Automatic macro rail

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

Moderators: Pau, rjlittlefield, ChrisR, Chris S.

morfa
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Post by morfa »

Thanks Andrew for linking to that great thread that I had completely missed!

Haha, wow! I can't believe Canon actually did everything right and then "forgot" to trigger the PC port (or something!!) when the electronic shutter opens. I now feel relieved from a large chunk of Canon jealousy! For natural light stacks it's still superior though, right?

lothman
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Post by lothman »

Linden.g wrote:This is a pre-production example, product will have an anodised finish
[Linden
Looks like a lot of machined parts, what about using ready alumina profiles (hollow, therefore light and very stiff) with integrated inox rails and a ball beared roller which will carry the camera.

Perhaps that's of interest.

Lothar

AndrewC
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Post by AndrewC »

morfa wrote:...For natural light stacks it's still superior though, right?
Mirror mode I'm not sure, the MP-E on the other hand is something I'd almost buy a Canon system just to have ! Actually, if I had the money I'd be giving it to RED http://www.red.com/ and stacking from frame grabs. meanwhile eBay is my friend :)
Last edited by AndrewC on Sun Jan 17, 2010 4:07 pm, edited 1 time in total.
rgds, Andrew

"Is that an accurate dictionary ? Charlie Eppes

AndrewC
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Post by AndrewC »

lothman wrote:
Linden.g wrote:This is a pre-production example, product will have an anodised finish
[Linden
Looks like a lot of machined parts, what about using ready alumina profiles (hollow, therefore light and very stiff) with integrated inox rails and a ball beared roller which will carry the camera.

Perhaps that's of interest.

Lothar
There aren't really that many complex machined parts. If you look at it the only one with a lot of machining is the camera riser. Everything else is just plates. Even if you use profiles you still need precision machining to get the alignment. So for compactness and lightness and for anything where you expect to sell more than a few samples this is a good design.
rgds, Andrew

"Is that an accurate dictionary ? Charlie Eppes

DQE
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Post by DQE »

morfa wrote:Thanks Andrew for linking to that great thread that I had completely missed!

Haha, wow! I can't believe Canon actually did everything right and then "forgot" to trigger the PC port (or something!!) when the electronic shutter opens. I now feel relieved from a large chunk of Canon jealousy! For natural light stacks it's still superior though, right?
Well, I can only offer my ad-hoc personal opinion, and selection of a camera body is at least as stressful as picking out an automobile brand - are you a Ford-oriented person or a Chevy-oriented person?! Maybe today cars are more of a "are you a Honda person or a Toyota person" situation?!

Anyway, I think I'd prefer to use Nikon camera bodies but Canon's MPE-65 lens is a "must have" component for me since it's so easy to vary the magnification in field macro use, and since its image quality seems to be competitive at 1-5x magnification. Also, I've been pleased with the image quality and high-ISO performance of my 5D and 5DII bodies but I have not personally made any direct comparisons with Nikon bodies. I've certainly enjoyed the fine detail image quality of the high-megapixel 5DII body. Yet from what I've read, I believe I would prefer Nikon's flash exposure automation system, but given the way I shoot field macro photos superior flash automation probably wouldn't make much difference to me in most real world field macro situations. I've never found a reason to use Live Mode, but suspect this is partly because of inertia on my part.

I mostly shoot field macro, so this MPE lens requirement makes my personal selection of Canon instead of Nikon a single-issue decision. To my way of thinking, field macro photography is so heavily manual technique-based for most users, the performance and features of the camera body are much less important than it would be for wedding photography, sports photography, etc. I believe one could make a VERY simplified, specialized field macro camera body for much less money than the current all-purpose bodies. Yet the macro camera body market must be much too small to financially justify such a design.

I really hate to be boxed in by a single factor such as compatibility with the MPE-65 lens, though. I guess I'm sort of a Nikon user wannabe but a Canon user in practice.

