The Photo Lab File Server

Photography & Digital Design
DVD 2 start to 19:20
Jump Start Your Photos #2
Get the Picture / Camera Functions / Lenses
The Three Planes of Focus
Park Bench
Middle Ground
Row of Cars
“Normal Lens”
Sees what you would see with the “naked eye”
Viewing Angle =
Same as the naked eye
Depth Perception =
Same as the naked eye
“Wide Angle Lens”
Viewing Angle =
Depth Perception =
Wider angle than a normal lens
Exaggerated Distances
The Three Planes of Focus are Farther Apart
Some distortion: Close items appear larger
Distant items appear much smaller
Viewing Angle =
Narrower angle than a normal lens
the stronger the lens, the narrower the angle
Compresses the Three Planes of Focus
The Three Planes are condensed
and closer together
“It isolates the subject”
also called a “short lens”
“Telephoto Lens”
also called a “long lens”
Depth Perception =
“Zoom Lens”
A “variable focal length lens” (as opposed to a “prime lens”)
could be just wide angle (18-35mm) ,
or wide angle + normal (28-55mm)
or normal + tele (50-150mm)
or could be all three, wide + normal + tele (28-105mm)
or could be just telephoto (80-250mm)
(all above mm sizes assume full frame DSLR or 35mm film camera)
Photographing Portraits…
Wide Angle Lenses = usually never used, very distorting and unflattering
Normal Lenses = Portraits still look unflattering
Telephoto Lenses = best choice, most pleasing. Manny recommends 85-105 mm (full frame sensor)
Jump Start Your Photo -- Lenses (con’t.)
Dissecting the Lens
What is a Lens ?
A group of optically ground glass that
collects the light at one end
and focuses the light at the other end.
Focal Point is on the
Focal Plane
(film or sensor)
Why multiple pieces of glass? All colors of light focus differently.
Set lens on infinity, 
The distance from the “optical center” to the point of focus (in mm) = Focal Length of the lens
The numbers below are for a 35 mm film camera or a “full frame” digital sensor.
Normal Lenses
Wide Angle (or short) Lenses
35mm or smaller
Telephoto (or long) Lenses
70mm or longer
Going beyond the DVD…..
Our Canon DSLR cameras use an APS-size sensor. That is smaller than “full frame.” The “Factor” to convert is 1.6 to 1
That means if you take the size of the Canon DSLR lens and multiply it by 1.6, you will get the “full frame” equivalent.
Likewise if you take the size lens you want based upon “full frame” numbers,
you would divide that number by 1.6 to get the lens size you would need for the Canon DSLR.
So for our Canon Digital Single Lens Reflex Cameras a Normal lens would be 50/1.6 = 31.25 or about a 30mm.
A Wide Angle Lens would be 35/1.6 = 21.875 or about 22 mm.
Most people view the 24 mm and below as a wide angle lens
A Telephoto lens would be 70/1.6 = 43.75 or about 44mm or longer.
We have some 50mm “prime lenses” for our portrait use.