In order to examine the techniques I mentioned briefly in the article “using non-macro lenses for macro photography”, I will consider all the methods in separate articles.
An extension tube does not impact sharpness because it is an empty device with no glass. We have the chance to include extension tubes into our setup when using all other methods, and we will use it a lot in the future.
In this article, we will try tubes of different length with different lenses and measure the magnification. We will attach the lenses to the extension tube, in normal way (not reversed), because the reverse mounting will be the subject of the next post.
We will use a set of 68mm long Kenlock and a set of 60mm long non-branded Chinese tubes and will see the results of 1 set of tubes and 2 sets of tubes separately.
Note: I certainly do not recommend Chinese tubes! They can have problems like jamming or dropping the lens. Use your expensive equipment with branded solid tubes.
Automatic Tube – Manual Tube
An extension tube may have an automatic diaphragm support in the form of a metal arm. If there are electrical connections, it already supports automatic aperture. Some expensive tubes even have auto focus support. If possible, at least choose one of those with auto aperture support. So you can control the aperture of auto-aperture lenses from the body. In addition, the aperture value will appear in the EXIF information. When an automatic tube is used, the aperture will be wide-open until the shutter release, offering a bright viewfinder. So we don’t have any trouble focusing. After you press the shutter button, the aperture is set to the desired value.
The manual tubes are completely empty. The quality of the work is the same, whether it is automatic or manual does not affect the photograph. You just need to set the aperture on the lens manually. Because there is no connection with the body, the body cannot see the diaphragm value. You can’t see it in the EXIF. It shows zero.
Note: This is not the subject of this article. But in fact, we would prefer to use the lens reversed. There are special adapters that provide electrical connection even in reverse mounting, but this is and exception. Generally, we cannot provide electrical connection in reverse mounting wheter the tube is manual or automatic. We have to adjust the diaphragm manually on the lens and get used to a dark viewfinder.
The following lenses will be used in the test:
- Pentax SMC M 28mm f2.8
- Pentax SMC M 50mm f1.7
- Volna 9 50mm f2.8 Macro
- Tamron 90mm f2.8 Macro
- Pentax SMC K 135mm f2.5
I added 2 different 50mm lenses to the list. One is in the standard 50mm lens class that most of us have, while the Volna 9 is in a different class as a macro lens.
I used a millimeter paper to measure the amount of magnification. Small squares are 1mm in length. When I was processing these photos, I applied a Photoshop auto-correction command, but I didn’t pay attention to anything aesthetically, except for magnification measurement. So the color and lighting can be in inappropriate levels, let’s ignore the sharpness problems because the aperture is wide-open.
When I took the photo, I measured the distance to the paper. In these measurements, I wanted to give a value closer to the practice by measuring from the outer edge of the lens, not from the optics of the lens. This will be the actual distance that will disturb the insect during a real photo shoot.
Pentax SMC M 28mm f2.8
It is a very successful and sharp lens for daily use. I use it a lot because it is small and light. It is renowned for macro abilities. I consider it to be full manual, especially in reverse connection.
The magnification is 0.13X when we use the lens at the closest focus distance of 29 cm. It does not work even as a close-up. Deformation is high. The sharpness decreases rapidly as it moves away from the center due to the wide-open diaphragm.
Normal mounting of the wide-angle lenses on extension tubes can move the focus distance even inside the lens. So we can’t create a clear image in any way. In this lens, I can only use a single thin tube part of 20mm in length. No focus on longer tubes. With a 20mm piece, the magnification has risen to 0.82X, while the working distance has dropped to around 3cm, which is hardly acceptable. A 28 mm lens to use in macro photography with normal (not reversed) mounting means to be stubborn. But this stubbornness has very different benefits. You can also enter that world by examining another article about macro shooting with wide-angle lenses.
Note: Pentax M 28mm will perform brilliantly when reverse mounted
Pentax SMC M 50mm f1.7
Pentax 50mm has high grades in terms of sharpness and color quality. Again macro lovers use it reversed. But I’ll test it normal mounted.
Our lens reached to the macro level having a magnification of 1.31X with 68mm of extension tubes.
We can start to reach extreme macro magnifications such as 2.44X with the 50mm using two sets of tubes. However, the working distance is quite short like 4 cm, with optical deformation and loss of sharpness on the edges. The fact that I used wide-open aperture greatly enhances these undesirable effects.
Note: Pentax M 50mm lens will be quite successful when reverse mounted.
Pentax SMC K 135mm f2.5
The K series 135mm lens is one of the most preferred old manual lenses for portrait photographs. It’s sharp and sought-after by Pentaxians.
Let’s see what we can do with our macro tubes.
We were able to work at 1:1 magnification, but we had a heavy lens stretched too far and put a load on the camera body. In this way, hand shots will be very uncomfortable. We had to use 2 sets of tubes to bring our Pentax 135 lens to a macro level. As you can see, as the focal length of the lens grows, it is more difficult to increase the magnification with extension tubes.
