Optical aberration or a possible stack artifact?

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rjlittlefield
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Post by rjlittlefield »

cmagno wrote:The only disadvantage I see in the immediate is that this technique is more suited to a vertical setup, which is not my case.
You might try adhering a cover slip to the amber with a thin film of oil. With a bit of fiddling, that should be doable even with a horizontal setup.

--Rik

cmagno
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Post by cmagno »

rjlittlefield wrote:You might try adhering a cover slip to the amber with a thin film of oil. With a bit of fiddling, that should be doable even with a horizontal setup.
A suggestion with an interesting challenge. I will definitely experiment.

Thanks and best regards,
Carlos Magno

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Post by JH »

I use vertical set up, mostly a microscope for my amber pictures. The deeper into the amber the insect is the larger the problems. I have a post with pictures that shows the differens between water, glycerol and oil; 
http://www.photomacrography.net/forum/v ... 565#163565

Glycerol or microscope oil can be verry usefull. I have one badly polished piece of amber that is more or less impossible to examine witout a drop of glycerol or microscope oil. But I am not sure If there are any long term effects from microscope oil on amber.

Do not use oil or anything else if the amber surface is not intact. One piece of amber that I have is so well polished that one of the leggs goes through the surface. I will not use any type of liquid on that.

My suggestion is that you use a lens with a lower NA, and a drop of glycerol or microscope oil to even out any scratches on the amber surface.

Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

cmagno
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Post by cmagno »

Hi Jörgen Hellberg
JH wrote:I use vertical set up, mostly a microscope for my amber pictures. The deeper into the amber the insect is the larger the problems. I have a post with pictures that shows the differens between water, glycerol and oil; 
http://www.photomacrography.net/forum/v ... 565#163565
Thank you for sharing your work.
The images with different liquids are very instructive.
There is no doubt that immersing amber into denser liquid has a positive impact on image quality.

The way I found to reduce the NA on the lenses I have is to use an iris, and in fact, it is thus possible to reduce the effects.

In your experiments, you used any specific lens to shoot through more dense medium? More precisely, what lens was used in the test photos?

Best Regards,
Carlos Magno

JH
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Post by JH »

cmagno wrote: More precisely, what lens was used in the test photos?
I use the Nikon 160/- 4 /0,13 W. This is more or less a 4x lens with a black plastic cone with a cover slip at the top of the cone. The 4x W objective was easy to find some years ago. I remeber a thread about this objective but I can not find it.

Any way, I think that if you follow the advise above from Rik; "adhering a cover slip to the amber with a thin film of oil." the result  with your Lomo 3.7x NA 0.11 will be similar to my resultas with the Nikon 4x W.

Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

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