so. Is there a practical difference from one to the other? I have also seen the #437 referenced elsewhere, would that be usable as well?

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Re: Microstar IV Camera Setup

#10 Post by Zuul » Tue Jun 23, 2020 3:58 pm

With achromats I'm sure some CA is expected
True, but the Neoplans should be better in this regard.

I’m following with great interest having recently received a Microstar IV of my own. Unfortunately, my plans have been slowed by a cracked lamp socket. It was working when I received the scope, but during my inspection and cleaning effort, it gave up the ghost.

apochronaut
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Re: Microstar IV Camera Setup

#11 Post by apochronaut » Tue Jun 23, 2020 4:36 pm

My computer has failed recently, so I have to use a tablet, which I find cumbersome. I tried answering your questions individually with quotes but by the time I was done, I was logged out, so I will just ramble.

The adapters that I have seen: several photostar set ups and Diagnostic Instruments are integrated with an optic.

Direct projection is problematic. The reference length for the system is around 180mm, so you might try that telan lens to sensor distance. I tried a direct to sensor approach and was unimpressed with the results. I think it was because, if your tube is too short, you take in too much of the telan lens diameter, straying into peripheral aberrations that the lens system as an entirety is designed to vignette out. Every lens system has peripheral aberrations, even apochromats: that's why lenses are always much bigger than the beam that passes through them. There was also the possibility that I was picking up the lmage in the wrong image plane.It was a long time ago and I don't remember all of the problems now but I remember that the background was uneven. I abandoned the idea in favour of using a relay lens.

A relay optic picks up the perfectly corrected central part of the image circle and passes a well corrected image circle to the sensor at a correct distance.Both the 181 eyepiece and the 145 or 145p eyepiece fulfill this role. The 145p has just a focusable photo framing reticle installed, so I remove that. The 437 is an older focusing ocular, made for the 34mm parfocal system, which required some further eyepiece corrections. In the 400 series system, it creates a little off axis ca.

Regarding alignment. I think you have two issues. Misalignmrnt of your relay optic and misalgnment of the illumination system. Misalignment of the relay optic will cause existing ca to be assymetrical. It won't create it, unless it is very severe. Misalignment of the illumination system is probably a consequence of someone frigging with the nospiece. That will not create ca in the image again, unless it is really off. Align the nospiece to the field diaphragm by manipulating the 3 allen screws that orbitally adjust it. Then bring the condenser in with tweaks to the nosepiece.

My sensor is an APS-C, and in order to achieve full field coverage with parfocality(while using a relay lens), my lens is about 150mm above the telan lens and the sensor another 100mm above the lens. I use a helicoid focuser for fine trimming of the focus. With a full frame sensor, you will need to go out to around 300mm.

There is no ceiling quality to your microscope/camera combination that is unique. Each of the two systems is what they is. A mismatch is due to the owner creating it.
I'm sure you know your camera well. The microscope makes an image as good as any other in it's class and era; better than most actually. Put planapos in it and it provides fine planapo imaging across a 20mm field. Put planachros in it and it provides fine planachro imaging. The ca is consistent with planachromat imaging; slight but uniform across the field. Skewed or increasing ca off axis is caused by mechanical and optical problems.

It is important to note that very few photomicrographs are representative of what the eyepiece sees. Most excellent images have been treated to a degree, sometimes high of post processing.
Last edited by apochronaut on Tue Jun 23, 2020 7:43 pm, edited 1 time in total.

apochronaut
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Re: Microstar IV Camera Setup

#12 Post by apochronaut » Tue Jun 23, 2020 4:43 pm

Zuul wrote:
Tue Jun 23, 2020 3:58 pm
With achromats I'm sure some CA is expected
True, but the Neoplans should be better in this regard.

I’m following with great interest having recently received a Microstar IV of my own. Unfortunately, my plans have been slowed by a cracked lamp socket. It was working when I received the scope, but during my inspection and cleaning effort, it gave up the ghost.
The opposite. The Neoplan objectives were a more budget friendly 45mm adaption of some of the 34mm designs. They were pitched at institutional use; schools etc.
They are not quite plan at 20mm, somewhere between semi-plan and plan.

