focusable photo relay lens... anyone use these can give advice?

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billben74
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focusable photo relay lens... anyone use these can give advice?

#1 Post by billben74 » Sun Dec 04, 2016 1:19 pm

Hello all,

My camera on my trinocular is attached via something similar to this
http://www.ebay.com/itm/CANON-DSLR-SLR- ... 0770947923

This has allowed my take a fair number of optically good images.
Its limitiations are:
a) not quite parfocal with most of my objectives. (I have recently aquired some objectives, some of which are more parfocal with this).
b) It magnifies x2 with respect to image seen on occulars (x10) meaning I lose a lot of my field of view in my photographs.

My thought is that something like this

https://www.aliexpress.com/store/produc ... 0.0.G0rMF0


will allow me to alter the focal plane of my camera to be parfocal with any objective I care to use and give me more field of view.

Has anyone got any experience with these, or suggest another option for solving a) and b)?

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Re: focusable photo relay lens... anyone use these can give advice?

#2 Post by zzffnn » Sun Dec 04, 2016 2:56 pm

What is your camera (sensor size), and what lens (if any) does that camera have?

That 0.37x may produce vignetting.

Another way is afocal: original scope eyepiece + 50-60mm full frame equivalent lens over camera sensor. There are a few resources online that teach that, one of which is Charles Krebs' web site.

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Re: focusable photo relay lens... anyone use these can give advice?

#3 Post by 75RR » Sun Dec 04, 2016 3:17 pm

This is a link to Charles Kreb's site.Some very useful info in it.

viewtopic.php?f=15&t=882
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Re: focusable photo relay lens... anyone use these can give advice?

#4 Post by billben74 » Sun Dec 04, 2016 9:53 pm

Many thanks 75RR and zzffnn.
Will bare all that in mind.

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Re: focusable photo relay lens... anyone use these can give advice?

#5 Post by 75RR » Sun Dec 04, 2016 10:24 pm

a) not quite parfocal with most of my objectives. (I have recently aquired some objectives, some of which are more parfocal with this).
Just reread your post - so your camera is parfocal with some of your objectives but not others?
All your objectives need to be parfocal amongst themselves, the only reason to have one that isn't is if it is a "special".
That way the camera only has to be setup once.
If you have bought some that are not parfocal and not "special" i.e. do not fulfill a function that the ones that are designed for your microscope can't do, then you should sell them and buy some that are parfocal.
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Re: focusable photo relay lens... anyone use these can give advice?

#6 Post by billben74 » Sun Dec 04, 2016 10:39 pm

My scope came with 5 objectives which were, of course, parfocal. But not quite with my camera.
The others are "special"
I recently aquired x60 0.80 0.17 objective which is, very slightly, not parfocal with the rest.
I can live with it and don't always use it (my turret is quintuple).
It is, however, more parfocal with my camera -> so when I want to use it this is an upside that pays for the slight lack of parfocality with the rest.

I also now have a x50 0.85 no cover slip objective. It is similar to the x60 so again as it I will only use it sometimes (and when I do it will be about photography not just looking) I can live with the situation.

The annoying bit is my "main" objectives which are not parfocal (not far off) with my camera.

To my mind the optimum would, therefore be, a set-up where I could easily adjust my camera's parfocality depending on which objectives I was using.

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Re: focusable photo relay lens... anyone use these can give advice?

#7 Post by 75RR » Sun Dec 04, 2016 11:51 pm

Can you post an image of the trinocular head and of how you have connected the camera?
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Re: focusable photo relay lens... anyone use these can give advice?

#8 Post by mrsonchus » Tue Dec 06, 2016 9:28 am

billben74 wrote:................
To my mind the optimum would, therefore be, a set-up where I could easily adjust my camera's parfocality depending on which objectives I was using.
Exactly old chap - that's what the optics I use gives me - although my set-up (5 objective) is 'std' and therefore permanently parfocal once set, removing the need to re-focus (which I do by turning the gold-collar seen in picture) although of course this is an easy 'as per objective' operation with such focusable optics.

Image
:)
John B

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Re: focusable photo relay lens... anyone use these can give advice?

#9 Post by billben74 » Tue Dec 06, 2016 11:04 am

First off - many thanks 75RR and zzffnn for taking the time and helping out.

Whats fab about this forum is that so many of us take the time to help/give advice etc.
:)

mrsconchus --> aha you seem to have something similar to thing I have seen and it sounds like I could be in buisness here.
Now I just need to work out the best way to image on my 1200D canon that has the small format sensor

Does your focusable relay tube have an an magnification information?
Are you using a c-mount camera with this or do you use a C to T mount adapter and connect to a DSLR (I thought you had a canon, maybe I dreamed that ;)

In an absolutely perfect world I would be able to
a) focus to parfocality as desired.
b) actually change the magnification/field of view --> not sure both are actually possible though????

b) is because my new "special" objective shows chromatic aberration /some spherical around the periphery so for this its actually good that the relay lens effectively crops.

