Different Ways of Getting Close
text and photography © Rod Barbee
First of all,
let's define some terms and start off with a common language. One term is
life-size. What this refers to is the size of the subject on 35mm film. Life
size on film means that if you take your slide (or negative) and place it
next to the actual subject, the subject on film and the real subject will be
the same size. Half life-size means that the subject on the film is 1/2 the
size of the real subject. Twice life size....well, I think you get it.
These terms are also sometimes referred to as magnification ratios. A ratio
of 1:1 is the same as life-size. A ratio of 1:2 means half life-size, 1:4 is
1/4 life-size. 2:1 is twice life size. These ratios are often engraved or
imprinted on the focusing scales of some macro lenses.
Understanding these terms will make the concepts of close-up photography
easier to grasp.
(With digital, it gets a little bit more complicated, what with all the
different crop factors out there. Suffice it to say, if you use the
techniques described below, just multiply the magnification by your camera's
crop factor to end up with total magnification for your camera.)
So let's look at a few ways of getting closer.
Extension tubes:
When a lens focuses, it's really moving the glass back and forth, the
farther away the lens is from the camera body, the closer you can focus. So
by adding extension tubes, you essentially "extend" the focusing range of
the lens, allowing you to focus closer to your subject. Extension tubes are,
as the name implies, just tubes; there's no glass in them at all. You will
loose light however, the more extension the greater the light loss. For
example, A 50 mm tube will cost you about 1 1/2 stops of light.
To determine the magnification you'll get by using extension, use the
following formula:
Extension divided by focal length equals magnification.
For 35mm film or full frame sensors, a 50 mm extension tube on a standard
100 mm lens will yield a magnification ratio of 1:2, or 1/2 life-size. A 50
mm extension on a 50 mm lens will yield 1:1, or life size on film. So more
extension means more magnification. For instance, 75 mm of extension on a 50
mm lens yields 1.5x life size on film. Any lens will focus closer with
extension.
Micro/Macro lenses:
These lenses yield the best quality but at a high price. Typical focal
lengths are in the 50 to 60 mm range, the 80 to 105 mm range, and the 180 to
200 mm range. There are also some true macro zooms like the Nikon 70-180 mm
zoom.
As the focal length increases, so does the price; a typical 105 mm macro
lens from the major manufacturers will run about $600.
As the focal length increases so does the working distance. With a 200 mm
macro you'll be about twice as far from your subject than if you were using
a 100 mm macro, for the same image size. As the focal length increases,
background coverage decreases; you'll have better background control. A 200
mm lens will have a narrower angle of view than a 100 mm lens.
Many newer micro/macro lenses will focus to 1:1 all by themselves because they have built in extension. Some will focus to 1:2 but require an extension tube to get to life size. Lenses with built in tripod collars (usually the 200 mm range) are a great benefit.
Zoom lens macro setting:
Many zoom lenses will have a "macro" setting. This setting is usually
limited to around 1:4 magnification (1/4 life size). As mentioned, there are
some true macro zooms.
Using extension with a zoom lens:
As stated before, any lens will focus closer with extension. This applies to
zoom lenses as well. Using an extension tube (or two, or three...) will
allow you to create some very high quality close-ups. This option is a
little awkward to use however. Every time you zoom in or out you'll change
your magnification ratio. Your focus point will also change. When you change
focus you actually change extension too. So every time you refocus your
magnification will change slightly. You'll end up working in a back and
forth manner; changing one parameter will change another.
Two-element close up lenses: (not to be confused with micro/macro
lenses).
These accessories screw into the filter thread of the lens, just like a
filter. Only they're not filters, they're magnifiers. For the money and
quality, this is probably the best way to go. Close up lenses are usually
used in conjunction with zoom lenses in the range of 70-300. By stacking
these little wonders, magnifications of 1:1 or better may be achieved. They
may also be used on micro/macro lenses to increase magnification. One great
advantage these have over extension tubes is that they exhibit no light
loss.
Be sure to get the quality two-element close up lenses, like those made by
Nikon or Canon, the single element close-up lens sets sold by some filter
manufacturers will do the job, but not with the same quality.
Here are the designations for the Nikon and Canon close-up lenses:
Nikon:
3T and 4T have filter thread size of 52 mm. 4T is stronger. $30-35
5T and 6T have filter thread size of 62 mm. 6T is stronger. $45-50
3T and 5T are rated at 1.5 diopters
4T and 6T are rated at 2.9 diopters (if that means anything to you)
Canon:
250D ("D" stands for "Dual" element): Designed for lenses in the 30-135 mm
range
500D: Designed for lenses in the 70-300 mm range.
The canon close up lenses come in filter thread sizes of 52 mm, 58 mm for the 250D and 52 mm, 58 mm, 72 mm and 77 mm for the 500D. Prices range from about $70-140. Canon also makes single element close up lenses for less money ($30 to about $80) but they are of less quality.
These two-element close up lenses placed in front of a medium to telephoto zoom (70-210, 80-200, 70-300...) make for a convenient, light, and compact close up system. Because they are of such high quality, the quality of your image will be mostly limited to the quality of your main lens and your photographic technique. They're easy to use and produce good results. This is the easiest and least expensive way to get into close up photography.
Using these in the field will take a little bit of practice. You'll need to get closer to you subject but once you've got something in focus, you'll be able to zoom in or out whole only needing to slightly touch up the focus. Put one of these on your zoom lens, you'll quickly get hooked.
Some other options:
Stacking lenses. Use this formula to determine magnification: Prime lens/stacked lens = magnification.
If you have a 100 mm prime lens (mounted on the camera body) and stack a
50 mm lens, the magnification will be 100 mm/50 mm = 2, or twice life size
on film. Stack a 24 mm lens on the same 100 mm prime lens and you'll end up
with 4 times life size on film! Control aperture with prime lens. Stacked
lens should be set at widest aperture setting. Use a "stacking ring" to
connect lenses. This is just a ring with filter threads on both sides so
you'll end up with two lenses "face to face".
Reversing a lens on the camera body.
Reverse mount rings are available for the different manufacturers' cameras
(Nikon, Canon, etc.). The mounting ring screws into the filter threads on
lens, and the other side mounts onto the camera body. You'll be able to get
closer, but be careful you don't touch the rear element of the lens with
your subject. Reversing a 50 mm lens will yield approximately 1/2 life-size
(an area of about 2x3 inches)
Tele converters:
Tele converters won't get you any closer but they will magnify what you
already have. They won't fit on all lenses (usually matched for certain
lenses in a manufacturer's lens line) but will usually fit on extension
tubes. 1.4x converters will cost 1 stop of light and 2x converters will cost
2 stops.
Mix and match:
You can combine your equipment to achieve different results. If combining
extension tubes and teleconverters, place the teleconverter behind the
extension tube, this will yield the most magnification.
For example: If using a 300 mm lens attached to a 50 mm extension and a 1.4x teleconverter behind that you'll be able to photograph 1/4 life-size, or an area of 4x6 inches:
(50 mm extension /300 mm focal length= 1/6 life size (0.166x). Add the 1.4x converter and you'll end up with 1.4 X 0.166 = .23, or 1/4 life size.)
By using the same equipment and swapping the extension tube and teleconverter:
300 mm x 1.4 = 420 mm. 50 mm extension /420 mm = .12, or about 1/10
life-size, which is an area of about 10x15 inches.
So, for the greatest magnification attach the extension tube to the lens and the teleconverter to the extension tube: lens | tube | converter | camera body
This should get you started in the world of close up photography. For
more, read my article on
close up techniques.
Recommended reading: John Shaw's Close Ups in Nature