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Re: Microstar IV Camera Setup

#13 Post by Zuul » Tue Jun 23, 2020 6:12 pm

apochronaut wrote:
Tue Jun 23, 2020 4:43 pm
The opposite. The Neoplan objectives were a more budget friendly 45mm adaption of some of the 34mm designs. They were pitched at institutional use; schools etc.
They are not quite plan at 20mm, somewhere between semi-plan and plan.
Wouldn't a simple "achromat" imply the objective is not particularly plan at all? Planachro would be a step above the Neoplan, but that wasn't what was said.

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Re: Microstar IV Camera Setup

#14 Post by apochronaut » Tue Jun 23, 2020 7:42 pm

There were no achromat objectives for that series. I think the reference to achromats was in a generic way, referring to a class of colour correction, which Neoplans also partake of, although with less correction for all aberrations and distortion at the periphery.

BrianBurnes
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Re: Microstar IV Camera Setup

#15 Post by BrianBurnes » Wed Jun 24, 2020 4:20 am

Thank you for taking the time to write such a detailed response apochronaut, this is very useful information. I've been able to realign the nosepiece and the quality seems improved.

In your setup, are you using a camera lens at all, or does the eyepiece project directly onto the sensor? If it is the latter, I did not realize that was possible, and I look forward to trying that. If you don't mind my continued questions, would I see an improvement using the 145 over the Microstar 181, or do they have roughly the same properties?

apochronaut
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Re: Microstar IV Camera Setup

#16 Post by apochronaut » Wed Jun 24, 2020 2:11 pm

No. A camera lens would be used if an afocal set up was desired. It would not matter whether the camera was mounted over an eyepiece or over the trinoc. Each would be afocal. Typically, a lens mounted on the camera of a shorter focal length than normal, works best. Camera lenses tend to introduce distortion or aberrations and may require cropping. This why phone cameras often produce better pictures than one would expect. They innately have greater depth of focus and some have software that automatically corrects for defects. Some even can stack. There is still the problem of the tiny sensor though.

Most set ups on the trinocular use a camera relay lens, that converts the convergent beam to a divergent beam. This can be anything that works. With some systems a reversed copy lens works, with some an enlarger lens, with some an eyepiece. Anything is possible as long as the lens produces a flat projected image which is free from distortion and aberration as far as the corners of the sensor. Different photo eyepieces can introduce different aberrations because in the system they were made for they are required to correct for aberrations innate to the system. That's why using a photo eyepiece other than that made for your system is trial and error.

In the AO/Reichert 400 series system, the telan lens located in the bottom of the head converts the infinity bundle tof rays to a convergent bundle focused at 180mm( approx.), where the eyepiece picks up the image, magnifying it 10X and reversing it to a divergent bundle. Projecting it. From the telan lens north, the image is fully corrected. If a planachromat image leaves the telan lens then a planachromat image projects from the eyepiece. No further corrections take place. Installing a 181 eyepiece in the photo tube works as a projection lens. Placing it at the correct distance from the telan lens and your sensor the correct distance from it, will give you as perfectly a corrected image to your sensor, as you get from the eyepieces.
I would recommend shooting for 178mm, glass surface to glass surface, for the eyepiece location. Mine sits at around 150mm, only because the photo star housing provided that resting place but I can still get parfocality. The original lens in the photostar was further up the line. I removed mine. With a full frame sensor you will need to place it another 100mm above the eyepiece. , probably less. Bear in mind that the working distance of your objectives will be progressively lessened inverse to magnification with the sensor sitting that high. Shimming the 2.5X and 4X are an option.

Something else you may want to try is to use a teaching bridge as a photo tube. This will pass the infinity bundle over to another head but instead of the head and telan lens, you attach a camera lens set at infinity as a convergent lens. For a full frame camera you will need probably a 300mm. You may even need a teleconverter. The quality will be determined by the lens quality. I have used an adapter I had Raf camera make up that went from the 2" dovetail to 52mm filter thread on a Nikkor Q 200mm prime lens. This worked pretty good with an APS-C sensor and covered a very wide f.o.v. , into parts of the image circle with correction defects. Cropping was therefore required but the field capture was exceptional. A zoom lens may also work but due to the moving elements and often physical restrictions in zooms, some of them will vignette.
Just a thought, if you wanted to stick to camera lenses. A 300mm apo might be great.

