eyes

Images taken in a controlled environment or with a posed subject. All subject types.

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mawyatt
Posts: 2497
Joined: Thu Aug 22, 2013 6:54 pm
Location: Clearwater, Florida

Post by mawyatt »

Adalbert,

Beautiful images indeed :D

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

JH
Posts: 1307
Joined: Sat Mar 09, 2013 9:46 am
Location: Vallentuna, Stockholm, Sweden
Contact:

Post by JH »

I like the pictures!

Sometimes polarized light through the lens - EPI light - can control the reflections.

I have also tried to have a circular polarizing camera filter between the lens and the subject - if you turn it the right way it will block al reflections, test on a mirror or a piece of aluminium foil and you can see it turn black. It gave a strange looking light – here is an old example with diffused light, circular polarizer and a 4x objective:

http://www.photomacrography.net/forum/u ... mmad_2.jpg

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

Adalbert
Posts: 2427
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi All-Ex,
do you use any big surface for diffusion?
mostly the medical-diffuser:
http://www.photomacrography.net/forum/v ... highlight=

the special one with the LED-ring:
http://www.photomacrography.net/forum/v ... highlight=

and for the small magnifications the double one :
Image

BR, ADi

Adalbert
Posts: 2427
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi Mike,
Thank you for the comment. I’m glad that you like it.
BR, ADi

Adalbert
Posts: 2427
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi Jörgen,

Many thanks for the link!

Usually I illuminate with 4 * YN660, so it is difficult to use the pol.-filters :-(
Maybe a pol.-foil?

BR, ADi

Beatsy
Posts: 2105
Joined: Fri Jul 05, 2013 3:10 am
Location: Malvern, UK

Post by Beatsy »

Adalbert wrote:...mostly the medical-diffuser:
http://www.photomacrography.net/forum/v ... highlight=

the special one with the LED-ring:
http://www.photomacrography.net/forum/v ... highlight=

and for the small magnifications the double one :
Image

BR, ADi
You've got some pretty large, unlit "dark disks" sitting in front of your specimens there - and little light emanating from in front of the specimen. That's the main cause of your "hex nuts" IMO. While you'll never get rid of the reflection of the objective completely, I think you can improve it enough so it's not an issue in your pictures (i.e. banish the hex nuts).

Here's some very quick snaps of one of my diffusers. It works well for mags from about 2x up to 10 or 20x (after which I move to just a ping-pong ball diffuser). The tube part is 4 layers of tracing paper separated by 1mm - double sided tape providing the spacing. It is a bit light-hungry, so I plan to make another with 3 layers and 2mm spacing. just waiting on the tape...

The front is just over half a ping pong ball with a small hole cut for the objective/lens to look through. Size determined empirically. The half ball was split and "stretched open" to attach to the inside walls at the front of the tube. This has the effect of flattening the hemisphere too, so more of it is facing the front of the specimen. For low mags (long working distances) the specimen sits quite far back in the tube (usually on a pin). At higher mags it has to be closer to the ping pong ball at the front, but that's fine as that helps with getting more light on the subject. The black disk stops stray light bouncing off the ping pong ball and back into the lens (not an issue for mitties, but causes veiling flare with my scanner lenses).
Image

Here's the diffuser on a stand (metal strip glued to it and a magnet on the end of the Noga strut). Any number of lights can be shone on it, and by pointing them at different areas of the diffuser you get a lot of control over the lighting effects and shading. In this pic, the lights are aimed to hit the ping pong ball (behind the black disk) and bleed a little over onto the side wall of the tube.
Image

And finally, a close crop of a fly I did recently with this diffuser (only 2x). I think the eyes look OK - at least not "hexnuttish".
Image

Maybe exploring options like this might help out?

Edit: I should add that this was my first "prototype" of this design (bodge), but it worked well enough to keep on using it :) I intend to stick some white paper over the the black disk that shows from the specimen side to further reduce the dark areas in front of the specimen. And the hole in the disk is 16mm diameter. This causes slight corner vignetting with my lower power scanner lenses on full frame, but since the lenses vignette a tiny bit too - it's not an issue.

Adalbert
Posts: 2427
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi Beatsy,
The tube part is 4 layers of tracing paper separated by 1mm - double sided tape providing the spacing.

That is a very interesting idea!
I have already tried with 2 layers-tube of the tracing paper separated by 10mm covers of the cream.
But my problem was the flexible mount. The background part was a tube from the flocked light trap from Protostar as inside of my rocket:
http://www.photomacrography.net/forum/v ... highlight=

BR, ADi

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