Short Description

Large SLR Lens Collection
giant Canon SLR lens collection If you own an SLR and you're serious about photography you'll start a lens collection. Håkan Dahlström's lens collection, via Flickr.

The easiest way to think about zoom is in terms of magnification, for instance a camera with a 4x zoom lens will allow you to magnify the image up to 4x bigger. Lenses get their zoom rating by taking the ratio between the longest and shortest focal lengths. So for example a 35-105mm lens will be rated as 3X ( 105/35 =3). The question you need to ask yourself though is magnified compared to what? That's a good question and we'll get to that in a second.

SLR vs Digicam

SLRs do not come with lenses built in, digicams do, that means you'll need a lens collection for your SLR, Although you may start with one you'll quickly feel the need to acquire more. Digicams on the other hand come with lenses built in, what they have is what you get.

Visual Difference Between Zoom Levels

When you hear 2X zoom you think twice as big, but that's actually not true. It's useful to understand zoom as a form of cropping. When you zoom in you take a crop of a portion of the scene and make it take up the whole image. Of course its done optically so you don't lose quality. When you zoom in 2X you capture 1/2 the height and 1/2 the width of your original scene. So 2X zoom means you can only capture 1/4 of the 1X image. The image below illustrates this difference - as you can see 8X zoom actually capture just 1/64 of the scene - which equates to a tonne of zoom - 64X the pixels of the zoomed in portion of the scene.

Visual Difference Between 1X, 2X, 4X and 8X Optical Zoom
image showing how much of a scene 1X, 2X, 4X and 8X zoom captures The following image illustrates how much area each zoom level captures of a scene. 1X zoom captures 100% of the scene where as 8X zoom captures 1.6% of the scene - a huge difference! Remix of Photo by Stuck in Customs via Flickr.

Examples of Different Zoom Levels

The following images each illustrates the zooms depicted in the scene above - illustrating the difference in a resulting photo.

Example of a 1X Lens
Example of 1X zoom of a scene This is the scene at 1X zoom, In this case 1X is 14mm so there is negative magnification relative to the human eye but a field of view that is close to the human eye.
Example of a 2X Lens
Example of 2X zoom of a scene This is the scene at 2X zoom, In this case 2X is 28mm so there is a slight negative magnification relative to the human eye and the field of view is smaller than the human eye.
Example of a 4X Lens
Example of 4X zoom of a scene This is the scene at 4X zoom, In this case 4X is 56mm which is similar to the magnification of the human eye but a much smaller field of view.
Example of a 8X Lens
Example of 8X zoom of a scene This is the scene at 8X zoom, In this case 8X is 110mm which is slightly more than twice the magnification of the human eye.

Travel Zoom Cameras

Here are some cameras, we refer to them as travel zooms, that are both compact and offer a high amount of zoom. These cameras represent an excellent compromise between size and zoom and are great for traveling. As you can see in the above example 8X zoom is quite significant and that is the minimum zoom we require for the travel zoom rating.

Sony Cyber-shot DSC-HX50V
Sony Cyber-shot DSC-HX50V
from $348
GPS Built-in GPS Help
Great for travel
Screen resolution High resolution screen Help
921k dots
3D Takes 3D photos Help
View photos in 3D on 3D televisions

Learn more about the Sony Cyber-shot DSC-HX50V

Panasonic Lumix ZS30
Panasonic Lumix ZS30
from $329
GPS Built-in GPS Help
Great for travel
Zoom Great zoom Help
20x
Touch screen Touch screen Help
Less buttons

Learn more about the Panasonic Lumix ZS30

Canon PowerShot SX700 HS
Canon PowerShot SX700 HS
from $329
External mic jack External mic jack Help
Record higher quality audio with a microphone
Screen resolution High resolution screen Help
922k dots
Movie format High resolution movies Help
1920 x 1280 @ 60fps

Learn more about the Canon PowerShot SX700 HS

Nikon Coolpix S9700
Nikon Coolpix S9700
from $60
Zoom Great zoom Help
30x
GPS Built-in GPS Help
Great for travel
Screen type OLED Screen Help
Bright and vivid

Learn more about the Nikon Coolpix S9700

Green arrow See more of the top travel zoom cameras

Understanding Zoom and Focal Length

Although there are technical definitions of what focal length means for the purpose of understanding a zoom rating its best to keep it simple. So we'll define focal length as the level of magnification you're getting, the more focal length the more magnification. On any given lens the shortest focal length represents the minimum level of magnification and the longest represents the most magnification, the ratio between them is the total zoom range of the lens. Most people would guess a 10x zoom lens would let them "see" 10x farther with their camera - but that's not true - you're actually getting less magnification than you think because part of the zoom rage is wideangle and has negative magnification - you need this for taking group shots and panoramic photos.

What a Zoom Rating Doesn't Tell You

Two cameras could both be rated 4x zoom and actually have different levels of magnification. For instance both these lenses are 3x zoom:

  • 35mm - 105mm (105/35 = 3)
  • 50mm - 150mm (150/50 = 3)

The problem is these are drastically different lenses - same magnification ratios but each covering different magnification spectrums. Not every camera has the same starting point (aka minimum focal length) and that's the best thing to look at.

Understanding Focal Length and Magnification

The best way to understand focal length is to use a point of reference. The best point of reference is the human eye. If you look through a camera and things appear about the same size than its convenient to think of that focal length as zero magnification - the focal length that corresponds to zero magnification happens to be about 50mm. If you look in and things are smaller its like negative magnification - you can fit more in the picture than you'd expect (we call that wide angle) - that's anything less than 50mm. Finally if you look in and things seem bigger than that's positive magnification - this is what you naturally think about when you think zoom, this applies to focal lengths great than 50mm.