Just some ad-hoc conversation.
-Phil

"Diffraction never sleeps"

ChrisR
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Post by ChrisR »

To get fine steps with economic motors/drivers you need microstepping, because leadscrews only go so fine. That reduces torque.
So an obvious bolt-on option might be a gearbox. I have one which is about 6.5 to one, which takes what would be 2.5 micron stepping down to about 0.4 micron.
Something like a 40/0.8 objective needs steps like that (if I ever overcome the "other" difficulties).

Linden.g
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Post by Linden.g »

Here are some of the opporating modes of the StackShot

Image

augusthouse
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Post by augusthouse »

Linden, thanks for uploading the images of the StackShot, automated macro rail.

Linden wrote:
The rail is 1.1kg
As a comparison regard weight. The Novoflex Castel L (for example) weighs 450g, so this rail at 1.1kg is managable, especially when considering its capabilities :)

Linden wrote:
This is a pre-production example, product will have an anodised finish
Will the anodised finish be black, grey or a sexy gunmetal blue-grey? (just cosmetics, mostly, but curious)

Craig
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"

lothman
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Post by lothman »

AndrewC wrote:There aren't really that many complex machined parts. If you look at it the only one with a lot of machining is the camera riser. Everything else is just plates. Even if you use profiles you still need precision machining to get the alignment. So for compactness and lightness and for anything where you expect to sell more than a few samples this is a good design.
You can buy high accuracy straight from the catalog at low price designing a macro slider without precision machining. As a mechanical engineer and designer I would say the solution could become cheaper and more precise. Then you would have ball bearing of the slider (low friction without backlash) instead of slide bearings, this would be much better for microstepping.

Sorry Linden for the disturbing your thread :wink: , I really like your solution and appreciate a lot sharing your knowledge.

Best regards
Lothar

Edit: I meant a solution like these parts from Isel just needs a spindle and two end plates.

DQE
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Post by DQE »

lothman wrote:
AndrewC wrote:There aren't really that many complex machined parts. If you look at it the only one with a lot of machining is the camera riser. Everything else is just plates. Even if you use profiles you still need precision machining to get the alignment. So for compactness and lightness and for anything where you expect to sell more than a few samples this is a good design.
You can buy high accuracy straight from the catalog at low price designing a macro slider without precision machining. As a mechanical engineer and designer I would say the solution could become cheaper and more precise. Then you would have ball bearing of the slider (low friction without backlash) instead of slide bearings, this would be much better for microstepping.

Sorry Linden for the disturbing your thread :wink: , I really like your solution and appreciate a lot sharing your knowledge.

Best regards
Lothar

Edit: I meant a solution like these parts from Isel just needs a spindle and two end plates.
I would prefer a mechanical assembly that is compatible with the software and controller that this vendor will provide. I am unskilled mechanically and with respect to digital hardware control and need a "turn key" solution with good customer support. My personal needs are not such high-precision since I only plan to use it for field macro stacks; I understand that others need much higher precision and accuracy and would like to use it for high-magnification photomicrography stacks.

Perhaps an ideal solution would use very high-precision components for photomicroscopy and something like the system being tested for photomacrography?

Just a few thoughts.
-Phil

"Diffraction never sleeps"

Linden.g
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StackShot

Post by Linden.g »

Thank you all for providing feedback, now is the time to do this in the final stages of development. All ideas are welcome and will help to make this product add value to the hobby.

Linden

AndrewC
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Post by AndrewC »

Linden: couple of things for your friends

- put a gaiter over the leadscrew. Even with a wiper on the drive nut assembly it is better to keep the dirt out.

- what are they doing for limit switches ? Stalling the stepper motor against a mechanical limit works but can lead to wear of the drive nut which introduces errors later. It would be easy to add robust Hall sensor limit switches. Little bit more code and a few wires but well worth it.Alternatively put an encoder on the drive and check for the stall through that.

Andrew

typestar
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@ Linden -- protection against dirt, accuracy

Post by typestar »

@ Linden

I like your idea very much. All the hunting for focus-blocks and adapting them etc. could have an end.

Here my simple cents to your setup:

1) Material -- is it made of stainless steel - which would be great - I think about using it mounted to a rigid enlarger stand or to the Nikon Multiphot as an replacement of the rail-guide for vertical work...

