Case study: "Portable" stacking set-up.

A forum to ask questions, post setups, and generally discuss anything having to do with photomacrography and photomicroscopy.

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ChrisR
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Post by ChrisR »

if I remove the head (as you described and as Rik has done)
I did did it too as well, though using an Oly dovetail, bits shown when focus blocks came up.

I considered a Trinoc but it would give a lot of vignetting with a 24x36 without a 2.5x projection eyepiece I think. I've got enough unexplored clobber for now. :wink:

Charles Krebs
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Post by Charles Krebs »

Enrico and Chris,

The trinoc head I'll be using has a three position slider... 100% viewing. 20/80 viewing/trinoc, and 100% trinoc. There is a thick piece of multi-coated flat glass in the 100% trinoc position. My guess is that this is there to keep it par-focal to the other positions that must use prisms.. but I'm not sure. Anyway, that's coming out. I'll match the focus in the camera to the 100% viewing and 20/80 split. If there is a focus shift going to the "clear shot" position after I remove that glass it won't matter too much since I'll be fine-tuning those on a HD monitor anyway.

As Enrico pointed out, the viewing eyepieces see only a 20mm diameter circle, but the camera (APS size) will record a diagonal of about 27mm. Since I intend to be using 5/10/20/40 objectives, my plan is to make an eyepiece reticle with the appropriate size "frame" that can be used with the next lower power to frame what the camera will see, and then switch up to the "taking" objective. (I do have a widefield Nikon trinoc with 26mm field view, but I'm not taking that baby apart! :wink: )

I'll try to get the camera focal plane at a 210mm distance from the nosepiece shoulder for the finite 210mm M Plans. I'll try to match this focus in the viewing eyepieces by extending them out... perhaps with something like Edmund Optics part #NT52-144, which provides a 42mm extension for a 23mm eyepiece tube.

If it works as planned, and there's no mechanical vignetting on the APS-sized sensor, it should be fun to use.

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Post by AndrewC »

ChrisR wrote:
ANdrew - ummm
I had to look up loc-line..
mauve = magnet, yellow = goo ..??
Image

How about using two holy magnets, lower one inverted - screwed down to something, even :?
Image
Pretty much like that yes - except I use the black Loc-line, I find it optically far superior :wink:

Using two CS magnets doesn't work for me - the casing isn't magnetic so weakens the grip to the base plate and I like having the double tapered profile of locline to grab it by when I move it from Stereo microscope to camera rig.
rgds, Andrew

"Is that an accurate dictionary ? Charlie Eppes

enricosavazzi
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Post by enricosavazzi »

Charles Krebs wrote:Enrico and Chris,

The trinoc head I'll be using has a three position slider... 100% viewing. 20/80 viewing/trinoc, and 100% trinoc. There is a thick piece of multi-coated flat glass in the 100% trinoc position. My guess is that this is there to keep it par-focal to the other positions that must use prisms.. but I'm not sure. Anyway, that's coming out.
Exactly. And yes, this is the one you need to take out.
I'll match the focus in the camera to the 100% viewing and 20/80 split. If there is a focus shift going to the "clear shot" position after I remove that glass it won't matter too much since I'll be fine-tuning those on a HD monitor anyway.
You will indeed get a focus shift between these two positions, but not substantial. In my case, I stuck a piece of black tape on the prisms that send some light to the photo tube, just to be sure I will not take pictures at these positions. But if you want to take movies, or shots in quick succession, then you will need the intermediate position(s). If you will use a photo tube of variable length (as I did), it is a quick matter to recalibrate its length for use with the intermediate position(s) of the beam splitter.
As Enrico pointed out, the viewing eyepieces see only a 20mm diameter circle, but the camera (APS size) will record a diagonal of about 27mm. Since I intend to be using 5/10/20/40 objectives, my plan is to make an eyepiece reticle with the appropriate size "frame" that can be used with the next lower power to frame what the camera will see, and then switch up to the "taking" objective.
Good idea, it should work.
I'll try to get the camera focal plane at a 210mm distance from the nosepiece shoulder for the finite 210mm M Plans. I'll try to match this focus in the viewing eyepieces by extending them out... perhaps with something like Edmund Optics part #NT52-144, which provides a 42mm extension for a 23mm eyepiece tube.
You could try it first with a 160 mm lens-to-sensor distance. My M Plan 20 and 40 ELWD cover the APS-C sensor well even at this distance, and image quality is good (magnification is of course lower). Just make sure the photo tube is wide enough.

