My New 3-Axis Macro Rig

[jessbussert]

Hi Folks,

It’s been a long, long time since I’ve posted anything here. I was first out with a medical issue and then I was engaged in building my next generation macro rig! That is now finished and I need your help to put it to use.

My previous rig was a home built rail controlled by an Arduino driving a hobby servo. It was built out of laser cut 1/4" ply and it worked fine for subjects in the range of 1cm or more. Once I got my reversing ring and could fill a frame with a 2mm subject, I found that the inherent play in the assembly was too much to get effective stacks. This was the catalyst for my building the new rig.

My new design is built around a 3-axis microscope stage with 1/2" range around each axis. This was initially a manual stage with micrometer controls to accurately move each axis. I attached steppers to each of these controlled by a touch screen, Arduino, and three Big Easy Motor Drivers in order to automate my shoots. I also attached a cheap IR remote to the Arduino so I could trigger my camera without having to wire directly into the camera. I then attached an old webcam mount to the microscope stage to allow me to rotate and tilt my subject in 360 degrees. Finally, I added light sources in the form of LEDs shining through diffusers. These move with my stage in order to maintain consistent lighting.

The software I wrote allows me to jog each axis for rapid motion as I compose my shot. I can then specify start and stop points for each axis as well as independent step amounts for each. The goal behind this was to allow me to perform a pan-and-scan process while building a focus stack. Ultimately I want to be able to create highly detailed images of larger subjects at the highest resolution possible on my rig. Imagine an image of an entire grasshopper at a few thousand pixels per millimeter! That’s what I’d like to accomplish.

Now my question to you: is there any existing software that will perform pan-and-scan stitches while also building a focus stack? If not, it looks like I’ll be in for a LOT of manual assembly!

I know there are a few reps for the various stacking programs that hang around in this group. Are any of you interested in helping me utilizing your software to maximize the capabilities of this rig? I currently use Photoshop for most of my builds. I also have Halicon but I haven’t been able to get as good of results with it as I have with PS. I think this might be due to my inexperience with the one versus the other but I’m not sure. Halicon only has a few parameters and I’ve played with them all. I just can’t figure out a rhyme or reason to optimize them. Perhaps one of you might offer some insight?

Being that it’s the middle of winter here and we’ve been experiencing sub zero temps, I’m not able to take the micro florals that I love so much. I’m currently experimenting with pine needles and dead bugs (ewww!). As I get some interesting images I’ll post them for your review.

Thanks,
Jessica

[jessbussert]

Hi Folks,

Here is my first bug. I didn’t spend a lot of time on it since it was just a test piece and I really don’t like taking photos of bugs! That said, I’m pleased with the detail I was able to pick up in the eyes.

This was done exclusively in Photoshop. I took 80 images and then made about 15 sub stacks that were later blended together.

I just downloaded the eval of Zerene and ZereneVS. I’d like to see if they give better results but I’m having a difficult time figuring out how to use it to make slabs. Anyone out there willing to offer some advice?

Thanks,
Jessica

[Chris S.]

I just downloaded the eval of Zerene and ZereneVS. I’d like to see if they give better results but I’m having a difficult time figuring out how to use it to make slabs. Anyone out there willing to offer some advice?

Jessica,

With apologies to Elf, who very kindly made ZereneVS available, it is not an easy utility for mere mortals to use. For your purposes, try Bill Eldridge's Bugslabber, which may not be quite as powerful, but has an easy-to-use graphical user interface. (You might also download the how-to document from another slabbing utility, SlabberJockey. This contains some information about slabbing that might help you. (I wrote SlabberJockey, but recommend Bugslabber to new users as it is more recent and has additional features; this said, my old how-to may still be useful. And there are other slabbing utilities that are not coming to mind at the moment.)

Zerene Stacker will in lots of cases do a much better job than Photoshop. If you add slabbing, this will not make a difference in your images per se. It may, however, make them easier to retouch in Zerene Stacker.

--Chris S.

[jessbussert]

Chris,

Thanks for all the info! I’ll check out your links.

I realize that I have a lot to learn. My aperture is a 1/4" hole in a piece of black cardstock that I cut with the laser and sandwiched in the end of my extension tubes. My tubes have no electronics and as such I have no way to adjust the aperture in the lens. I started with a 1/8" hole but was getting vignetting. I know there are all kinds of formula for choosing your aperture but I just have to guess and see what looks good without causing too much diffraction. How do all the formula take into account things like reversing rings and extension tubes? It seems like each configuration would need a different formula.