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Re: Microstar IV Camera Setup

#17 Post by hans » Sat Jul 25, 2020 11:31 pm

I just tried direct projection with the 10X plan achro from the camera port to a Nikon D5100 and got a similar amount of transverse CA, more than is visible through the eyepieces. I set the field diaphragm to match the field stop in the eyepieces as closely as possible to give a clear reference for where the image would normally be cropped.
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Re: Microstar IV Camera Setup

#18 Post by hans » Sun Jul 26, 2020 7:42 am

BrianBurnes wrote:
Mon Jun 22, 2020 2:48 am
... where the slider moves a prism out of the way so that there are no optics between the trinocular port and the tube lens (other than a mysterious glass cylinder) ...
Seems likely the glass cylinder is there to add similar abberations to the camera path as are added by the prism, splitter, and relatively thick glass window behind the eyepiece? It is difficult to access the components for measurement but it looks like the thickness is similar to the total path length through glass going to the eyepieces.

I did a comparison with direct projection through the telan lens alone by removing the screws from base plate of the head so I could easily lift the entire upper housing with glass cylinder and binocular assembly in and out of the path. I see very little difference in the transverse CA, but maybe that is expected for a flat glass plate? These in-focus images of the calibration slide are probably not very revealing of differences in spherical aberration or axial CA if that is what the glass is adding. They are cropped to only the upper right quadrant of the field, with the lower left corner of the images being the optical center.
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Re: Microstar IV Camera Setup

#19 Post by hans » Wed Jul 29, 2020 2:59 am

I believe the element missing from the camera port responsible for the severe transverse CA is the thing that looks like a thick glass plate at the base of the binocular eye tube. I started a new thread about it.

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Re: Microstar IV Camera Setup

#20 Post by Plasmid » Mon Dec 21, 2020 3:05 am

hans wrote:
Wed Jul 29, 2020 2:59 am
I believe the element missing from the camera port responsible for the severe transverse CA is the thing that looks like a thick glass plate at the base of the binocular eye tube. I started a new thread about it.
hans, I just picked up a second Microstar, this one with a trino head, my goal is to be able to take videos not so much super high quality pictures using a Dslr camera ( which I haven't purchased yet) I read this thread and the one you posted and to be honest 99% seems alien to me ( due to my lack of knowledge) My questions is what would be the easiest approach to being able to connect a camera to the trino head, without the photostar system?

hans
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Re: Microstar IV Camera Setup

#21 Post by hans » Mon Dec 21, 2020 6:36 pm

Plasmid wrote:
Mon Dec 21, 2020 3:05 am
hans, I just picked up a second Microstar, this one with a trino head...
Risky thinking, I don't want to admit how many I have now, but at the prices individual components typically sell, very tempting to buy the relatively complete surplus ones whenever they show up cheap with desirable accessories.
Plasmid wrote:
Mon Dec 21, 2020 3:05 am
...my goal is to be able to take videos not so much super high quality pictures using a Dslr camera ( which I haven't purchased yet) I read this thread and the one you posted and to be honest 99% seems alien to me ( due to my lack of knowledge) My questions is what would be the easiest approach to being able to connect a camera to the trino head, without the photostar system?
Two questions: Would you be buying the DLSR specifically for microscope use, or planning to also use it regularly for other photography? Do you have a dedicated area to leave the microscope and camera set up or does it need to be easy to disassemble/reassemble everything?

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Re: Microstar IV Camera Setup

#22 Post by Plasmid » Mon Dec 21, 2020 7:01 pm

hans wrote:
Mon Dec 21, 2020 6:36 pm
Plasmid wrote:
Mon Dec 21, 2020 3:05 am
hans, I just picked up a second Microstar, this one with a trino head...
Risky thinking, I don't want to admit how many I have now, but at the prices individual components typically sell, very tempting to buy the relatively complete surplus ones whenever they show up cheap with desirable accessories
.
At sub $80 with a trino, a full neoplan set and in really good shape overall, it was hard to pass, my plan was to purchase a trino for my Microlux but that head itself is going for $500, so the Reichert is a no brainer :) .Im seeing a lot of them pop up on ebay but not in great shape and the prices are definitely on the way up.



