Macro photography using microscope lenses

When I took a few pictures with my macro lens for the first time, I still remember the pleasure of being able to view flowers and insects so close. I thought that was the end point for a long time. Most of the time, I didn’t even make a 1:1 magnification. I thought I had enough detail. Why would I need a closer look?

But when I look at the old times, I remember my microscope that I bought with great enthusiasm by saving money in the middle school years. Even though it was half toy, I was trying to examine whatever I find in 1000X magnifications. I was getting terrible results most of the time. After a while I liked 50X more. I spent more time with images that were brighter and clearer, and I made pages of drawings.

I never thought I could do the same thing with my camera.

High magnification in macro

Anyone who deals with the macro is somehow obsessed with magnification. In a short time this is becoming a race. How big can we enlarge the object we photograph? How do they capture the amazing photos we see on the Internet? Can a portrait of an ant be taken?

Tubes, bellows, reverse 28mm lenses, my lens size has become more and more smaller. I was able to get about 10X magnification with palm-sized enlarger lenses and then with microfilm lenses smaller than half size of a finger. But I found the quality insufficient. From this point on, it was necessary to move to another level.

Microscope lenses

I was thinking of writing this article in more detail, but the use of microscope lenses in macro photography was a matter that many of my friends were interested in. So I want to give some general information, and talk about my experiences with Lomo 8x.

Microscope lens types

Microscope lenses can be considered as a specialty. Even professional macro photographers who have been doing this work for years have trouble deciding whether a lens is suitable for photography. Sometimes a high quality lens can be bought for cheap because the model information is not fully written. Sometimes even though we pay a large amount of money, we receive an optically defective model. There are countless models according to their technology, glass material, usage purpose and design. And of course, according to the magnification …

We can mount every microscope lens to our camera. But the vast majority are somehow unsuitable.

• We cannot use very high magnifications in practice. Microscope lenses from 2X-60X are more suitable. Over 10x the challenges are increasing. However, very special lenses can still work. Practically 10x and below are more usable.
• Many microscope lenses have been produced to work with the ocular, also called eye lenses. When used alone, there are color distortions and optical problems.
• In the immersion lenses, the lens works by contacting a special oil dripped onto the specimen. These are not suitable for us.
• The lens gives a circular image. In some lenses, this circle is not large enough so it causes a high amount of vignetting. This happens frequently, especially on full-frame cameras. It can be compensated to a certain extent by increasing the magnification, but it is better to investigate before purchasing.

Finite microscope lenses

These lenses can be used alone by simply mounting on a bellows. They create an image with the magnification written on them at a given tube length. For example, a lens with 160 written on it, gives its own magnification value when we use a 16cm bellows length. We can change the magnification by slightly increasing or decreasing the size of the bellows. 50% more or %50 less magnification can usually be used. But for the best quality, it is better to use the lens at its own magnification.

Most of the commonly found and affordable microscope lenses in the market are finite type.

Infinity corrected microskope lenses.

This design is used in modern microscopes. The light rays of the magnified object emerge from the lens as parallel. So if we connect it to a bellows, we can still get an image, but it’s not sharp enough. It is necessary to focus those rays on the sensor using an extra lens called the tube lens. There are special tube lenses produced only for this purpose. But don’t worry, you can use any lens that works around 200mm as a tube lens. Select a longer focal length for a larger magnification or select a shorter focal length for a lower magnification.

First, we mount the tube lens to the camera. Then we mount the microscope lens onto the tube lens using a suitable adapter. You might think it looks a bit strange in appearance.

So if you have a 70-300 zoom lens, when you set it to 200mm, you’ll work at 10X with a 10X infinity microscope lens. When you set the zoom lens to 100mm, the magnification will be 5X (10X *100/200), at 300mm, you will get 15X (10X * 300/200).

Since it is an extra lens, it has a direct effect on the image quality. It would be a good idea to choose a sharp lens as a tube lens.

Infinity microscope lenses are the new generation of technology, we can expect better color correction and sharpness. But quality finite type lenses are definitely not worse than these. It would be unfair to expect too much from a cheap lens, no matter what type it is.

Abbreviations on microscope lenses

We see a lot of abbreviations and numbers on microscope lenses. Let’s take a look at the most commons.

Plan

Plan statement, which is a common feature in macro lenses, can be explained by the fact that the focused area is a flat-field. Expressions like semi-plan means a more curved focus area. In fact, we will do focus-stacking, so this curvature is significantly compensated. Still, we want our lens to have the Plan feature.

