Diatoms New Workflow

Mitch640 · Post by **Mitch640** » Fri Apr 08, 2011 4:31 pm

I found a little puddle up the road here and stopped today with a jar for a sample. It was loaded with diatoms of all kinds and some algae.

I set up the scope to shoot with the flash, camera in manual mode and used the zoom view in EOS Utility to get the best focus I could. I used the 20x Plan Apo exclusively, after centering the condenser. I also cleaned this lens on both ends using some cleaning swabs I got recently.

fpelectronica · Post by **fpelectronica** » Sat Apr 09, 2011 1:30 am

Very nice resolution and focus Mitch
Francisco

Mitch640 · Post by **Mitch640** » Sat Apr 09, 2011 2:23 am

Thanks Francisco. Using the zoom view on EOS Utility seems to be the secret. You can focus with the regular screen, until it looks right on, then switch to zoom view and you see it's still way off. I'll have to do some more testing to make sure that's what the problem was.

Charles Krebs · Post by **Charles Krebs** » Sat Apr 09, 2011 11:53 am

These look very good Mitch.

You can focus with the regular screen, until it looks right on, then switch to zoom view and you see it's still way off.

This is why it is so desirable to have some method for continuous fine adjustment (up/down) of the camera when initially setting up your microscope. If you can do this, you can use the magnified "live-view" to adjust the camera height and make the camera very accurately parfocal with the viewing eyepieces. Once this is done you can confidently achieve very accurate camera focus through the viewing eyepieces. For static (or very slow) subjects focusing off of a magnified live-view screen image is no problem, and very effective. But if you chase active critters around a slide (and use electronic flash), you really do want the camera focus to always be a dead-on match for the viewing eyepieces. In these instances you simply do not have the time to check a magnified screen image.

(And somewhat counter-intuitively, your depth-of-focus... the amount of "leeway" you have at the sensor location... is very much less at low magnifications. So when setting up the position of a camera on a microscope it is best to use a 4X or 10X objective)

Mitch640 · Post by **Mitch640** » Sat Apr 09, 2011 12:30 pm

Thanks Charles. I was able to get it very close, about 1/3 turn of the fine focus knob. But with the equipment I have, using extension tubes, I am limited in how much fine adjustment I have once it is all set up. In other words, I do not have the flexibility of a bellows.

I do have one set of cheap tubes that screw together, and one set of the Kenko brand tubes. I am going to order another set of the screw type, because I can get some adjustment out of the thread connections, and I think it will be enough to get parfocal set perfectly.

Still, with the Fluophot, I am limited to using live view, no matter what. I can not use flash, and look through the oculars to focus on the subject. The trinocular head is 100% eyepiece view or camera view, no half and half. Further, to use the flash at all, I had to take the Halogen lamphouse off the dovetail at the rear of the base and move it to the top rear of the arm dovetail. They are the same size, although one is meant for the halogen light and the other for the mercury vapor lamphouse.

The flash then lays flat behind the open hole where the halogen lamphouse use to be, pointed into the hole. For the halogen lamphouse to work as direct illumination, now that it sits at the back of the arm, I have to flip a mirror in the base into the 'out' position and the DIA/EPI mirror in the DIA position. confused yet? LOL This directs the light of the halogen lamp down the hollow vertical support to another mirror at the rear of the base, reflected forward, through the various filters and up into the condenser and so on.

That mirror at the rear of the base, in the position to direct the light forward, is cutting off the light that the flash will put out. After I focus, using live view, I have to quick, turn that mirror to the in position, flip in a ND filter and get to the mouse in a hurry to push the shutter button in EOS Utility. Phew.

It's all really easier than it sounds, but it still takes two to three seconds to do. It was a real head scratcher to figure out, especially being so new to all this. Once I took the bottom cover off the Fluophot base when I was cleaning it, it became pretty obvious what I had to do.