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Author Topic:   Decisions, decisions......
Tanypteryx
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Posts: 1549
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.3


Message 46 of 56 (808819)
05-13-2017 11:27 AM
Reply to: Message 45 by NosyNed
05-12-2017 10:09 PM


Re: Focus Stacking
I am under the impression that you use some sort of rail to little tiny bit by little tiny bit move the camera to change the plane of focus.

Yes, I use a device called a Stack Shot, made by an outfit called Cognisys. It has a stepper motor that can very precisely move the camera in steps down to 1 micron.

STACKSHOT - AUTOMATED MACRO RAIL FOR FOCUS STACKING

But it seems to me that would change the magnification of some part of the subject as you moved closer to it. If that is the case how can software assemble that into a correct image?

Yes that is true and in the early days when I started experimenting with this technique the software was quite limited. It took a lot of post processing to get a decent image. The limitations were pretty frustrating.

Another frustrated stacker, who is a math wizard and a programmer started creating a program to address all of the problems encountered in processing stacks. I was one of his beta testers and he created an absolutely amazing program that has been very successful. The program, Zerene Stacker, aligns and resizes all the images in the stack and then builds a composite.

Some subjects will always have problem areas that the program cannot decide how to process. Specimens where there is spatial separation between features, for example head features with antennae above and legs below. The features would be sharp in different sections of the stack and an affect called diffraction allows you to see features that are directly below those that are out of focus.

Zerene has a very useful retouching tool that lets you paint from any layer in the stack to fix stacking flaws. It also has a module that lets you control the Stack Shot including setting the step size.

At high magnification depth of field is extremely shallow, so some of my stacks take 500 or more separate images to show the features I want.

As with all photography lighting is the key. Very small subject introduce their own issues with lighting. Most of us use various diffusion and reflector materials to avoid blown highlights and shadows with no details. Some people use continuous light sources, but I prefer electronic flash.

Edited by Tanypteryx, : No reason given.

Edited by Tanypteryx, : No reason given.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


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Tanypteryx
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Posts: 1549
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.3


(1)
Message 47 of 56 (809834)
05-21-2017 1:27 PM


This is the head and thorax of a male Chironomid midge, species ID unknown.

This stacked composite is my first tests of some new electronic flashes. I fried 2 of my old standby Nikon flahes so had to get some cheapie replacements.

The composite took 350 stacked images. Shot through my Mitutoyo 10x objective.

I wonder what sorts of molecules these antennae evolved to detect? The females do not have all the fine setae (hairs) on their antennae and normally in cases like this the females produce pheromones that the males can detect and track from long distances. The pheromones of some insect species are used in lures for sampling traps. A common one you may have seen is used in commercial Yellow Jacket traps.

This is probably the last stacked shot I will have time for before I leave on my road trip to Virginia. A new road trip


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


    
Tanypteryx
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Posts: 1549
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.3


(3)
Message 48 of 56 (815068)
07-15-2017 4:05 PM


This is a male Pachydiplax longipennis. I am trying to develop a technique to photograph dragonfly eyes that shows the optical effects of the individual ommatidia (facets). I can see this in normal photos but the high magnification extended depth of field shots show surface details but not the internal "glow" caused by the lens in each ommatidia.

Note that eyes are divided into 2 different sizes of ommatidia, larger on the upper eye and smaller looking down. It is thought that the smaller ones provide finer resolution eyesight. The upper ones provide keen enough eyesight to spot very small prey and I have seen dragonflies suddenly fly straight up to investigate other dragonflies that are so high that I could not see them unaided. Binoculars were necessary to see them at all.

Dragonflies not only have incredibly keen eyesight in almost every direction, but they can process the visual information at very high speed considering the acrobatic maneuvers during high velocity flight.

Enjoy.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


    
Tanypteryx
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Posts: 1549
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.3


(4)
Message 49 of 56 (816006)
07-27-2017 6:52 PM


Another male Pachydiplax longipennis male, anterior head.

Imagine all that visual information being processed during high speed flight maneuvers.

This is a male Sympetrum illotum.

I have been experimenting with my lighting this week. These were both shot with a single diffused flash and a reflector.

Enjoy


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


Replies to this message:
 Message 50 by jar, posted 07-27-2017 7:46 PM Tanypteryx has responded
 Message 51 by New Cat's Eye, posted 07-27-2017 7:49 PM Tanypteryx has responded

    
jar
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Posts: 29180
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.8


Message 50 of 56 (816010)
07-27-2017 7:46 PM
Reply to: Message 49 by Tanypteryx
07-27-2017 6:52 PM


In the top picture. What is the difference between the upper larger eye spots and the smaller lower eye spots?

My Sister's Website: Rose Hill Studios My Website: My Website

This message is a reply to:
 Message 49 by Tanypteryx, posted 07-27-2017 6:52 PM Tanypteryx has responded

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New Cat's Eye
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Posts: 11639
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.5


Message 51 of 56 (816011)
07-27-2017 7:49 PM
Reply to: Message 49 by Tanypteryx
07-27-2017 6:52 PM


Imagine all that visual information being processed during high speed flight maneuvers.

