Trouble shooting butterfly wing scales

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ranstice
Posts: 10
Joined: Wed Mar 12, 2014 1:30 pm

Trouble shooting butterfly wing scales

Post by ranstice »

This photo is not good but it displays the lighting trouble I am having. In order to not overexpose the light scales everything else is very underexposed. I still get light haloing around some of the light scales. I have tried adjusting the flash intensity and direction, as well as turning off the continuous lighting, and just using the flash. This setup uses an Olympus LMPlanFL 20x/0.40 BD ∞/0 2 microscope objective on a Canon 80-200 lens on a canon 5Dsr. I am looking for some lighting guidance on how to correct this haloing or reflection. I use 3 Ikea Janko lights (name spelling may be wrong) as well as a Canon MT-24EX Macro Twin Lite Flash.

I stacked 40 images in Zerene.
Image

Image

AdminCS edited title/moved thread

Chris S.
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Post by Chris S. »

Ranstice,

I've moved your thread from the gallery to Technical Discussions, where you're more likely to get helpful feedback on your issues. I also added a couple words to the title of your post for the same reason.

As a first step, I'd suggest shooting a much deeper stack than 40 images, and make sure your increment between shots is small enough. I'm not certain that all elements of your light-colored scales have in-focus images to stack from. For a similar subject and lens, I'd use an increment of 1.8 microns, and likely shoot 100-200 images (or more, if I also wanted the dark scales in focus).

If that doesn't work, a question: Is this butterfly wing the first subject you've photographed at 20x on your rig? If so, I'd suggest testing your rig with something less problematic than a butterfly wing. My choice would be a piece of paper with fine, tightly-spaced laser printing, cut out and pasted with a glue stick onto a glass microscope slide. Can you take nice, sharp stacks of that?

If so, try further immobilizing your butterfly wing by using the gluestick to paste part of the wing flatly and firmly onto a glass slide. Then mount the slide on something solid and try photographing it again. A butterfly wing glued to a toothpick (as shown in your setup photograph) may move or flex during photography, due to equipment vibrations, air movement, the sound of your flash, or rapid heating/cooling of the black wing scales caused by the light of the flash and imparted by the black scales to the wing.

If you can't get sharp images of a laser-printed target, you may need to make your rig stronger and less susceptible to motion. This seems distinctly possible, because your rig shows aspects that could make magnifications like 20x problematic: Subject appears more susceptible to motion than is ideal; camera rig appears more susceptible to motion than is ideal; camera and subject are not mechanically coupled to reduce impact of subject and camera motions.) To shoot at 20x, you may need a more solid rig. (For, examples, see Example macro rigs).

These thoughts are just a start, but can help you eliminate some of the more common problems. I'm sure other members will suggest good ideas.

By the way--and you likely know this already--when you get this issue fixed, and want to include both the light and dark scales nicely exposed in a single image, you can likely due so by carefully shooting raw. For similar butterfly wings, I shoot raw and overexpose the light scales by about 2.25 stops. Then in my raw development software, I pull the highlights left into the range a tiff file can handle, and pull the shadows right, also into tiff range. Then process from raw to tiff and stack the tiffs. How many stops one can compress dynamic range varies by camera and possibly conversion software, and needs to be determined by testing.

Good luck! :D And please keep us posted as you test things.

--Chris s.

Macro_Cosmos
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Location: Sydney

Post by Macro_Cosmos »

Problems and suggestions at first glance:
1. Remove that battery grip to lower the centre of gravity, you don't need it at all. An L bracket works very well.

2. Your ring flash
It's moving on your stackshot, you want to keep it stationary with respect to the specimen. Either lighting and specimen moves together with camera fixed, or the opposite.

3. Stackshot
What's the plate underneath it? I'd remove that too

4. Tripod?
Is your stackshot on a centre column? I would seek a more stable and fixed setup, search up "photomacrography setup" on pinterest. When you see something you like, you should be able to find the link to it. If not, drag the image into google for a reverse image search.

I recommend vertical setups.

You can use a tripod without centre columns and add a bunch of weight to it. Bottles of water is good. Since lots of us are indoors, I'd assume everyone may have some empty bottles to repurpose.

A very quick and nice setup would be some large wooden cutting board, just mount the stuff on and add weight using bottles of water. Fancier? Get a large slab of marble or granite. At 20x, any vibrations will show.

5. Step size
You quoted 40 exposures. That's far far too little. For your subject, I'm seeing at least 120 exposures.

6. BD Plan
Have you blocked out the internal light path? That can sometimes generate very weird issues, gaffers tape does the trick. I do see what I think is stray light entering your camera. You're using an actual dslr lens, not a specific tube lens so lens tube flocking is out of the equation. I can thus only attribute this to either the BD Plan or lighting issues.

7. Specimen holding
This is why I recommend vertical setups. Vertical shooting allows you to just place the subject on a flat surface, then place the diffuser on top.

If you must use horizontal setups, I'd suggest a foam board. Hold the specimen down using strips of paper and pins. This is how people set butterflies (ie make the specimen open its wings). Mount the foam board on that film duplicator/enlarger looking thingy at the back.

You should start by imaging laser printed text, just to see if everything is working properly or not. The dynamic range issues can be fixed with post-processing. My Z6 allows me to pull the shadows out.

Lou Jost
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Post by Lou Jost »

Also the diffusion of the Janso lights is inadequate. They are so far from the subject that they will look like very small points, from the viewpoint of the subject. The paper does almost nothing because it is too close to the lamp.

MarkSturtevant
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Post by MarkSturtevant »

You have some super heavy hitting advice there, and that particular subject looks like it would be exceptionally challenging. I don't know if this is even a viable idea but here goes.
Could you make two stacked pictures and them merge them again as a 2nd stack? For example, make a stack under settings that show the white scales well, and a 2nd stack under settings that show the dark scales well. Then stack these two again in the stacking program. At this point you would use the touch up tools to combine the best of each. For example 'paint' over the underexposed dark scales with better exposed dark scales.
Mark Sturtevant
Dept. of Still Waters

nernelly
Posts: 13
Joined: Thu Feb 25, 2010 9:12 am
Location: Germany

Post by nernelly »

Hi ranstice,

I suggest you shoot in raw. Then make sure to expose to the right, so much that the jpeg histogram shows serious overexposure, but the raw histogram is still intact. During raw-development reduce the overall exposure, increase shadows and reduce highlights.

ranstice
Posts: 10
Joined: Wed Mar 12, 2014 1:30 pm

Post by ranstice »

Than you for all of the help. I am revamping. Sarting with a granite base on up. When I get there I will post some, hopefully, better photos!

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