<div dir="ltr">Thanks a lot for looking into this, it'll be helpful as I build more focus stacking set-ups! :)<div><br></div><div>- Joel</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jan 18, 2022 at 5:29 PM <a href="mailto:HuBandiT@gmail.com" target="_blank">HuBandiT@gmail.com</a> <<a href="mailto:hubandit@gmail.com" target="_blank">hubandit@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<div>Literature on the Stackshot (
<a href="https://cognisys-inc.com/stackshot-macro-rail-package.html" target="_blank">https://cognisys-inc.com/stackshot-macro-rail-package.html</a> ) says
its smallest step size is 2 micrometers.</div>
<div><br>
</div>
<div>The smallest step a 9600 DPI scanner
(Canon 9000F) needs to do is 2.64 micrometers.</div>
<div><br>
</div>
<div>The smallest step a 4800 DPI scanner
(Canon 8800F) needs to do is 5.29 micrometers.</div>
<div><br>
</div>
<div>Of the three, the Stackshot has the
smallest steps, at least on paper.</div>
<div><br>
</div>
<div>Plus the Stackshot has a sturdy rail
and mounting system that is sized to take the weight of a
mirrorless camera + lens. In comparison a scanners rail system is
weaker, plus it is not sized to support the extra weight of a
camera and lens, plus mounting is more problematic.<br>
</div>
<div><br>
</div>
<div>Therefore, on paper, your arrangement
of using these scanners to move your camera does not offer
benefits compared to the Stackshot.</div>
<div><br>
</div>
<div>What I would recommend you instead is
to find an USB-attached stepper motor controller that you can
easily direct with text commands from Linux. That you can then
trivially make it do steps from a command line. Trinamic is a
german company who does very nice work on providing very smooth
movement control for stepper motors (and also BLDC motors). They -
or someone using their parts - might have something that allows
you to control it from a serial port that you can then attach to
Linux (I am assuming Linux is a requirement for you?).</div>
<div><br>
</div>
<div>As for mechanism, you might find
someone has made a mechanism for this exact purpose (focus
stacking is an easy-to-implement but high-value niche hobby or
research project). Or if you don't, then it is not terribly
difficult to find mechanical parts normally used by hobbyists for
building home CNC machines, and whip up a linear actuator
mechanism (rail + carriage, pushed by a threaded rod turned by a
stepper motor). With a little engineering work, using precision
parts and fine microstepping enabled by Trinamic drivers and
stepper motors, you might perhaps be able to achieve even smaller
step sizes than your factory-made Stackshot.<br>
</div>
<div><br>
</div>
<div>2022.01.14. 17:35 keltezéssel, Joel
Penner írta:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi everyone,
<div><br>
</div>
<div>Thanks for the feedback everyone! Thanks for the
info Povilas about the genesys backend. I do have some
scanners that use it. Would you have some pointers for how to
issue those commands to a scanner via the backend? </div>
<div><br>
</div>
<div>You're right Ralph, it might be easier to control them
directly. I had thought of the buffer approach as well, maybe
I'll experiment with that.</div>
<div><br>
</div>
<div>Thanks,</div>
<div><br>
</div>
<div>Joel</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Tue, Jan 4, 2022 at 12:47
PM Ralph Little <<a href="mailto:skelband@gmail.com" target="_blank">skelband@gmail.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi,<br>
<br>
On 2022-01-04 9:05 a.m., Joel Penner wrote:<br>
> Hello,<br>
><br>
> I am doing microscopic focus stacking with mirrorless
cameras. I have <br>
> a Cognisys Stackshot rail that I am doing this with, but
I also have a <br>
> bunch of Canon 9000F & 8800F scanners, so I am
wondering whether I <br>
> could use the precision these devices have to move a
camera forward by <br>
> small increments.<br>
><br>
> I have already been experimenting with attaching a
stepper motor to a <br>
> microscope, controlled by a Big Easy Driver and a
Raspberry Pi. This <br>
> person used a scanner for focus stacking by connecting a
scanner motor <br>
> to an external driver:<br>
><br>
> <a href="https://petapixel.com/2013/01/24/focus-stacking-macro-photographs-with-a-hacked-flatbed-scanner/" rel="noreferrer" target="_blank">https://petapixel.com/2013/01/24/focus-stacking-macro-photographs-with-a-hacked-flatbed-scanner/</a>
<br>
> <<a href="https://petapixel.com/2013/01/24/focus-stacking-macro-photographs-with-a-hacked-flatbed-scanner/" rel="noreferrer" target="_blank">https://petapixel.com/2013/01/24/focus-stacking-macro-photographs-with-a-hacked-flatbed-scanner/</a>><br>
><br>
> This would work for me, but would it be possible to
manually move the <br>
> scanner imaging head with SANE and the scanner's firmware
and <br>
> circuitry? Basically, I would need SANE to move the
scanner imaging <br>
> head forward by a tiny increment, pause for a few seconds
for the <br>
> camera to take a photo, move forward again and so on. I
just need <br>
> total control of where the scanner imaging head is moved
to and how <br>
> small the increments are. My goal is to use this rig to
do timelapse <br>
> microscopic focus stacked images of plant growth.<br>
><br>
> Ideally, the scanner imaging head light would be turned
off too but I <br>
> could also use tape or disconnect the LED array. I have
other scanner <br>
> models as well if the firmware or drivers of these Canon
scanners <br>
> isn't suitable.<br>
><br>
> Any ideas would be appreciated, thanks!<br>
><br>
> Joel<br>
<br>
This *might* be possible if the usual movements that the scan
head would <br>
make are sufficient for your need.<br>
<br>
What you can definitely do is to arrange for the scan head to
move from <br>
home quickly to a start position and have the head move more
slowly to <br>
an end position (speed depending on the requested resolution)
after <br>
which the head would usually return to the home position. By
controlling <br>
the rate at which the scan data is received from the machine,
you might <br>
also be able to get the scan head to pause when the scan data
buffer is <br>
full. Within the SANE API, those are really your options.<br>
<br>
Some scanners have a more high-level control, such is the case
with the <br>
protocols that are handled by the pixma backend. I see that
Povilas has <br>
answered regarding the genesys backend and the scanners that
are <br>
supported there. The genesys controllers provide much more
control over <br>
the hardware. Even then, using the SANE API is going to be
quite <br>
limiting, but you could use the genesys code to directly
control a <br>
genesys scanner.<br>
<br>
Honestly, you might be better off harvesting the components
from the <br>
scanner and using an arduino or something. ;D<br>
<br>
Cheers,<br>
Ralph<br>
</blockquote>
</div>
</blockquote>
<p><br>
</p>
</div>
</blockquote></div>