Superzoom Cameras

Super-zoom digital cameras provide a minimum of 8X zoom with some cameras offering as much as 30X zoom, most offer at least 15X zoom. These offer incredible levels of optical zoom so that you can get close to the action regardless of where you are. Great for sports and wildlife photography when you're a significant distance from your subjects.

Canon PowerShot SX50 HS
Canon PowerShot SX50 HS
from $379
Zoom Great zoom Help
50x
Supports 24p 24p movies Help
For that film look
Screen flips out Flip-out screen Help
Great for movies

Learn more about the Canon PowerShot SX50 HS

Sony Cyber-shot DSC-RX10
Sony Cyber-shot DSC-RX10
from $998
True resolution High true resolution Help
20 MP
Sensor size Large sensor Help
Nikon CX 13.2x8.8mm
Overall image quality Great image quality Help
69.0

Learn more about the Sony Cyber-shot DSC-RX10

Nikon Coolpix P600
Nikon Coolpix P600
from $427
Zoom Great zoom Help
60x
External mic jack External mic jack Help
Record higher quality audio with a microphone
Screen flips out Flip-out screen Help
Great for movies

Learn more about the Nikon Coolpix P600

Sony Cyber-Shot DSC-HX300
Sony Cyber-Shot DSC-HX300
from $398
Zoom Great zoom Help
50x
Screen flips out Flip-out screen Help
Great for movies
Screen resolution High resolution screen Help
921k dots

Learn more about the Sony Cyber-Shot DSC-HX300

Green arrow See more of the top super zoom cameras

Digital Zoom

Digital zoom is not zoom, it is simply an automated way of cropping the picture and resizing it back up creating the effect of zoom by "zooming in on the image". This crop ends up creating the same effect as zoom but quality is sacrificed as only a portion of the sensors resolution is used. Optical zoom on the other hand uses all of the sensors resolution. We highly recommend you never use digital zoom and turn it off on your camera settings so it doesn't engage.

Optical Aberrations in Zoom Lenses

The greater the zoom on a lens the more likely there is to be some form of optical distortion, typically chromatic aberration and field curvature, and especially at the high end of the zoom range. Nonetheless, most consumers may not even notice the effects given gains made in construction techniques of compact lenses that correct reasonably well for problems. The alternative is to own an SLR and with a huge collection of lenses that will provide a equivalent range to a super-zoom, this is likely an order of magnitude in additional cost to a super-zoom and for most people spending 10x the amount isn't an option.

Conclusions

  • 8X or greater zoom is significant - up to 64X the print size of a distant object
  • The lens on most digicams is both telephoto and wide angle so the magnification relative to your eyes will be about 1/2 as much

Related Info

Discussion

Showing 13 comments

Avatar for GunnyNinja GunnyNinja (1:23 AM, May 23, 2014)
There is nothing impolite about correcting mistakes, only in how you do it, kinda like your inferring that Anon did it to "appear smart". Notice how his rather polite critique was corrected, but your snarky one was not. This reminds me of a saying involving pots an kettles...
 
Avatar for torr10 torr10 (5:06 PM, December 05, 2013)
If you're going to be that picky and try to appear smart...perhaps you should also mention that 'it is' should be abbreviated with an apostrophe. Pointing out one typo while overlooking another so close by is not very smart, nor polite.
 
chris (8:32 AM, June 05, 2013)
ur dads a dick u slag
 
Sheila (11:20 PM, January 22, 2013)
What is this new "super resolution zoom" that olympus has in it's TG an SZ cameras? How is it different from digital zoom?
 
Avatar for Cp Cp (0:15 AM, December 15, 2012)
If I had a 35-105mm zoom lens on my old Canon AE-1 film SLR and I want a similar zoom on a DSLR camera, I understand the mm are different. Can someone please remind me if I've got this right... I was told at Penn Camera that the new zoom for the DSLR would be 18-135mm. Is that correct anyone?
 
Thapa (6:52 AM, October 31, 2012)
woowh....info really helping me to learn photography... thanks a lot
 
Ranjini (11:13 AM, September 24, 2012)
Thanks so much ! Finally the pieces of the puzzle fit !
 
Mitch (10:08 AM, June 10, 2012)
Good info i found this very useful.
Cheers
 
shruti (2:26 PM, May 02, 2012)
Can you explain how 42x zoom is 40% higher than 35x zoom? refer to your comparison of Canon SX40 vs Nikon P510.  
 
mom (5:42 PM, September 05, 2011)
Is the samsung wb210 a good travel zoom camera for an amateur
 
 
Vt_ms (6:51 AM, August 04, 2011)
incompare of Canon IXUS 115HS vs Fujifilm S4000 in this page : http://snapsort.com/compare/Canon-IXUS-115HS-vs-Fujifilm-S4000you specify for Fujifilm S4000 :" 30x vs 4x Around 56.5x more zoom "Can you explain how computed "56.5x" more zoom?because 30/4=7.5 not 56.5thanks.
 
Avatar for Snapsort Snapsort (4:19 PM, April 05, 2011)
Thanks, we'll fix that!
 
Anon (3:05 PM, April 05, 2011)
Typo in 3rd paragraph (Visual Difference Between Zoom Levels):
"Of course its done optically so you don't ->loose<- quality."
"loose" should be "lose"