[yeatzee]

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Have you tried a motor drive on the stage? It seems to me a clock motor setup might have low enough vibration so you could automate the process; just turn on the drive & shoot a pic at regular time intervals.

A rubber tube coupling the motor shaft to the micrometer shaft might be ok.

On the other hand what you are doing is not a lot of effort I guess but automation might free you up to do other things while the stacks are being generated.

Newport 420 - $50
Stackshot automated rail - $500

Im in highschool remember

[newarts]

Newport 420 - $50
Stackshot automated rail - $500

Im in highschool remember

Clock motor $3.95 at walmart or I'll send one to you if you want.

maybe small 1rpm synchronous motor would be better; how far do you turn micrometer barrel for each exposure?

[Damian]

I came across this not long ago while looking into ways to build a Macro Rail as I'm a cheap bastard and don't like the idea of paying $100 for a glorified screw driven platform.

Check out this Video

And an explaination of what the guy did to make it work
Motorized macro rail on the cheap - PICAXE Forum

This easily could be adapted to a Linear stage or a larger screw driven macro rail with the right motor.

I probably won't attempt this as I have no patients for programing, and do not particularly enjoy soldering but someone else might find it interesting.

[yeatzee]

Clock motor $3.95 at walmart or I'll send one to you if you want.

maybe small 1rpm synchronous motor would be better; how far do you turn micrometer barrel for each exposure?

I haven't a clue about anything regarding electronics, programming, wiring, etc. I wish I did, but honestly Im beyond clueless how I would even begin with a motor!

Lately I've been using what I was told to be .05mm increments, as each "tick" is apparently 0.025mm.

I came across this not long ago while looking into ways to build a Macro Rail as I'm a cheap bastard and don't like the idea of paying $100 for a glorified screw driven platform.

Check out this Video

And an explaination of what the guy did to make it work
Motorized macro rail on the cheap - PICAXE Forum

This easily could be adapted to a Linear stage or a larger screw driven macro rail with the right motor.

I probably won't attempt this as I have no patients for programing, and do not particularly enjoy soldering but someone else might find it interesting.

i wish this all made sense to me, because I'd certainly love to have an automated stacking system

[jstevewhite]

Well, I got a couple of images I like from stacking the 35mm with the 100mm macro; figured I'd share my 'successes' Thanks for the info on the diffuser, crewl1, and the info on stacked lens magnification, yeatzee!

[Stone G.]

Nice setup Stone.

I cant help wondering over the DOF when using that kit?
Is there anyway we can get some sample shots taken of that ruler but from say a 45degree angle?

So, in response to your request and as promised, here's a quick-and-dirty test setup for DOF with the ruler at a so-so 45 degree angle to the sensor plane:



Idealy the horizontal centerline of the ruler should have been exactly parallel with the do. sensor centerline, and ideally the focus point should have been at the center of the field of view at all times but, well, I was in a bit of a hurry to make this tests.

Let's say, then that this mimics a "real-life situation" with the following results:


M = 1.3 : 1


M = 1.7 : 1


M = 2.6 : 1


M = 3.9 : 1


(For those of you not so familiar with geometry, the 45 degrees tilt means that over 5 mm on the ruler, the lower part will be approx. 3.5 mm closer to the sensor plane than the upper)

You can readily control the M-ratios shown: The sensor is 15.7 mm high

Lens, camera and eyepiece is the same as in my original post. The lens was stopped down to f/8 (as it also was for the original test images).

I hope this responds adequately to your speculations?

[Douglas_of_Sweden]

A microscope lens mounted on a bellows. This lens has no diaphragm, so it is wide open and at very thin DOF.


Scale is here approximately 2:1. Finger print.


Approximately 3:1. Grass straw.


Approximately 5:1. Leaf.

All hand held in natural light on the K-5.
I don't have the original Pentax K-RMS (Royal Micriscipe Society) thread adapter, but use a new m42-RMS adapter and a K-m42 adapter.
Lots of strange optical features in the OOF. Haven't had time yet to try with flash, bugs or stacking. Would like to get hold of a microscope lens with apperture blades (there are some, but they are rare and cost more).

[newarts]

I haven't a clue about anything regarding electronics, programming, wiring, etc. I wish I did, but honestly Im beyond clueless how I would even begin with a motor!

Lately I've been using what I was told to be .05mm increments, as each "tick" is apparently 0.025mm.



i wish this all made sense to me, because I'd certainly love to have an automated stacking system

I'm not talking fancy here!

That looks like an English micrometer. One full turn of the thimble (the part you turn with your thumb) is .025" - about 0.6mm. http://en.wikipedia.org/wiki/Micrometer

There are 25 subdivisions on the thimble so each one is .001". You are moving in steps of 1 subdivision or .001" which is about .001x25.4 =.025mm each step.

If you hook the shaft that drives the minute hand of a clock to the thimble it'll make one complete turn in an hour; so if your camera takes a photo every minute you'd have 60 photos in an hour at .01 mm spacings.

That seems slow to me & you probably want a faster rate of taking photos so you get a faster motor, like 10 rpm...

