Help to choose bellows set-up

[Tony T]

As Rik's suggestion I used my lowest power microscope objective; just a 3 engraved on the barrel, the diam. of the front lens is 7mm.
Made a cardboard disc to fit over the end of an extension tube, cut a hole in the disc to accomodate the lens. Total extension 126mm, gave me a working distance of about 5mm. Used my SB800 flash off camera.
RRS focussing rail not much use for this set-up but did manage to get 2 shots, stacked with Helicon Focus.
I'm quite pleased with this 1st attempt, it actually shows the striations on the scales. Lots of room for improvement.
Compare with earlier images, same dimensions: full frame, 800 actual pixels. Not an identical part of the wing used in the 1st set of images.

[rjlittlefield]

Looks like you're on your way, Tony.

As you note, the big problem with microscope objectives is very shallow DOF, requiring equally shallow focus steps.

Given the equipment that you have in hand, I'm thinking that your microscope stage may provide what you need.

At least one guy I know has gotten good mileage from rigging an extension to the stage, sticking out far enough for his bellows rig to clear the microscope frame. Subject mounts on the extension, fine focus does the stepping while fixed camera & bellows takes the pictures, and the rest of the scope just sits there like a really heavy paperweight.

That doesn't work so well with the scope that I have, which gives only 0.15 mm of fine focus, after which the coarse focus kicks in and I'm better off using the milling table. But if your fine focus has more range, it might be just the ticket.

--Rik

[DaveW]

Tony,

You say bellows looks more professional than unsupported extension tubes. Why are you not supporting them? Many of these extreme extensions are "lash-up's" of one form or another. There is no problem making wooden blocks or something similar to go under the tubes to support them and remove vibration. As Rik says it does not matter whether you move the camera or the subject, so with extreme extension it is often best to "bolt" the camera down and pack up under the tubes and simply move the much lighter subject on a focusing slide.

DaveW

[rjlittlefield]

Even with bellows, you're likely to want more support than is naturally built into the unit.

Take a look at my high-magnification setup at http://www.photomacrography.net/forum/v ... .php?t=155. See that block of wood under the camera? There's a 1/4-20 threaded rod running through that thing, screwed into the bottom of the camera, with a wingnut under the platform to suck it down tight and keep it there. That increases the lever arm of the support from something like 2" if I used just the bellows base, to more like 10". That 5X improvement helps a lot.

Even so, at the magnifications permitted by microscope objectives, vibration can kill your sharpness in a hurry. It's not so bad with flash, like you're using. I generally use continuous illumination because I like to fly the lights around to see what I'm getting, and I don't have a combined continuous modeling / flash exposure setup. What I find is that even with everything bolted down solid to that big metal table, and even using mirror lockup, there is still enough vibration just from shutter opening to cause obvious blur on exposures under 1 second when I'm using 10X and 20X objectives.

Vibrations like that can also couple for long distances. When I was shooting some Noctua pronuba scales (here), I had more than the usual problems with vibration blur. By playing around with different configurations, I eventually figured out that shutter vibration was coupling through the whole apparatus to make the insect pin vibrate. Exactly the same setup worked fine with a fly on a regular #2 insect pin, but not with the much heavier moth on the same type of pin.

Perhaps just using flash will take care of all these problems for you. But it's good to know about them, just in case. Support carefully, and stay aware.

--Rik

[DaveW]

Tony,

George Dingwall's setup probably looks more like yours using tubes:-

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

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

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

I said elsewhere to George I did not think so much bellows hanging over the front was a good idea in the above link, and at the end of the link you will see he provided additional support.

Stop adding additional extension Tony when the lens goes out of your front door! The more support under the tubes along their length the better. Obviously, as said previously, it eventually gets more sensible to "bolt" the camera assembly down and just move the much lighter and less complicated subject stage.

