Digital Camera Lenses and Focal Lengths

Lenses are a key part of your creative arsenal in photography. They allow you to crop in or zoom out and to frame and re-frame a composition to your hearts content. Lenses can help draw attention to a subject by blurring the background, or by keeping every detail sharp as far as the distant horizon. They can magnify distant subjects so they fill the frame or make them look quite small. They can squeeze a tall building into a single frame, even if you are standing right next to it. With the right lens on your camera, the whole world is your photographic plaything.

After you decide which DSLR camera is best for you, you can start buying all the fun lenses that go along with it.

The first thing you should know about a new lens for your DSLR camera are the parts of it and what all the numbers and letters mean.

My Canon Zoom Lens EF 75-300mm
My Canon Zoom Lens EF 75-300mm | Source

Most lenses carry a series of letters and numbers on their barrels. These tell you the features and functions that the lens offers. Here's a guide to some of the terminology you will see on your lens.

  • EF (Electronic Focus) - Used to denote Canon's range of autofocus lenses.
  • EF-S (Electronic Focus, Short) - Digital-only lenses that have a short back focus for non-full frame DSLRs.
  • IS (Image Stabilizer) - An in-lens system that detects camera shake and corrects it in the lens itself.
  • USM (Ultra Sonic Motor) - A focus motor offering fast and quiet focusing.
  • DO (Diffractive Optical element) - A combination of lens elements used to combat chrmoatic aberration (colour fringing) and reduce lens size.
  • AF-D (Distance) - The lens supplies distance information to the camera to assist focusing.
  • AF-I (Internal) - An internal autofocus motor used to speed up focusing.
  • AF-G (Genesis) - Similar to AF-I but features a newer internal drive motor and lacks a manual aperture ring altogether. The G classification is to be found on most new models.
  • AF-S (Silent) - These lenses feature a silent wave motor (SWM) which enables faster and quieter autofocus.
  • IF (Internal Focus) - A system used so that the lens doesn't change length during focusing. This gives a more compact design, a non-rotating front element and a closer focusing distance.
  • ED (Extra-low Dispersion) - A type of glass used to help reduce chromatic aberration (colour fringing) on lenses.
  • VR (Vibrations Reduction) - A system of sensors and tiny gyros inside the lens to help minimize problems with camera shake.
  • Micro - Nikon's term for macro. These lenses have a very short close focus distance allowing you to get very close to your subject.
  • DX (Digital Only) - These lenses are for all Nikon's digital cropped-sensor DSLRs.
  • FC (Full-Frame) - The latest DSLR sensor format from Nikon, with a sensor measuring around 36X24mm.

Focal Length

The focal length of your lenses are described in terms of their focal length, measured in millimeters, which in turn determines the lens's angle of view (how much of the scene you can get into frame). The shorter the focal length, the wider the angle of coverage. These are known as wide angle lenses. The longer the focal length, the narrower the angle of view. These are known as long or telephoto lenses.

The wide angle lens has the smallest focal length and allows you to get even more of the scene in your shots. You will notice that may wide angle lenses will overlap with the shorter end of your standard lens but the wide angle lens will usually go down to 10mm or 12mm at the shortest end for a greater angle of view.

Most DSLRs come supplied with a standard zoom lens. These lenses give you a range of focal lengths around 18-55mm. The lens is fine for most every day subjects such as landscape views, holidays and family outings.

18mm Zoom

At 18mm zoom you can see the whole door and windows and the sidewalk as well as part of the sky
At 18mm zoom you can see the whole door and windows and the sidewalk as well as part of the sky | Source

24mm Zoom

At 24mm zoom you can see the flag and most of the door and windows
At 24mm zoom you can see the flag and most of the door and windows | Source

55mm Zoom

At 55mm zoom you can see the whole flag
At 55mm zoom you can see the whole flag | Source

Although any lens longer then 35mm can be classed as a telephoto lens, you will find that the focal lengths for most telephoto zooms start between 55mm to 75mm. This means they are the perfect complement to your standard lens, with hardly any overlap. At the longer end they usually go to either 200mm or 300mm, allowing you to pick out distant subjects and magnify them in your image.

