Vibration problems

[75RR]

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I have been playing around with direct projection again as I tend to do when I get fed up with the hot spot I seem to be unable to avoid in afocal.

Suspect it might be the Olympus OM legacy lenses but that is a matter for another thread.


My previous foray into direct projection with the camera suspended on a tripod over a raised eyepiece worked well, apart from two drawbacks.

Dust and having to refocus the camera every time I set it up, changed battery or just jogged it.


This time I decided to try a fixed setup, with the camera connected directly to the microscope.

After searching for a while for the Zeiss parts and missing out on a chance or two I decided to try my luck with an Ihagee ‡ mount microscope adapter as I liked how it gripped firmly on 3 points.

‡ Ihagee microscope mounts were subsequently marketed under the Pentacon brand.


I had hoped that the Ihagee thread would be a standard 39mm, to aid in connecting it to the camera, unfortunately they use 40mm.

After a bit of head scratching and some internet searching I found what looked to be a potential solution, an Exakta EXA to M4/3 mount.

Happy to say that when it arrived it fit both parts perfectly and therefore solved the problem.


The setup is pretty solid and I have managed to get sufficient parfocality for further testing.

This of course leaves me with what was always going to be the biggest hurdle: vibration!

Apart from the Anti-Shock, which I maxed out at 30sec (only slight improvement visible) what other steps could one take with an Olympus E-P2 or more generally to reduce vibration?
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[janvangastel]

If you did not already take care of this:
(1). It might be 'shutter shock' I had this with bird photography when I started using a mirrorless camera (Panasonic). As a cure you could set the camera to electronic shutter. As soon as I did this with my Panasonic the problem has gone.
(2). And it's also a good idea to use a remote control instead of pressing the shutter button by hand.

[MichaelG.]

After a bit of head scratching and some internet searching I found what looked to be a potential solution, an Exakta EXA to M4/3 mount.

Happy to say that when it arrived it fit both parts perfectly and therefore solved the problem.

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Yes, the Exakta and Exa were made by Ihagee

http://camera-wiki.org/wiki/Ihagee

MichaelG.

[75RR]

Thanks janvangastel and MichaelG.

If you did not already take care of this:
(1). It might be 'shutter shock' I had this with bird photography when I started using a mirrorless camera (Panasonic). As a cure you could set the camera to electronic shutter. As soon as I did this with my Panasonic the problem has gone.
(2). And it's also a good idea to use a remote control instead of pressing the shutter button by hand.

Am using a remote control to activate the shutter, so ok there, however I think the problem is that my Olympus E-P2 does not have an electronic shutter :(

Was hoping the answer would not be get a new camera ... looks like it might be.

Yes, the Exakta and Exa were made by Ihagee

http://camera-wiki.org/wiki/Ihagee

MichaelG.

Indeed, that is why I ordered it. Always nice though when things (when they finally arrive) fit snugly when tested :)
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[75RR]

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Anyone using anti vibration mats and do they make a big difference?

[Wes]

The regular shutter cycle of my Canon 50D produces a terrible mess but it has an electronic shutter with live view shooting option. Even then the live preview is a tad bit sharper than the final image (which is why I've been thinking about uncoupling the camera from the microscope but haven't gotten anywhere near that..yet). When I'm lazy (most of the time) I just use a 2 sec timer for the electronic shutter, in those 2 seconds most of the vibrations from me handling the camera subside.

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Anyone using anti vibration mats and do they make a big difference?

I'd suggest sorbothane hemispheres. They are cheap and effective but make sure to get the right size for the appropriate load. I have a styrofoam pad but I doubt it makes a difference, it mostly protects the table.

I get fed up with the hot spot I seem to be unable to avoid in afocal.

I get this with an otherwise very nice S-Kpl eyepiece.

[MichaelG.]

Indeed, that is why I ordered it. Always nice though when things (when they finally arrive) fit snugly when tested
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[/quote]

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Sorry, I obviously misinterpreted what you wrote ... I thought you were pleasantly surprised to find that Exakta was compatible with Ihagee.

I bought a little Exa 500 new [around 1969, I think] and have always admired the system.

MichaelG.

[MichaelG.]

On the vibration isolation issue

The best solution I have seen [short of a very expensive commercial table] is to put a go-cart inner tube between two heavy paving slabs.

I probably can’t get to the relevant book for a while, but I will add a reference when I can.

MichaelG.

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Done: http://www.lesterlefkowitz.com/bio.html
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6CC07FFF-78F1-41FF-B9BE-E22C8E79EBFF.jpeg (147.59 KiB) Viewed 8450 times

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Edit: Forgot to mention : The sneaky bit is that he had the valve moved to the outside, to allow the pressure to be adjusted without dismantling the unit.

[Hobbyst46]

Anyone using anti vibration mats and do they make a big difference?