DaveW

[Tony T]

Tony,

You say bellows looks more professional than unsupported extension tubes. Why are you not supporting them?
DaveW

I have tried supporting the extensions. One of my problems is that I am never satisified, as soon as I get a system that works (or, more often, doesn't work) I try to improve upon it. Recently I have been moving the subject in x-, y- axes and the camera and extensions in the z-axis. Thus it not possible to get an exact vertical support for the tubes; perhaps if I had a laboratory-type jack.
Everything about my technique is still evolving thanks to input from you, Rik, Charlie, et al.

[Tony T]

Dave: my set-up basically the same as George's, not quite as sophisticated
Thanks Rik: I've heard it said that imitation is the best form of flattery, I have ordered a bellows and well on my way to imitating your set-up - but I'm sure to make adjustments!

[rjlittlefield]

Obviously, as said previously, it eventually gets more sensible to "bolt" the camera assembly down and just move the much lighter and less complicated subject stage.

It's been discussed before that there are a couple of disadvantages to this approach, too. One is that it can become more difficult to look through the camera while adjusting framing, magnification, front and back focus limits, etc. That aspect will go away with the new "live view" cameras feeding to external monitors, but not all of us have those yet. Another disadvantage with moving the subject is that it means you have to reposition the subject to shoot a stereo pair. It can be tricky to do that correctly (rotate only around the vertical axis), and with some types of lighting, moving the subject changes the positions of shadows, which introduces non-matching detail and degrades the quality of the result. As usual, there are tradeoffs.

In any case, I'm a bit puzzled how things get "less complicated" by moving the subject. "Lighter" is easy to see, but either way you need the same degrees of freedom and the same precision. DaveW, what are you thinking about that I've missed here?

--Rik

[Charles Krebs]

I think either a "subject mover" or a "camera mover" can give equally fine results. As Rik mentioned, even when you have gone to extraordinary lengths to bolt down the camera, you still need to exercise caution simply because of shutter vibration.

We talk frequently about the ability to do fine "z" access increments, but whatever you are moving also needs a device that is free of "wobble" as well. Tony alluded to this when he said he needed to lock down his focus rail for each shot, I believed Rik mentioned that he has tweaked his machine slide to minimize this. Most camera bellows and camera focus rails are not up to the task when you go over about 5X. I must say however, that I am surprised at just how well Helicon Focus can accommodate some slight x/y "jiggle" between images, but it is obviously better to avoid it. (I've even gone to a cheap radio remote release because during the boring process of shooting a stack I would sometimes find myself slightly applying a minute amount of "pull" by moving the release cable around between exposures. I could actually see a slight displacement between images.

Since I am not "automated" one big reason I prefer a "camera mover" is that it can be a pain to reach forward to the subject platform between each shot, look at some (too small) scale while making the appropriate distance adjustment. Often the subject is well across the table from where I am sitting, and I need to reach through a bunch of "set" items (wires, reflectors, diffusers) that I must avoid moving. I generally find it easier to make the adjustments to the camera platform. (Although admittedly, it does at first seem to make more sense to bolt down the heavy stuff, and just move something that weighs a few grams at best).

Tony:

One of my problems is that I am never satisified, as soon as I get a system that works (or, more often, doesn't work) I try to improve upon it.

And thus it will ever be!

Welcome to the club!

[Tony T]

Glad to be a member of the club
In my "moving the subject phase" I found it quite convenient to move around the table but this may be partly due to the way the D2Xs can operate. It has a mirror lock-up feature that moves the miror up the 1st time the shutter release button is pressed. The neat feature is that if you don't press the button a second time it automatically fires after 30 secs. Combining this with Charlie's method of rear curatin syn. (I use a flash) and a shutter speed of 1 sec. I get a vibration-free exposure. So for me, it's easy to stand at the subject end of the table to make the x-axis adjustments and lean forward to press the shutter release button.
I only wish the automatic time was closer to 10 secs. I use this method because I noticed that pressing the shutter release button a second time resulted in a minute but perceptible downward movement of the camera.
I must check the self-timer function, but I think the mirror moves up at the end of the delay rather than at the start. The former (i.e., at the end of the delay) results in vibration.

