Wednesday, May 22, 2013

What use is a 180mm macro lens?

I've long wanted a long macro lens and finally, in October 2012, opportunity and finances coincided and I was able to buy a relatively (£320 from MPB Photographic) low cost used Sigma 180mm EX HSM APO f3.5 macro lens.  This is not the newest f2.8 OS version, or even the one before that with the DG digital coatings, but the one before that.  Although years from manufacture, it was in good condition and I couldn't wait to try it out.  So, bearing in mind that I already owned the Canon 50mm f2.5 compact macro and Tamron 90mm f2.8 macro, was it worth the money and how useful would it be?


The longer macro lenses (150, 180 or 200mm) are usually described as specialist lenses.  Big, relatively heavy, limited to a single focal length, hardly suitable for hand held use at close up range, let alone 1:1 macro distances, they lend themselves to slow, unhurried work with a tripod, remote release and, where necessary, mirror lock up.  Exactly what I needed for my primary interest of plant and garden photography and a useful addition to my nature and insect photography equipment.  There are two main advantages over my shorter macro lenses.  Firstly they narrow the field of view, and secondly they provide a greater working distance.

What the narrower field of view means in practice is that the background in a shot is selected from a far narrower angle and is also more blurred.  It is far easier to get an image with the subject beautifully framed against an almost smooth background.  In this comparison I've shot a single, small head of a perennial wallflower with my three macro lenses.  (Click the images to embiggen.)


All three shots were taken at ISO 200 and f8.  The background is the rest of the bush and a large variegated Yucca (Yucca gloriosa 'Variegata') with prominent yellow edges.  With the 50mm macro you can just see the spiky leaves of this.  The 90mm macro is better, but the 180mm is rendering the background into a far smoother blur.

Obviously I've had to adjust the position of the camera and lens for each shot so the framing and subject size isn't absolutely identical.  Even so, the differences in background blur are obvious.  Of course, with careful selection of subject (smaller is better!) and background (far, far away is best) smooth backgrounds are achievable with any of these lenses.  It's just a lot easier with the longer macro lenses.  For example:

Apple blossom, Cotehele, Sigma 180mm macro, grass bank behind
Gaura lindheimeri, lawn behind.  The fly will  give an idea of scale.
Tricyrtis hirta.  Gravel path in the background.
Yes, I could achieve similar background blur with any good, long telephoto lens.  But not at the price I paid - and they don't go down to 1:1.

The second important advantage is working distance.  It's easy enough to find tables of working distance at 1:1 for any of these lenses.  The longer, the further.  But what does it mean in practice at less than 1:1 close focusing distances?  Well, here's the working distances for the wallflower shots.  Bear in mind that the macro ratio is about 1:3 or 1:4 (1/3 to 1/4 life size on the sensor).  I've topped and tailed the actual wallflower head with blue highlighting.


Working distances for the wallflower shots

For my interests, in many situations, distance lends enchantment.  I hate trampling in my own borders to take close up shots of plants at a distance from the path - and I wouldn't dream of doing it in anyone else's garden.  The extra reach of the 180mm macro is very useful in such cases.

There is another useful feature of a longer telephoto lens that combines the effects of extra working distance and the narrow field of view.  This involves compression of the image.  Because the background occupies a smaller angle of view it appears larger in the shot.  Which means I can more easily position the camera and lens to provide a pleasing background in those situations where the heavily blurred background isn't possible, or in some cases, desirable.  In the two shots below I've shot from a distance (no trampling to get a close up), at a low angle, and into a carpet of flowers.  Unlike with a wide angle lens the background is confined within the carpet.

Snake's head fritillaries, Fritillaria meleagris, in a meadow setting

Bluebells, Hyacinthoides non-scriptus in local woodland
Of course, sometimes it doesn't work.  This shot of the giant leaves of Gunnera manicata gives no impression of size .  It could be a miniature landscape rather than an accurate depiction of the 6ft / 180cm tall stems and giant parasol leaves of this massive perennial.  A wider angle would have given a better impression of scale - but trampling down the stream to frame the shot would probably have been frowned on.

Gunnera manicata in the valley garden at Cotehele
I'm only just starting to explore the usage of greater working distance combined with 1:1 macro capability for insect and other nature work.  With the need for tripod or monopod support (for me, at least) it's too cumbersome to easily follow active subjects around.  Chilled insects, before they warm up in a morning or on colder days do lend themselves to the slower, more studied approach.  For example, this hoverfly, Eristalis pertinax, wearily landed on a Rudbeckia I was photographing on a cold day last October and gave me a chance to take a few shots as it rested.  The light was terrible so I had to work at 400 ISO, 1/80sec, f8 so it's not as sharp and with as much depth of field as I'd like - but showing promise for what should be achievable this year as the insects come out in greater abundance.

Eristalis pertinax on a Rudbeckia flower.  Uncropped image.
In a previous post I showed some shots of crab spider predation on a hoverfly, shot with the Sigma 180mm macro.  Of course, when the subject has a commitment to remaining static it does become easier:

Garden spider on her web
The acid test for me will be with natural light shots of butterflies, dragon and damselflies.  I've only had the one chance to test the lens in this situation so far.  I was photographing some wild flowers a little earlier this year when a brimstone butterfly wandered within about 5ft / 150cm and stopped to feed on a dandelion.  I managed to get off a single grab shot before it flew away.  Hardly a competition winner but the combination of working distance and image quality promises much as the warmer weather brings out more and more possible subjects.

Brimstone butterfly feeding on dandelion
So, to re-examine my original question 'was it worth it and how useful would it be?' the answer is well worth the cost and incredibly useful for my photographic needs.  Big and awkward the lens may be but it's ideal for my purposes.  In fact, it may even be a little too short for some shot requirements.  I'm now looking at buying a 1.4x teleconverter for even greater working distance.

Two final points.  Even though the lens is an older version it works well with my more recent Canon 600D body.  I use manual focus most of the time but the HSM autofocus is accurate and fast in normal use (slow when cycling from macro to infinity distances but this is hardly unexpected and can be countered by using the range limiter switch).  Secondly - and oddly - the EXIF data records the Sigma as the Canon 180mm f3.5L macro lens.  Sigma reverse engineer the lens - camera communication protocols and have had problems with older lenses and newer Canon bodies in the past.  I wonder if they simply copied the Canon protocols and applied them to their identical focal length and aperture lens?  If so the lens is future proofed and I can look forward to many years of service.

3 comments:

  1. Thanks for review, it was excellent and very informative.
    thank you :)

    ReplyDelete
  2. Dear John,

    I am setting up an exposition in the Hortus botanicus Haren (http://www.hortusharen.nl/). Currently I am making informational posters and I want to use your image of Snake’s head fritillaries. This species is also growing in our gardens and I think it is particularly beautiful. Since we are a non-profit organisation and the goal of the exposition is educational I cannot offer you any financial compensation. I can however refer to you on the poster (name, website, etc.).

    Best regards,

    Aaldrik Hinrichs

    P.S. You can contact me on a.hinrichs@student.rug.nl

    ReplyDelete