The first aspect to consider when choosing a lens, or lenses, is the focal length. Keep in mind that lenses are broadly grouped into four categories — wide‑angle, standard, telephoto and macro — according to their focal length. It is often assumed that the wide‑angle lens is for landscape photography and the telephoto lens is for objects in the distance. I believe, however, that any lens can be used for any subject, and your choice of lens’s focal length will determine “what it sees”. It comes down to what you want your picture to say. Nonetheless lens if your focus is to be on the botanical world, from trees to flower close ups, you could find a lens that suite your budget that covers this broad range of subjects.
Field (or angle) of view is an important aspect of assessing a lens and is determined by its focal length (for example 35 mm, 120 mm, 300 mm). Also important is its range of f‑stops (apertures, such as f 22, f 8, f 5.6) and resolution. This will dictate how much of the image can be magnified and its quality when enlarged. Apertures directly affect depth of field. The largest aperture opening (the smallest f number) that the lens will achieve gives a rating for the “speed” of the lens. Lens resolution varies between brands and higher quality lenses are understandably more expensive than lower quality ones. Lens speed (the maximum available aperture) also affects the cost of a lens. Perhaps auto‑focus mode is another choice you would like to have available.
The following is a guide only and not intended to be a brand and quality review. There are many such sites online and you only need Google the various options. What I have prepared is a general guide for people starting out and or changing focus to botanical subjects.
14–35 mm wide‑angle
You can’t go wrong with these two focal lengths. The zoom lenses of around 14-24mm ranges are perfect perspective for floral habitats, shrubs and trees. I use the 24-700mm zoom as a standard lens and find it an excellent choice for botanical photography. For trees I also like to use 10 mm fisheye, usually for fun and for effects.
Macro lenses – zoom and fixed focus
Even though many modern lenses have the ability to focus close up, you will never get the magnification or the optical quality of a macro lens that has been specifically designed for close‑up photography. If you are interested in nature, with a passion for photographing flowers, frogs, reptiles or insects, you have choices — around 60, 105 or 200 mm lenses, depending on brands. An option may be to use a zoom macro. i have used the now discontinued 70-180mm Nikon Zoom Macro for many years. When I had mine stolen I was able to pick one up on eBay for under a $1000. Sensational lens, sharp as a tac. The great advantage of zoom macro is that you are able to vary your shots from say full plant to macro close up of a flower with ease. You may in on your belly and find it hard to move backwards and forwards when you wish to vary the amount of plant content you have in your viewfinder. A Sigma and or Tamron with similar capabilities may also be worth considering.
Long Telephoto Lenses – 200 to 600mm
As the longer focal length lenses have a shorter depth of field, a photographer is more able to control the aesthetic appeal of the background. For example, a 200 mm macro lens with its aperture wide open (the smallest aperture number) can produce a nice soft background. This effect when combined with the selective focus of the plant can produce a very appealing photograph. While these sorts of focal lengths may not be first u when considering flower photography, they should certainly be on your agenda to trail. Having a shorter depth of filed than wider macro lenses, the background effects can be grand. However you may need a windless day and a tripod to set up the shots. I use my 500mm for botanical subjects often when shooting birds.
Auto extension rings/tubes
A set of extension rings, or tubes, is a good way to start close‑up photography if you don’t have a special purpose macro lens. They are light and therefore portable for fieldwork, and are an ideal choice while you consider wether you need a macro lens. The extension rings also allow you to obtain interesting effects with floral arrangements. You will need to check the specific brand before purchase, but modern DSLR extension rings should enable you to retain automatic diaphragm and metering coupling when attached. The primary benefit of extension rings/tubes is that they provide a low‑cost alternative to buying a macro lens for close‑up work. They offer another advantage when you wish to magnify even further than your macro lens will allow.
Close‑up attachment lenses
Close‑up attachment, or accessory, lenses, used mostly for macro photography, can be purchased for most lenses because they are little more than a filter with a magnifying glass. Do not expect the results to be as crisp as those images shot with lenses designed specifically for close‑ups. The attachment lenses are better used with longer focal length lenses to enable even greater magnification. Lenses between 80 mm and 150 mm would be perfect. Lenses can be used in combination. One benefit is that close up attachment lenses are highly portable, easy to use and low entry cost for a beginner.
I wanted everything in this photograph to be as much in focus as possible. So, using a focal length of 105mm I set the camera up on a tripod, stopped down the lens, and used a cable release to ensure there was no camera movement.
My own technique when shooting flowers is to use the depth of field preview and, rather than focus the lens via either auto or manual, I set the focus distance (based on the composition I want) and use my body as a fulcrum rocking back and forth. Image taken in very low light, 200mm macro.
The technique for this image was to use a long focal length macro, 200mm, with a wide aperture so as to blur the background. I wanted all emphasis on the bell and the raindrop.
You may like Wild Australia Guide to Photographing Flora, Photography and text Steve Parish. Steve Parish Range/Pascal Press