Photographing plankton is a lot of fun but can be tricky, especially if the plankton is still alive. What is even more fun than photographing plankton is filming plankton! If your camera is able to film in high resolution, you can later edit individual film images as photos.
Using a macro lens
With an ordinary camera with macro lens or macro stand you can often already take beautiful photos of larger plankton such as jellyfish and comb jellies. Photograph them from above in a transparent container with water, or in a specially made narrow glass or plexiglass aquarium, a cuvette. In both ways you get the best result with a black background, for example a piece of black cardboard or plastic. The lighting is best done from the side with a LED spotlight, a cold light source or a flash. A flash unit is useful for live plankton, or when you are on a moving ship. However, you do need a way to use your flash separately from your camera, such as a flash cable or a set of radio triggers.
With a black background, a camera with standard automatic exposure settings often takes overexposed photos because it wants to make the black lighter. This can be remedied by manually setting the exposure or using the exposure compensation function. This can often also be done on your smartphone in the more advanced camera apps.
A way to support the camera can be useful, such as a tripod or a reproducing stand.
Using a microscope
Phone or compact camera + microscope
The cheapest way to take pictures through a microscope that often works surprisingly well is with your phone!
- Make sure that the image in the microscope is sharp,
- Fold your hand around the eyepiece so that it protrudes just above the eyepiece,
- Place your phone on your hand around the eyepiece in such a way that the camera lens looks exactly in the middle of the eyepiece. You will then see a circular image appear on the screen.
- Move your hand around the eyepiece a little up and down until the round image in the phone is the largest.
- Take a picture. If you don’t want a round image, you can crop it later or zoom in a bit.
There are also special clamps available which you can attach to your eyepiece and then clip your camera/telephone into it. Usually attaching these clamps is rather cumbersome and you might as well do without them. What can still be useful is a small tripod as support.
Dedicated microscope camera + microscope
A camera specially made for photography through a microscope sounds like the best option, but often it’s not. Even photographing with your phone often gives much better pictures! This is because there is a huge market for smartphone cameras and consumer digicams and they are constantly being improved and further developed. The microscope camera market is very small and focused on medical and research laboratories, so the sensor in these cameras is often hopelessly outdated and/or the camera is extremely expensive. In Chinese webshops reasonably cheap cameras can be found (and three times as expensive cameras in Dutch webshops that look suspiciously the same…) but this remains a gamble. Only for professional or very specific purposes I would consider a microscope camera. One advantage is that with the supplied software you can often also analyse the images taken and measure or count organisms, for example. However, you can also do this with the setup below and, for example, the free program ImageJ.
Single lens reflex/mirrorless camera + microscope
In my opinion, the best way to take pictures through the microscope is with a dslr or mirrorless camera with a large sensor. Here you connect the camera, without lens, to an adapter that you put into the third eyepiece position of your microscope. With a microscope with one or two eyepieces you can remove the eyepiece and put the adapter in its place, but this is very unstable because the camera is very heavy. You can also take pictures directly through the eyepiece using a camera, just like with a smartphone. This is a bit laborious but can give good results. It does not work with all lenses.
Advantages of using a DSLR or mirrorless camera are that you can use a camera with a sensor with high light sensitivity and resolution, have a lot of adjustment possibilities and can also use the camera for other photography. You can also connect most cameras to the computer via a program from the manufacturer so that you have the image of the microscope directly on your screen. Often it is also possible to connect the camera directly to a screen via the HDMI connection although the HDMI output is not always “clean”.
The biggest disadvantage of such an arrangement is the cost. Both cameras and adapters can be expensive, and microscopes with a third eyepiece position (trinocular) are often more expensive and difficult to find than mono or binocular microscopes. I have used a “cheaper” microscope to DSLR adapter with 2x magnification and found its image quality a bit disappointing. I am now achieving the best results with coupling the camera directly to the 3rd ocular position without any optical elements in between. This is done using a series of adapter rings: a 1 cm K-mount extension tube is connected to the camera, to the front of which a Pentax K-M42 adapter ring is fitted. Finally I screwed in a M42 – 30 mm microscope adapter into the M42 adapter ring, which fits in the 30 mm Zeiss port.
I use a DSLR but I think that mirrorless cameras are better. They don’t suffer from vibrations caused by the mirror flipping in and out of view, and often have good video capabilities.