A (perhaps better) way to increase the length of the optical path is to insert an extension tube between nosepiece and stand, or alternatively between stand and trinocular head. A coaxial epi-illuminator stripped of its optics should be about thick enough.
--ES

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Post by Charles Krebs »

Enrico,
You could try it first with a 160 mm lens-to-sensor distance. My M Plan 20 and 40 ELWD cover the APS-C sensor well even at this distance, and image quality is good (magnification is of course lower). Just make sure the photo tube is wide enough.

A (perhaps better) way to increase the length of the optical path is to insert an extension tube between nosepiece and stand, or alternatively between stand and trinocular head. A coaxial epi-illuminator stripped of its optics should be about thick enough.
The problem I've found in the past when playing around with this is getting the camera body close enough on the trinocular tube to be parfocal with the eyepieces when using 160mm tube length. Since I really want to do this for the 210mm tube length M Plans, I now have the "luxury" of another 50mm of working space. With the Edmund extensions, the eyepieces will be at a 202mm tube length. I will hopefully then have plenty of room above to make a nice rotating mount for the camera body.

I want the 20/80 "intermediate" position to be very accurately par-focal with the eyepieces. That way, If I'm trying to get a good small "stack" of a subject that tends to move I can watch for any motion as I'm taking the pictures. When I move to the 100% trinocular position I won't be dealing with moving subjects, so I'll have the time to observe and make fine focus adjustments on a monitor. (But now that you've mentioned it, I'll think about providing a height adjustment to make up for any focus shift.)

JB
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Re: Case study: "Portable" stacking set-up.

Post by JB »

Charles Krebs wrote:I took the focus post from a stereo microscope stand and made a base of maple. (I had two bases I could have used but one was too short, and the other, cast iron, was far too heavy). Three 5mm machine screws attached it to the wooden base. To the vertical post I attached an Arca-Swiss clamp.
Charles,

thanks for this very inspiring post. Some time ago I also started making a vertical setup using a stereo microsope focus post, but the quality of the column was insufficient because the rack-and-pinion had some plastic parts...

I assume your column is all metal? It looks like a Nikon? How is the Arca-Swiss clamp attached to the vertical post?

regards, Jörn.

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Post by ChrisR »

SO you get hold of an expensive trinoc head,
take it apart,..
er..
Image

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Post by elf »

Image

Charles Krebs
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Post by Charles Krebs »

JB,
The AS clamp I used has a beveled hole in the center. It's bolted on with a stainless 6mm machine screw, using the same tapped hole that the bracket for the stereo scope had been attached to. It "looks" Nikon, but I think it's a Chinese copy. But very good really, and all metal. Works nicely.


Chris,
SO you get hold of an expensive trinoc head,
take it apart,..
... hmmm... sounds about right!

Actually it's an old Olympus Vanox head. Built (and weighs!) like a tank. Seem to remember getting it for less than $100. I like it for this use because the entire top comes off with the 4 screws you can see in the picture. This should make it easier to come up with the camera attachment I want. (The dovetail on the bottom fits all my Olympus stands, and the back is flat with tapped holes. So it has many "mounting" possibilities.)

Image
I think this picture is actually the "superwide head" with 30mm eyepiece tubes, but the regular one looks identical

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Post by Chris S. »

Charles Krebs wrote: (snip) the “ball/socket base” shown here very much up to about 10X, but over that it is nice to have some sort of x/y control to position the subject instead of manually sliding the base unit. So I envision an Olympus BHMJ block with a stage such as eBay 120561186690 or eBay 200464611561 attached to an “L” bracket that’s fastened to the plate on the focus block that moves. This would mean more careful subject preparation since I would lose the ability to tilt the subject as I can with the ball/socket base shown here. (But there are always ways… (snip)
Charlie, did you see the goniometer and rotation stage I have set up on my BHMJ focus block? Seems rather parallel to the solution you are envisioning. If not familiar, please check out photographs 1, 3, 4, and 5 in the post below:
http://www.photomacrography.net/forum/v ... php?t=8247

By the way, my setup could easily fit in a Pelican case for checked-in air travel, though I'd likely carry the lenses and camera in my hand luggage. And I have the suspicion--since the setup couples the camera and subject so that vibration affects both equally, and since the base has mass, that if I were in a vibrating building, I could stick a drugstor inflatable doughnut under the rig and tune the inflation to remove most of the local vibration, as per Lefkowitz. I'll soon take my rig on the road, and may have a chance to test this conjecture.