(Why a lietz NPL objective is doing this when my chinese no brand objectives are not i.e.they seem better, is another interesting, but not directly relevant, matter - I mean my scope is infinity as are all the objectives so should be fully corrected by themselves...)

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Re: focusable photo relay lens... anyone use these can give advice?

#10 Post by johan » Tue Dec 06, 2016 12:24 pm

billben74, I'd be very interested to see your results as I may well be after one in the future.
mrsconchus - it does look like exactly the same thing, rebranded!

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Re: focusable photo relay lens... anyone use these can give advice?

#11 Post by mrsonchus » Tue Dec 06, 2016 6:27 pm

Hi Bill, you're right there - this is a very great place to enjoy the hobby, regardless of the occasional mindless, attention-seeking, pernicious troll slithering amidst the good folk here.

As far as the Canon goes - I do indeed have the beautiful Canon EOS 1200D - and a dashed fine camera it is - the focus to the tiniest point in normal (non-microscopic application) use is a dream - a lightning-fast 'snap to focus' that I love every time I see it in action.

[the adapter pictured at the start of the thread is the same one I use with the Canon - and I made it parfocal with the use of a simple 'shim' to raise the whole thing - camera and all - about 5mm higher in the trinoc-tube. This isn't as you say so simple when you need to be able to vary that distance on an as-per-objective basis and you'll need as you rightly say a version that is adjustable or perhaps simply a set of shims, each labelled as being for a particular objective or set of objectives...]

However I can't get it to perform anywhere close to the humble little 2mp ToupCam UCMOS camera that I was originally using before the Canon - hence my recent purchase of it's bigger & better cousin the LCMOS 5mp Toupcam - similarly great performer through the 'scope - truly a 'what I see the camera images' (not in terms of FOV, but colours and contrast - spot-on) - used with the focusable adapter.
As far as I know, and I've tried, the focusable adapter with the gold ring that I use with my Toupcam/s will vignette when attached (with a simple cheap 1200D -> cmount adapter thread) to the Canon unfortunately - but I've yet to seriously investigate this further - there may be a way.

I don't know why, but the Canon simply can't seem to handle the colours and dynamic-range demanded by brightfield, transmitted-light imaging of stained, sectioned and permanently mounted slides....

I think it must be possible, but I have tried all settings on the 1200D believe me, and I can't improve the situation - hence my return to the oh-so-easy Toupcams...

Sorry this isn't much help but any info shared usually comes in handy somewhere to someone I think, :D :D :)

Good luck with it - someone's bound to have a solution to this tricky problem. :)
John B

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Re: focusable photo relay lens... anyone use these can give advice?

#12 Post by billben74 » Tue Dec 06, 2016 8:53 pm

Many thanks mrsonchus.
Interesting about your experience with the toup cam.
I do find my 1200D colour balance to be a bit pants but as I have never had anything to compare it with I just put this down to cameras in general.
Maybe not.
Still, I need lots of mega pixels and the toup cam ones with lots of mega pixels are lots of money.
Interesting though. I should really try my friends nikon one of these days to see if its colour balance/handling the dynamic range is better - it would just require the nikon mount adapter....

Then there is that magic lantern thing you can hack your canon with...that might improve matters...or maybe not...

In case you hadn't heard about magic lantern: there is a firmware patch (well I think technically its something else but its like a firmware patch) that you can install on a canon (probably our 1200Ds) that turns it into a more expensive camera.

Really.

And despite the web site suppling this open source free ware thing giving warnings left right and centre it has never actually broken cameras - it just gives you access to features normally found on expensive camera.
Its been on that huge list of things I mean to try....

It may, however, not include better colour balancing etc., but it might, if your interested in another avenue to explore on your canon.


As to the ultimate in adaptable relay attachments... we await further installments....

Any one with experience of this kind of relay adapter please speak....

I may try the other place in case the more photographically minded folk over there know something...

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Re: focusable photo relay lens... anyone use these can give advice?

