Surface net & spores-Stemonitis axifera

Walter Piorkowski · Post by **Walter Piorkowski** » Mon Oct 16, 2006 9:06 pm

Nikon type S microscope
Brightfield
40X achromat
10X projection eyepiece
Canon 10D camera

Please see an image of Stemonitis axifera on my post Myxomycetes II on the photomacrography forum.

Thanks
Walt

rjlittlefield · Post by **rjlittlefield** » Mon Oct 16, 2006 10:26 pm

Walt,

Nice image!

I'm confused by this phrase "10X projection eyepiece". I would normally think that 10X means it takes the image cast by the objective and projects it to be 10 times larger at the film/sensor. But that doesn't make sense because the resulting image would be about 200mm diameter, much larger than the camera's sensor.

Can you clarify? What is the scale of this image?

Thanks!
--Rik

Ken Ramos · Post by **Ken Ramos** » Tue Oct 17, 2006 3:09 am

Great image Walt, especially at 400X. I can resolve them at 400X quite well but usually I have to use my 100X oil to get any really good detail of the S. axifera spores or any others for that matter but then again it also depends on the size of the spores. I have tried moist chamber cultures in the past to propagate plasmodia and fruiting bodies but have failed miserably and have only ended up with a dish of white fungi.

However my passion for these little guys overrides my failures and I continue to experiment with the culture chambers. At present I have constructed a terrarium in hopes of bringing about fruitification of spores by that means.

beetleman · Post by **beetleman** » Tue Oct 17, 2006 5:11 am

Nice shot Walt. Is the surface net just a holding structure until the spores ripen and get dispersed? Ken, make sure you keep a good lid on your terrarium. Remember what happened in the old movie "THE BLOB"

Walter Piorkowski · Post by **Walter Piorkowski** » Tue Oct 17, 2006 2:23 pm

Oops, I forgot to mention the relay lens. Any way Rik my setup is nothing out of the ordinary for for my 1970 vintage Nikon.

Above the trinocular head is the 10X projection or photo-eyepiece and then a 1/2X relay lens above it in the CFM unit that contains a focusing and composition eyepiece. Its onto the film plane from there.

As far as the scale here is a stage micrometer image shot that day at 10 micrometers per division.

As for for you Doug you are partially correct on the surface net holding the spores. It also acts as the superstructure to support the entire dried sporangium which is somewhat special to Stemonitis although other species retain some integrety after the spores are all gone. On some species the capillitium and spores are so tightly packed that only the base remains after spore dispersal. These capillital elements which Stemonitis does not possess are facinating in their own respects for their variety.

To help you see this point I have 2 images of Stemonitis splendens that show the dried, almost spore free remains, now mostly the surface net and a low magnification view of the same under the microscope. Ken should enjoy these as well.

Stemonitis splendens

Flattened tip of net with spores.

And finally Ken I am most impressed with yor plasmodium petry dish experiment. I may try that some day if I get to retire. I think I have used up my posting of images rights today if I understand the rules so some other time I will resond to your, me having all the fun post, with some plasmodium images in the field.

Regards to you all,

Walt

Ken Ramos · Post by **Ken Ramos** » Tue Oct 17, 2006 3:20 pm

Thats some set up there Walt, needless to say, I envy you

Some great shots of S. axifera and the capillitium

Believe it or not Doug, that thing did get out once but did not stay out for long. They do some strange stuff, I have been wanting to put one in a maze and watch it navigate towards some food, an article I read several months back said that the plasmodium does exhibit some sort of pseudo-intelligence.

rjlittlefield · Post by **rjlittlefield** » Tue Oct 17, 2006 8:18 pm

Walt,

As Ken said, that's some setup!

Pardon my head-scratching, but I'm still trying to figure out how this all goes together.

As I count, the stage micrometer shows about 125 microns across the frame. But I'd expect the frame width of a 40X objective to be more like 400 microns, assuming an eyepiece field diameter of 20mm projected to just fill a frame having 3:2 aspect ratio.

I'm guessing the cause is that your eyepiece and relay lens are conspiring to make the projected field something like 3 times bigger than the 22.7 x 15.1 mm of the Canon 10D's sensor.

In any case, with a 125 micron field width, the apparent magnification of your images is more like what I'd expect from a 120X objective, if there is such a thing. Looking at it another way, your image physically measures 175 mm wide on my screen, and 175 mm / 0.125 mm = 1400X. So it seems like you're getting quite high magnification, but of course at only the NA of your 40X objective, whatever that is.

Have I done something wrong here? Or does your camera actually record only about 1/3 of the field width that's visible in the normal eyepieces?

Thanks,
--Rik

PS. I really like that low-mag shot of the nearly empty fruiting bodies. The lighting does a great job of showing off the transparency of the remains.

Edit to clarify "eyepiece field diameter of 20mm".

Charles Krebs · Post by **Charles Krebs** » Wed Oct 18, 2006 8:37 am

Walt... you and Ken are going to make me look at some new subjects I have disregarded so far! Very nice.

Rik... When I moved the the current Olympus stand I am using I needed to "re-think" my relay optics. To make sense of it all I put together this spreadsheet:
http://krebsmicro.com/relayDSLR/relay_micro.xls
It's kind of interesting to play around with. It also shows how it is not that easy to come up with the properly "corrective" eyepiece to put an image on the "smaller" digital sensors (when using lens-less camera bodies). In the days when most of our microscopes were made 4x5" or Polaroid was the "norm", and the 35mm frame size was about as small as anyone used.

rjlittlefield · Post by **rjlittlefield** » Wed Oct 18, 2006 9:32 am

Charlie,

That's a nice spreadsheet! I'm encouraged that it matches my recent experiences with microscope objectives used as macro lenses (equivalent to Relay Magnification = 1). For example the spreadsheet shows that pixel size required to catch all the resolvable detail from a 20X NA 0.4 objective is 8.4 microns. My camera's pixels are actually about 30% smaller than that, and sure enough I can shrink my images by 20% but not 50% without losing detail.

--Rik

Walter Piorkowski · Post by **Walter Piorkowski** » Thu Oct 19, 2006 3:37 pm

Rik, You seem to be a number crunching sort of fellow which I certainly am not. How I approach this business is simply to darken the room, take a good piece of ground glass and hand magnifier and place the glass were the film plane will be. Moving the glass higher increases the size of the image. Back when I took these shots I was just experimenting this way to get a sharp image that wasn.t too large in diameter. If I remember correctly the image circle on the ground glass was possibly 2 inches in diameter.

Don't always believe the power value on a eyepiece. I'ts the focal lenght that counts. Sorry have to run for now. Hope this helps.

And Charles if you are going to start imaging myxomycetes I will have to get all my images in quick because no one will want to look at mine anymore.

Walt

rjlittlefield · Post by **rjlittlefield** » Fri Oct 20, 2006 1:16 am

Walter Piorkowski wrote:Rik, You seem to be a number crunching sort of fellow ... Sorry have to run for now. Hope this helps.

Dang -- busted!

I think I've got a clear enough understanding now. Thanks for the additional info.

--Rik