Chris Nelson. Master Guide for Glamour Photography: Digital Techniques and Images. 2007

(C. Jardin) #1
ever, use a sensor that is smaller than
that—meaning you’re not using the
full lens area that you are paying for.
As a result, all of your lenses become,
effectively, longer. Most cameras
with a smaller-than-35mm sensor
have a magnification factor of about
1.5. That means your normal 50mm
lens is effectively a 75mm. A com-
mon zoom lens like a 28–135mm is
effectively a 42–202mm. This is a
good thing if you want more tele-
photo out of your lens; it’s a bad
thing if you like wide angles. It’s a
good thing if you like a big depth of
field; it’s bad if you like it shallow.
Another thing that is not so ob-
vious is the fact that smaller-sensor
cameras do not use all the lens area.
The smaller sensors only use the cen-
ter of the lens. On the positive side,
this is the sharpest part of the image
formed by the lens, especially if you
are using a less expensive lens. If you
are using a good one, though, the
lens is designed to give you beautiful
fall-off of focus as you get toward the
edges of an image. With a smaller-
sensor camera, you’re not using this
natural vignetting. A quick glance at
Janilee’s portrait illustrates this effect
(facing page).
What really sets lenses apart is not
focal length, though, it’s speed. My
favorite lens for glamour work is the
Canon 70–200mm f/2.8 IS. It’ll set you back about $1600. A lens with a
similar focal length in an f/4 to f/5.6 will cost you only $300 to $400, but
you’re giving up two full stops, which could make the difference between
shooting at^1 / 60 second and^1 / 15 second. Those are two stops you’d really like
to have when it’s getting dark on your shoot. The image stabilization (IS)
gives you about another stop, maybe two, if you’re handholding the lens. So
you see how much more the faster lens lets you do.
You’ve already seen examples from my tire-factory session with Jennifer,
but an extreme example of the advantage of fast lenses comes from the
same shoot (next page). Shooting by street light only, I leaned on the bridge

DIGITAL TECHNIQUES AND ENHANCEMENTS 87

Angie’s image was taken as the sun was set-
ting. I was able to handhold the camera and
take the image f/2.8 at^1 / 40 second with the
camera set to ISO 100.

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