#13 Post by 75RR » Wed Dec 07, 2016 12:43 am

(Why a lietz NPL objective is doing this when my chinese no brand objectives are not i.e.they seem better, is another interesting, but not directly relevant, matter - I mean my scope is infinity as are all the objectives so should be fully corrected by themselves...)
Finite microscopes are corrected in part in the objective and in part in the eyepiece, so if you add an objective from a different manufacturer you just need to add the specific eyepiece and you are good to go. Infinity microscopes correct in the objective and in the microscope tube, that means that objectives from other manufactures are not really compatible. That is most probably why the Leitz NPL shows chromatic and spherical aberration.
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Re: focusable photo relay lens... anyone use these can give advice?

#14 Post by cuxlander » Wed Dec 07, 2016 12:24 pm

Hello,
ToupTec make (or rebrand?) this type of adapters.
See http://www.touptek.com/product/product. ... &class2=56
AMA for adjustable, FMA for fixed, followed by the magnification factor.
They suggest:
The possible maximum size for the image sensor is 18mmX0.37=6.66mm for the 0.37X camera adapter
The possible maximum size for the image sensor is 18mmX0.50=9mm for the 0.5X camera adaptor
The possible maximum size for the image sensor is 18mmX0.75=13.5mm for the 0.75X camera adapter

I have used the FMA050 on a trinocular Müller Microscope and, as ocular on my Zeiss Junior, with a Tucsen and a ToupCam (both CMOS/USB2) camera, all were parfocal.
Cheers,
Hans

PS all these require c-mount thread on the camera
Last edited by cuxlander on Wed Dec 07, 2016 12:39 pm, edited 2 times in total.

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Re: focusable photo relay lens... anyone use these can give advice?

#15 Post by cuxlander » Wed Dec 07, 2016 12:32 pm

@bilben:
My camera on my trinocular is attached via something similar to this
http://www.ebay.com/itm/CANON-DSLR-SLR- ... 0770947923
I believe this is a combination of an adapter to the proprietary lens mount of a DSLR and a housing for an ocular. Without any optics, just tubes.
Hans

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Re: focusable photo relay lens... anyone use these can give advice?

#16 Post by billben74 » Wed Dec 07, 2016 7:28 pm

Thanks 75RR - somehow I'd missed that. Always good to learn though.
The lietz still images fairly well in a semi-plan kind of way so not a total loss.

cuxlander, many thanks for the information on magnification and image sensor size. Thats useful.

The link to the ebay item appears broken though.

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Re: focusable photo relay lens... anyone use these can give advice?

#17 Post by c-krebs » Sat Dec 10, 2016 3:39 am

Your 1200D has an APS-C sized sensor (22.3 x 14.9 mm for Canon). Ideally, if you are using 10X eyepieces on your microscope, you will want a magnification of about 1.5-1.7x from the trinocular tube into the camera body. Unfortunately the only ones I am aware of in that range are extraordinarily expensive. (Which is sort of odd since so many people want to use that sensor size on microscopes). The adapter you showed at the beginning of this thread provides a 2X magnification into the camera body. This is about the best compromise for a reasonably priced way to go, but the magnification is a little on the high side... thus the "crop" you get from the viewed image.

The one you referenced on Aliexpress has a magnification of only 0.37X. As cuxlander mentioned there are also similar ones with 0.50X and 0.75X. All of these have a magnification that is too low. They are made for c-mount cameras with much smaller sensors. If used "properly" they will vignette with your camera.

You can try to see if it is possible to make your current adapter parfocal with your 5 original objectives (that you said were parfocal with each other).
First let me ask a some questions...

1) How far "off" is the camera focus from the eyepiece focus? After proper eyepiece focus is obtained, how much do you need to turn the fine-focus knob to bring the camera into focus? Does the focus direction needed to make the camera in focus move the stage up or down?

2) Is there any height adjustment possible on your trinocular tube, or is it a fixed length?

3) Can you adjust one or both of your eyepieces tubes (as you might do to correct for a vision difference between your eyes)? On most microscopes one eyepiece is usually fixed and one is adjustable. I ask because if both are adjustable it is possible to have them both adjusted improperly too far out or too far in. This could make a properly made adapter non-parfocal.

If you give the answers for these questions we can see if there is a way to get your current adapter parfocal.

Your 1200D is three years and 2 generations "newer" than the T3i that I use a great deal. I believe it uses the same 18Mp sensor (with whatever improvements they made in those three years... if any). I find the results from the T3i to be very good. I am not sure why John has experienced the difficulties he mentions, but I never actually used a 1200D.

If you are satisfied with the image quality you are getting with your current 2X adapter, but the "crop" is just "psychologically" annoying, you might want to see if your microscope manufacturer sells 12.5X viewing eyepieces.

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Re: focusable photo relay lens... anyone use these can give advice?

#18 Post by billben74 » Sat Dec 10, 2016 9:34 am

Many thanks Charles.
Really great to get your help.
Just juggling my 4 year old at the moment, but when I get some quiet time will look to each of your points...

