Camera Vs Eyepiece

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by McConkey » Sun Aug 28, 2016 1:16 am

Hello All!

Just a quick observation i've noticed and wanted to see if anyone has the same problem or if i'm just out to lunch!

The quality of what i'm viewing decreases when i'm viewing it via my camera compared to when i'm viewing through the eyepieces.

Eyepieces are crisp, sharp and very detailed. When i switch over to my camera and view it on my tablet the image just isn't the same sharpness, the detail that i see via the eyepieces just isn't there and the overall quality of what i'm viewing goes down.

An example would be a Closterium. Through the eyepiece everything is crisp and sharp but via the camera/tablet its clunkier...the cell wall lines look thicker, it doesn't reach the same pinoint detail that i get through the eyepiece.

Is this normal and to be expected? I understand that camera sensors create noise but i figure an 18mp T3i should be able to give me close to what i see via the eyepiece. Does using liveview create this decrease in quality? I use a low ISO (100, 200...rarely 400).

Don't get me wrong, the image's that i do shoot i'm very happy with...i'm just curious if anyone else experiences this difference.

Any thoughts, opinions and comments are greatly appreciated!

Karl

AO21 with Canon M3

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Re: Camera Vs Eyepiece

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by mrsonchus » Sun Aug 28, 2016 3:40 am

McConkey wrote:Hello All!

Just a quick observation i've noticed and wanted to see if anyone has the same problem or if i'm just out to lunch!

The quality of what i'm viewing decreases when i'm viewing it via my camera compared to when i'm viewing through the eyepieces.

Eyepieces are crisp, sharp and very detailed. When i switch over to my camera and view it on my tablet the image just isn't the same sharpness, the detail that i see via the eyepieces just isn't there and the overall quality of what i'm viewing goes down.

An example would be a Closterium. Through the eyepiece everything is crisp and sharp but via the camera/tablet its clunkier...the cell wall lines look thicker, it doesn't reach the same pinoint detail that i get through the eyepiece.

Is this normal and to be expected? I understand that camera sensors create noise but i figure an 18mp T3i should be able to give me close to what i see via the eyepiece. Does using liveview create this decrease in quality? I use a low ISO (100, 200...rarely 400).

Don't get me wrong, the image's that i do shoot i'm very happy with...i'm just curious if anyone else experiences this difference.

Any thoughts, opinions and comments are greatly appreciated!

Hi Karl, yes my friend - this is the truly frustrating situation for me and I'm pretty sure almost every one here... :(

It's soooo downright perplexing when the eyepieces are showing a beautifully crisp image with high resolution and perfect colour etc but the switch to camera downgrades this by about 90% - it's as if the camera - and I too use a Canon EOS 1200D as the UK calls it - is a basic 500K model from 15 years ago!

Colours are always a problem too - especially the dreaded reds! At the hint of condenser-iris closure the colours alter and not in a nice way! I suspect that part of the root of this problem may lie, as suggested by apo' I think, in the awfully poor quality of the basic Abbe condensers that most of us are using - if I could 'get this problem sorted' by throwing out my old Abbe and investing in a high-quality replacement I'd gladly do so - and be willing to spend as much on this as on the darned camera if necessary - it's a major problem as far as I'm concerned and a constant source of frustration and disappointment when I see ghastly images emerging where my 'scope is sparkling with quality and resolution of eyepiece image....

A definitive answer to this conundrum would make a very happy man indeed. :)

Brightfield photomicrographs are about the most unforgiving image-type I've ever encountered! :D:D:):(

Sorry that's not a lot of help, but at least you know you're not alone with this problem my friend... :)

John B

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Re: Camera Vs Eyepiece

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by Oliver » Sun Aug 28, 2016 9:29 am

Hello,

Yes, I can also observe that camera views (images) are of lower quality than through the eyepiece. I always do some post processing to increase the contrast). From what I have found out, it is the generally lower dynamic range of cameras that give me a problem. When looking through the eyepiece, I can see details in both bright and dark areas. In digital images details in these extreme areas are often swallowed up and can not be seen. Maybe it is not only a camera issue. The human eye will adjust for different amounts of light dynamically. If you look at a dark area then the pupil opens up to see more detail there. So subjectively you see more, because when you look at something the focus of attention is at the central part of the vision (which the eye adjusts dynamically).

Another reason might be that microscope cameras only capture a small part of the central field of view. It adds magnification and the image might appear more blurry. I have found out that by using afocal photography (connecting a pocket camera), the images do appear more like you see them, but there are other problems that are introduced (blurry sides, reflections etc).

