Extension tubes and zoom lens

Hoverfly, Nikon 105mm macro lens

In my previous post I discussed my first experiments with extension tubes. I noticed that my Nikon 50mm f/1.4 prime lens is doing quite well as far as magnification is concerned, while my 135mm prime lens is not. However, the distance from the front side of the lens to the subject is more comfortable with the Nikon 135mm lens, especially for moving objects like bees and butterflies. I also noticed that by using too many extension tubes you lose a lot of light, decreasing the quality of the picture.

Butterfly, Nikon 28-300mm & 300mm

So, my next step is to experiment with my Nikon 28-300mm zoom lens. For all kinds of photography and if I am taking only one lens it is this one. For this experiment I choose the 20mm extension tube to make sure there is some magnification and enough light.

One thing that I noticed right away is that by zooming you actually focus (in a similar way by getting closer or further away). This is very handy for finding the focus area. For actual fine tuning it is much better to use Live View (and zoom in) and to focus with the focus ring. This is the best way to get really sharp picture. This means that you also have to use a tripod. I use my Peak Design Travel Tripod.

Bee and Chinese rose, Nikon 28-300mm @ 68mm

I also noticed that for the combination of the zoom lens and the 20mm extension you really need a lot of light, or you have to increase the ISO. An other observation is that below 35mm there is hardly or no focus area at all. Also, for the 150mm and above the magnification is minimal.

What I really like about using the zoom lens is that if a bee is hopping from one flower to the other it is easy to adjust the zoom and still get a sharp picture (just like with normal photography). Of course, the quality of the picture does not match the ones of the Nikon 105mm macro lens. The flexibility allows me to take pictures that are not really macro pictures, which means that I have to crop a lot afterwards (losing a lot of detail).

So, to conclude, the zoom lens in combination with an extension tube works fine for regular pictures (if you know the limitations). However, my personal experience is that I get better pictures with my Nikon 105mm macro lens. As soon as my macro lens is back from repair I will try it in combination with a small extension tube.

Succulent, Nikon 105mm macro lens

Experimenting with extension tubes

Nikon 105mm macrolens

Recently I noticed that the autofocus of my Nikon 105mm macrolens did not perform properly and that the lens gave a high-pitched squeak. When I brought it in for repair I bought Caruba extension tubes so I could continue my macrophotography.

Nikon 50mm with extension tubes

I had been reading a bit about extension tubes being a cheap way of doing macrophotography. The promise is that for 100 euros you can get a better a magnification than a 1000 euro macrolens. The basic idea is that the hollow tubes put the lens further away from the sensor, thereby reducing the minimal focus distance. So, you can take a picture from closer by. As a result of getting closer to the subject the magnification increases. Just as you would expect, if you put something right in front of your eyes it looks bigger than if you hold it at arm’s length. For example, 68mm of tubes gives 1.5 magnification for a 50mm lens. Notice, a macrolens only gives 1.0 magnification! It looks like paradise.

So, after unpacking I put my 50mm lens on all the tubes together (68mm) right away. I was shocked: the camera could not focus! After reading some more (in Dutch), I realised that the range in which the camera could focus was reduced from 45cm-infinity (without tubes) to a few millimeters at a distance of a few centimeters (with all tubes) in front of the lens. Understandable that the autofocus could not handle this. The subject was out of the focus range.

Nikon 28-300mm @ 115mm with extension tubes

Getting sharp pictures in macrophotography is quite a challenge. The size of depth-of-field (DoF)—a portion of the range in which the camera can focus—depends of course on the aperture. So, we are talking about a millimeter or even less. In practice this means that when holding the camera in my hand, and by breathing and by keeping balance, the subject is getting in and out of focus continuously. So, you really have to try to press the button at the right time! Of course, you could use a tripod, however, that does not work very well with bees and butterflies flying everywhere. However, for flowers it works perfectly. I use my Peak Design Travel Tripod.

Furthermore, when using extension tubes you lose some light. Trying to get more DoF, to make focussing a bit easier, you choose a smaller aperture, which again means less light. The combination results in higher ISO. As a consequence, the dynamic range decreases and it introduces some noise in the picture, which becomes visible if you decide to crop to further increase magnification.

How about other lenses? It turns out that wide-angle lenses do very well as far as magnification is concerned, however, if you use too many tubes the focus area will end up inside the lens. Making wide-angle lenses almost useless for macrophotography. Telelenses, on the other hand, do not do so well as far as magnification is concerned.

My provisional conclusion is: Focussing in macrophotography is already a challenge, using extension tubes it is even more a challenge if you push it to the limits by using too many tubes.

My advice is to use mainly one of the smaller tubes (12 or 20mm). It already gives you a substantial magnification for mid-range lenses and you don’t have to put your lens right in front of the subject. Furthermore, you do not lose a lot of light.