Here's a 10 rpm motor on ebay for $8.50 delivered: ROBUST SYNCHRONOUS MOTOR AC110V 10/12RPM CW/CCW STOCK | eBay

The only problem I can think of is vibration from the motor. But I'm pretty sure a rubber tube coupling the motor shaft to the micrometer thimble should kill the vibration.

[aliasant]

So, in response to your request and as promised, here's a quick-and-dirty test setup for DOF with the ruler at a so-so 45 degree angle to the sensor plane:



Idealy the horizontal centerline of the ruler should have been exactly parallel with the do. sensor centerline, and ideally the focus point should have been at the center of the field of view at all times but, well, I was in a bit of a hurry to make this tests.

Let's say, then that this mimics a "real-life situation" with the following results:


M = 1.3 : 1


M = 1.7 : 1


M = 2.6 : 1


M = 3.9 : 1


(For those of you not so familiar with geometry, the 45 degrees tilt means that over 5 mm on the ruler, the lower part will be approx. 3.5 mm closer to the sensor plane than the upper)

You can readily control the M-ratios shown: The sensor is 15.7 mm high

Lens, camera and eyepiece is the same as in my original post. The lens was stopped down to f/8 (as it also was for the original test images).

I hope this responds adequately to your speculations?

Excellent report! Thanx.
That seems to be a very very good DOF.

Maybe I will grow some hair one day and try something like that myself.
Just scared to fail again.. Tried many weird things but so far none has been really usefull in the field

Earlier today I rebuilt an old Canon Auto Bellows so that it works on myK5 with PK lenses. I can view thru an open lens and it stops down when I take the shot. Just as any PK lens. The bellows itself is extremely heavy though so Im not sure its very usefull... yet another failed attempt

[newarts]

A good dof equation for macros is dof=2cn(1+1/m)/m

Where n is f-number & c is "circle of confusion" which for an 8x10" print from an ASP-C sensor camera is usually taken to be about .020mm. You are taking macros so you may want to enlarge the image by 2x. So let's say c=.010mm

The f-number at m=2 should be something like f:4 to avoid diffraction softening. Putting all this together says the dof is about 2x.01x4*3/4=.06mm.

It seems to me you might get by with bigger steps between exposures; I think you are stepping at about 1/3 the dof for each shot; maybe you could get by with 2/3 dof? It might be worth a try.

I hope I've got these numbers right. I'm in no way trying to criticize you and think what you are doing is great. I've learned a lot from your work.

Thanks from a lot of us,
Dave

[yeatzee]

A microscope lens mounted on a bellows. This lens has no diaphragm, so it is wide open and at very thin DOF.


Scale is here approximately 2:1. Finger print.


Approximately 3:1. Grass straw.


Approximately 5:1. Leaf.

All hand held in natural light on the K-5.
I don't have the original Pentax K-RMS (Royal Micriscipe Society) thread adapter, but use a new m42-RMS adapter and a K-m42 adapter.
Lots of strange optical features in the OOF. Haven't had time yet to try with flash, bugs or stacking. Would like to get hold of a microscope lens with apperture blades (there are some, but they are rare and cost more).

Ya that looks a LOT more than the magnification estimated..... Whats the objective?

[yeatzee]

A good dof equation for macros is dof=2cn(1+1/m)/m

Where n is f-number & c is "circle of confusion" which for an 8x10" print from an ASP-C sensor camera is usually taken to be about .020mm. You are taking macros so you may want to enlarge the image by 2x. So let's say c=.010mm

The f-number at m=2 should be something like f:4 to avoid diffraction softening. Putting all this together says the dof is about 2x.01x4*3/4=.06mm.

It seems to me you might get by with bigger steps between exposures; I think you are stepping at about 1/3 the dof for each shot; maybe you could get by with 2/3 dof? It might be worth a try.

I hope I've got these numbers right. I'm in no way trying to criticize you and think what you are doing is great. I've learned a lot from your work.

Thanks from a lot of us,
Dave

I've found F/5.6 with the magnification I get with the reversed 50mm on tubes and a hollowed out TC to be just about optimal as far as I can tell I can probably afford bigger steps between shots but I do this just to be safe. The stacks are flawless so I don't want to change whats not broken I'm fine with "wasting" some of my time for this

I determined the steps by taking two images and comparing with the "compare" feature on the K-7 until I get what looks to be good overlap No math required

[crewl1]

@jstevewhite - good work there!

@yeatzee, thanks for the info on the stage.

Everyone else: appreciate the discussions, learning a lot.

[newarts]

I've found F/5.6 with the magnification I get with the reversed 50mm on tubes and a hollowed out TC to be just about optimal as far as I can tell I can probably afford bigger steps between shots but I do this just to be safe. The stacks are flawless so I don't want to change whats not broken I'm fine with "wasting" some of my time for this

I determined the steps by taking two images and comparing with the "compare" feature on the K-7 until I get what looks to be good overlap No math required

Experience ALWAYS beats theory!

The math is useful for exploring possible improvements extrapolating from experience....

Dave

[jstevewhite]

@jstevewhite - good work there!

@yeatzee, thanks for the info on the stage.

Everyone else: appreciate the discussions, learning a lot.

Thanks.

You know, the thing that brought me to Pentax is the color. I'm constantly amazed by the color my systems produce. It *really* shows in the macro images.