Marine amphipod crustacean (Gammarus?)

Charles Krebs · Post by **Charles Krebs** » Wed Sep 07, 2016 8:55 pm

The post I made yesterday (jelly larva and fish egg) was notably lacking in color. But today I'm really going in the other direction. My net sample provided a couple amphipods (genus Gammarus I think), often commonly referred to as "scuds". Not all that colorful in regular light, they become almost psychedelic when you put them between crossed polarizers and throw in a wave plate for good measure. Below I start with the straight brightfield shot to give you an idea of the actual appearance. Then I start playing with crossed polarization and a 560nm full wave plate.

These were all taken using the MM-11/Oly hybrid scope, and the Olympus MPLFLN objectives (5X 10X 20X 50X).

Jacek · Post by **Jacek** » Wed Sep 07, 2016 9:46 pm

Amazing, great pictures

GaryB · Post by **GaryB** » Thu Sep 08, 2016 5:34 pm

Holy mole, these are amazing!

Dang you have a great eye for this stuff.

Johann · Post by **Johann** » Thu Sep 08, 2016 10:44 pm

Amazing - looks like paintings!

hkv · Post by **hkv** » Thu Sep 08, 2016 10:56 pm

Amazing work! What was the retardation of the wave plate?

Jacek · Post by **Jacek** » Thu Sep 08, 2016 11:18 pm

Charles, how to mount a polarization in his microscope?

fpelectronica · Post by **fpelectronica** » Fri Sep 09, 2016 10:11 am

zzffnn · Post by **zzffnn** » Fri Sep 09, 2016 10:54 am

Very beautiful!

carlos.uruguay · Post by **carlos.uruguay** » Fri Sep 09, 2016 10:56 am

Excellent

Charles Krebs · Post by **Charles Krebs** » Fri Sep 09, 2016 10:08 pm

Thanks for the kind remarks.

hkv wrote:Amazing work! What was the retardation of the wave plate?

Jacek wrote:Charles, how to mount a polarization in his microscope?

hkv,
It was this 560nm full wave plate:
http://www.knightoptical.com/stock/opti ... 0mm-560nm/

Jacek,
For the upper polarizer I used one from my vertical illuminator (BH2-UPO-NIC) and placed it into the slot shown in the picture. It is a little smaller than the slot but by adding a couple layers of tape to each side it fits pretty well. This one is really nice to use because the wheel rotates the polarizer 360 degrees.

For the lower one I had made up an "illuminator" to fit under the Zeiss stage that I use. It was made from one of those right-angle "spy" attachments. I added a diffuser and diaphragm to the top. I simply lay a polarizing filter over the top when desired. I lay the retardation plate over the polarizer. By placing a "spider" stop on top I can also get darkfield up to 20X. (I shine a light or flash in from the side.)

RogelioMoreno · Post by **RogelioMoreno** » Sat Sep 10, 2016 7:45 am

Charlie,

Beautiful set!

Rogelio

Saul · Post by **Saul** » Sat Sep 10, 2016 11:06 am

Charles, thanks for the information, great setup !

I added a diffuser and diaphragm to the top

What are benefits of the more diffused light in this case and diaphragm ?
Can be bottom polarizer rotated instead top one ?

Sumguy01 · Post by **Sumguy01** » Sat Sep 10, 2016 11:24 am

WOW!
Amazing.
Thanks for sharing.

Charles Krebs · Post by **Charles Krebs** » Sat Sep 10, 2016 2:43 pm

Thanks again!

Saul...
I opted for this arrangement for my lighting as opposed to conventional condensers because of the huge versatility it affords with the varied subject matter I deal with on this microscope. (Keep in mind that I primarily use LWD "M" type objectives from 4X to 20X... with an occasional 50X. Higher powers would need a more conventional approach.) The diffuser (a piece of Lee diffusion material, removable if desired) along with the diaphragm lets me do brightfield in a manner not unlike the old Zeiss Lucigen. (See this article: http://www.microscopy-uk.org.uk/mag/ind ... cigen.html ). Instead of raising and lowering the unit as with the Lucigen, I can simply adjust the aperture size. I can also "offset" the aperture in relation to the subject to get a nice oblique effect. I really like the "look" of the darkfield and brightfield that I get with it, especially at the low magnifications (2X-10X). Nice even darkfield is normally kind of tricky to do with 2-5X on a compound microscope.) This just gives a slightly different look, hard to describe. Depending on the condenser or method used, darkfield in particular can have a sort of "harsh" look to it. This provides, for lack of a better term, a pleasing "soft" darkfield.

The bottom polarizer could be rotated if desired. (You would want a handle on it unless you had extremely skinny fingers

)

This thing sort of fits in with the whole philosophy I had when putting this scope together. It was for low to modest magnifications of a very wide variety of subjects, many of which (but not all) would be primarily illuminated from above. So I start with a large blank base, plenty of room and adjustment capability, and add lighting and positioning components as the subject and imaging intent dictates. It's been a lot of fun to use. I like the results, and it satisfies a certain desire to constantly "tinker" and experiment.

Saul · Post by **Saul** » Sat Sep 10, 2016 4:31 pm

Charles, thank you very much for your very detailed information !

Looks like I have all needed parts, except the retardation plate (will try cellophane or something similar). I'm using old Labophot base without condenser, so no need for the right-angle "spy" attachment

Are these retardation plates OK ?
http://www.ebay.com/itm/5-NEW-Mica-1-4- ... cl6MpgwACg