Lenses #1 - Introduction to DSLR lenses.

[RichardTaylor]

Lenses #1
Introduction to DSLR lenses.

I see lots of questions regarding lenses on the forum.
This multipart series is an attempt to help.

A lens has two main properties:
(1) Focal length, expressed in mm (millimetres)

The focal length determines how much how much of a scene the camera can record and perspective - a future posting.

Low numbers are "wide angle" ie: "get it all in".
For a "consumer/crop frame" DSLR they will start at around 15-18mm for a wide angle and 10-12 mm for an ultra wide angle.
For a full frame" DSLR they will start at around 24mm for a wide angle and 18mm for an ultra wide angle

eg; Scenery

(Example #1)

Canon 350D (RebelXT) with Tokina 12-24, F4 lens.
ISO 400, 1/30 @ F4 & 12mm. Hand Held.

or for when you don't have a lot of working distance to your subject.

(Example #2)


Taken with the same lens/camera combination, probably at 12mm.

Large numbers are telephoto lenses which are ideal for filling the frame from a distance.
For a "consumer/crop frame" DSLR they will start at around 50mm.
For a full frame" DSLR they will start at around 75mm.

They are ideal for filling the frame from a distance, especially when you can't get close.

(Example #3)

Camera Canon EOS 40D
Exposure 0.002 sec (1/640)
Aperture f/5.6
Focal Length 310 mm
ISO Speed 400

or for picking out detail
(example #4)

Camera Canon EOS 40D
Exposure 0.003 sec (1/400)
Aperture f/5.6
Focal Length 400 mm
ISO Speed 200
Exposure Bias -2/3 EV

---------------

(2) Aperture
How much light the lens will let in which is determined by the aperture (size of the hole) in the lens. Aperture is expressed in F stops (numbers) and as it is a ratio it may be a bit confusing. Low F numbers let in a lot of light, increasing the F number stops more light.

I won't completely re-invent the wheel.
See the second part, aperture, of this tutorial (on this site).
Exposure (2) ISO + Intro to Aperture

and this one

Exposure (3): Aperture

======================
More to come, including.

Zooms & primes.
Edit:
For a good introduction to zoom and prime lenses see this post (on this site).
http://www.digital-photography-schoo...which-are-best

(2) "Standard" zooms
Lenses #2 - Standard lenses

(3) Super zooms.
Lenses #3 - Superzooms.

(4) Wide angle zooms.
Lenses #4 - Wide angle.

(5) Telephoto -
Lenses #5 - Telephoto

(6) Fast lenses.
Lenses #6 - Fast lenses

Thanks for looking.
Feel free to ask questions and feedback would be appreciated.

Richard

[mfalcon009]

Thanks for the nice tutorial. Just bought my first D SLR and this tutorial really helps us as beginners.

[RichardTaylor]

Thanks very much and glad to help out.

[FlyingKiwiGirl]

I love your tutorials Richard, easy to read, concise and in plain English. I read and reread them many times as I learn more and more about my camera and photography. Thanks for your efforts.

[RichardTaylor]

Thanks very much.

[MoreLightTheBetter]

Richard i must say your tutorials are simply PERFECT!!

Even though ive been into photography for about a year, i still consider myself a noob and reading your well thought out and put together tutorials always makes it a better day.

Just wanna say thanks for that and keep doing what your doing!!

[RichardTaylor]

Thanks MoreLightTheBetter

[Jakama]

Hi Richard, just thought I'd add my thanks and gratitude for your tutorials, technical advice and tips. They're very much appreciated and are a godsend for the many of us who are new to photography and who have found it both stimulating and fustrating in all its complexities. I look forward to reading more of them.

PS: great pictures mate

[RichardTaylor]

Thanks mate.

[JhunSals]

Thank you for your tutorials Richard. It help me a lot.