Macro photography: Alternatives to macro lenses

Shivan Parusnath Macro, Shivan 2 Comments

While a purpose-built macro lens is the easiest tool for doing macro photography, there are alternative ways of getting close to your subject. Namely, through the use of extension tubes, lens diopters, and lens reversal rings. Using these pieces of equipment may allow you to get all the way to a 1:1 magnification ratio, but come with their own set of caveats. In this article, I will discuss the use of each macro lens alternative (in use with a 50m f/1.8 STM lens), advantages and disadvantages of each, and analyse sample photos comparing these tools with a proper macro lens.

Note 1: I spent some time looking for macro subjects to photograph for this article, but unfortunately invertebrates and reptiles were elusive on the chilly days I went out searching. So instead, I’ve photographed a small wire gecko and a set of lens filters to demonstrate the magnifying effects of each macro alternative here.

Note 2: I have used an aperture of f/16 for all photos, while ISO and shutter speed have been adjusted accordingly to allow a similar exposure for direct comparison.

1. Extension tubes

IMG_9762

A set of 12mm, 24mm, and 36mm extension tubes.

An extension tube is a glassless, hollow tube that is inserted between your lens and your camera body. It moves the front element of your lens closer to your subject, and with this closer focusing distance comes an increase in maximum magnification ratio. Extension tubes come in different lengths – the longer the tube, the closer the element gets to your subject, and the higher your magnification ratio. Some extension tubes are simply plastic spacers, while others have mechanical contacts (like those pictured above), and allow for aperture control from the camera body like a normal lens would. Get these.

Here are some example images showing how different extension tubes and combinations compare to the native closest focusing distance of the test lens:

50mm (2)

50mm 12mm far50mm 12mm near

50mm 24 far (2)50mm 24 near

50mm 36 far50mm 36 near

50mm all far50mm all near

100mm nearest100mm 12mm

100mm 24mm100mm 36mm

Analysis:

The 50mm f/1.8 STM lens with the 12m, 24mm and 36mm extension tubes in combination provides a 1:1 magnification ratio that is almost indistinguishable from using a 100mm f/2.8 at 1:1. The bokeh is noticeably smoother in the 100mm images, due to the longer focal length of the 100mm lens and the 9 diaphragm blades in the 100mm, compared to 7 in the 50mm. However, the focusing/magnification range with each extension tube or combination tubes is quite limited – so knowing which combination to use for which subject is important if extension tubes are to be used efficiently in the field.

Advantages:

  • Extension tubes are cheap and a whole set (12mm, 24mm, 36mm) can cost you less than a dedicated macro lens second-hand.
  • Each tube will provide a different magnification ratio, and can be stacked for numerous close-up possibilities.
  • Because there is no glass in them, there is no reduction in image quality when used.
  • Can also extend the magnification ratio when used on a proper macro lens.

Disadvantages:

  • The focal range when an extension tube is attached is restricted, and infinity focus is lost. This can be quite limiting in the field.
  • Even though a set of extension tubes can allow for a decent range of close-up possibilities, removing and attaching them when photographing subjects of different sizes is time-consuming and can lead to lost opportunities.
  • An extension tube creates a cavity between body and lens which light gets lost in. The more extension tubes used, the greater the loss of light.

2. Lens diopters

IMG_9825

+2 and +3 lens diopters.

A lens diopter is a glass filter that screws onto the front of your lens, and is effectively a magnifying glass for your lens. A diopter will do the same job as an extension tube, however since it is made of glass, has a higher chance of degrading your image quality if the glass is not of a high standard. Here is a comparison of the standard 50mm close focus to various combinations of lens diopters and a true 1:1 macro lens:

50mm (3)50mm 2x

50mm 3x50mm 2x2x

50mm 2x2x3x100mm

Analysis:

The lens diopters provide a decent range of magnification ratios in their different combinations, but even with two 2+ and one 3+ lens diopters stacked, do not quite get up to 1:1, as shown in comparison to the 100mm lens.

Advantages:

  • Easier to use than extension tubes since they can easily be screwed on and off when needed, without having to detach the lens from the body.
  • Can be stacked to achieve greater magnification ratios.
  • Can also extend the magnification ratio when used on a proper macro lens.

Disadvantages:

  • The focal range is limited, and infinity focus is lost.
  • Stacking lens diopters can lead to a drop in image quality if the diopters used are not of high quality (and therefore expensive).
  • The more lens diopters attached to your lens, the more light lost on the way to the sensor.

3. Lens reversal rings

IMG_9797

Canon 50mm f/1.8 STM lens reversed on a Canon 70D.

A lens reversal ring allows you to attach your lens back to front to your camera body. This serves the same purpose of an extension tube in that it will move the front element (in this case the rear element) closer to your subject. The rear lens element is designed to project an image on a flat plane close to the sensor – and instead of projecting a large image onto a small sensor, you will be projecting a small image onto the sensor, providing a significant magnification effect.

50mm (3)

50mm reversed

100mm

Analysis:

The reversed 50mm lens allows for three times a greater close focusing distance and magnification ratio than when attached to the body normally, but not quite 1:1. It does, however, provide a higher magnification than the lens diopters, and doesn’t risk a drop in image quality because of poor quality glass.

Advantages:

  • Reversal rings are the cheapest of the three options here.
  • Image quality will depend on the lens quality, and nothing else. If you already have a high-quality prime lens, it will result in high-quality macro photos.
  • Technically, you don’t even need a reversal ring to use this technique. As long as no light enters between the lens and body, you can hold the lens reversed against the body.

Disadvantages:

  • Reversing the lens exposes the rear element, with no option of filters to protect it.
  • Since there is no mechanical contact between body and lens, aperture cannot be controlled when the lens is reversed. This means either shooting with the aperture wide-open, or selecting an aperture with the lens attached the body normally and detaching the lens while holding down the depth of field preview button (if your camera has that option).
  • No mechanical contact also means a lack of focusing ability when using lenses such as the Canon 50mm f/1.8 STM lens that only focus when in mechanical contact with the body.

Conclusion

So there you go, a few simple alternatives to using a dedicated macro lens to achieve macro magnification ratios. Having used all of these options before, I can recommend at least trying them out to figure out whether macro photography is for you. Chances are though, that if these tickle your fancy, having a dedicated macro lenses that has all the advantages of these options without any of the caveats is sure to entice you enough to purchasing one.

Please feel free to ask any questions about the equipment and techniques discussed in this post in the comments section below, doing so helps both of us grow!

My next technical article on macro photography will look at lighting for macro photography – without a doubt one of the most important facets of producing beautiful, natural looking macro images. In the mean time, look forward to more behind-the-frame posts, and see more macro photography on my Instagram or 500px.

Cheers for now.

About the Author

Shivan Parusnath

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I am currently doing my PhD research on the conservation of the Sungazer (Smaug giganteus), a threatened South African lizard species, at Wits University in JHB. Working with reptiles over the past 6 years has fueled my obsession with macro photography. My aim with photography is always to portray a subject on its own level, whether a lion, a lizard or an ant. I am also excited by in-habitat shots, where the subject is shown in the context of its natural habitat. This is great specifically for rare or threatened species, so people who might not readily get an opportunity to see these animals can gain a greater appreciation for where the species fits into the bigger picture.

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