Oliver.

Image Oliver Kim - http://www.microbehunter.com - Microscopes: Olympus CH40 - Olympus CH-A - Breukhoven BMS student microscope - Euromex stereo - uSCOPE MXII

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Re: Camera Vs Eyepiece

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by JimT » Sun Aug 28, 2016 2:35 pm

When looking through the eyepiece, I can see details in both bright and dark areas. In digital images details in these extreme areas are often swallowed up and can not be seen.

One way to overcome this limitation (for stationary objects) is to shoot three exposures; under exposed, over exposed, and correct exposure, Then combine them in post processing with High Dynamic Range software.

JimT

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Re: Camera Vs Eyepiece

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by McConkey » Sun Aug 28, 2016 2:40 pm

Well I'm glad I'm not the only one experiencing this!

Makes me feel much better knowing it's a common issue!

Oliver: thanks for the feedback, if I can make space at my work station I might try some afocal stuff!

I was also going to suggest HDR imaging but Jim just beat me by a few seconds!

mrsonchus: Big help knowing I'm not alone in this situation! Thanks for the confidence boost! I've found using a custom white balance in my camera has given me the colour corrections I want. It's not perfect but it's a nice improvement! If I invent a better condenser for cheap I'll let you know :)

Karl

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Tom Jones

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Re: Camera Vs Eyepiece

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by Tom Jones » Sun Aug 28, 2016 2:55 pm

It's very likely normal, and it's not the condenser.

Look at the camera live view output resolution. It's probably much less than the sensor is actually delivering to the file, particularly in older cameras. Even the sensor cannot deliver what your eye can see unless you are dealing with wavelengths not normally visible. How about the tablet resolution? Are there limits to the resolution the connection will support? What resolution is the display set at?

There also may be issues with how the image is displayed than can be modified in camera to help a bit. Check to see if the output can have the contrast and saturation increased, or decreased for that matter, or the sharpening changed to make the live view image show better. Different "picture styles" might help. I've never tried it though.

The colors are likely not all that accurate either unless you can set a custom white balance that matches the light source. If it's standard incandescent or halogen, the color balance will change as you increase or decrease the light intensity. Auto color balance doesn't always do a good job or correcting the problem. That's why some microscopes have a "photo" setting on the intensity control so color balance was at least stable for film use.

Live view isn't really intended for continuous viewing, as most of it, at least in the older cameras, is not a direct sensor feed. You wouldn't look through the camera viewfinder instead of the microscope optics. Live view is a replacement for the viewfinder and primarily intended for framing and focusing.

I had a Canon 40D, and still have a 5D MkII. Live view resolution isn't as good as the view through the eyepieces on either of those. Even my GH4, when shooting in 4K and down sampling in camera to full HD, using an HDMI connection and displayed on a 27" HD monitor doesn't really match the eyepiece view. Why? Even HD is much lower resolution that your eyes. Interestingly however, the camera shutter speed will sometimes sync with flagellar movement so the are actually more visible on screen and in the recording! A 4K display will probably get a lot closer, since the GH4 will send a 4K signal through HDMI, but I don't have one yet. That signal is designed for recording on an external recorder as is the highest quality available.

Tom

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Re: Camera Vs Eyepiece

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by mrsonchus » Sun Aug 28, 2016 4:18 pm

Ah yes, I've tried and optimised many camera-setting groups and used custom WB from a blank 'white' picture taken at various objective/intensity/subject predominant colour - all to little avail...

Live-view is of course far inferior - but the problem I'm bothered by is the final image captured by the camera - yes I've also build custom parameter-sets using RAW image data - none of these strategies makes a significant or even worthwhile difference... :(

John B

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Re: Camera Vs Eyepiece

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by kinase » Sun Aug 28, 2016 4:50 pm

I even have this problem and I'm using this scope and this camera. I pretty much only use phase, DIC, or fluorescence. Now that I read I can see that it's not truly a 17mp camera but using pixel shifting to achieve a higher resolution. I'm truly not sure what causes it, I've tried as much optimizing as I can think of and I can still never get it 100% of what's in the eyepieces.

I also think there's something to be said about using various kinds of CCD's vs. a CMOS sensor. I think sCMOS is probably better for brightfield stuff but when it comes to absolute light detection, the emCCD is better as far as signal to noise ratio goes.

