stereo hamuli

Charles Krebs · Post by **Charles Krebs** » Thu Jul 07, 2011 10:31 pm

Sometimes everything seems to go wrong when working on a shot. This was an instance. For starters I really messed up the wing trying to get it into a good position... should have quit at that point but I forged ahead and took some images anyway. The single image was not very interesting so I made a stereo run in Zerene Stacker.

This is a subject that is hard to visualize well in 2-dimensions, so I thought I would post the 3-D version. These are the hooks on the leading edge of the hind winds of Hymenoptera. Their function is to hook over a "rail" at the rear of the front wing to couple them together.

rjlittlefield · Post by **rjlittlefield** » Thu Jul 07, 2011 11:33 pm

The hooks are like little screws! I would never have guessed that from the single shots!

Nice capture too of the small bristles sticking up and down from the two faces of the membrane.

--Rik

dennisua · Post by **dennisua** » Fri Jul 08, 2011 4:14 am

Stereos are so cool. I didn't realize at first that hooks look towars me and not away as it seems on single pictures. How do you do stereo with microscope? Take a set of pictures, shift the stage and take another set?

canonian · Post by **canonian** » Fri Jul 08, 2011 6:58 am

Good to hear I'm not the only one having an offday at shooting every once in a while.

And still you manage to make it look great.
Only in stereo you can see it sort of looks like a open spiral, as found on a notepad.
How wonderful are the mechanics of nature. It never ceases to amaze me.

The stereo effect is amazing.
If I may be so bold to ask you, what values did you use here in: "First/Last Image Maximum Shift in X and Y" in Zerene's Preferences ?
These allways puzzles me and I'm never sure how to set this.

René · Post by **René** » Fri Jul 08, 2011 7:05 am

ooff, I had to reduce them considerably before they could fit in my brain. Nice effect though, do you use something special to look at them Charlie??

Thanks, René

rjlittlefield · Post by **rjlittlefield** » Fri Jul 08, 2011 9:42 am

dennisua wrote:Stereos are so cool. I didn't realize at first that hooks look towars me and not away as it seems on single pictures. How do you do stereo with microscope? Take a set of pictures, shift the stage and take another set?

Zerene Stacker allows to make a stereo pair from a single stack. See http://zerenesystems.com/cms/stacker/do ... eticstereo.

--Rik

canonian · Post by **canonian** » Fri Jul 08, 2011 11:01 am

rjlittlefield wrote: See http://zerenesystems.com/cms/stacker/do ... eticstereo

Oops, its all there. Thanks Rik.
RTFM or "Read The Fine Manual"
Is there an optimal value for shift XY ?
Is it better to choose a lot of rocking images at small shift to refine the choice for left/right and create a good looking stereo image?

rjlittlefield · Post by **rjlittlefield** » Fri Jul 08, 2011 11:43 am

canonian wrote:Is there an optimal value for shift XY ?
Is it better to choose a lot of rocking images at small shift to refine the choice for left/right and create a good looking stereo image?

I've tried calculating from theory, but I gave it up because the results didn't seem reliable enough to be worth the trouble.

So as a practical matter, yes, it's better to try a lot of values and see what works best for your situation. Once you find a value, that same value will work well for other similar stacks.

What I usually do is to set Image Pre-sizing to a fairly small value like 25%. That will run a lot faster than 100% while still giving me more resolution than I need to evaluate the separation. Then I'll run a sequence of 11 frames from -5 to +5. When they're done, I'll poke through the set using Stereo > Start Preview until I find a separation I like. If in addition I like the images I already have, then I'll quit. Otherwise I'll change Image Pre-sizing to make bigger images and run two more frames at the separation I liked best, or some intermediate value if I think I can do better. Generally I end up using something around +-3, but it varies by magnification, aperture, and the nature of the subject.

--Rik

Charles Krebs · Post by **Charles Krebs** » Fri Jul 08, 2011 12:09 pm

I see Rik has addressed the details of stereo creation... (far more authoritatively than I could have).

René

do you use something special to look at them Charlie??

Well if it's a hot summer day a couple of Margaritas seem to help.

. Seriously though, no...just basic "cross-eyed" viewing. I realize that some people have difficulty doing this (and some simply seem unable to do so). Initially it required some practice on my part but now it comes quite easily. (I can't freeview "parallel" stereo images. Years ago when I first dabbled with stereo I used a "PokeScope Pocket Stereoscope" for parallel viewing, but I greatly prefer "cross-eyed".)

BTW... here are a few older shots (not 3-D) I have posted of this subject:
here.
here.
here.
...and some 30 million year old hamuli here.