Two questions: Would you be buying the DLSR specifically for microscope use, or planning to also use it regularly for other photography? Do you have a dedicated area to leave the microscope and camera set up or does it need to be easy to disassemble/reassemble everything?
The DSLR will only be used for the Microscope only, and the space is not a problem, I have a whole office with plenty if table room
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hans
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Re: Microstar IV Camera Setup

#23 Post by hans » Mon Dec 21, 2020 9:38 pm

Plasmid wrote:
Mon Dec 21, 2020 7:01 pm
The DSLR will only be used for the Microscope only...
May want to consider a mirrorless camera. Seems like the through-the-lens optical viewfinder of a DSLR is not very useful on a microscope (I never use mine) and the mirror is just a source of vibration. (Although it seems like the mechanical shutter, still present on mirrorless cameras, is typically the more problematic source of vibration so you will want to research carefully what electronic shutter modes the cameras you are looking at have.)

There are two basic decisions about how to connect the camera optically and mechanically. It may not be obvious from looking at photos of specific setups but the choices are independent -- you can use either optical method (afocal vs. projection) with either mechanical method (camera attached directly to microscope head vs. on a separate stand/tripod).
Plasmid wrote:
Mon Dec 21, 2020 7:01 pm
...and the space is not a problem, I have a whole office with plenty if table room
This makes setups with the camera on a separate stand/tripod practical, for example:
crude: viewtopic.php?p=90978#p90978
nicer: https://www.krebsmicro.com/microsetup2/index.html

The other option is to attach the camera directly like Brian's 3D-printed mount: viewtopic.php?f=12&t=10550

Direct attachment is obviously more compact and portable but the separate stand/tripod provides a lot of vibration isolation (so the camera does not disturb the sample, if that is a problem) and also requires less fabrication skill since the part attached to the microscope head only has to support the weight of the eyepiece, not the whole camera.

Then you also have to decide optically whether the image goes:
  • Afocal: objective -> telelens -> glass plug -> color correcting doublet -> 181 eyepiece -> camera lens -> sensor (Doublet, eyetube, and 181 are removed as a complete assembly from the binocular and placed above the camera port.)
  • Projection: objective -> telelens -> glass plug -> 145 eyepiece lifted somewhat from normal position -> sensor (Need to ask apochronaut for details on this -- I do have a 145 now but have not experimented with it yet.)
There are other possibilities optically but they are either known to not work well (excessive lateral CA) or not thoroughly tested that I know of.

For comparison, when you do afocal with your smartphone mount on a binocular eyepiece the image goes:
objective -> telelens -> prism -> beam splitter -> mirrors -> color correcting doublet -> 181 eyepiece -> smartphone camera lens -> sensor

The glass plug in the camera port has thickness similar to the total path length through the prism and splitter in the binocular (thickness of glass much be reasonably well matched, for similar reasons as why it is important to use the correct cover glass thickness) so theoretically an afocal setup with doublet+181 over the camera port should give an image very close to the one you get through the normal binocular.

I don't know how image quality compares doublet+181 afocal vs. 145 projective, but projective is less expensive if you don't already have a suitable camera lens and would have to buy one. I use AF-S DX NIKKOR 35mm f/1.8G, $200 retail new, because I already had it for normal photography. I would guess somewhere in the $100-300 range to get a suitable lens depending on which camera system and new or used.

A stack of off-the-shelf adapters like that RafCamera one and extension might work. I didn't look into that possibility much. In the afocal case you would probably still need to do at least a little fabrication to mount the eye tube with its square 4-hole flange at the appropriate position.

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Re: Microstar IV Camera Setup

#24 Post by apochronaut » Mon Dec 21, 2020 10:34 pm

I have been using a Sony a5000 mirrorless APS-C with few problems. In fact I move it around from a series 4 to a series 10 or 20 to a Diastar, each with dedicated well corrected photo eyepieces ; a Wild 6X on the 4, AO 1054( same as the 437) on the 10 & 20 and 145 on the Diastar. My mounts are not particularly rock steady but the Sony is pretty vibrationless even at slow shutter speeds.
I can't say I would recommend using a DSLR, especially a full frame DSLR, on any of my mounts which are modified factory aluminum photo tubes on the 4, 10 and 20 and a modified photo star body on the Diastar. You probably could make them rigid enough but for a full frame sensor you need a pretty long projection, another 100mm or so more than that for an APS-C, so that just increases the vibration potential.