If you're using a DSLR you should definitely shoot in RAW and use a histogram to make sure that there's no blown out highlights. If you've got the highlights in good detail, you can most likely recover the shadows.

I know someone who has just about perfect results between the eyepiece and the camera with the way they work it, I'm going to ask them for some pointers.

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Re: Camera Vs Eyepiece

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by McConkey » Sun Aug 28, 2016 6:57 pm

kinase wrote:I know someone who has just about perfect results between the eyepiece and the camera with the way they work it, I'm going to ask them for some pointers.

That would be greatly appreciated! aha if your getting the same results from your equipment then i don't stand a chance!

Tom Jones: You make a good point bringing up the capabilities that the connection can support, and the fact that you still experience a difference when using 4k, HD and a HDMI cable makes me think that it all stems from the capabilities of the camera and the sensor. I'll take another poke around the various camera setting again and maybe see if there's some liveview options that can be enhanced.

Thanks for the responses!

Karl

AO21 with Canon M3

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Re: Camera Vs Eyepiece

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by gekko » Sun Aug 28, 2016 7:53 pm

For what it's worth, in addition to what was said above, I would just like to add that the resolution of the monitor (if you are working with the camera "tethered") and the resolution of the camera"s LCD are usually far lower than the resolution of the camera's sensor, and limit the detail that can be displayed. These can be especially limiting with low power objectives. You can use Mr. Krebs' spreadsheet to calculate the minimum camera sensor resolution you need given the various parameters, and I would guess that the same minimum value should apply to the camera's LCD (or computer display monitor if working tethered) in order to see the same detail that you see through the eyepiece. Please check out Spreadsheet for DSLR relay optics as well as Article for DSLR relay optics from the following link to Charles Krebs' website: http://www.krebsmicro.com/.

ADDED LATER: If monitor/camera LCD is the main limiting factor in your case (as I had assumed above), then obviously looking at an image significantly larger than fills the screen (by cropping it or looking at part of the image and scrolling) should improve the visible resolution. As has been mentioned in this thread, parfocality is very important to ensure the correct tube length in the light going to the camera, as is the use of the proper optics between objective and camera (all those points are covered very carefully and very clearly by Charles Krebs on his website).

Last edited by gekko on Tue Aug 30, 2016 11:51 am, edited 1 time in total.

https://vimeo.com/user30158560/videos

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Re: Camera Vs Eyepiece

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by apochronaut » Sun Aug 28, 2016 11:32 pm

It's the nature of photography. It can be a a third generation medium at best. A photograph can never recreate the experience and the image through a microscope can be a first rate experience, difficult to capture. One can spend thousands of dollars on equipment and develop excellent skills in order to get a photograph close, or even adjust the image towards a psychological ideal but it can never be the original experience. It can be a facsimile only.

Probably, when superior technology that is already a reality becomes more common and inexpensively available, the gap will close between reality and image capture. Right now, it takes a certain amount of heroic endeavor to overcome the current deficiencies and present them on a screen.

I've never been totally pleased with any photomicrograph I have ever taken but then being a microscopist first and a photographer second, I tend to reflect on the event more than relying on a 2 dimensional image of the event to remind me of it.

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Re: Camera Vs Eyepiece

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by McConkey » Mon Aug 29, 2016 12:00 am

Thanks for the link gekko, I'll have to read it a few more times and really try to soak up and understand everything that Charles explains.

Apo - Thanks for the response! I think i'm a photographer first so i'm looking to re-create (as best as i can) exactly what i'm seeing, after the responses in this thread i can at least stop banging my head again the desk trying to figure out why i'm not seeing the same thing through the camera!

Karl

AO21 with Canon M3

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Re: Camera Vs Eyepiece

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by mrsonchus » Mon Aug 29, 2016 4:50 am

McConkey wrote:Thanks for the link gekko, I'll have to read it a few more times and really try to soak up and understand everything that Charles explains.

Apo - Thanks for the response! I think i'm a photographer first so i'm looking to re-create (as best as i can) exactly what i'm seeing, after the responses in this thread i can at least stop banging my head again the desk trying to figure out why i'm not seeing the same thing through the camera!

That's the healthy option Karl.... We've all had this potentially depressing realisation at one time or another, as apo' says - it's a compromise at best and for those (myself included as I've been taking and processing my own prints for about 40yrs - digital now thankfully!) very familiar with the superb results 'ordinary' (i.e. non-microscopic) photography can give it comes as a bit of a shock! :(

Onward-ho my friend, we can only do our best - and quite often superb images do 'pop-out' even from the accursed bright-field photography mire...

