Canon Macro Lenses vs. Extension Tubes.
August 12th, 2010 
Photography
Last year, when I was in Japan photographing cherry blossoms, I used a wide-angle lens and extension tubes for taking macro photos. This was because I had left my specialized macro lens at home. But the whole time I was there, I wondered: “would I get a better photo had I packed the macro lens?”
Finally, I decided to find out. Hence, this Canon Macro Photography Lens Shoot Out, featuring the following contenders:
- A bunch of extension tubes,
- a Canon 16-35 mm f/2.8 wide angle lens,
- a Canon 50 mm f/1.8 normal lens, and
- a Canon 180 mm f/3.5 macro lens.
All photos were taken with a Canon 5D Mark 2, at ISO 100, unless otherwise specified. The camera was set to RAW mode. All photos were lit by indoor light, except for the ones taken with the 180 mm lens, which were lit via a Canon Ring Flash. The short subject-to-lens distances when using extension tubes with normal lenses made it impossible to use a ring flash.
And yes, I know the lighting means it’s an apples to alligators comparison; fortunately, there’s a part two further down.
The subject was a flower on my sofa… This photo was taken with the 16-35 at f/22.
For each lens and close-up ring combination, there are two photos of the flower here:
- A full-frame photo, cropped to a square (i.e. full height), then resized to 800 pixels, and
- An 800×800 section of the actual pixels of the full-size image.
Adobe Lightroom was used for doing the RAW conversions; some photos received an exposure boost of between +0.15 and 0.75.
The following sequence of actions were then performed in Adobe Photoshop CS5:
- Smart Sharpen, Amount = 80, Radius = 1.0, Remove Gaussian Blur,
- Convert profile from AdobeRGB to sRGB,
- Convert from 16-bit to 8-bit mode, and finally
- Save as PNG file
With all that out of the way, let’s go on to the photos:
Canon 180 mm f/3.5L Macro Lens, at f/32:
Canon 16-35 f/2.8L lens, at 35 mm, f/22, and 20 mm extension tube:
Canon 16-35 mm f/2.8L lens, at 26 mm. f/16, and 35 mm extension tube:
Note these photos were taken at f/16, unlike all the others, which were taken at the lens’ minimum aperture. This is because the exposure was 30 seconds at f/16, and my camera does not allow setting the 60 second shutter speed that would have been required for an f/22 exposure. Also note that the front element of the lens was actually touching the flower in these photos; that’s why there were taken at 26 mm instead of 35 mm – It was impossible to focus at any other length!
This is what I’d call “too close” and shall speak of it no further…
Canon 50 mm f/1.8 lens at f/22, with 20 mm extension tube:
Canon 50 mm f/1.8 lens at f/22, with 35 mm extension tube:
Comparison of full-frame images:
In my opinion, the 180 mm macro, and the 50 mm + 35 mm extension tube are both pretty good, so it’s time to go to a bake-off!
All of these images were shot at ISO 400, since it’s now night-time. Exposure was adjusted in-camera to get approximately equivalent lighting. These images are all full-frame, processed the same as the previous sets.
The spices are star anise, sesame seeds, some other kinds of seeds that I forgot to label, kosher salt, and dried red pepper. I tried to focus on the nearest point of the center on the front star anise.
Conclusions:
- None of the combinations are bad; You can do good close photography with the cheapest lens I tested. Granted, the 50/1.8 is well known for being one of Canon’s sharpest lenses.
- Because of the short working distances using extension tubes, it’s nearly impossible to get as much magnification as with the dedicated macro lens. For the 50 mm + 35 mm shot, the lens was about 2 cm from the anise. For the 50 + 20, about 4 cm. However, with the 180 mm macro lens, the lens was about 50 cm away.
- Also, you can’t use ring flash with the extension tubes on anything other than the dedicated 180 mm lens.
- On the other hand, the 180 mm macro weighs more than all the other lenses and tubes combined! Given I travel with only one small backpack that I keep with me at all times, I do have to watch the weight.
- You get a surprisingly wide depth of field with either the 35 or 50 mm lens, and the 20 mm extension tube.
- I shant be getting rid of any of my lenses as a result of this, so don’t ask! ;)
A Suggestion for future work: It would be nice to compare a shorter focal length macro lens, such as the Canon 100 mm f/2.8L macro lens, or even the egregious MP/E 65!
And just for fun – What happens when you stack 67 mm of extension tubes onto the 180 mm lens? Answer – A photo you can’t get any other way.