What do you know about their brains?

I question it being "all that" information If each lense is just detecting a 1 or a 0, then it wouldn't be that much info in total. Prolly less than just two eyes that can distinguish over a range of hundreds of nanometers of wavelengths each.

But I'm guessing.


This message is a reply to:
 Message 49 by Tanypteryx, posted 07-27-2017 6:52 PM Tanypteryx has responded

Replies to this message:
 Message 54 by Tanypteryx, posted 07-27-2017 11:23 PM New Cat's Eye has responded

  
New Cat's Eye
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Posts: 11639
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.5


Message 52 of 56 (816012)
07-27-2017 7:52 PM
Reply to: Message 50 by jar
07-27-2017 7:46 PM


What is the difference between the upper larger eye spots and the smaller lower eye spots?

Their diameter


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Tanypteryx
Member
Posts: 1549
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.3


Message 53 of 56 (816014)
07-27-2017 10:35 PM
Reply to: Message 50 by jar
07-27-2017 7:46 PM


What is the difference between the upper larger eye spots and the smaller lower eye spots?

In Message 48 I commented about this:

quote:
Note that eyes are divided into 2 different sizes of ommatidia, larger on the upper eye and smaller looking down. It is thought that the smaller ones provide finer resolution eyesight. The upper ones provide keen enough eyesight to spot very small prey and I have seen dragonflies suddenly fly straight up to investigate other dragonflies that are so high that I could not see them unaided. Binoculars were necessary to see them at all.

I hope that helps.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


This message is a reply to:
 Message 50 by jar, posted 07-27-2017 7:46 PM jar has not yet responded

    
Tanypteryx
Member
Posts: 1549
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.3


(2)
Message 54 of 56 (816016)
07-27-2017 11:23 PM
Reply to: Message 51 by New Cat's Eye
07-27-2017 7:49 PM


Imagine all that visual information being processed during high-speed flight maneuvers.

What do you know about their brains?

Insects have pretty simple brains compared to, for example, mammals, but observations in the field indicate that dragonflies and damselflies engage in complex behavior that is dominated by eyesight.

Dragonflies know where moving objects will go, just like us

This is an active area of research right now to understand how seemingly simple neuro-nets can be programmed for complex behavior.

I question it being "all that" information If each lense is just detecting a 1 or a 0, then it wouldn't be that much info in total. Prolly less than just two eyes that can distinguish over a range of hundreds of nanometers of wavelengths each.

Each ommatidium (facet) has a lens that projects a focused image at the base where pigment molecules called opsins activate a nerve. So, rather than a single image being projected by a lens on a retina of rods and cones the each sees a small portion of the whole image, dragonflies have thousands of narrow-angle images being focused on the light sensitive receptors.

The light sensitive opsins are activated by light in distinct wavelength ranges. Humans have 3 opsins and very rarely 4 that determine the full wavelength range we can detect and what colors we perceive.

Dragonflies have 13 or more opsins and can see a wider range of wavelengths and that range is divided into more discrete bands of wavelengths than humans see.

I will try and find a link to a very interesting paper on recent research into dragonfly eyesight that explains a lot of these discoveries. I had to move a bunch of papers off my laptop on my roadtrip to make room for photos.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


This message is a reply to:
 Message 51 by New Cat's Eye, posted 07-27-2017 7:49 PM New Cat's Eye has responded

Replies to this message:
 Message 55 by RAZD, posted 07-28-2017 7:38 AM Tanypteryx has acknowledged this reply
 Message 56 by New Cat's Eye, posted 07-28-2017 12:04 PM Tanypteryx has acknowledged this reply

    
RAZD
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Posts: 18855
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.5


(1)
Message 55 of 56 (816035)
07-28-2017 7:38 AM
Reply to: Message 54 by Tanypteryx
07-27-2017 11:23 PM


The light sensitive opsins are activated by light in distinct wavelength ranges. Humans have 3 opsins and very rarely 4 that determine the full wavelength range we can detect and what colors we perceive.

The result of our heritage from a nocturnal primate, that didn't need many opsins

Each ommatidium (facet) has a lens that projects a focused image at the base where pigment molecules called opsins activate a nerve. So, rather than a single image being projected by a lens on a retina of rods and cones the each sees a small portion of the whole image, dragonflies have thousands of narrow-angle images being focused on the light sensitive receptors.

Dragonflies have 13 or more opsins and can see a wider range of wavelengths and that range is divided into more discrete bands of wavelengths than humans see.

It would seem that the compiled image would be very free of distortions typical of wide angle single lenses, they must get a pretty accurate globular view of the world.

Enjoy


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This message is a reply to:
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New Cat's Eye
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Posts: 11639
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.5


Message 56 of 56 (816056)
07-28-2017 12:04 PM
Reply to: Message 54 by Tanypteryx
07-27-2017 11:23 PM


That's fascinating, thank you. Looks like I guessed wrong
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