Learning digital photography issue 2
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In photography, the sunny 16 rule is a method used to estimate correct daylight expo-
sures without using a light
meter. The rule is based on the
quantity of light falling on the
scene and or subject and was
given as an easy formula printed
on datasheets included in every
box of film sold.
Basically, the sunny 16 rule
says on a sunny day, set the aperture to f/16 and set the
shutter speed to the reciprocal
ISO number. For example, if
you set the ISO to100, set the
shutter speed to 1/100 second
or to the nearest shutter speed
to approximate the reciprocal
of the ISO setting. With the f-
number constant, the shutter
speed varies according to the
If youre shooting in manual mode, keep your camera set so
that youre ready for any photo opportunity. As a quick guide to
setting aperture in various
conditions, set the f-number as
shown in the following table:
The Sunny 16 Rule
Taking Sharp Photographs
There are many reason
why your photographs might not look as sharp
as youd like. The main causes:
Poor Focus. Focusing on the wrong part of the
image, being too close to your subject for the cam-
era to focus, or selecting an aperture that gener-
ates a very narrow depth
of field all contribute to poor focus.
Subject Movement creates blur in shots is if
your shutter speed is too slow.
Camera Shake can cause blur if you move
even slightly while taking the image. Use a higher
shutter speed or a tripod
to keep the camera still. Noise caused by high
ISO settings make a pho-to look pixilated, covered
with little dots all over. Watch your ISO settings
if you want crisp, clean photos.
August 2008 Volume 1, Issue 2
How to Read
Learning Digital Photography
Valda Hilley at the
Fitton Center for
101 S. Monument
Ave., Hamilton, OH
f/22 Snow or
Distinct with glare
f/16 Bright sun Distinct
f/11 Hazy or
Soft around edges
f/8 Overcast Barely visible
f/5.6 Heavy over-
cast or shade
On a bright
any subject is
f/16 at the
nearest to the
the ISO setting.
Page 2 email@example.com
A histogram is a graph (bar chart) that can help you evaluate a digital image. It shows the relative distribution of pixel color values
from black to white using a linear scale of 256 levels where 0 is solid black and 255 is pure white. The darkest shadow values are shown
at the left end of the horizontal axis, and the lightest values or high-lights are at the right end.
The peaks and valleys at each position across the graph represent the number of pixels at each level. A tall vertical line indicates a
large number of pixels, and a short line indicates a relatively small
number of pixels at a particular level. Together, all the vertical lines make up the shape of the histogram.
Use the histogram to judge the brightness of a shot image noting
that the greater the bias towards the left of the axis, the darker the image, and bias towards the right of the axis, the brighter the image.
If the image is too dark, adjust the camera's exposure compensation to a positive value and if too bright, adjust to a negative value.
How to Read Histograms
Values across the range with
gentle peaks, good exposure.
Mostly low values (weighted to
the left) for low key/dark images.
Mostly high values (weighted to
the right) for high key/bright
A sharp peak toward one
extreme or the other, with few
values across the axis indicate
over or under exposure.
A comb-like histogram indicates
a poor image with missing values
and too many of the same values.
Working with the Levels
Histogram Image editing programs have a tool called
Levels used to precisely determine and
adjust the brightness, color, and contrast of
an image. Like a cameras histogram, the Levels histogram shows the brightness of
the image, shadows on the left side and
highlights on the right, the distribution of
pixel values. The three triangles directly
beneath the histogram represent shadows
(black), highlights (white), and midtones
(gray). If an image has colors across the
entire brightness range, the graph extends
from black triangle to white triangle as
shown in the histograms for the pictures to
the left. The tones in these images are well
distributed from black (0) to white (255).
To adjust the black, white , and gray points
of an image 1) Drag the left triangle to the
right to the point where the histogram
indicates that the darkest colors begin. 2)
Drag the right triangle to the left to the
point where the histogram indicates that
the lightest colors begin. 3) Drag the mid-
dle triangle a short distance toward the left
side to lighten the midtones.
Page 3 Volume 1, Issue 2
June 30, 2008 Liberty Playland in West Chester. Nikon D80 fitted with an 18-135 F/3.56-F/5.6 zoom lens.
Camera settings (except where noted): ISO 100, Programmed Auto, Center-weighted metering mode. The images were cropped to fit space.
Shape is relative so theres no such thing as a correct shape for a histogram. Every image is different. Take a look at these three histograms.
Each is correct for the corresponding image yet different from image to image.
Many digital cameras include a histogram to
assist you in making proper exposures. Use the camera's histogram to evaluate the range of
tones in a capture, and if possible, reshoot the image with different exposure settings to get a
These landscapes have data distributed across
the entire axis of the histogram. This indicates a wide range of tones. If you have a histogram that
indicates a low dynamic range, or a lack of con-trast, you can use tools in an image editing pro-
gram like Photoshop to expand the range of values in the image.
A RAW file is essentially the data
that the camera's chip recorded
along with information about the
cameras settings. A JPG file is one that has had the camera apply white
balance, contrast, saturation, and file
Reasons to Shoot JPG
A JPG file directly from the cam-
era can often produce high quality
For many applications image
quality is sufficient (snapshots,
Files are smaller, more of them fit
on a storage card, and theyre
easily transmitted online.
Many people don't have the time
or desire to post process their
Many cameras cant shoot quickly when working in raw. Some cam-
eras can't record raw files.
Reasons to Shoot Raw
A RAW file holds exactly what
the imaging chip recorded. Noth-
To extract the maximum possible
image quality, whether now or in
The camera does not set white
balance when recording RAW
files. It tags them with the
camera's white balance setting
at the time you take the pic-
ture, but the actual image data
remains unchanged. This allows
you to set any color tempera-
ture and white balance you
want after the fact without
degrading the image file. Note
that once the file has had in
camera processing applied such
as in JPG files, you can no long-
er properly set white balance.
The raw file is tagged with
contrast and saturation infor-
mation as set in the camera, but
the actual image data has not been
changed. You can set contrast and
saturation on a per-image basis
rather than use one or two gener-
alized settings for all images.
About Valda Hilley
Ive had many occupations over the years; engineer, author, IT Consultant; photographer is
one that gives me great joy. Im eager to share it with you. -
Learn Digital Photography
Tuesdays 6:00 to 8:30 p.m.
Learn Adobe Photoshop
Thursdays 6:00 to 8:30 p.m.
At the Fitton Center for the Creative Arts
In Hamilton, Ohio
Get out and Shoot
Flora 1. Choose a focal length that will
give you the picture you want. (Zoom in or out) A macro