Random Micros

Ken Ramos · Post by **Ken Ramos** » Mon Mar 12, 2007 6:46 pm

Mayorella

Distigma proteus w/diatom

A Tail of Shattered Dreams (Shattered diatom w/nematode tail)
All Images:
Sony DSC-P200
Manual mode
1/100 sec. @ f/2.8 ISO 100
Zeiss Axiostar Plus (40X/0.65 CP Achromat)
Oblique Halogen w/18mm stop off center

ralfwagner · Post by **ralfwagner** » Tue Mar 13, 2007 11:13 am

Hello Ken,

I like the first picture best, amoebas are one of my favourite critters

.
It looks very sharp, I suppose due to that "Oblique Halogen w/18mm stop off center". Is it a special method for oblique illumination? What does that "stop off center" mean?

Ken Ramos · Post by **Ken Ramos** » Tue Mar 13, 2007 3:04 pm

Hi Ralf

The 18mm stop is about the size of a US dime (10 cents), is a piece of black electrical tape cut out in a circle using the dime as a pattern to go by. The dime sized "stop" is placed in the center of a very light blue glass filter and placed in the the filter tray of the scope. By opening the condenser iris fully and then adjusting the Kholer iris for contrast, you can move the stop just slightly off center from the beam of light coming through the condenser, this is what gives the oblique effect. With the stop dead center of the condenser and the iris's fully open, you have of course, darkfield illumination. Thanks Ralf

Charles Krebs · Post by **Charles Krebs** » Wed Mar 14, 2007 9:40 am

I must say Ken, you use that little piece of electrical tape to good effect. As I have said several times before, I find oblique brightfield to frequently be more "photogenic" then regular brightfield.

Hairyduck · Post by **Hairyduck** » Wed Mar 14, 2007 10:05 am

Great photos Ken, I'm amazed by the amount of diatoms etc in my fish tank mulm, such fascinating geometry, hopefully I'll get some nice pics too in the non to distant future!

beetleman · Post by **beetleman** » Thu Mar 15, 2007 1:17 pm

Some really great photos Ken. I like the first one also. It has some great detail for an amoeba. Are you going to try and put the 30D on your scopes for a trial run???

Ken Ramos · Post by **Ken Ramos** » Thu Mar 15, 2007 5:00 pm

That 18mm round piece of electrical tape sure does do the trick I think, especially if you can't afford DIC stuff there Charlie

. There is a guy over in the Yahoo Group of microscopist who asked permission to use that last image in a web article that he is putting together. Some sort of diffused contrasting or something like that I believe. Keith Shaw is the gentlemans name if I am not mistaken, anyway I gave my permission for him to use it.

Kev, I once kept a fish tank just for the purpose of raising diatoms and protozoa, however, I had little luck with the protozoa but the diatoms, desmids, and other algae took off like a rocket, as did cyanobacteria. I used a fluorescent bulb for illumination and took my water, about 2.5 gallons from a creek, and a few rocks and sand to start the aquarium with

.

As for putting that 30D on the scope...nayh

I got other plans for that Doug

, like a set of Kenko extention tubes and possibly a macro ring flash here in the near future. Now the thought of the 20D on the Axiostar did cross my mind though but I would want to set it up like Charlies rig. Although adapting a flash unit to the Axiostar may present an engineering problem or two. Prowled around Zeiss to see if they had one especially made for thier scopes but as yet no such luck in finding one.

Thanks Guys