100mm Zoom

At 100mm zoom you can see almost all of the flag
At 100mm zoom you can see almost all of the flag | Source

200mm Zoom

At 200mm zoom you can still see part of the stripes on the flag
At 200mm zoom you can still see part of the stripes on the flag | Source

300mm Zoom

Zoomed in on the flag at 300mm you can see the stitching of the stars
Zoomed in on the flag at 300mm you can see the stitching of the stars | Source

A macro lens usually has a focal length of between 50mm and 105mm. The difference between macro and the normal telephoto lens is that macro lenses allow you to focus really close to the subject, allowing you to record small subjects such as flowers and insects at life-size magnifications.

When you are purchasing a new lens for your camera there are a few things you need to keep in mind.

  1. What focal length are you wanting to get?
  2. Which type of lens will best fit the needs you are looking for?
  3. Make sure the lens is the correct one for your camera (most lenses are not interchangeable with different cameras).
  4. You don't have to purchase every lens to get the picture you want.

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Comments 21 comments

Lynn S. Murphy 4 years ago

Great information and love how you pare it down and make it understandable. voted up!


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

Lynn S. Murphy - Thanks for the votes and the comment :)


krsharp05 profile image

krsharp05 4 years ago from 18th and Vine

Cassy, I love your new dingbat! Thank you for such a detailed explanation of lenses. I had to get my camera out and follow along. Very helpful information. -K


kelleyward 4 years ago

I love the tips you provided here. Voted up and shared! kelley


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

krsharp05 - There is so much information on your lenses :) I, too, now know what all those little numbers and letters mean! Glad you were able to follow along as well! Thanks for the comment :)


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

kelley - I'm glad you enjoyed my tips :) Thanks for the votes and Shares :) Always appreciated!


SidKemp profile image

SidKemp 4 years ago from Boca Raton, Florida (near Miami and Palm Beach)

Very helpful - meets me right where I am with my Cannon DSLR and my zoom telephoto and zoom wide angle. I'd like to get a macro lens next - getting into close-up photography!


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

SidKemp - Glad this helps you with your lenses. I don't have a macro yet either but I'm still having way to much fun with the two lenses I do have :) Amazing how just those two can keep me busy for hours! Thanks for your comment :) And good luck in your photography!


E V Thomas profile image

E V Thomas 4 years ago from India

good one :)


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

Thanks :)


billybuc profile image

billybuc 4 years ago from Olympia, WA

I love taking pictures, but I have never invested in decent equipment and I never take the time to really practice the art. I could learn so much from you.....I will be a much more loyal follower from now on. Maybe you can teach the teacher.


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

Billy - I've got so many more hubs in the works about photography and what equipment to use and what all the buttons and knobs mean :) Once I get back from vacation my life will be all about hubbing (when the kids let me that is LOL) I hope you do learn some great things from my hubs :) Just remember, it's not about how expensive or how much equipment you have, you just have to know how to use what you got! Thanks for the comment :)


soundtrack junkie profile image

soundtrack junkie 4 years ago from New Hampshire

great tips.. thanks for sharing


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

Glad you liked it soundtrack junkie :) Thanks for stopping by!


Simone Smith profile image

Simone Smith 4 years ago from San Francisco

This is SO USEFUL!! When I first started learning about lenses and focal lengths, I was so flummoxed. This Hub would have been a lifesaver for me back in my beginning photography class.

Thanks for the great photo demonstrations and that super helpful explanation of common lens feature acronyms.


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

Simone - There are so many little bits and pieces and acronyms on a lens that I too was overwhelmed at first. It really does help knowing what it all means and how to read it :) Thanks for the comment!


j-matlock profile image

j-matlock 4 years ago from Somewhere.

Great hub, thank you.


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

j-matlock - your welcome :) Thanks for the comment!


cam8510 profile image

cam8510 4 years ago from Columbus, Georgia until the end of November 2016.

I've just begun using a DSLR.Thank you for the descriptions of lens parts. I use a Sony Alpha 390 with Minolta film camera lenses. Most people are surprised to hear that the auto focus works with this set up. It is so much cheaper for lenses and I get to buy the best lenses Minolta ever made. My 50mm Minolta Maxxum AF is my favorite. Thanks again.


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC Author

cam8510 - Wow, I didn't know that set up worked either! I've never shot with a Sony, I started with a Kodak and graduated to my Cannon I have now. I do have a bit bigger Cannon on my wish list for Christmas so I might be learning a new camera all over again. Good thing it's mostly the same! Thanks for stopping by and the comment ;)


jainismus profile image

jainismus 3 years ago from Pune, India

Thanks for sharing this information. I found a page which readers of this hub may like: https://www.facebook.com/photo.equipment

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