In my next post I will share my experience with extension tubes and a zoom lens.

Nikon 28-300mm @ 300mm with extension tubes


Challenges of macrophotography

Budding of pink rhododendron flowers

In this post I will discuss two challenges of macrophotography:

  • small depth-of-field (technical)
  • right background (creative)

Due to the corona crisis I spend a lot of time in the garden. I never realised the variety of flowers in our garden, including our tub plants. Almost every day I scout my garden to find new flowers or new compositions. I rediscovered macrophotography. Also a webinar of Janneke van de Pol about macrophotography inspired me to look at taking macro pictures differently.

Only first row of stamens of Delosperma is sharp

The first thing you notice when you enter the macro world is that the depth-of-field is very small. For example, with my 105mm macrolens at a distance of 30cm with an aperture of f/8 the depth-of-field is only 2mm. By just moving a little bit the subject is already out of focus. I find it difficult to judge the quality of a picture on the screen of my D800. So, in practice this means that I have to go to my computer to see whether the subject is in focus or not.

To deal with this small depth-of-field I have two approaches depending on whether the picture is for Instagram (have a look on the right) or for Dreamstime. For Dreamstime I try to keep the ISO as close as possible to 100 to avoid noise in the picture. For Instagram this is less important. The settings of my camera are normally:

  • ISO is automatically increased if the shutter speed becomes below 1/60sec. If the ISO exceeds 6400 then the shutter speed is lowered.
  • AF-ON is used to focus. Normally I use that for focussing on moving subjects. Now I use it also to compensate for my own stabilising motions.

For Instagram this is perfect. I take a couple of pictures with different apertures and on my computer I decide which picture I want to share on Instagram. For Dreamstime, I want to keep the ISO close to 100. So, I switch off the automatic increase of the ISO. If there is sufficient light this is no problem (fast shutter speed). Otherwise, due to the slower shutter speed, I use my Peak Design Travel Tripod. To avoid any further vibrations I use Arsenal for wireless control to focus and to hit the shutter. The resulting pictures are of very high quality.

Cornflower with waving corn as background

The second thing you notice with macrophotography is that the right background is very important. I observed that in the beginning I was too concentrated on getting the subject in focus that I often forgot about the background. Sitting behind my computer I saw the disturbing background which is of course hard to fix in Lightroom.

So now I spend more time on the composition (which includes the vague background) before getting my camera. Although this is not an easy task -we deal with the imperfections of nature – it is important to look at lines and light and dark spots. Also colours are more important than I thought. Try to look at the subject from different angles and decide on the one you like. Creativity plays a central role in this decision. Composition rules are helpful, however, do not be too rigid. By experimenting you get a feeling of what wow pictures look like. Feedback on Instagram also helps me.

What I like about macrophotography is the combination of the technical and creative challenge. My appreciation of nature has increased substantially. After the corona crisis I will continue taking macro pictures.

Enjoy the beauty of nature; taken during sunset

Rediscovering macrophotography

Forget-me-not

A couple of years ago I bought a secondhand macro lens (Nikon 105mm Micro) and did some focus stacking with withered roses to get a sharp image all the way down into the roses. Now, during the corona crisis, that I am confined to my house and garden, I start to value the little things in life, like a budding flower, or a bumblebee. So now, I am using my macrolens continuously to capture all these beauties. I never thought I would be taking pictures of flowers and insects. Honestly, it is much harder than I expected. Almost always I am facing challenges, and I love it.

Budding of pink rhododendron flowers

To share the love for these beauties of nature I hunt everyday in my garden to find new buds, flowers, or insects. I know my garden now much better than before. The pictures I like, I share them on Instagram (have a look at the right column of this blog). The pictures that are of the highest quality are submitted to Dreamstime. Currently the review process takes less than one hour.

In the ideal world a flower (or a detail) should be the main subject of the picture, well-lit, tack sharp, with a non-disturbing blurry background. And, of course, no noise in the picture. The combination turns out to be a challenge.

As you probably know, shutter speed, aperture, and ISO depend on each other. Changing one has an effect on the others. This is called the Photographic Triangle.

For example, the depth-of-field at 30cm from the flower for a 105mm lens at f/11 is only 0.4cm. Can you imagine! If you move just a little bit the flower is out of focus. Increasing the depth-of-field to 0.7cm by going to f/22 means either a slower shutter speed or an increase of ISO (introducing some noise in the picture).

A consequence of an increase of ISO means that objects in the background become more visible, distracting attention from the flower. A slower shutter speed, on the other hand, seems fine if we use a tripod; however, if it is too windy or if the insect is moving, it is not going to work. All in all, it is not as easy as I thought.

In the upcoming posts I will have a closer look at some of these challenges.

Tiny white-purple flowers