I use 5 pieces of Sorbothane, 30x30x4mm each, and cannot really tell how good they are. One is supposed to tailor the anti-vibration mat to the expected mechanical noise of the system, which I can't do. Anyway, your photos are so beautiful and sharp (including the recent Synedra Ulna) that - what is there to improve ?? never noticed a hot spot there.

Does the direct projection include an eyepiece or just the Zeiss Mipro 0.63X adapter ? if it does, is the eyepiece raised by the 2.5, 5, ...mm sleeve ring above the phototube rim ?

...

An Exa 500 camera is nostalgy itself. Was once described in a Popular Photography issue of the 1960's, together with iconic stuff like Nikon FT, Contarex, Konica Autoreflex T, Leica M4, Icarex, Voigtlander, ... unbelievable how they all joined the fate of the slide rule...

[75RR]

On the vibration isolation issue
The best solution I have seen [short of a very expensive commercial table] is to put a go-cart inner tube between two heavy paving slabs.

Thanks, that sounds effective.

Found this: https://www2.lbl.gov/Science-Articles/A ... ggles.html

Concrete and neoprene according to them, sure I can get my hands on a couple of marble slabs as a concrete substitute, they seem to use them everywhere in Spain.

Scuba diving suits are made of neoprene I believe.

[75RR]

Anyway, your photos are so beautiful and sharp (including the recent Synedra Ulna) that - what is there to improve ?? never noticed a hot spot there.

That is courtesy of Photoshop, and I suppose I can live with that. Video however is another matter, not much one can do with it. WYSIWYG!

Does the direct projection include an eyepiece or just the Zeiss Mipro 0.63X adapter ? if it does, is the eyepiece raised by the 2.5, 5, ...mm sleeve ring above the phototube rim ?

Using a 12.5x Kpl at the moment, not sure how far I have raised it as it sits on the Ihagee rim, about 5 or 6mm total I imagine. Will try to measure more precisely.

[75RR]

I get fed up with the hot spot I seem to be unable to avoid in afocal.

I get this with an otherwise very nice S-Kpl eyepiece.

Thanks Wes

I am going to have investigate further, so far it happens with a delaminated 10x Kpl a 12.5x Kpl and the Projektiv f=63x which is why I am (perhaps unfairly) blaming my OM lenses.

Will have to find a cheap alternative lens at some point just to test.

[hans]

Am using a remote control to activate the shutter, so ok there, however I think the problem is that my Olympus E-P2 does not have an electronic shutter

Anyone using anti vibration mats and do they make a big difference?

If you are thinking the mechanical shutter is the problem then putting a mat under the microscope probably will not help. But for a temporary experiment to see if it makes any difference you could use just about anything, the thicker/softer the better, as long as the microscope is not "bottoming out" (fully compressing the foam) and there is not too much risk of tipping over. A thick sofa cushion, for example, could work for a quick test and should actually be much more effective than a thinner "anti-vibration" mat at removing external vibrations.

Might also be worth experimenting with adding back some isolation between the camera and microscope, something in between the very rigid setup you have now and the very isolated setup you had with the tripod. Not necessarily a good long-term solution, but as a test, maybe you can cut a hole in a piece of soft polyurethane packing foam so that it slips partially over the top of your adapter stack leaving a flat foam surface that the detached camera body can rest on just above the adapter stack:

shutter-isolation.jpg (66.68 KiB) Viewed 8301 times

[75RR]

If you are thinking the mechanical shutter is the problem then putting a mat under the microscope probably will not help.

That is a good point. It may get rid of some additional vibrations but it is not addressing the camera issue.

Interesting problem linking the camera and the microscope via some vibration absorbent material - will ponder on it! Thanks

[MichaelG.]

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Found this: https://www2.lbl.gov/Science-Articles/A ... ggles.html

Concrete and neoprene according to them, sure I can get my hands on a couple of marble slabs as a concrete substitute, they seem to use them everywhere in Spain.

Scuba diving suits are made of neoprene I believe.

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Mmm ...

The slabs are a meter thick and more than three by four meters wide; each weighs 34 tons. To prevent any contact of the slabs with the surrounding foundation and to aid in damping vibration, the spaces between them are filled with neoprene, the same material used in wet suits.

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34 tons makes a nice ‘mechanical earth’ but might be excessive for the typical amateur’s situation.

MichaelG.

[75RR]

34 tons makes a nice ‘mechanical earth’ but might be excessive for the typical amateur’s situation.

Indeed! Was thinking marble floor tiles (slab was a bit of an exaggeration), the smaller ones tend to be 30 cm x 60 cm by 15mm or so. One cut in half should make a nice neoprene sandwich.

[75RR]

Interesting problem linking the camera and the microscoe via some vibration absorbent material - will ponder on it! Thanks

Well pondered for a bit. A good place for the vibration absorbent material would be the inside of the gripper (sure that is not the correct name).

