Successful close ups – Some helpful hints
In close up photography depth of field
becomes more and more shallow (down to tiny fractions of an inch) the
closer you approach your subject. To help overcome the shallow depth,
use small f-stops whenever feasible, not only to increase depth but to
improve general image quality as well.
Remember that the marked f-stops on any lens
refer only to infinity position. As the lens is extended out for closer
focusing, actual light transmission decreases rapidly from the indicated
aperture. Restore the lost light by adding exposure time rather than by
using larger f-stops.
Depth of field in close ups is split 50-50
in front of an behind the point of focus. Therefore, when two equally
important picture elements are at slightly different distances from the
lens, try focusing halfway between them and stopping down all the way.
If this doesn’t bring them both onto focus, pick one to be sharp and
sacrifice the other. Or, better still, change the camera angle (or move
the subject) so that both are in the same plane of focus.
When copying flat material (photographs,
newspaper pages and so on) always keep the sensor plane and the subject
matter as close to parallel as possible and try to center the subject on
the lens axis.
In the close up range focusing cannot be
accomplished simply by adjusting the lens position. The entire
camera/lens assembly as a unit (or subject itself) must be moved back
and forth until a sharp image appears. Only then can fine tuning be done
with the lens focusing ring or the bellows knob.
The minimum focusing distance for an
ordinary (non macro) lens is about ten times its focal length, producing
images of one eighth to one tenth life size. To get closer, you need
close up lens attachments, extension tubes or bellows. For
magnifications greater than full life size, the lens should be reversed
so that the rear element faces the subject. This can be down with a
special reversing ring. Image quality will greatly improve, but you will
lose automatic control.
Like long telephoto shots, extreme close ups
suffer from shakiness and vibration. The smallest movement of camera,
lens or subject is magnified many times in the image. Therefore,
hand-held exposures should be taken only at the very highest speeds,
which is a problem because you must also use small stops to achieve
greatest depth of field. The solution is to utilize a sturdy tripod or
copy stand (along with slower speeds) whenever possible, tripping the
shutter with a cable release at least 30.5cm (12inc) long or a rubber
bulb air release. Outdoors remember to wait for the wind to stop.
If mirror movement during exposure still
causes too much vibration for extreme close ups, another method may be
used. Determine exposure time by tables or by counting the number of
seconds of auto exposure during a practice run. Then cover the lens with
a piece of black cardboard, set the shutter for a time exposure, and
release it. When all vibration has stopped, uncover the lens by hand for
the correct amount of time. Then cover it again and close the shutter.
Be careful not to have bright light shining into the lens around the
piece of cardboard, and be equally careful not to jiggle the setup when
moving the hand held “shutter”.
If subject size is important to know later,
include a ruler or other object of known dimensions in the picture along
with the subject.
A telephoto lens used with a short extension
tube makes a good combination for close ups where more camera to subject
distance is desirable.
Always go beyond mere technical competence
by arranging lighting, camera angles and backgrounds to present the most
interesting effects. Create pictures, not just snap shots.