Thanks so very much, Charlie, for sharing what you learn--not just this time, but over the years. I've studied your work constantly, and have learned a lot from it and been inspired even more. You move into a new area, bring brilliant insights and hard work to it, and produce astounding results. Then you teach us all how to do it, and then you move on to something even greater. I and the rest of the world owe you a huge thanks. Your place in history as a photographer and innovator will deserve renown. But your place in history as a teacher and mentor should be even greater.

As the Bard wrote, "Thanks, and thanks, and ever, thanks."

Cheers, and very best regards,

--Chris S.

Charles Krebs
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Post by Charles Krebs »

Chris S,
... Wow!.... Thank You!!
Charlie, did you see the goniometer and rotation stage I have set up on my BHMJ focus block?
Actually yes. The set-up you showed was one of the things I had in mind at the very beginning of this post when I mentioned how impressed I was with some of the various hardware implementations. And there were many others.

I've added your post, and a bunch of other links, to the "sticky" for "Tabletop Macro". It'll be good to have these links "collected" in one place.

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Post by enricosavazzi »

Charles Krebs wrote:
I would actually use an old Exacta bellows (see picture). This is similar to this Pentax in many ways... even uses the same rail… but it is much heavier and locks down more solidly than any bellows I have ever seen. The Pentax shown above is cast metal, but “hollowed” (don’t know the correct term). The Pentax standards lock via a fairly short single point on the locking side. The Exacta bellows are solid cast.
...
(I should mention that I think there may be some versions of this bellows that were made without the rotating camera mount, so if that's a feature you want and you start looking for these be sure to check that out).
Hi Charles,

I started to look out for Exacta/Ihagee bellows and got one from the bay. They are indeed very solid, and comparable in stiffness to the ones on Nikon Multiphot and Leitz Aristophot stands. A couple of things I found out is that there are models with solid castings (like yours and mine) as well as much lighter ones with hollow standards. Mine does not have a rotating rear mount, so you are right on the last point above (the mounts of mine will have to go, so not a big loss). Indeed, these bellows will make an improvement in rigidity over the Nikon PB-6 I mostly used so far as "short" bellows, although their portability may be questionable (like the metallic light blue paint of my specimen...).
--ES

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Post by Barry »

Charles & Enrico,

For a while now I have an Exacta bellows, similar to that of Charles's first post. Mine has hollow parts, is very lightweight and sturdy.
I obtained it together with an "Exacta VielzweckGerät" which is a complete reprostand system. The "VielzweckGerät" means something like "many-angle-device"..... some German words are magnificent aren't they.
It indeed has many joints/pivots, so you can rotate the camera to any desired angle.
Thinking of it, it is a pity such versatile devices are not build anymore...
I can make scans of the manual if you would like.

Regards,
Barry

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Post by Barry »

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Charles Krebs
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Post by Charles Krebs »

Enrico and Barry,

Interesting replies. Barry, thanks for adding the "Exacta VielzweckGerät" information. Yes, there certainly was a large amount of equipment once made for close-up/macro that is not available anymore.

Also, in looking back at this post I realized that I have been referring to the M42 bellows initially shown as "Pentax", when of course it is a Pentacon/Praktica bellows with the M42 mount. In the USA some of us think of the M42 mount as the "Pentax screw mount" when in reality it originated with those East German cameras long before Pentax used it. (While I never owned a 35mm Pentacon, I sure had a lot of fun with the Pentacon 6 medium format camera in the early 70's. ... except for the times it was in getting the film advance mechanism repaired! :x)

From the limited information I have found, there were a few variations over time with Pentacon/Praktica/Exacta implementation of this basic bellows design. Some had rotating backs, some didn't. One version of Ihagee/Exakta had the solid castings with the "split" standard locking design (I've not seen a Pentacon version like that).

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