Unfortunately there is not enough room for anything thick enough to make a difference. Something to think on anyway.
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[MicroBob]

Hi Glen,
my wife had a similar Olympus and it had quite a strong shutter shock. Compared to metal working machines microscopes are much less ridgidly constructed with 3 contact point connections etc. This doesn't hold up to these shocks. So it probably is necessary to buy a camera with EFSC to further improve your very good images. Other solutions would be flash or long exposure times.

Hotspot: I mainly used a Pentax Q7 with 8,5mm standard objective to take micro photos as it is so nice to use and I use it for my documentary everyday photography. This worked very well on several microscopes with only slight sacrifices compared to bigger sensor cameras. Then I got the Phomi one and a hot spot when photographing through one of the bino tubes. The camera objective has a flat front lens and I suspect that this leads to light bouncing back and forth between it and an other flat surface in the optical train of the microscope. The problem was solved when I used my Nikon 1J5 instead. The old Tamron 90mm macro also had this problem with its flat back lens surface and reflecting digital sensors. So flat lens surfaces became something I look for when I encounter hot spot problems.

Bob

[hans]

Well pondered for a bit. A good place for the vibration absorbent material would be the inside of the gripper (sure that is not the correct name).

Unfortunately there is not enough room for anything thick enough to make a difference. Something to think on anyway.

Yeah, could be difficult to come up with a nice, permanent solution that also keeps the camera aligned well -- conflicting goals. Depending on what exactly is happening, isolation between the camera and microscope could actually make the problem worse, so probably best to try something crude first.

Do you notice more blur (relative to pixel size) at higher magnifications? If it increases proportional to magnification then maybe shutter shock is transmitting down into the microscope and causing relative motion between the specimen and objective, in which case even a little isolation might help a lot compared to direct metal-metal contact. On the other hand, if the blur is roughly constant with magnification maybe the problem is more due to the sensor moving relative to the projected image, in which case softening the mounting of the camera might make things worse. The fact that you did not notice a problem with the tripod setup already seems like pretty good evidence for the former case (transmitted shock causing relative motions within the microscope).

[75RR]

Hi Glen,
my wife had a similar Olympus and it had quite a strong shutter shock. Compared to metal working machines microscopes are much less ridgidly constructed with 3 contact point connections etc. This doesn't hold up to these shocks. So it probably is necessary to buy a camera with EFSC to further improve your very good images. Other solutions would be flash or long exposure times.

Hotspot: I mainly used a Pentax Q7 with 8,5mm standard objective to take micro photos as it is so nice to use and I use it for my documentary everyday photography. This worked very well on several microscopes with only slight sacrifices compared to bigger sensor cameras. Then I got the Phomi one and a hot spot when photographing through one of the bino tubes. :shock: The camera objective has a flat front lens and I suspect that this leads to light bouncing back and forth between it and an other flat surface in the optical train of the microscope. The problem was solved when I used my Nikon 1J5 instead. The old Tamron 90mm macro also had this problem with its flat back lens surface and reflecting digital sensors. So flat lens surfaces became something I look for when I encounter hot spot problems.

Bob

Thanks.

Looks like I am going to have to embrace EFSC if I go with direct projection - half expected that so until funds appear, I will put it on the back burner.

Will look into your tips on the Hot Spot - fingers crossed. If I can find a solution then quite happy to continue with afocal

[75RR]

Yeah, could be difficult to come up with a nice, permanent solution that also keeps the camera aligned well -- conflicting goals. Depending on what exactly is happening, isolation between the camera and microscope could actually make the problem worse, so probably best to try something crude first.

Do you notice more blur (relative to pixel size) at higher magnifications? If it increases proportional to magnification then maybe shutter shock is transmitting down into the microscope and causing relative motion between the specimen and objective, in which case even a little isolation might help a lot compared to direct metal-metal contact. On the other hand, if the blur is roughly constant with magnification maybe the problem is more due to the sensor moving relative to the projected image, in which case softening the mounting of the camera might make things worse. The fact that you did not notice a problem with the tripod setup already seems like pretty good evidence for the former case (transmitted shock causing relative motions within the microscope).

Agree. Most probably end up going round in circles in my attempts to adapt an unsuitable camera. Will put the Ihagee into storage for now and concentrate on finding a cure for the hot spot!

Thanks to all for your suggestions

[MichaelG.]

34 tons makes a nice ‘mechanical earth’ but might be excessive for the typical amateur’s situation.

Indeed! Was thinking marble floor tiles (slab was a bit of an exaggeration), the smaller ones tend to be 30 cm x 60 cm by 15mm or so. One cut in half should make a nice neoprene sandwich.

It won’t do any harm ... but I think you would be disappointed.