Also, lighting is a bit of an issue. The only reliable flash I have is on top of my camera. When I use that I need to bounce it. Otherwise I use LEDs shining through diffusers. I’m reading that this might not be the best because a flash eliminates more motion. I’m not sure which is correct.

I am also reading that a lot of people are using HD screens as their backdrop. I’ve only used a piece of velvet so far but I have a cheap digital picture frame I could use. I guess I could even use my smart phone. Do you have any thoughts?

Do people ever use lighted stages? I guess I could rig something up in that regard and use it in addition to the strobe.

I wish there were others in my area with this as an interest. I’m on my own at this point.

Thanks,
Jessica

[rjlittlefield]

I started with a 1/8" hole but was getting vignetting.

Vignetting means that you have two apertures that are fighting with each other. Edge rays that would get through one are blocked by the other.

When adding an aperture, it works best to mount it as close to the main lens as possible. Check both sides to see which works better.

My tubes have no electronics and as such I have no way to adjust the aperture in the lens.

Reading between the lines, I'm wondering if you have not reversed your lens. This is because a reversed lens has no electronic connection, regardless of whether the tubes do.

When working at magnifications greater than 1X, most lenses give better images when reversed. You still won't be able to adjust the aperture, of course.

How do all the formula take into account things like reversing rings and extension tubes? It seems like each configuration would need a different formula.

The simple formulas generally assume a "thin lens". This is OK for ballpark calculations, but not completely accurate.

An accurate formula must incorporate what's called "pupil ratio" or "pupil factor". You can read about that at FAQ: What is "pupil ratio" and why would I care?

That gives a single formula that is good for all configurations, except that the pupil factor changes depending on where you place the added aperture!

I am not aware of any simple formulas that generally work well with added apertures.

--Rik

[jessbussert]

Hi Rik,

Thanks for the info. I’m surprised to learn that about vignetting. I was under the assumption that the aperture on the lens opened wide up when no power was supplied. As such I would have had a fully open lens paired with a 1/8" cardboard aperture in my first iteration and a 1/4" cardboard one in my second. I’ve got the cardboard one situated right next to the lens at the end of my tubes.

I’m using tubes and a reversing ring for my smallest subjects. I only use the tubes for larger images. I only have two lenses. The one I usually use for macros is a Canon 18-55 kit lens. The second one is a Canon 75-300 kit lens. I’d love to have the funds to spend on better kit but the last time I looked in my purse I heard echoes coming back at me!

I’ll check out the pupil faq.

Thanks for your help!

-Jessica

[rjlittlefield]

I was under the assumption that the aperture on the lens opened wide up when no power was supplied.

Canon lenses normally do open up when no power is supplied. But even when wide open, an 18-55 mm kit lens can have a pretty small aperture, buried deep inside the lens.

Rather than adding an external aperture, I suggest using the trick of stopping down the lens with DOF Preview and then removing it while power is still applied. Sounds scary, works fine. See Shooting with a reversed 18-55 mm Canon kit lens for more info.

--Rik

[RobertOToole]

I was under the assumption that the aperture on the lens opened wide up when no power was supplied.

Canon lenses normally do open up when no power is supplied. But even when wide open, an 18-55 mm kit lens can have a pretty small aperture, buried deep inside the lens.

Rather than adding an external aperture, I suggest using the trick of stopping down the lens with DOF Preview and then removing it while power is still applied. Sounds scary, works fine. See Shooting with a reversed 18-55 mm Canon kit lens for more info.

--Rik

Hi Rik,

You are right, no problem with this technique. This is a time lapse photography trick. Setting the aperture size physically this way, will avoid exposure variation that can occur, even in manual mode!

Robert

[johan]

I am also reading that a lot of people are using HD screens as their backdrop. I’ve only used a piece of velvet so far but I have a cheap digital picture frame I could use. I guess I could even use my smart phone. Do you have any thoughts?

Hello Jessica,

I don't think there are many people that use HD screens - I happen to have used one in the past, but I've since found that the mix between continuous light and flash creates some complications and my advice if you're using flash would be to start out with simple coloured card first, or even something else like modelling clay. Good luck!

[jessbussert]

Great idea about the colored card stock. BTW, I love your images. Someday I hope to be that skilled!
-J