[DaveW]

Obviously Rik the longer length of tube or bellows you have on the camera the more impractical it is going to get to move such a mass and be able to support it properly. Moving the subject "should" be more practical and I cannot see with some of the larger fixed lighting set-up's I have seen in use here the shadows will change considerably, particularly when using diffusers, during the few millimeters the subject is moved. If you are using fibre optics the ends of the fibre light guides could be fixed to the subject stage too since they are flexible, so move in unison with it.

As to getting to the subject to move it, that depends on how you have arranged your set-up. It would be difficult with the large board you have behind the subject Rik, but George Dingwall's set up seems to have much clearer access behind, as Tony seems to imply his set-up was. So if the set-up is on a central table, access all around it should be possible. With a remote release, after initially setting the camera, surely it is then a case of simply moving the subject stage in so many set increments, therefore you do not need to look through the camera viewfinder again, and that is impossible anyway with the mirror locked up. Therefore during the exposure sequence why do you need to be at the camera end anyway?

You are the experts at photostacking, you tell me why my suggestions would not work?

DaveW

[Charles Krebs]

Tony,
I purchased a cheap radio release from China... they're all over eBay. Works like a charm! Dave could make you up a 4 foot long extension tube and you could stand at the subject end of the table and fire that D200 to your hearts content. Never have to touch the camera at all.

I like the fact that the D200 has the mirror lock-up on that top dial (instead of in a menu like the Canon). But unfortunately you can't get a mirror up and then a short self timer before release (don't know about the D2Xs). If you can work in a room with a very low light level(or turn them down before taking a series of pictures, you can often get away with simply setting the shutter for about 3 seconds. (Do a test with the flash off to be sure nothing "registers" without the flash firing. Then just hit the shutter once. Generally all vibrations from touching the camera will dampen out in less than 2 seconds. So I seriously doubt there would be any vibration issue. I'd go nuts if I had to wait 30 seconds for each shot

[rjlittlefield]

tell me why my suggestions would not work?

Dave, I don’t see it as a question of "would not work". This is not a go/no-go situation. It’s a matter of tradeoffs.

You are the experts

Now that you bring it up, that is an odd aspect to these discussions.

We have on one hand a fellow who quite correctly points out that there are some mechanical issues in moving the camera.

We have on the other hand a different fellow who says yep, but there are some other issues to think about too.

One of these fellows regularly posts results and methods, and has shot several hundred stacks up to and including magnifications that biologists have previously considered as being usable only by SEMs.

The other one seems to have little or no experience with stacking at any level.

So how come it’s the guy with little or no experience who persistently says "my issues are the most important ones, and everybody should design their systems my way because my issues are the most important ones"?

Please pardon the paraphrasing, and yes, the redundancy was deliberate emphasis.

It vexes me to repeatedly hear about how awkward it looks to be moving a camera, when my experience is that moving the camera is pretty straightforward, works well, and avoids other issues that would crop up in moving the subject.

Design changes have a way of snowballing.

It’s certainly easy to say "oh, just use flexible fiber and let ‘em move along with the subject". But when you actually try it, you suddenly realize that you need brackets to hold the fibers, and now the brackets have to move along with the subject too. The brackets have to be big enough to hold the fibers in any position you want, and they also have to be adjustable so that you can fly the fibers around to get the lighting you want. Pretty quick, moving a housefly on a pin has turned into moving an illumination platform, which by the way has to move smoothly and predictably even though it’s now dragging some pretty hefty fibers. You know, having not actually tried it, I’m far from confident that it’s not easier to just move the camera. At least that thing is self contained and battery powered. Does the illumination really need to be moved along with the subject, to get good stereo? Probably not, when it’s highly diffused. But I have seen stereo pairs with sharp shadows that would have been useful, if only they had not been wrong. Why would I build a system with a known limitation, to avoid an issue that’s been demonstrated to not matter?