Keep it up my friend, you never know quite what the next image will deliver! :D:D:)

John B

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Re: Camera Vs Eyepiece

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by apochronaut » Mon Aug 29, 2016 3:37 pm

get good enough, and you might be able to get on the shower curtain stage.....not sure , though; looks like the market might be cornered.

http://fineartamerica.com/shop/shower+c ... microscopy

wait : i think there might still be some openings for Micrasterias Apiculata shower curtains ; the page isn't full yet.

http://fineartamerica.com/shop/shower+c ... +apiculata

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Re: Camera Vs Eyepiece

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by McConkey » Mon Aug 29, 2016 11:44 pm

mrsonchus wrote:...Keep it up my friend, you never know quite what the next image will deliver!

:D

:D

:)

I have a pretty good idea about my next image! Lets just say it came from across the pond!

Apo - ahah that's too funny! My wife would be thrilled if i switched out our shower curtain for "one of my own". I now have something to aspire to!

Karl

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Re: Camera Vs Eyepiece

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by kinase » Tue Aug 30, 2016 2:39 am

When you guys have issues, is it when trying to take photos of stuff that's moving or stuff that's still? Unless I'm doing cancer stuff, which means it's probably fluorescence and fixed and embedded in a hard setting mountant with DAPI, then it's usually stuff that's moving. I found some odd corkscrew organism that moves along the ground by just rotating and I just can't get the DIC system to work with it, I'll have to try oil lenses. It's awfully rigid looking though, I'm not sure what it's made of. Actually maybe I'll just do an SEM of it tomorrow, that sounds more fun.

Oh man, those shower curtains... What else I can I put micrographs on?

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Re: Camera Vs Eyepiece

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by kit1980 » Tue Aug 30, 2016 4:16 am

McConkey wrote:An example would be a Closterium. Through the eyepiece everything is crisp and sharp but via the camera/tablet its clunkier...the cell wall lines look thicker, it doesn't reach the same pinoint detail that i get through the eyepiece.

You probably already checked this, but the description sounds like the camera and eyepieces are not parfocal - the specimen is in focus for eyepieces, but not for camera.

Omax microscope with Nikon CF objectives

Olympus OM-D E-M10 Mark II camera

http://sdymphoto.com/

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Re: Camera Vs Eyepiece

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by billben74 » Tue Aug 30, 2016 11:36 am

I think we have all felt this one.

Seeing is thinking or more scientifically image processing.

Your eye/retina/visual cortex is a serious bit of technology and can create a crisp, bright, clear, wonderfully colourful image. But its not a passive sensor.

Its transforming the data that comes into the eye in ways that computer vision people know that don't undertstand. For example there is an outstanding colour constancy issue, here is an introduction http://www2.cmp.uea.ac.uk/Research/comp ... stancy.htm and here is an article that the authors are saying that colour (of an object) is not an instrinstic property

http://journals.plos.org/plosone/articl ... ne.0135029. Which is to say we don't fully understand how we perceve colours.

I learned about colour vision when at Uni as a science undergrad. Later when I did some post grad computer science I found out the colour stuff I learned in physiology was a gross oversimplification and that no one understands exactly what the eye/retina/brain is up to (especially with colour).

However in spite of this keep on checking the simple stuff. Your camera will almost certainly be slight afocal with you eyepieces, you have removed any polarising filters? - they can make things blurry.

And feel free to manipulate image, the camera's colour balance (its solution to the colour constancy problem?) is not similar to my visual system's solution. So I push the hue/levels/saturation etc to make it more like how I perceive colour. The clarity you preceive with your minds eye, may due to very cleaver edge detection/shadow detection processing that the retina/visual cortex does. You can always try sharpening tools.

At least you can see it this way: its good sport for all of us hunting the beauty we see with our eyes through the glass.

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Re: Camera Vs Eyepiece

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by apochronaut » Tue Aug 30, 2016 1:32 pm

What else I can I put micrographs on?

you could probably sell a line of underwear with chlamydia, trich. or the clap on them, next door to tattoo parlors.

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Re: Camera Vs Eyepiece

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by billbillt » Tue Aug 30, 2016 5:05 pm

STRANGE..