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Re: Microstar IV Camera Setup

#25 Post by Plasmid » Tue Dec 22, 2020 12:48 am

Wow thank you hans, breaking it down that way helped me a lot to understand which path to take.
One question
Afocal: objective -> telelens -> glass plug -> color correcting doublet -
The telens is the glass that the bottom of the head?
Glass plug and correcting doublet ? Are those extra or do come already assemble inside the head?

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Re: Microstar IV Camera Setup

#26 Post by Plasmid » Tue Dec 22, 2020 2:13 am

apochronaut wrote:
Mon Dec 21, 2020 10:34 pm
I have been using a Sony a5000 mirrorless APS-C with few problems. In fact I move it around from a series 4 to a series 10 or 20 to a Diastar, each with dedicated well corrected photo eyepieces ; a Wild 6X on the 4, AO 1054( same as the 437) on the 10 & 20 and 145 on the Diastar. My mounts are not particularly rock steady but the Sony is pretty vibrationless even at slow shutter speeds.
I can't say I would recommend using a DSLR, especially a full frame DSLR, on any of my mounts which are modified factory aluminum photo tubes on the 4, 10 and 20 and a modified photo star body on the Diastar. You probably could make them rigid enough but for a full frame sensor you need a pretty long projection, another 100mm or so more than that for an APS-C, so that just increases the vibration potential.
Apochronaut, when it comes to modifying phototubes, what size should I be looking for to fit on the dovetail end of the tri head? I ask because Im considering a Sony NEX series. This is all new content for me ..... including (specially) cameras and so is my understanding that the distal end of the tube would have to use am adapter for each specific brand of camera? With that being said is it just the body that is needed ? Pretty much exposing the sensor to the image or are lens required?

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Re: Microstar IV Camera Setup

#27 Post by hans » Tue Dec 22, 2020 2:47 am

Plasmid wrote:
Tue Dec 22, 2020 12:48 am
Afocal: objective -> telelens -> glass plug -> color correcting doublet -
The telens is the glass that the bottom of the head?
Glass plug and correcting doublet ? Are those extra or do come already assemble inside the head?
Yeah, telelens is the one in the bottom of the head, glass plug is the thick cylinder you see looking in the camera port from the top, and the doublet is the thing that looks like a window at the base of the eye tube when you remove an eyepiece and look in. There are some photos of various pieces scattered throughout the thread about the doublet:
#27 -- Glass plug looking down camera port from the top with the dovetail piece removed.
#86 -- Both eye tubes assemblies removed with doublets visible.
#139 -- Eye tube disassembled then mounted above camera port for afocal use.

Will be curious to hear what you find researching cameras, I have been looking for something to replace the Nikon D5100. Seems like common advice is that Canon, Panasonic, or Sony are best for video use and the smaller Canon EF-M, Panasonic Micro Four Thirds, and Sony E-mount cameras (such as the a5000 apochronaut mentioned) all look promising.

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Re: Microstar IV Camera Setup