Likewise, I’m not impressed by the suggestion that moving the camera is obviously difficult because obviously very long extensions are required. Very long extensions are a recipe for empty magnification. If you’re hung up on magnification and not on showing as much detail as possible, great. But if you want maximum revealed detail, the effective path is to use shorter lenses with wider apertures. That path culminates in microscope objectives, which by design don’t need very long extensions. Why would I base a design decision on difficulties of a feature that’s not needed?

It’s pretty clear that viable systems can be built either way. Charlie and I move the camera, Wim moves the subject. At least within this forum, I think I hold the current record for highest magnification using an open system, with a field width of 340 microns [ref, pic 2]. It’s either me or Charlie, and we’re both using move-the-camera systems.

I’m not hard-over on either type of system. They both work. That’s why, as I said, it vexes me to hear one particular approach pushed persistently from a position of no track record. I’m sorry if that sounds harsh. It’s honest. I show what I do, explain how I think it works, and people are welcome to emulate it or not. I'm delighted to see better results from different methods that I can emulate. I’m also happy to hear suggestions about how to do better, but bottom line, the way to convince me that I’m doing something wrong is to demonstrate better results than I have. I sincerely look forward to seeing those images and hearing how they were produced.

Sorry for the bluntness...

–Rik

[DaveW]

Rik,

Yes I have never tried it, but logic does not always demand you to put your hand in the fire to know it's hot! The basic principles from other fields generally hold good, it is always harder to move a larger assembly than the smaller one. And yes brackets to hold fibre optics would add mass to the subject stage, but still probably less than the mass of the camera assembly.

You seem to be saying "my way is correct nobody must suggest anything different"? You, Charles and George Dingwall have all come up with different methods of holding the subject from what I have seen. Yours seems to be the most massive assembly of the three, and you are using a dual axis camera slide (I have the same one) for the subject stage mounted vertically as well as your machine table for the camera, so you have at least one axis of movement duplicated in your assembly because both the slide and the camera can move laterally.

I agree, your present set up precludes you working from the subject end, but it does not stop others, and you would need to radically change your subject stage to do so. But from what I have seen both Tony and George Dingwall are working with considerable extension and moving the camera assembly is becoming less of an advantage over moving the subject. As Charles points out, with remote releases of many types now there is no longer any need to be stuck at the camera end of the assembly.

Who knows in the future somebody may even be rash enough to try turning the whole assembly up vertically and mounting it on a massive copy stand like a mega microscope, but I would not be dismissive before it was tried and say it would not work. Oh, come to think of it the Orthophot and Nikon Multiphot did just that!

I wonder before you built your assembly Rik if you had gone along to Nikon and proposed it they would have adopted a similar dismissive attitude and said "that is not the way to do it you need to mount everything vertically as in our Multiphot!".

Everybody gets to heaven in their own way Rik, there is no correct way for anything, only ones that work. If you ain't tried it, don't rubbish it! I have been in the building trade for 51 years and shifted enough heavy and bulky objects in my time to know that given a choice you always move the lightest and least bulky.

That principle was established by trial and error by the working man for generations before academia came onto the scene and started theorising from that point on! It is still a case that an architect can span a chasm with a bridge by drawing a few lines on a plan, but it is still the working man that actually has the nous to do it, and bridges were built by the working man ever before architects and draughtsmen were ever thought of. So don't be so condescending of the non academic artisan Rik, because when "push comes to shove" which practically is really the least essential of the two in this world, if you had to dispense with one of them?

All the best,

DaveW

[puzzledpaul]

<< The brackets have to be big enough .... // ...even though it’s now dragging some pretty hefty fibers. >>

Isn't there also the possibility of transmitting vibrations (from fan and /or transformer) too, if there's some sort of direct coupling involved?

pp