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Re: Camera Vs Eyepiece

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by McConkey » Fri Sep 02, 2016 8:46 pm

ahah well it's an interesting idea apo. Can't say the wife would be happy with my bringing in chlamydia, trich or the clap even if it was for science and profit! :P

Bill - Thanks for the links. Excellent read! I try not to manipulate the image too much in post-processing. I've been using photoshop for about 15years and can sometimes get carried away and go overboard with image alterations!

Kit1980 - Originally the eyepiece and camera were not parfocal but after some adjustments they are pretty much spot on! Thanks

Karl

AO21 with Canon M3

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Re: Camera Vs Eyepiece

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by apochronaut » Fri Sep 02, 2016 11:06 pm

McConkey wrote:ahah well it's an interesting idea apo. Can't say the wife would be happy with my bringing in chlamydia, trich or the clap even if it was for science and profit!

:P

just pictures on undies. the tatoo parlor cliente would love it. it' would be kind of like kittens on toilet paper wrappers, to them, or endangered trees on tissue boxes.

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Re: Camera Vs Eyepiece

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by c-krebs » Sat Sep 03, 2016 10:45 pm

This discussion seems to have split has split into two different (but related) paths.

McConkey wrote:Through the eyepiece everything is crisp and sharp but via the camera/tablet its clunkier...the cell wall lines look thicker, it doesn't reach the same pinoint detail that i get through the eyepiece.

I think Tom Jones (and some others) have pointed out some of the reasons why this would be the case (and not unexpected).

The other path has to do with why the actual final camera still images may not look as good as we perceive through the eyepieces. There are quite a few reasons for this. Some can be addressed, some probably cannot.

Think about the (unconscious) procedure when viewing through eyepieces. You are constantly changing focus to maintain a sharp view of the exact subject area you are looking at. You are constantly changing x/y positions, often moving the area of immediate interest to the center (highest quality portion) of the view. The mind/eye is amazingly good at seeing into dark areas and seeing detail in bright areas ("dynamic range"), and it is quite good at "neutralizing" all but the most extreme color imbalances brought about by different light sources and characteristics. So you put together a "mental image" that is really tough to reproduce with a camera. But there are some optical and mechanical considerations that, if properly addressed, will allow you to maximize the photograph image quality.

A) Mechanical vibration issues. Any camera that uses mechanical shutters will produce vibration. (Separately, the mirror in a SLR is a well-known and notorious source of vibration, so it almost does not need mentioning... SLR mirror movement on a microscope mounted camera must be avoided.) Many cameras today can utilize an "electronic first shutter curtain" that eliminates the motion of the mechanical first shutter curtain at the on-set of an exposure. This is a huge benefit. Canon has this on most models. (Unfortunately, after the 50D they made some internal changes on most models. There is now a very slight internal "squish" noise that can be heard at the start of the exposure concurrent with a very slight vibration. This is far less than that caused by a mechanical shutter curtain, and generally not a concern. But on an especially vibration-prone setup it might deserve consideration.) Quite a few cameras now offer the EFSC feature today. The ideal in this regard is a fully electronic shutter capability, which has shown up in a few consumer cameras relatively recently.

B) Camera and eyepieces parfocal. This is not just a convenience issue. If you need to refocus the camera considerably from the eyepiece view you are changing the optical parameters for which the objective was designed, thus introducing aberrations in the pictures. This is typically not a big deal, or even noticeable with low power, low NA objectives, but can get to be a real problem with high NA objectives.

C) Over-magnification of the objectives intermediate image into the camera. Oliver mentioned this in his reply. This can be quite significant, and is sometimes hard to avoid. Looking through the eyepieces you typically see a field number (FN) of about 18 to 20mm diameter for 10X eyepieces. (This varies, the range encountered is about 18-26.5mm). Ideally you would like to record, in the camera, nearly all of the field you observe across the diagonal of your camera sensor. If you use optics to the camera that enlarge the image created by the objective (the "intermediate image") too much, you record only a small portion ("crop") of the viewed field and you can severely reduce the resolution obtainable in the final camera image. (This is analogous to taking a full digital image file of a landscape from your camera, cropping it severely in post-processing, and then making a large print from the cropped image. In no way would the print quality look as "good" as if you had been able to use the entire camera created image.)

One example to show what I mean. I have an older Nikon Diaphot TMD inverted that has a built-in camera port with a built-in 2.5X (intended to be used for “35mm” cameras with a 24x36mm recording area). With a 35mm camera I record (diagonally) a FN of 43/2.5= 17.2mm... pretty good compared to the 18-20mm FN typically seen through the eyepieces. But if I put on my Canon APS-C camera I record a FN of only 26.7/2.5 = 10.7mm diagonally across the sensor. I am "leaving behind" (not recording) a huge portion of the 18-20mm diameter image created by the microscope objective.

