[EN] Focus stacking technique 1

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[EN] Focus stacking technique 1

Postby Gian Luca Agnoli » 02 Feb 2011 18:10

I'm trying to focus on a quick and easy method to make quality images of the species stored in my collection. So, in the past days I've started to experiment with something.

Considering that the final image is the result of the phases of Photo shooting, Focus stacking, and Photo editing, and the time required for each phase is substantial, I have assumed 5 initial conditions:

    the method must be robust and repeatable, with reduced, optimized times for shooting;
    the photo set should be the simplest to mount and adjust;
    the lights should be optimal, but should not affect the agility of the set;
    the background must ensure the best possible result for the subjects and also to minimize the postproduction editing;
    the method must be suitable for all the subjects, whatever their size and reflectance.

Damn! They are a lot of conditions!


1) Photo set
Instead of building a vertical set, I've built a horizontal one, light but strong and easy to move. I have positioned the camera|lens|lamp on a Macro Focusing Rail Slider and the subject on a second rail. Then, again on eBay, I've bought two ring lights for stereo-microscopes, a fluorescent one and a 64-LED one, dimmable.



2) Photo shooting
My EOS 40D camera features a LiveView and a remote capture controlled by the personal computer, so it is possible to preview the images on the computer's monitor in order to check the correct exposure and focusing: this advantage simplifies the job.



The ring lights behave quite well on non-reflective subjects; otherwise they mark an unnatural reflection. Some Chrysidids with sculptured integuments are quite suitable for those lights, while others absolutely no - such as. Chrysis and Chrysura with very smooth cuticle, Elampini, Stilbum, etc.

I have put under the lights a specimen of Hedychridium vachali Mercet, 1915, characterized by a non-reflective cuticle.

However, the two lights used with an automatic white balance, have revealed some differences. With a pure white background the two lights seem to be comparable and only slightly different on some colors:



With a dark gray background the differences become more evident. The LED light seems to reveal better some colors, eg. green on the thorax, while with mixed colors the result is more tricky: the blue-green of the head shifts in the direction of green with the LED light and in the direction of cyan with the fluorescent light; the red of the gaster shifts to magenta with the LED light and to red with the fluorescent light:



Curious the different result of the background: the same dark gray background placed at the same distance is lighter with the LED light, probably due to the fact that its intensity is higher.

In front of the similar results obtained with the white background and the sensibly different ones of the gray background, I've decided to use a white background but a little bit darker and with a rougher surface, in order to avoid an excessive overexposing. Also, I've decided to use the fluorescent light, which is characterized by a more diffused light.

To do things in a good way I've performed a Custom White Balance using a 18% gray card (you take the photo of the card at the working distance and light, then you select the Custom White Balance choosing that photo as reference).

The exposure: 1/30" at F/4.0 and 100 ISO in Manual mode.


3) Postproduction
We have used the stacking software CombineZP to process the image stack, with the standard procedure: New stack > Align and Balance Used Frames > DoStack. After that, we have processed the resulting picture in order to remove the defects (dust and hairs) and to lighten the white background.

Here is the result:

Gian Luca Agnoli - www.chrysis.net
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Gian Luca Agnoli
 
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Name: Gian Luca Agnoli

Re: [EN] Focus stacking technique 1

Postby AlfredoCortez » 27 Aug 2013 07:49

Gian Luca Agnoli wrote:I'm trying to focus on a quick and easy method to make quality images of the species stored in my collection. So, in the past days I've started to experiment with something.

Considering that the final image is the result of the phases of Photo shooting, Focus stacking, and Photo editing, and the time required for each phase is substantial, I have assumed 5 initial conditions:

    the method must be robust and repeatable, with reduced, optimized times for shooting;
    the photo set should be the simplest to mount and adjust;
    the lights should be optimal, but should not affect the agility of the set;
    the background must ensure the best possible result for the subjects and also to minimize the postproduction editing;
    the method must be suitable for all the subjects, whatever their size and reflectance.

Damn! They are a lot of conditions!


1) Photo set
Instead of building a vertical set, I've built a horizontal one, light but strong and easy to move. I have positioned the camera|lens|lamp on a Macro Focusing Rail Slider and the subject on a second rail. Then, again on eBay, I've bought two ring lights for stereo-microscopes, a fluorescent one and a 64-LED one, dimmable.

2011_01_20_7528.jpg


2) Photo shooting
My EOS 40D camera features a LiveView and a remote capture controlled by the personal computer, so it is possible to preview the images on the computer's monitor in order to check the correct exposure and focusing: this advantage simplifies the job.

remote_live_view.png


The ring lights behave quite well on non-reflective subjects; otherwise they mark an unnatural reflection. Some Chrysidids with sculptured integuments are quite suitable for those lights, while others absolutely no - such as. Chrysis and Chrysura with very smooth cuticle, Elampini, Stilbum, etc.

I have put under the lights a specimen of Hedychridium vachali Mercet, 1915, characterized by a non-reflective cuticle.

However, the two lights used with an automatic white balance, have revealed some differences. With a pure white background the two lights seem to be comparable and only slightly different on some colors:

confronto_bianco.jpg


With a dark gray background the differences become more evident. The LED light seems to reveal better some colors, eg. green on the thorax, while with mixed colors the result is more tricky: the blue-green of the head shifts in the direction of green with the LED light and in the direction of cyan with the fluorescent light; the red of the gaster shifts to magenta with the LED light and to red with the fluorescent light:

confronto_grigio.jpg


Curious the different result of the background: the same dark gray background placed at the same distance is lighter with the LED light, probably due to the fact that its intensity is higher.

In front of the similar results obtained with the white background and the sensibly different ones of the gray background, I've decided to use a white background but a little bit darker and with a rougher surface, in order to avoid an excessive overexposing. Also, I've decided to use the fluorescent light, which is characterized by a more diffused light.

To do things in a good way I've performed a Custom White Balance using a 18% gray card (you take the photo of the card at the working distance and light, then you select the Custom White Balance choosing that photo as reference).

The exposure: 1/30" at F/4.0 and 100 ISO in Manual mode.


3) Postproduction
We have used the stacking software CombineZP to process the image stack, with the standard procedure: New stack > Align and Balance Used Frames > DoStack. After that, we have processed the resulting picture in order to remove the defects (dust and hairs) and to lighten the white background.

Here is the result:

Hedychridium_vachali.jpg

Very very nice looking technique I must say.. Thanks for sharing it in detailed manner and I will surely implement it in coming days
AlfredoCortez
 
Posts: 1
Joined: 26 Aug 2013 10:26
Name: Alfredo Cortez


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