Tri Stacker: Quick Test Run #1 [Subject: Hard Drive Head]

GemBro · Post by **GemBro** » Wed Dec 17, 2014 7:42 am

Related thread links for the new rig ... called Rig II: Bamboo ...

Tri Stacker: Design & Build:
http://www.photomacrography.net/forum/v ... 545#159545

Tri Stacker: Quick Test Run #1 [Subject: Hard Drive Head]
http://www.photomacrography.net/forum/v ... 529#159529

Tri Stacker: Quick Test Run #2 [Subject: Woolly Bear]
http://www.photomacrography.net/forum/v ... hp?t=26082

Rig II: Bamboo - Design, Build & Test - Designed around a Bamboo Chopping Board, this is the new rig
http://www.photomacrography.net/forum/v ... hp?t=25391

TRI-STACKER: QUICK TEST RUN #1 [Subject: Hard Drive Head]

Just finished the draft construction, to get a working model, of my new Automated Stacking System (A.S.S.), which I call 'Tri Stacker' ...

This system is based on the Trinamic board (PD3-110-42-232) to drive the stepper ... the beauty of this board, is, it's completely compatible with Helicon Remote (via a proper FTDI USB cable) ... I was able to grab the board and a nice Hi-Res Stepper, for silly money off eBay, about a 1/4 of the cost of the £200 retail ...

http://www.heliconsoft.com/heliconsoft- ... on-remote/

I've wired it all up and it functions perfectly (apart from an issue, see below) ... I am using a different stepper, to one I bought with the board, as it was too precise and is not nessecary for stacking (I'm using that in another project) ... I am now using a standard NEMA 17 12v motor, with 1.8deg steps ...

AN ISSUE:
A little issue has arisen with the geometry movement ... when stepping, it dances around a bit and causing the geometry to shift (you can see this in the dust trails) ... hence why I havn't secured the stepper properly ... I have put the motor on some springs to dampen the wobble ... there could could be a few things causing this wobble issue:

1. Wobble in the long(ish) bolt which is screwed into the fine focus knob (replacing the original but longer just enough to reach the coupler) (similar to how Rylee coupled his motor) ... this in turn is connected to a shaft coupler that then connects to the stepper itself ...

2. The focus block not being dead center, as in a perfect 90 degrees to the stepper shaft axis ... this would cause wobble ... need to check this as this is the main issue of the Olympus CH microscope as it has a slight curve to the back of the stand ... and if you've seen my setup, the stand is laid down, in the horizontal position on the Rig ...

3. The actual fine focus knob is off axis a bit ... but this doesn't look so when rotated on it's own using my fingers ...

NEW SUBJECT:
I decided to try a different subject, instead of insects and Protozoa and went for something to do with my everyday life of I.T. ... after having a clear out at the weekend I found an old 4GB Samsung (single platter) hard drive and totally stripped that down and decided to use the read/write head as a subject ... but only to find out Steve beat me to it a few days before ...

... his shot is brilliant and well lit btw ... http://www.photomacrography.net/forum/v ... 172#159172

Anyhow ... I took 3 varying stacks, with the new system, as the goal was to really test how stable the system is (I'll post more on the this when I've finished it) ... so I have posted 3 images taken with the Tri Stacker ... not bad being as there's a little wobble injected into the stack images ... but the wobble is not that much when each iage is taken, only when the motor runs constantly for selecting the foreground/background focusing peaks ...

SETUP Common components for all 3 stacks are::
Canon 550D (T2i) DSLR
RMS to M42 Conned adapter (new & linned with black velor)
Nikon Plan 10X 0.25 160/-
Tube length 150mm (bellows)
Ikea Jansjo 3 LED lamps

Note: All images are set at 2592 x 1728 resolution, as that's the default resolution for Helicon Remote's Evaluation version of the program ... I have then resized them to my standard 1200 x 800 ... then uploaded here ...

FIRST: Stacked images = 227
Using vellum tracing paper ... the stack seems ok (from what I can see) but disregarding the accuracy of the stepping, I was concerned about the light flare/spikes around the wires ... could this be reflection from something (possibly the chrome lens cover itself?) ... did I do too many images for the stacks? ... added a little post to sort the colours and white balance, plus a tad sharpness ...

SECOND: Stacked images = 201
The second, still using the tracing paper for diffusion but at a different angle, although a little darker ... still shows the light spikes ... is it the diffuser? ... so I decided to try a different diffuser for the third stack ...

With the previous 2 shots the platter itself was still attached (before I took if off for the 3rd shot) ... hence you can see the head reflection ...