I see there have been several more posts since my last visit
... I need to read them before making any further comment.

MichaelG.

[MichaelG.]

If, as has been suggested [and is probable], the vibration is induced by the camera shutter ... then neither (a) isolating the camera body from the microscope tube, nor (b) isolating the microscope from the floor is likely to bring much benefit.
(a) would simply allow the camera body to move in relation to the tube
(b) would be irrelevant

What I think you need to do first is check for looseness and flexibility in the microscope
... quite possibly at the dovetail connection between the head and the frame
... also possibly flexure of the stage mount.

If the camera is the source of energy, then it needs to be fixed firmly to the microscope and the microscope needs to be ‘very stiff’ [‘rigid’ is only an hypothetical condition] ... That way, the specimen and sensor stay in the same positional relationship even if the whole thing is rocking.
... Note: a wet sample in a cavity slide would cause much more difficulty !

MichaelG.

[Scarodactyl]

Anti-vibration precautions won't help if the problem is the shutter. They work to isolate the system from the outside, but if the call's coming from inside the house....

[hans]

I believe 75RR already confirmed that vibration isolation between the camera and microscope (in the form of a tripod) works:

My previous foray into direct projection with the camera suspended on a tripod over a raised eyepiece worked well, apart from two drawbacks.

Dust and having to refocus the camera every time I set it up, changed battery or just jogged it.

Presumably in this case motion of the specimen relative to the objective is having a larger effect overall (due to the magnification involved) than motion of the camera relative to the microscope. That is why I suggested adding back some milder (compared to the tripod approach) isolation between the camera and adapter stack. Of course the practical difficulty, as 75RR pointed out, is how to do this in a nice way while maintaining accurate camera positioning, which was one of the original complaints with the tripod.

[MichaelG.]

Elements of this story seem strangely familiar:
http://www.microscopy-uk.org.uk/mag/art ... camera.pdf
... although he appears more content with the results.

I note the phrase “kicking like a mule” in relation to your camera model

MichaelG.

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Edit: I’ve now seen your contributions to this thread:
viewtopic.php?t=6264
... are you he ?

[MichaelG.]

I believe 75RR already confirmed that vibration isolation between the camera and microscope (in the form of a tripod) works:

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But both the optical configuration and the mechanical arrangement are different there ^^^
(i) There is a camera lens included
(ii) The tripod adds mass and inertia to the camera
(iii) The camera is [presumably) totally detached from the microscope, except for any coupling via tripod/floor/table

MichaelG.

[hans]

I understand 75RR will probably not be pursuing this further, but I hope is is ok if I continue the discussion a bit since I have similar issues with a Nikon D5100, and also strongly dislike the tripod setup for various practical reasons.

(i) There is a camera lens included

My understanding was that, while the most recent setup was afocal, the part I quoted was referring to an earlier attempt at direct projection involving a tripod.

(ii) The tripod adds mass and inertia to the camera

This is a good point and I suppose additional mass could be added artificially on the camera side if necessary. Actually something like you mentioned with inner tube between two heavy plates, scaled down, might work very well between the camera and tube. Even better, for afocal, the plate/inner tube thing seems like it should have low stiffness for horizontal shearing with relatively higher stiffness in terms of keeping the plates parallel. I think that could work out nicely because the shutter shock is presumably mostly horizontal and afocal is insensitive to horizontal motion, but still somewhat sensitive to changes in angle.

(iii) The camera is [presumably) totally detached from the microscope, except for any coupling via tripod/floor/table

Yes, but I don't think there is any really fundamental difference vs. putting isolation between the camera and tube, which is why I somewhat-jokingly referred to it as "vibration isolation in the form of a tripod".

When I had the D5100 on a tripod afocal I still saw some blur in certain conditions, which I did not test too carefully, but suspected was shock coupling via the table into the microscope causing specimen-objective motion. (Afocal should theoretically be even less sensitive to camera-microscope motion than direct projection, I think.)

[75RR]

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No problem if anyone wants to continue the thread - valid points have been made.


I think MichaelG.'s total stiffness suggestion has merit. Still going to cause problems on a wet slide of course.

I have started recently to hang 5kg of sand (ex beach) in two plastic containers (ex olive) from the tripod, each leg of which is placed on a 2mm slice of cork (ex wine).

Not something that would be easy/practical to do with a direct connection between the camera and the microscope.


I think Charles Krebs' use of a photographic enlarger stand avoids most of the tripod problems as long as one has room for a permanent installation.

[hans]

I think Charles Krebs' use of a photographic enlarger stand avoids most of the tripod problems...

And also the butcher block and very sturdy-looking bench it is on forming a good "mechanical earth" as Michael put it.

...as long as one has room for a permanent installation.

Yes, and even with plenty of space, it is still nice to have the option of easily moving the microscope out of the way for other uses occasionally.