How to Adjust the Eyepiece and Camera

01:00:15.04 Okay, we're going to talk about eyepieces.
01:00:17.08 So, this is often a neglected part of the microscope. First of all,
01:00:23.10 what often happens is that dirt accumulates on the eyepiece.
01:00:29.04 These are pretty clean in this case, but dirt will definitely
01:00:35.21 make it harder to see things. And so what you want to do is
01:00:40.14 to clean them using an optical tissue, and you don't have to
01:00:47.28 be too anal about it, you can just blow a little bit on them and
01:00:54.19 then wipe off the dirt and just visually inspect to make sure that they're nice
01:01:00.21 and clean. Now something else that is important in the eyepiece
01:01:06.06 is the ability to focus. So each of the eyepieces individually has
01:01:11.21 a very big range, and what you will often find is that they're sitting there
01:01:17.15 in very strange positions. Like one all the way in, the other all the way out.
01:01:23.11 And to your surprise, you'll see that you're actually able to focus with your eyes
01:01:31.29 even in a situation like this. But you will be focusing both eyes differently,
01:01:38.01 and that will not feel very good. And after observing through the microscope
01:01:42.26 for a while, you will feel sick to your stomach. So at the very least, before
01:01:48.25 you start, make sure that the eyepieces are set somewhere in a neutral
01:01:54.23 position. Now then, another issue with the eyepieces is that
01:02:03.16 what you will often encounter, that the image on your camera is not
01:02:09.25 in the same focal plane as the image that you see through your
01:02:13.24 eyepieces. And that is because the camera is focused to slightly a different
01:02:20.23 plane than the image you observe through the eyepieces.
01:02:26.14 In the ideal world, we would have a focusing c-mount, so we would
01:02:31.06 have the ability to move the camera back and forth, so that we can
01:02:36.04 focus the camera directly. But in reality, that is almost never the case.
01:02:41.10 And the only way to now correct for this is to use the eyepiece
01:02:47.15 focusing. So what you want to do is to focus an image on the
01:02:51.29 camera, once it's focused there, you want to take your eyepieces,
01:02:57.12 focus each of the eyes individually, so that it's in the same focal
01:03:01.25 plane as what your camera observes, and from then on, you can just
01:03:06.23 go anywhere and look through the eyepieces and switch to the
01:03:10.28 camera, and have it in focus already. So we're going to do that now.
01:03:14.15 Okay, so I'm now going to first focus the image on the camera.
01:03:21.20 So I use the software, and use the focus define focusing knob,
01:03:27.22 I make sure that my image is more or less focused on the camera.
01:03:34.24 So I now will switch to the eyepiece, and observe it through the oculars.
01:03:43.12 And then each eye individually will find focus.
01:03:54.13 So I'm trying to look at the same part that was observed on the
01:04:04.05 camera there. So I focused the left eye, and now keeping my right eye
01:04:11.18 closed -- sorry, my left eye closed, I'll focus the right eyepiece.
01:04:18.09 And now I'm parfocal with the camera. So at this point in time, wherever I go
01:04:30.17 and then focus, and now switch to the camera, we should be
01:04:41.03 fairly close, if not in perfect focus. And that's exactly what we see.

This Talk

Speaker: Nico Stuurman

Audience:

Researcher

Recorded: April 2012

Talk Overview

When switching the microscope from the eyepiece to the camera, it is useful that the camera is immediately in focus. This video tip shows you how to adjust the eyepiece and camera and shows you how to setup your microscope such that this is the case.

Speaker Bio

Nico Stuurman

Nico Stuurman is a Research Specialist at the University of California, San Francisco, in the lab of Ron Vale. Nico combines his expertise in computer programming and microscopy to advance many projects including the Open Source software, Micro-Manager. Continue Reading