Another thing that draws our attention with this lens is the lines that are not deformed indicating a flat field, and minimal loss of sharpness towards the edges. The K 135 lens works well optically.
The next two lenses need to be examined with a different perspective. Because these are macro lenses. They can close focus without using extension tubes. They have a high level of sharpness and flat field, it means, they have no deformation. Let’s see what changes with macro extension tubes.
Volna 9 50mm f2.8 Macro
I’ve got the 1987 version of the full manual Russian lens, the Volna 9, which has a certain fan base, a very high contrast and is a very sharp lens. It has a special star-shaped diaphragm and has a very soft bokeh character at f2.8 aperture value. Although Volna 9 is a macro lens, it works at 0.5X magnification, because it is the older generation. Such 0.5X lenses are called half macro.
Volna 9 gave me exactly 0.5X magnification when I didn’t use any tubes. The parallelism of the lines and the sharpness are again the characteristic of macro lenses. We measure 9cm as the working distance.
When we test it with a set of macro tubes and then 2 tube sets, we see that the magnification has increased considerably.
We can go up to 3X with Volna 9 and extension tubes. We do not have a problem with image quality, but the working distance of 1cm is a problem in lighting. We can improve our 0.5X lens to a certain level with macro tubes, perhaps, but the use of long tubes will not be possible in practice.
In this Test, Volna 9 once again won my heart. The bright image, vibrant colors and creamy bokeh character make this lens indispensable for me.
Volna 9 is very successful in low-magnification macro photography such as flowers, butterflies and also portrait photography.
Tamron 90mm f2.8 1:1 Macro
I talked a lot about Tamron 90, so I’m gonna talk too. I like it very much, from low-magnification close-up shots to 2x magnification (with additional accessories). It is very useful in portrait and macro to meet your general needs. I always take Tamron with me, no matter what I want when I’m on field shots. Raynox is a good friend of the DCR 250 outdoors.
The lens, which is already known to provide 1:1 magnification, creates a picture that will show the size of the sensor, so 1:1 lenses allow us to measure the size of the sensor. 🙂
If you count the squares in the first picture (1:1), you will see the sensor size of the Pentax K-x, 23.6 mm x 15.8 mm. It’s not a surprise, of course. The purpose of taking this photo is to provide a comparison reference image that will allow me to measure all other magnifications. In this picture, I see that a square size is 184 pixels. I compare it with the square size of the picture I took with another equipment and calculate the magnification. You can also make the same by proportioning the length of squares that appear in two different photos..
Since the Tamron has a 90mm focal length, it’s a tele lens. We cannot quickly increase the magnification with a macro extension tube. It needs longer tubes.
Let’s take a look at the sample photos
Tamron 90mm, just like the Volna 9 is produced for the purpose of macro shooting. Colors and sharpness are in the desired level even in the corners. Being a 90mm, the advantage of the working distance allows you to approach live insects at high magnifications.
As a result, if you are going to use a lens with the macro extension tubes in normal mounting (not reversed), the lenses you choose should be true macro lenses. We can’t push the lenses made for everyday use to very good points with normal mounting. Even if we can increase the magnification, the sharpness is not very good.
Different application areas of macro extension tubes
Tubes are like magic wand. They can adapt to every type of connection, anywhere. If you’re going to have a lot to do with macro photography, I recommend you to buy a few sets of tubes with different properties.
Tubes compatible with the body
We can use them in both reverse and normal mounting. For example, I do not directly mount the bellows to the body. It can collide with the camera body when it rotates. I place a thin tube between the body and the bellows, so it is easier to mount and unmount. Sometimes I do the same thing in front of the bellows. It is better to insert a thin tube between the lens and the bellows instead of directly mounting the lens to the bellows.
I also use a thin tube to focus closer than the lens allows when using a tele lens. Or it would be annoying not to photograph a bird near me because the lens does not allow. We can get through this using a tube.
M42 is an old standard known as screw mount. Lens, bellows or tubes, the M42 equipments are usually much more affordable than the modern ones. M42 systems can be converted into every system using adapters. So the M42 is a transitional standard for me. For example, instead of looking for an RMS-Pentax adapter for an RMS microscope lens, I get an RMS-M42 adapter. And I don’t have to get another RMS-Sony adapter again because I am currently using a Sony. I already have an M42-Sony adapter, so I can use the whole system with a Sony camera.
M42 adapters are very common and very cheap for all systems. Therefore, M42 tubes are also very useful as a transition element for any type of system.
M39, which is used by Leica brand, is the little brother of M42. For us, the importance comes from enlarger lenses. Almost all of these lenses are M39 mount. We won’t directly use the M39 side because we will reverse the enlarger lenses in macro, but the M39 tubes are still very important for us.
There is no focus ring on an enlarger lens. If we use an enlarger lens in normal mounting, we need to use a tube or bellows to adjust the focus to a certain distance.
We often reverse these lenses. Then the M39 side looks out and we put a short M39 tube in there and made a “hood”. One of the simplest ways to increase the contrast of our photo is to use a hood like this.