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Re: focusable photo relay lens... anyone use these can give advice?

#19 Post by johan » Sat Dec 10, 2016 1:12 pm

cuxlander wrote:@bilben:
My camera on my trinocular is attached via something similar to this
http://www.ebay.com/itm/CANON-DSLR-SLR- ... 0770947923
I believe this is a combination of an adapter to the proprietary lens mount of a DSLR and a housing for an ocular. Without any optics, just tubes.
Hans
No, there is a lens in there. Several - you can just make out the bottom one on the picture.

FWIW I have observed the same thing - it is not parfocal.

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Re: focusable photo relay lens... anyone use these can give advice?

#20 Post by billben74 » Sat Dec 10, 2016 10:36 pm

Ha Ha. Thanks Charles.
So to answer the lack of parfocallity it appeared I needed to move the focus about 16 microns down to get the camera focus for the camera.
But more importantly...
My trinocular head has an extention tube that can be adjusted slightly as it is held in place by a screw.
To be honest I had never really realised this. I had once messed about with moving the tube a bit, but now I'm more focused due to your questions the penny has dropped.
I have raised the adapter tube by 3 mm. This has brought to what I believe is an acceptably parfocal view to the camera. :)
There is now a slightly uncomforatble gap around the adapter and the trinoc head, but as there is an inner tube coming down from the adpapter tube that I believe is snug to its female part coming out of the trinoc head and I don't think dust etc. can get in.
It seems reasonanbly sound mechanically sound/stable although perhaps only with some time will this be born out to be definately true.

But I think (fingers crossed) we have a solution. :)
If I am doing some work with my other objectives I can move the adapter about. Not perfect but reasonable. I know that 3mm will right the situtaion for my main objectives.

Many thanks to all, 75RR,zzffnn, mrsonchus, johan, cuxlander and c-krebs for you interest and help.
The idea of focusable relay tube is still quite an attractive one -> but one that I can't punt on to the "I have more pressing matters" list.

In fact, I am thinking of buying a Olympus BH2 which is currenty up for grabs....... sorry that wasn't in my mind when I started this thread.

I may not do this anyway... though I feel a "possible advice about that well regarded model question brewing..." but that can wait....
Again many thanks.

johan --> do you have any movement options for your adapter/extention tube? Could you raise it slightly and could that help as it has in my case?

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Re: focusable photo relay lens... anyone use these can give advice?

#21 Post by c-krebs » Sat Dec 10, 2016 11:07 pm

Great!

Some additional thoughts...
If I am doing some work with my other objectives I can move the adapter about. Not perfect but reasonable.
I would not entertain the idea of adjusting the adapter to accommodate an "oddball" objective that does not agree with your primary 5 objectives. I think it is best to adjust and fix your camera position using your original objectives that came with the microscope and keep it there. When setting up the camera position use a very contrasty, detailed slide with a low power objective. 4X if you have one, but no more than 10X. It is somewhat counter-intuitive, but a low power objective, while it has more depth-of-field on the subject, has much shallower depth-of-focus at the sensor. By depth-of-focus we're essentially talking about the image plane at the camera sensor, and with a low power objective the camera (sensor) position is much more critical than with a high power objective.

Put your slide in and focus very carefully using the 4X or 10X. Then put your camera into live-view and magnify the central portion on the camera LCD screen. Don't change the microscope focus, but carefully raise/lower the camera+adapter using the trinocular tube length adjustment until the magnified view on the camera LCD back is in focus. Check this again a couple of times with both the 4X and 10X, making whatever fine adjustments in camera height are needed.

You are actually adjusting your trinocular head so that the camera focus matches you eyepiece focus... which is exactly what you want. If you have an objective or two that are not exactly parfocal with the 5 objectives that came with your scope, you accommodate that with the microscope focus knobs, not by fiddling with your camera adapter.
There is now a slightly uncomforatble gap around the adapter and the trinoc head, but as there is an inner tube coming down from the adpapter tube that I believe is snug to its female part coming out of the trinoc head and I don't think dust etc. can get in.
I can't visualize this "gap" without a picture. If the end result was that the camera+adapter needed to be "raised" about 3mm, and you are uncertain about the trinocular tube extension "gap", you could perhaps put it back where it was and just shim up around the tube on your adapter so that it sits 3mm higher.

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Re: focusable photo relay lens... anyone use these can give advice?

#22 Post by billben74 » Sun Dec 11, 2016 7:23 pm

Again, many thanks Charles.
It is counter intuative about the x4 being best (at least to me) so thats really great information which I will be able to use to good effect.

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