I amost always use an APS-C sized sensor camera.

When I use the 4/0.13 objective on the Diaphot I get a 10X magnification into the camera. So I am getting a 10X “on sensor” magnification with an NA of 0.13. With one of my other microscope set-ups I use Olympus objectives with a FN of 26.5mm and project directly from the objective (+ tube lens) onto the camera sensor. So using my 10/0.30 objective I obtain a 10X magnification into the camera at an NA of 0.30. I get 230% higher resolution in the second case, even though the in-camera image is the same size (10X)! That means that the smallest detail I can resolve with the 4/0.13 in 2.58 microns, while the smallest image resolvable with the 10X is only 1.12 microns... and again, keep in mind that the image is the same magnification "in-camera" in both cases. When I use an APS-C sensor camera for 10X on these two configurations the difference between the images is noticeable in all but the smallest image presentations.

This does not even bring into the discussion of the quality of the optics used to “feed” the image into the camera body. They could be excellent or quite marginal.

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Re: Camera Vs Eyepiece

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by McConkey » Mon Sep 05, 2016 3:28 am

Charles - Thanks for the response! Really appreciate the input. The math was easy to follow and made alot of sense!

I've adjusted some camera/tablet settings which made a small improvement on what i'm seeing via liveview. I've also adjusted my mindset/expectation and know not to expect the same quality that i am getting through the eyepieces. This was a big help!! All the input from everyone has being a real big help.

A mirrorless camera is also on my mind. It'll be a while before i can grab a decent one but it's on my list!!

Something that was mentioned was the camera and eyepieces being parfocal and over magnification. With my current setup i can get the eyepieces and camera parfocal but it causes a big loss in my field of view ( as mentioned...over magnification) OR i can retain the same FOV in both eyepiece and camera but they are not even close to being parfocal. Would i be right in assuming we want the best of both worlds...parfocal and a matching FOV?

Thank you again everyone for all your advice!

Karl

AO21 with Canon M3

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Re: Camera Vs Eyepiece

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by c-krebs » Mon Sep 05, 2016 4:52 am

McConkey wrote:Would i be right in assuming we want the best of both worlds...parfocal and a matching FOV?

Yes, if possible that should be the goal (or at least as close as it is reasonably possible). Both are pretty important in the overall scheme of things if you are trying to maximize picture quality. Being relatively new here I am not familiar with your microscope/camera connections and optics. Can you give me a brief rundown on this... (or is there another thread somewhere that that covers it)?

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Re: Camera Vs Eyepiece

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by McConkey » Mon Sep 05, 2016 5:47 am

Charles - My scope is an AO20 and camera is the Canon T3i. Right now I'm using an AO phototube which slides into the Trinoc head. It has an adjustable lens inside the tube housing ranging from 2.8x to 5x and a 67mm extension tube (removable) which the camera attaches to. With the phototube fully assembled I'm parfocal but my FOV is reduced by at least 50%. If I remove the adjustable lens I'm slightly wider than eyepiece FOV but nowhere near parfocal.

The last hour or so I've been doing some measuring and math and think I've figure out the sweet spot where my camera needs with the 2.8x - 5x adjustable lens removed. Just need to pick up some supplies tomorrow when the stores open and I should be able to get it working.

I know that there is a better way to go about throwing my camera on the AO20 using a combination of a specific focusing photo eyepiece and photo tube for the Trinoc head but I'm only here for another 2 weeks then work gets in the way, so this quick fix is just to keep me going until I'm back from my travels!

Karl

AO21 with Canon M3

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Re: Camera Vs Eyepiece

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by c-krebs » Mon Sep 05, 2016 8:47 pm

c-krebs wrote:I know that there is a better way to go about throwing my camera on the AO20 using a combination of a specific focusing photo eyepiece and photo tube for the Trinoc head but I'm only here for another 2 weeks then work gets in the way, so this quick fix is just to keep me going until I'm back from my travels!

My AO20 is "boxed" right now, and I never did explore mounting a camera to it when I had it set up.

