Differential interference contrastmicroscopy

Light path of a polarized light microscope. Note the polarizing filter below the sample and the analyser above the sample which allow discrete polarizations through.

Ensuring the condenser is in the right position is vital for all of these techniques. To perform the correct alignment on the condenser requires a technique called Kohler Illumination, which examples and further explanations can be found here.

Normal white light is unpolarized, however optical elements can filter only one specific polarization as per the image below.

In the images below, the fibers do not appear to have a lot of contrast (a), however when illuminated by darkfield microscopy (b) much more contrast is apparent. In some circumstances you have too much contrast (c) when using conventional brightfield, this can also be improved when using darkfield (d) where less contrast is achieved.

Optical microscope

Funny how such experiences shaped us, growing up! But we got pretty good at solving technical problems. Newer generations…? My daughter, this morning: ”Dad, my TV lost the internet connection. Can you fix it?” And dad does what dads do…

DIC LightPath in an upright microscope. Here the two Nomarski prisms are visible above and below the sample stage. Note in this arrangement there is also a fixed polarizer and attached Quarter wavelength plate which allows you to rotate 90 degrees in the imaging plane.

Lightfield microscopy

Brightfield imaging or transmitted light microscopy usually has very low contrast between signal and background, therefore there are a number of techniques available which will be explained below.

I so wanted to play Strike Commander as a kid, but one of the floppies in my set was unrecoverable bad. I am still grumpy today.

Just find your controller in the columns and double click on the command that you want to change. This opens another window and you press the button, on the controller, that you want to use for this command.

Confocalmicroscopy

In a polarized light microscope a polarizing filter is added immediately after the brightfield light source and an additional polarizing filter is fitted above the sample before the eyepieces or image capture device. The polarizer below the sample is usually adjustable by rotation to select for different polarization angles. See the light path diagram below.

Fluorescence microscope

Virtual flight school. LOL. I went to flight school in my late teens but stopped after my 1st solo cos I couldn’t manage it plus my A level exams. Wasn’t mature enough back then.

I picked up a Chinese brand HOTAS, the PXN-2119 to use with DCS 2.5. So far I’m quite liking the stick, it is pretty sturdy, responsive and accurate. I however have a problem I hope you guys could help me with. On my throttle, there is a 2nd POV hat and two rotary axis, X & Y. I wanted to map these to use for trimming my rudder & elevators and a few other functions. While the device driver recognizes these buttons as POV2 and Rotary X, Rotary Y, I can’t find these options in the DCS 2.5 key bindings options. All my buttons on my stick and throttle are recognized but not these 3. Does anyone use this stick or know of a work around? I’m still practicing with the TF-51 and SU-25. Planning to get the P51 and FC3 once I’ve proficient with the basics.

Darkfield microscopy is a technique to increase contrast in your image when the refractive index of your sample very closely matches the refractive index of your imaging media. The technique works by blocking the light that comes directly onto the sample, and instead relies solely on stray rays of light to illuminate the sample from the image border.

Phase contrastmicroscopy

As light passes through the sample where small changes in refractive index occur (eg the presence of cellular membranes) the two polarizations will be affected, and hence the interference will change, altering the resultant image.

A cut-away of the light path of a phase contrast upright microscope. The condenser annulus is visible below the condenser which only allows through one phase of light. Above the sample plane the phase plate (or sometimes called phase ring) blocks one specific phase of light, and lets through any light that has been refracted by the sample.

Polarized light microscopy is a contrast enhancing technique that improves resultant images where the sample being imaged has birefringent properties. This technique is often used for materials science, however can be very useful for some biological applications.

Thanks guys!!! I managed to figure it out. Assigned the various additional axis. will have to adjust the sensitivity later as a slight twist of the rotary sends my trim all the way to each end. Sure way to crash out. The POV2 buttons though aren’t yet assigned. I don’t see the POV2 buttons in the drop down list for buttons assignment. Will figure it out!

Widefield microscope

Yeah, Strike Commander was the one that I felt I enjoyed the most. Before that I had Microprose’s F-15 Strike Eagle and after SC, I had Falcon 4.0.

Differential Interference Contrast (DIC) microscopy is a method used to enhance the contrast of transmitted light images by using polarization of light. By the introduction of two Nomarski prisms (one above and one below your sample), light is sheered into two discrete polarizations which interfere with one-another at the sample plane.

Darkfield microscopy

Welcome @IamTinCan Cool handle by the way. The top left of your screen. Instead of button assignements, you need axis. Go in there and you will find what you seek. Just open say, Rudder trim and either move the axis on the joystick you want to assign or use the pull down menu.

@Maico Thanks! hehe I’ve been running with this handle since i started gaming. Used to play Silent Hunter and since destroyers were nicknamed Tincans and I like destroying stuff… hahaha

Brightfield microscopy is one of the most basic light microscopy techniques whereby the sample is illuminated by white light that is transmitted through the sample onto the detector. There are different methods available to increase contrast in brightfield images (phase contrast, DIC, Polarized Light and Darkfield) which are available on different systems.

I don’t have that Throttle column. But it turns out, that my POV2 is a 4 way hat and is recognized as Buttons 17 - 20. So managed to fix the assignments. But my DCS seems to be randomly hanging after I started assigning the additional axis and buttons.

Phase contrast microscopy is a technique used to increase contrast within transparent samples such as cells or thin tissue sections. The technique works by using an annulus at the condenser to only allow certain phases of light though the condenser and onto the sample. At the rear of the objective there is a matching (but inverted) phase plate, which blocks light let through the condenser annulus. Light that is diffracted by the sample will no longer be in the same phase and will bypass the phase ring and be directed onto the camera or imaging device.

Example of a darkfield light path below the sample plane, where only stray rays of light are collected into the rear of the objective.