Please, try to make it a MICRO rail, not "only" a macro-rail ... :lol:

2) Accuracy -- as some of the professionals here pointed out: it would be nice to enhance the precission and accuracy from 0.1 mm to at least
0.002 mm , better down to one micron (=0.001 mm) in order to use microscope lenses "higher" than 10x up to 50x and for deep high-res stacks also -- and to have the possibility in the controller and setup to "jump" to larger scales for "rougher" needs. But I really do NOT know, whether a macro rail can work this fine way like a microscopes focus block.

3) protection against dirt: as some here think about the "field-use" - (which I think is difficult in any case ...) it should really more protected against dirt & dust, even in a studio environment. So a light full cover (that can be screwed off with a few screws would help more. No the full function ist to be seen nicely but it seems not protected !

4) What about the lenght of the cable of the controller, that is connected to the rail? If it is mounted on a vertical stand, the cable should come as a plug-in version in different - long enough versions.

Thankyou for your answers and please keep us informed here...

christian
Last edited by typestar on Tue Jan 19, 2010 2:29 pm, edited 7 times in total.

Chris S.
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Post by Chris S. »

Linden, I'll add my two cents.

The device seems like a decently automated version of the focusing rails commonly used in the field, but I would want something with finer step increments and the mechanical capability of handling higher magnification optics with ease. I don't care much about field portability; if I invested in such a system, I'd primarily want it to work well in my studio with all my objective lenses, and would consider field portability as a "nice to have" characteristic.

The device's current 10-micron steps would be fine for my 4x NA 0.2 objective, but would only sometimes handle my 10x NA .3 objective. It would not handle my 20x, 40x, or 60x objectives. And since the potential focus banding of a 10-micron step at 10x NA .3 would not be discernable until later post-processing, I wouldn't be comfortable making the capture images with this step even at 10x. I'd want to capture at 4 microns in the field, rather than do all the field work only to find out too late, during post processing, that my focus steps were too coarse.

So the device, at it's current step increment, would for me only be useful at my lowest magnifications. A problem with that is that at these low magnifications, not too many separate images are needed, and I can't see investing in automation that only works where I least need it. Where I really want automation is for deep stacks, not shallow ones. Manually incrementing and snapping 30 exposures doesn't feel too bad. When it's more like 300 exposures, bring on the stepper motor.

My sense is that reducing the useful step increment by an order of magnitude would require not just a finer-pitch drive, but more expensive engineering all over, which would probably make the unit too expensive for the likes of me.

By the way, using microscope focus blocks has spoiled me for standard macro rails even for field use at low magnification. I now much prefer using a focus block clamped to an Arca-style plate, which in turn is clamped in the tripod head. Much more pleasurable to use than a macro rail. I get rough positioning from the Arca rail, and use the focus block for the stepping--but with far less stiction, vibration, and other perturbations than with a macro rail. Since switching from a macro rail to a focus block felt like going from a Yugo to a Ferrari, a fairly standard macro rail with automation strikes me as Yugo with cruise control.

As for why Elf would want a .001mm (one-micron) focus step, I'm right there with him, and in fact need to go a bit finer. Using a 40X NA .5 objective, for 50 percent DOF overlap at the violet end of the visible spectrum on a Nikon 200 sensor, the focus step is 1.1 microns. With the 60x NA .7, the step is half a micron.

Best,

--Chris

Linden.g
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Response

Post by Linden.g »

Ok this is good feedback, I'm seeing a definite trend here.

1. Step incriment down to 1 micron, versus currently 10. Does anyone have any targets for precision in the X, Y dimensions 90 degrees to the Z ?

2. Many prefer a target towards bench work, although being able to do course work in the field would be a bonus

3. Integration with standard mounts would help

4. Protection of the drive from dust could be an issue

In terms of materials the main body is aluminium which will be anodise, fastners are stainless, I'll check on the drive shaft and rails.

I would like to find out if people would be interested in a modular product where the user can just buy the motor and controller. The current software can take rotational calibration for any drive ratio. I'll also find out what the smallest angle of rotation can be supported.

Linden

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