As you say, the trinocular tube is removable. It would be interesting to know just where the "intermediate image" is actually located in space above the "base" trinocular head with the tube removed. This could be roughly determined by removing the trinocular tube and holding an eyepiece above the head, moving it up and down until that eyepiece matched the focus of the viewing eyepieces. This distance is always nice to know since it lets you know what camera options might be viable and which ones could not (physically) work. IMO 2.8X is too strong for an APS-C sensor (unless you are either only after rather small web images, or your objectives have a very small "flat, high quality" image area). If (big IF, given the 44mm body depth of a Canon SLR body) there is enough room it might be interesting to see what could be accomplished with a 1.4X converter on the camera body using an appropriately long tube.

But I'm hesitant to make suggestion since I've never set up an AO for photography. There are folks here making excellent images with their AO scopes, and they have far more experience with the possibilities. I would be curious if anyone here has a parfocal setup that yields about 1.4-1.6X magnification onto a camera sensor.

McConkey wrote:A mirrorless camera is also on my mind. It'll be a while before i can grab a decent one but it's on my list!!

Remember that "mirrorless", in and of itself, is not a vibration solution, you still want at least an electronic first shutter capability.

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Re: Camera Vs Eyepiece

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by apochronaut » Mon Sep 05, 2016 11:21 pm

I have been using both a 10X focusable photo reticle lens and direct to sensor on AO systems. I also use the same 10X photo reticle lens on the photo tube of the series 4 160mm phase microscope.

AO had a series of microscopes called photostars. For these, they manufactured complete photo systems. The camera adapters were made to fit the various dovetails of the systems over time, and had built in shutters and tube lenses connected to exposure control units. The tube lenses were adjustable for the camera format and offered a magnification of between 2.5x and 5X, depending on the format used. These units are very useful for their physical structure, to attach digital cameras to. I use the last one made for the series 400 with the shutter removed and recently the tube lens too, so I am shooting direct to sensor. With this set up I get about 125 % linear, of the visible field on an APS- C sensor ( or about the equivalent of a 25mm field of view), so having a low power, well corrected tube lens, is something I am going to investigate.. There is a small amount of lateral chromatic aberration , which I would like to correct eventually but the results are not too bad. The distance from the correcting lens in the head is about to the sensor is around 19 cm. at parfocal. I do have a photo framing lens for the series 400 too but I have yet to take the time fit it into the photostar shutter housing, although the procedure looks to be very easy. Here are some fairly recent pictures taken with that set up.

viewtopic.php?f=6&t=3716

They also made a photo tube, for the series 4, 10/20 and 100/120, which could take a photo eyepiece, although I am not sure they ever made a dedicated photo eyepiece. I have seen some marked P but they seem to be the same as the focusing reticle eyepiece sans the reticle, which was used so the microscopist could see exactly what he was framing in the camera. They seem to be slightly less sensitive to any small aberrations when it comes to the camera and as well are focusing , so I use one of those in the photo tube. At parfocal, with the 10X photo reticle eyepiece, the distance to the sensor from the correcting lens in the head is 28 .5 cm. , on my series 10 and 20 and I get about 75, maybe 80% of the visual field. I can adjust the camera on the tube quite easily to capture the field edge to edge, and the focus is very slightly off. A recent post with that set up.

viewtopic.php?f=5&t=3728

I also did some fiddling, using a 200mm prime lens as a tube lens on a series 400. In this set up, I used a decent quality prime lens( Nikkor Q) set at infinity and by passed the correcting lens in the head by fitting it to a teaching arm. The 200mm prime lens filter thread was attached to a 25.00 custom adapter made by RAF camera for me, which has a 2" dovetail on it to fit into the teaching arm. I didn't do any more with that but it does have potential, with the right camera lens.

Here is an old post I did, on another forum.

http://www.photomacrography.net/forum/v ... highlight=

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Re: Camera Vs Eyepiece

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by c-krebs » Tue Sep 06, 2016 5:37 am

apochronaut wrote:and had built in shutters and tube lenses connected to exposure control units. The tube lenses were adjustable for the camera format and offered a magnification of between 2.5x and 5X

apochronaut wrote:The distance from the correcting lens in the head is about to the sensor is around 19 cm. at parfocal.

apochronaut,

Lots of way to skin this cat apparently. I want to make sure I am understanding the way the AO trinocular works, and some of your terms have confused me a bit (not too hard to do ;) ). So let me ask a few questions. All of the infinity trinocular heads I have used (Olympus and Nikon) have the required "tube lens" ("telan lens", "converging lens") built into the lower part of the head by the mounting dovetail. At the trinocular port on top the image has thus already passed through the "tube lens" required for infinity optical systems, and a completed real image can be found at some distance above the port. Then you might want to add reduction or magnification optics to better fit this image onto the camera sensor, but they are not necessary to actually form the image.

