Digital Photography in Available Light

essential skills: digital photography in available light

The pentaprism is an integral part of the creation of the optical view in an SLR camera

The LCD screen of a DSLR is used to ‘review’ rather than ‘preview’ the image

Viewfi nders and LCDs

Single Lens Refl ex (SLR) cameras use a mirror and pentaprism design to display an optical view

of your subject in the viewfi nder prior to capture. The view is typically bright (especially if you have

a wide aperture lens fi tted) and detailed so that you can focus the image easily and quickly if you

have to switch to manual rather than auto focus. The image is not a ‘what-you-see-is-what-you-

get’ image as feedback on issues such as how the sensor will handle the subject contrast together

with the effects of your choice of exposure and depth of fi eld are not being previewed. A depth of

fi eld preview button is available on some DSLR cameras that allows you to preview the image with

the aperture stopped down to the one that will be used to capture the image rather than the widest

aperture which is normally used to provide the optical view. Although useful in some instances the

subject can appear very dark in the viewfi nder making precise depth of fi eld diffi cult to determine.

This information is now more easily viewed on the LCD screen and not in the viewfi nder after the

image has been captured. The prosumer digicam on the other hand has no mirror, pentaprism and

usually no optical viewfi nder.*

* Ricoh’s GR Digital uses an optional optical fi nder to overcome the shortcomings of EVF

technology. Leica has been developing a digital rangefi nder camera to supplement its range

of prosumer digicams, but at the time of going to press this camera has not materialized.

Although this camera would offer a signifi cant choice in the digicam range it is important

to note that the view from a rangefi nder camera does not mirror exactly what the sensor

sees and at close range there are the typical issues of ‘parallax error’ that is inherent with

all rangefi nder cameras. Allowances have to be made at close range to readjust the framing

from the view that is displayed in the viewfi nder.