THE THIRD: Stacked images = 176
I went back and re-done the stack again ... and as you can see after a day a few bits of dust/debris has accumulated ... this time I actually removed the whole head off the hard drive for this shot (head/arm assembly was removed from the platter) ... but in this shot I used a ping pong ball for diffusion and enclosed the lens and subject, within the ball, to reduce outside reflections ... seems to have worked and looks a lot better (wish I done a deeper stack now) ... again, added a little post to sort the colours and white balance, plus a tad sharpness ...

As with all stacks I had nothing shielding/masking the actual objective lens at this point but after reading Steve's post I may try masking the lens ...

THIRD - 100% CROP:
This is a 100% crop of the Third image ... you can actually see the twisted wire strands inside the PVC sheath covering, as well as the clear blobs of resin, on the wires connections, to keep the wires intact & stable ... and you can now see why a tiny bit of dust could crash a hard drive just by getting in between the drives head (obviously not the case in theory as the drives are hermetically sealed) ...

...

FOURTH:
A mobile phone photo (sorry about this, the DSLR is on the Rig) ... the actual hard drive head itself, complete with the spring mechanism, on the aluminium support arm ...

Steve only done 19 for his image

... drawing board, back to I reckon ...

EDIT: Doh! ... Steve's image is a full frontal shot ... so 19 shots was probably enough ...

Gem

steveminchington · Post by **steveminchington** » Wed Dec 17, 2014 8:28 am

Gem, I like the angle of No 3 - it makes for a good composition. The wires are a problem though. I did a Dmap stack with the threshold at 80 to bring in the flare and combined it with the Pmax. Didn't use any sharpening though - seemed ok as it was.

GemBro · Post by **GemBro** » Wed Dec 17, 2014 9:04 am

Thanks Steve ... yeah, I hear you ... I haven't played with Dmap at all yet so I need to read up on that ... cheers for the tips

mawyatt · Post by **mawyatt** » Wed Dec 17, 2014 5:22 pm

Gem,

Those are really nice, love the colors. I am trying to use the IKEA LED lamps too. Using a styrofoam cup surrounding the subject as a diffuser. The Lamps are good deal for $15 IMO.

Mike

GemBro · Post by **GemBro** » Wed Dec 17, 2014 6:32 pm

Mike thanks ...

I've tried flash on a few occasions but still go back to the Ikea LEDs ... so much more easy to use, although I haven't perfected the lighting setup, as yet ...

I think when I tried the tracing paper (vellum) (for the above 1st 2 images) there must've been light leakage, possibly from reflections, coming in from underneath somewhere ... need to either cone it or make a cylinder and enclose it as tight as possible ... hence why the ping pong ball was a lot better ... will try vellum again in the future ...

Yes styrofoam cups (50 for a £1 @poundland ... http://www.poundland.co.uk/50pk-eps-cups), ping pong balls and now (recently) tracing paper are always in the toolbox ... I find white laser paper is ok but I think more for flash use, as I lose quite a few stops when I use that with the Ikea LEDs ...

They're averaging about £16 each here in the UK at the moment ... I'm now finding that using the 3rd Ikea LED does help a bit more now and gives me another stop or 2, if placed right ...

Note: Don't grab, or use, the USB version of the Ikea LEDs, as they are very low wattage, something like 0.1W ... the clip-on or desktop versions are both 3W and fine ... the desktop versions are a lot longer than the clip-ons too ...

Soooo much to do with this (supposedly relaxing) hobby eh? ...

mawyatt · Post by **mawyatt** » Wed Dec 17, 2014 8:03 pm

Gem,

I got 4 of the clip on Ikea LEDS, and using all 4. I may try another level of diffusion in addition to the stryrofoam cup. The light distribution isn't as uniform as the dual tents, but doesn't require the complex setup either!! The dual tents loose lots of light which is another drawback.

Now I just need to convince the wife that I need the new Nikon 400mm f2.8 for Christmas since I am saving so much with the Ikea LEDS!

ChrisR · Post by **ChrisR** » Thu Dec 18, 2014 12:20 am

the clip-on or desktop versions are both 3W and fine

NB they can be different colour temperatures.

GemBro · Post by **GemBro** » Thu Dec 18, 2014 9:25 am

Chris yes ... all of them can have different colour temps ... depends on the batch you buy from, at the time ... even the 'white' versions vary, same as the 'warm' versions ... a bit of post will sort that all out for you though ...

Rylee Isitt · Post by **Rylee Isitt** » Thu Dec 18, 2014 6:04 pm

Gem,

Nice shots. It looks like a very tricky lighting situation with those highly reflective wires. Aesthetically, I prefer the greater contrast in your first two images, and the first image as it has fewer light spikes. The third image, though, has a high-key dreamy look to it which is still quite pleasing.