CF – Achro – Achromat – APO

These expressions indicate that there is a fix for chromatic abberrations. Correction in APO lenses is more successful. It is very important to have one of these abbreviations in terms of colors because we will use our lens alone without the ocular.

BD – EPI

Refers to the form of lighting. BD lenses have an empty channel around the lens that will pass through the light above and illuminate the object below. If you are going to use it for macro, this channel must be filled and sealed with an opaque material when connecting it to the camera. In EPI lenses, the object is illuminated from above and the light is sent through the lens itself. EPIs behave like normal lenses if this feature is not used.

NA

It means numerical aperture. The larger this value, the more detail our lens will resolve. Typically, it is about 0.10 for 5X level, 0.20 for 10X level, 0.40 for 20X level, and as the magnification increases, the NA value advances. The larger the NA value for the same magnification, the better the lens will likely achieve. However, our depth of field and working distance will decrease.

LWD – ULWD – SLWD

Indicates that the working distance is longer than normal. WD means working distance. L – Long, UL – Ultra Long, SL – Super Long abbeviations respectively shows increased working distance. As the working distance increases, it is optically necessary to sacrifice some of the NA value and therefore the sharpness.

Difficulties in using a microscope lens

We will be experiencing overall high magnification challenges.

Vibration

Vibration in microscope lens shooting is our biggest problem. We have to fix both the camera and the object we are shooting as firmly as possible. It is advisable to use a cable or remote control. We should wait a few seconds after each shot and make sure the vibration is off. EFSC-assisted bodies provide great help in preventing vibration.

Working distance

With a microscope lens, we’re only a few centimeters away from the insect. As the magnification increases, we’re so close to the object to be expressed in millimeters. It is very difficult to create the frame and maintain the frame steady during tens of exposures.

Creating the first frame will be exhausting. It may be difficult to predict where the object stand in front of the lens because we cover it on all sides with diffusers. When trying to focus from the viewfinder, we move the lens back and forth. It’s possible to make the lens touch to the object, contaminate the lens, even worse, scratch the lens. It is a very common method to position a dead insect using a needle, so we can scratch the lens with the needle without realizing it.

Lighting

Long exposure is very difficult when using a microscope. Fully vibration-free camera body (EFSC supported) and vibration-free environment is required. Or these problems can be overcome significantly by using a flash.

A working distance of 1 cm requires creative ideas for smooth lighting. Plastic or paper picnic cups, yogurt boxes and ping-pong balls can be used effectively for diffusing the light. However, it is important that the ball or the cup does not reach too far in front of the lens. Otherwise, the reflected light will infiltrate and create a fogging effect.

Depth of field problem

With a microscope lens, our focused area is as thin as a film layer. After you’ve photographed the whole piece in order, you’ll have to spend the labor and time to combine them in the computer. A simple(!) portrait photo may require up to 100 pictures or more. For information about this method, called focus stacking, see:

Focus Stacking

In this series of photos from the front to the rear, the sharpness disappears immediately after the last picture. In order to avoid this unnatural appearance, we can extend the shooting process a little more towards the background. Or, with a more advanced technique, we can use the microscope lenses with external diaphragms. It’s a challenging but very effective solution to narrow the aperture in the last pose and naturalize the background.

Mounting

Connecting these tiny lenses to our camera can sometimes be complicated. There are many different mounting standards for microscope lenses. I can sort them as: RMS, C-mount, M25, M26, M27.

Since RMS is quite common, it is better to have an RMS adapter.

Lomo 8X 0.20

You can also find a short article link about Lomo 8X at the bottom of the page. It’s a 1970 model Russian lens, which does not carry many of the desired features. It bought it to develop my technique because it would be my first microscope experience. At the same time, it was a cheap lens worth taking a risk.

Although designed for 8X magnification, you can use it in the 5X-12X range. It is a finite type lens used by mounting directly to the bellows.

There is a lot of CA deterioration in the colors, but the focus stacking process can greatly improve them. CA in bokeh areas cannot be easily corrected and depending on the situation, is not not pleasing to the eye.

I can easily say that Lomo 8X meets my expectation as the resolution. Pinpon ball lighting provides the desired light level.

Photographs taken with microscope lenses

Reviews of other microscope lenses

You can click on the links below. Turkish articles will be translated soon.

• Carl Zeiss 2.5X
• Lomo 3.7X
• Lomo 8X
• Lomo 20X
• Noname 20X
• Mitutoyo 5X