| Macro photography technically starts
at 1:1 magnification. This means that the subject appears at life
size. Anything less than 1:1 is strictly speaking close-up photography
rather than macro. Some macro lenses (typically 100mm and over
in focal length) can achieve 1:1 (1x) but some of the shorter
50mm macros frequently only reach 0.5:1. However, greater magnifications
are obtainable by adding extension tubes or bellows. To read about
choosing and using macro lenses click
here.
Canon also makes a lens called the MP-E 65 mm macro which begins
its work where the other macros finish and it is capable of covering
the range 1x to 5x magnification without using extension tubes.
It is a very specialised lens as it cannot focus to infinity and
it is manual-focus only. At these magnifications autofocus is
more of a hindrance than a help, so that is no bad thing.
The working distance of this lens can be very restrictive - around
4 inches at 1x, down to just 1.6 inches at 5x magnification, so
subjects have to be very tolerant and co-operative. The depth
of field (DOF) at these magnifications is unbelievably shallow
(down to less than 0.1mm at wide apertures at x5). To see a table
of DOF vs aperture
click here. The image in the viewfinder becomes pretty dark
when the lens is extended out to 5x.
As can be seen in the tests performed below, the lens suffers
badly from the effects of diffraction at small apertures so you
have to choose between depth of field vs image softness when selecting
the aperture to use. Finally, when working at high magnification
at small apertures, you see every dust or oil spot on your sensor
with irritating ease - so be prepared to do lots of work with
the healing brush in post-process !
Canon Mp-e 65mm macro
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The lens is therefore not for the faint-hearted and is challenging
to use successfully. At high magnification, every movement or vibration
becomes amplified enormously and unless the subject and camera/lens
is clamped totally still - such as in a studio environment you will
get motion blur or poorly focussed shots. You will probably also
need to use a remote cable release and lock the camera mirror up
as well to reduce vibration. Many macro shooters therefore tend
to opt for the much easier option of using high-speed flash as the
sole light source. This enables a great deal of freedom by permitting
handholding, as the very short flash duration arrests all movement.
I have used a Canon 580exII flashgun fitted to the hotshoe angled
down slightly in the bounce position with a Lumiquest
Ultrasoft diffuser fitted with good results. Alternatively
off-camera flash can be provided by a single regular flashgun
held on a pivot arm close to the subject (fed by an off-camera
lead).
Finally there are the MR14-EX ring flash and the MT-24EX twin
flash which are the perfect partners for the lens. All images
in this article were taken with the MT-24EX diffused with Stofen
omnibounce diffusers. I use the flash heads in the position shown
below, adjusted 1 click up from the fully down position.
When flash is the sole light source, black backgrounds become
the norm unless the background is very close behind the subject.
(You can use a coloured card close behind the subject if the subject
will let you). The dedicated ETTL (evaluative through the lens)
flashguns are fantastic as they take away the need to do a lot
of complicated and laborious calculations to work out the exposure.
It becomes possible to use the camera as a very sophisticated
point-and-shoot when set up as follows:
Camera to manual mode, flash metering set to evaluative (on the
flashgun), the flash synchronisation speed set to e.g. 1/250th
sec (see your user manual) and the aperture to your own preference
(say f11 for starters). ISO to 100 for maximum quality if your
flash is powerful enough to deliver sufficient light, otherwise
use a higher ISO. However, the bit I skirted around here was "focus"
because this is where the user's skill comes in. More on this
later. I should also add that the camera's flash metering is excellent
but not foolproof - so you may have to consider appyling positive
or negative flash exposure compensation (FEC) just as you would
have to apply exposure compensation in general (available light)
photography when the scene does not equate to a midtone grey.
What do these magnifications look like ?
The following images are uncropped except the last one, which is
a 100% crop (i.e. as the image would appear on the computer screen
in Photoshop at "Actual Pixels" size.)
|
Butterfly's wing 1x |
|
Butterfly's wing 2x |
|
Butterfly's wing 3x |
|
Butterfly's wing 4x |
|
Butterfly's wing 5x |
|
Same 5x image at 100% |
What aperture to use -
the effects of diffraction.
Although this is an f2.8 lens, I have not used f2.8 or f4 as the
depth of field is so thin at these aperures as to be virtually
useless for macro work unless you are after something very "arty"
so I have excluded these apertures from the tests below.