#28 Post by apochronaut » Tue Dec 22, 2020 1:23 pm

Plasmid wrote:
Tue Dec 22, 2020 2:13 am
apochronaut wrote:
Mon Dec 21, 2020 10:34 pm
I have been using a Sony a5000 mirrorless APS-C with few problems. In fact I move it around from a series 4 to a series 10 or 20 to a Diastar, each with dedicated well corrected photo eyepieces ; a Wild 6X on the 4, AO 1054( same as the 437) on the 10 & 20 and 145 on the Diastar. My mounts are not particularly rock steady but the Sony is pretty vibrationless even at slow shutter speeds.
I can't say I would recommend using a DSLR, especially a full frame DSLR, on any of my mounts which are modified factory aluminum photo tubes on the 4, 10 and 20 and a modified photo star body on the Diastar. You probably could make them rigid enough but for a full frame sensor you need a pretty long projection, another 100mm or so more than that for an APS-C, so that just increases the vibration potential.
Apochronaut, when it comes to modifying phototubes, what size should I be looking for to fit on the dovetail end of the tri head? I ask because Im considering a Sony NEX series. This is all new content for me ..... including (specially) cameras and so is my understanding that the distal end of the tube would have to use am adapter for each specific brand of camera? With that being said is it just the body that is needed ? Pretty much exposing the sensor to the image or are lens required?
AO used imperial measure for most of their fittings. Occasionally you come across a metric hex head screw but most of it is imperial. The dovetail exiting the trinocular for the 400 series is 1 9/16”, which is just under 40mm. There are a couple of options.
1) buy an off the shelf collar like the one above. That gives you a threaded coupling that you can use . You will have to remove the registration screw next to the dovetail but from the 52mm threaded end on the above collar, you can reduce to a 23.2mm eyepiece diameter collar, then out again to a standardized thread like a T , add in some distance pieces including a helicoid focuser , finishing with a male T thread to take a female T to your chosen bayonet adapter. The helicoid focuser need not be a permanent part of the system. I use one because I move the entire rig from microscope to microscope, so the helicoid allows me to tweak the image circle size and get as close to parfocal as possible. The Sony shutter is gentle enough that the relative weakness of that part is not usually a problem. However, for a fixed stable system, never moved from the microscope, if you can use one of the short ones, relatively unextended it probably can stay but if it is a long one and somewhat extended , it will probably be shakey, especially with a DSLR. Use it to get your measurements, then replace it with a fixed piece.
2) A cheaper option is to use the above collar reduced to a standard T thread, then make up a temporary telescoping tube from cardboard, with a suitable collar afixed on top to receive your eyepiece. Then make up a suitable telescoping mechanism for the camera. Once you have the measurements you can set about buying the correct adapters and distance pieces. This could still include a short helicoid focuser if you like but I am pretty sure that if you use one with a DSLR and especially a full frame DSLR, you are going to get vibration ptoblems. DSLR's are only useful on microscopes if you can guarantee stability.
3) A third way is to shop for some of the off the shelf AO parts that included the 1 9/16" dovetails. The photostar box is one. There were also distance pieces that went to 4X5 or polaroid backs. These include a female and male dovetail top and bottom. They are nice and rigidly coupled, leaving only the switchover to the bayonet to be accomplished.

As for the actual measurements. I don't know which eyepiece you are using or what camera, which determine the dovetail to eyepiece and eyepiece to sensor distances. It seems to me that you are in a situation where you need to decide on first what photo relay lens and what camera you are going to use.
I don't quite understand why the 181 eyepiece set up that Hans uses is considered afocal and why the 145 is projective?
I have used them both as projective eyepieces. The distances are different that's all and the quality of the image with the 145 is superior, I feel at this point anyway. Adding a camera lens into the system seems to just complicate things. I would try to go direct to sensor. All of the stuff above, assumed that. You would just need a mirrorless camera back.
The only reason I use a Sony a5000 is because I got it free with air miles. Mechanically, electronically and optically it is great but it has pretty generic settings. If I were buying one, I would probably step up to an a6000 back. It has a broader latitude of settings but if you are on a budget as I was at the time, an a5000 is pretty good. I don't think the a6000 is any different in performance, just in how easy it is to get there. Other mirrorless may be better too. Sonys are basically Minoltas, or where Minolta would have gotten to, if they hadn't made some blunders.

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Re: Microstar IV Camera Setup

#29 Post by hans » Tue Dec 22, 2020 6:45 pm

apochronaut wrote:
Tue Dec 22, 2020 1:23 pm
I don't quite understand why the 181 eyepiece set up that Hans uses is considered afocal and why the 145 is projective? I have used them both as projective eyepieces.
I was just listing two specific, complete configurations that have been tested and recommended and considering things like 181 projective or 145 afocal as "other possibilities optically ... not thoroughly tested that I know of." Are you talking about using the 181 projective with or without the doublet? I did some testing (not very carefully) of 181 projection without the doublet and my impression was that lifting it was having minimal effect on lateral CA over a pretty wide range of magnification. I have not tested 181 projection with the doublet but would like to at some point. The extra degree of freedom to adjust doublet-181 spacing independently from overall magnification should be interesting to experiment with.

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Re: Microstar IV Camera Setup

#30 Post by apochronaut » Wed Dec 23, 2020 4:10 pm

When I looked at the pictures of your set up, I was surprised that you had a camera lens attached. I guess it is because you are using a full frame camera? Without the lens , the extension would be somewhat more I guess but I am always leery of putting in an extra optic, especially when the photo relay optic is producing a well corrected image and could go direct to sensor.
When putting a camera over an eyepiece in the viewing body, it makes sense to do an afocal set up because of the lateral extension that is usually required without it but when attaching a camera vertically , adding another optic just increases aberrations and distortions, small perhaps but unless the lens is remarkable, it is still something extra to consider.

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