You just showed me the light as to why a dedicated stepper controller board can, in some circumstances, be a better choice than just an H-bridge chip for stacking. I am not convinced that microstepping and acceleration/deceleration features are useful for stacking purposes, but compatibility with stacking software is actual useful. I may have to look into how to add the necessary communication protocol to get my own controller recognized by Zerene as a StackShot, haha. If it's just done over serial, it should be easy as pie.

As to your wobble issue, do the dust trails indicate random wobbling, or is there a pattern? I think I can see the trails you are referring to and they look random. But if you can find a dead or stuck pixel (most cameras have a few) and crop out the trail formed, that would be very easy to see.

In my rig I don't have noticeable random wobbling, but what I do get is progressively greater sagging of the camera on the BHMJ block as the camera's center of gravity becomes more and more offset, putting progessively greater shear force on the block as the stack progresses. I can see the result in the occasional dead/stuck pixel which creates a trail of dots that is not quite radial, but is offset from center. This doesn't happen often, it really depends on what camera and lens I use. I expect this to largely go away if I were to center the mass of the camera and lens on the block.

Can you post shots of the hardware (focus block, connection to the motor, etc)? Maybe somebody will spot a possible source of wobble...

GemBro · Post by **GemBro** » Fri Dec 19, 2014 5:51 am

Rylee ... thank you ...

LIGHTING:
Yeah the lighting was a quick setup for testing the stepper system and wasn't really meant to be a decent stack (light wise) ... but I have found valuable info from others who have experimented and posted recently, regarding reflection issues ... as much as I like to be close to the original colours, I also like variation as that's what photography is all about, isn't it

...

I am happy with the image results from this (rough) test ... they turned out ok and proves that the stacking system works (to a degree), which was the main reason ... I didn't expect them to be as good (disregarding the lighting) ... but I think it has a lot to do with Rik's great software (ZStacker) lining up all those wobbled images ...

DEDICATED STEPPER BOARDS:
Yep ... I got a stack (pardon the pun) of stepper driver boards here ... the Trinamic board, I discovered a year or so ago (when I found the Helicon Remote software) and always wanted to try it out but at a cost of (back then) £200+ (inc. board and motor) was a bit much of a gamble ... luckily, I recently found a seller on eBay selling the Trinamic boards seperately and cheaply ... was definitely worth purchasing now (might buy another) ...

I personally prefer using dedicated PC software for driving my stack steppers, as everything is then in one package (control and Live View) ... also it's saves on one less component (the dedicated controller) to setup and carry around with you ... most functions are included in Helicon Remote (could do with a few other options) ... plus it gives you extra control over the Trinamic board itself, as well ...

MOBILE - IN THE FIELD:
I'm not that bothered about being mobile, with my Rig, but as you will see later in this thread, it could be transported around, due to using my Samsung (old but brilliant) notebook ... or any other notebook for that matter ...

THE WOBBLE FACTOR:
As you found out with yours, pressure/force is applied on the motor and the fine focus control (with the wobble issue), especially if I secure the motor in position ... at this point, I didn't want the stepper to be too secure all the time there is force applied to both items, hence why my stepper is loose and on a (simple) spring base damping support, for now, until the wobble issue is sorted ...

The wobbling is not noticable (much) while doing the actual stack shots but it does obviously move due to the result of the stacked images (dust/hot pixel trails) ... the wobble is only really noticable (visually) if I run a test loop on the Trinamic board (yep, it has it's own Micro Computer built-in to the board as well - arduino style), which runs the motor back & forth for a set number of steps ... great for checking this sort of thing ...

I've taken some photos of the setup and will post them here very soon ...

Rylee Isitt · Post by **Rylee Isitt** » Fri Dec 19, 2014 11:43 am

If you think the motor is causing the wobbling, make sure you use it with timing pulleys and a belt, and attach the body of the motor to a different surface than the focus block is attached to. I have mine on a separate metal base with rubber feet.

GemBro · Post by **GemBro** » Fri Dec 19, 2014 6:11 pm

That's the trouble Rylee, I don't know if it is that yet

...

I may use nucleobyte's idea of a cog coupling setup ... I got loads of cogs from an old printer/scanner here ... I may give that a go as another option first ... thoretically the gap between the cog teeth would vary (slightly) if wobble is still present and therefore not produce any force on either the stepper or the focus control, once calibrated ...

nucleobyte: Did you have any wobble issue with your cog coupling? ...