In the first quote above you mention a "tube lens" that is adjustable in the camera adapter. Does this mean that on the AO head you need to have a separate "tube lens" ("telan lens", "converging lens") added to the trinocular tube in addition to the one used for the viewing eyepieces, or has the image already passed through the same internal lens as the binocular eyepieces? In other words, is the "tube lens" you mention in this first quote a lens used to re-size the (already completed) image, or is it actually needed to complete the "infinity" system?

Also, what is the purpose of the "correcting lens" mentioned in the second quote, and where is it located in the head?

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Re: Camera Vs Eyepiece

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by apochronaut » Tue Sep 06, 2016 12:06 pm

The AO heads have a correcting, telan lens in them , yes, which converts the parallel bundle to a convergent bundle.

In the first example, the sensor was receiving the direct convergent rays from the telan lens at a distance of 19cm., parfocal with the microscope eyepieces.

In the second example given, the sensor was receiving the image from a 10X focusing photo framing eyepiece at a distance of 28.5 cm. from the telan lens and again parfocal with the microscope eyepieces.

In the third example given , the camera was coupled to a 200mm prime lens , mounted in such a way as to receive the parallel bundle prior to being corrected by the telan lens. The camera lens was set at infinity and f 4. One of the obvious benefits of this system is that one does not need a trinocular head, although a teaching arm is necessary and for photographers, existing lenses can be used. The teaching arms can be rotated to any position of convenience and are available in various lengths. There is some small reduction in the intensity of the image with longer arms. Subsequent to my original request for some adapters for AO, from RAF( the 2" dovetail is unique and I have not seen any offered for sale, otherwise), the 6 I originally discussed with him were made up in some quantity and offered on ebay. I don't have a terrific array of camera lenses available, so my goofing around with this system was limited. Better results could probably be obtained with a different focal length lens and likely with a finer lens($$) than I used. In comparison tests though, http://www.kenrockwell.com/nikon/200mm- ... arison.htm and he also did a corner sharpness comparison, the aged Nikkor Q fared quite well.

The 6 adapters were all made to be used in various ways on a 420 Diastar, although there are two common dovetail sizes between the 10/20, 100 and 400 series, so they are also useful on those earlier series. Some may be useful on other microscopes too. The two detailed threads of 52mm and 46mm , used on the two adapters with a 2" dovetail on the other end, were to specifically mount into the filter threads of the two lenses, I tested. These could be altered with further threaded adapters for other camera lenses.

Re: Camera Vs Eyepiece

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by c-krebs » Tue Sep 06, 2016 7:02 pm

OK...

So when you say "tube lenses" in your previous answer...

apochronaut wrote:and had built in shutters and tube lenses connected to exposure control units. The tube lenses were adjustable for the camera format and offered a magnification of between 2.5x and 5X, depending on the format used

...you are referring to optics whose purpose is to resize the "completed" image and send it to the camera sensor, and not the "telan/tube lens/converging lens" that is an inherent part of the infinity optical system.

apochronaut wrote:With this set up I get about 125 % linear, of the visible field on an APS- C sensor ( or about the equivalent of a 25mm field of view), so having a low power, well corrected tube lens, is something I am going to investigate.

It has always puzzled me that APS-C sized sensors are so common, yet it is very hard to find a 1.4X-1.6X projection type photoeyepiece that can be used with them. I have heard of some getting good results by incorporating a 1.4X "tele-converter". Too bad the Sony Alpha one is so expensive. (There are plenty of good used 1.4X for other SLRs, perhaps one could be "adapted")

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Re: Camera Vs Eyepiece

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by apochronaut » Tue Sep 06, 2016 10:56 pm

Well it seems that a 1.4X would be called for because the sensor is 27.85mm diagonal. I haven't taken the time to see what is available. I'm sure there is something that could be adapted.

The photo tube upper portion , on the 10/20 allows the adapter to slide up and down, so the camera can be positioned easily enough to capture the full field that the eyepieces are seeing and focus trimming isn't too bad on the a5000 because it has a very nice focus magnifier.

Those little Sony alpha cameras are quite good microscope cameras, actually. Mirrorless, easily controlled remote shutter release( bluetooth or a cable), so vibration isn't really a factor and a 180 degree screen. You can also bluetooth to a remote screen or control the whole thing from a phone.