1x
|
|
f5.6 |
f8 |
 |
 |
f11 |
f14 |
|
|
f16 |
|
| 2x |
|
|
|
f5.6 |
f8 |
 |
 |
f11 |
f14 |
|
|
f16 |
|
| 3x |
|
|
|
f5.6 |
f8 |
|
|
f11 |
f14 |
|
|
f16 |
|
4x |
|
|
|
f5.6 |
f8 |
|
 |
f11 |
f14 |
|
|
f16 |
|
5x |
|
|
|
f5.6 |
f8 |
|
|
f11 |
f14 |
|
|
f16 - The ring is an oil spot from the
shutter lubricant on the camera sensor |
|
Conclusions on aperture
At all magnifications the wider apertures provide the sharpest
images. F16 provides much greater depth of field than f5.6 of
course but loss of sharpness due to diffraction is significant
and gets progressively worse as magnification increases. The user
will have to juggle the choices between the depth of field required
to get sufficient of the subject in focus vs sharpness at each
aperture
From these results I would recommend using the following settings
if you are after high quality and reasonable depth of field:
| Magnification |
Maximum
aperture |
1x |
f14-f16 |
2x |
f11-f14 |
3x |
f8-f11 |
4x |
f8 |
5x |
f5.6-f8 |
Alternatively, you could try using f16 up to 2x magnification
and f11 thereafter. It is easier to remember and will still yield
great results biased slightly towards depth of field.
Focusing the lens
There are two methods of focusing on your subject. You can either
set the lens to the desired magnification and just move the camera/lens
in and out by moving your body until the subject comes into focus
or start at the lowest magnification and gradually increase it
by turning the focusing ring while simultaneously slowly moving
your body toward your subject. I tend to do the latter as it can
be very difficult to locate the subject in the viewfinder at high
magnification - it is a bit like looking for a needle in a haystack
down a dark, out-of-focus tunnel !
In the field, unless your subject is static and you have time
to set up the camera on a sturdy tripod, hand-holding with flash
is a far more practicable option as most macro subjects have a
habit of scuttling away or flying off. The difficulty is focusing
on the subject as the image continually moves in and out of focus
in time with the photographer's swaying. You get a lot better
with practice, but it is very difficult to work freehand above
2x magnification unless you are very steady indeed.
There are a few things that you can do to increase your chances
of keeping the camera still. Firstly, I hold my breath at the
critical time, secondly, I brace the camera or camera arm on my
knee or against a tree/log/rock/the ground or anything nearby
if possible. Also, some creatures will allow you to hold the stem
or leaf that they are on while you twist it or move it backwards
and forwards into a better position.You do this with one hand
while holding the camera with the other hand. It's not as bad
as it sounds. It may also be possible to simultaneously rest your
camera hand on the arm/hand that is holding the stem/leaf or whatever
the creature is on. This additional bracing can be very effective.
It is even possible to slide the camera backwards and forwards
along your arm or hand to focus it. This all sounds a bit impossible
until you try it, but it is really not as bad as it seems.
If you have a very static subject which allows you to set up the
camera on a tripod you will find that a focusing rail or a long
quick release lens plate that enables you to slide the whole lens/camera
back and forth will make life much simpler as the only alternative
is to move the tripod itself.
A right angle finder is a great aid to focusing and prevents a
stiff neck if working at ground level, but if your camera has
"Liveview" it is incredibly useful as a focusing aid.
Ensure that exposure simulation mode is switched to off in the
custom functions or the image will darken excessively as you stop
it down at small apertures. You can then get the manual focus
absolutely spot-on at 10x view in the screen. This is exactly
what I did to obtain the images of the butterfly scales in this
article.
In summary
The MPE-65 is tricky to use, but the potential rewards are very
high for those prepared to master it. It is an incredible lens
as it enables you to explore the world in an entirely different
way. Familar subjects such as common insects reveal that they
are covered in hairs or have flight stabilisers or extra eyes
that you didn't know that they had. For example, the hornet below
has three extra eyes (occelli) on the top of its head - and even
wasps have them too. When focused correctly and used at the correct
aperture for the subject, this lens is capable of very sharp and
vibrant images.
For all the reasons covered in this article, I would not recommend
this lens to a beginner - I would suggest getting getting used
to handling a normal macro at up to 1:1 first. For my other tutorial
on choosing and using macro lenses, please click
here.
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