PART 2: UNDERSTANDING THE NUMBERS ON LENSES:

HERE WE GO! UNDERSTANDING ALL THOSE NUMBERS

You have your new camera, and so far you like it. Now it’s time to look at adding more lenses to your equipment. Not sure what all those numbers mean? That is what we are here for!

WHAT DOES THE FIRST SET OF NUMBERS MEAN?

As you look at the top of your lens, or the front of your lens, the very first set of numbers, or number, tells you what the focal length of your lens is. For example the photo above show the focal length of your lens to be: 24-105mm. How does that equate to anything? Here is your reference point:

A normal lens is one who’s focal-length is equal to the diagonal of the sensor or film. This is said to give a natural perspective similar to that of a single human eye.

On a full-frame DSLR, it is usually a 50mm lens. On a cropped-sensor (APS-C) DSLR, a normal lens falls around 35mm but from 30 to 55mm, it would still be considered normal. For Four-Thirds and Micro Four-Thirds, you would use a 25mm. Usually most manufacturers make sure to have one bright prime that corresponds to the normal focal-length for the sensor-size.

Then going back to the lens above, let’s suppose your camera is a DSLR camera. The normal lens would then be about 30mm. If you were to look through the lens, it would appear that the image is the same size as what you see, without the camera. Then, if you go below the number 30mm you enter the range of wide angle lenses. Which means that the lens pushing the image back further to get more into the picture.

Definition of “WIDE ANGLE LENS”

(Photography) a lens system on a camera that can cover an angle of view of 60° or more and therefore has a fairly small focal length. Any number that is less than 30 is therefore a wide angle lens.

Definition of “telephoto” lens:

A telephoto lens is a lens that appears to magnify distant objects. To do that, they need to have a focal length longer than that of a normal lens, or a lens that approximates the optical qualities of the human eye. A normal lens has a focal length of 30mm on a full frame camera so any lens with a focal length longer than 30mm can be considered a telephoto lens. The longer the focal length, the more magnification there is.

WHAT IS THE PROPER USE OF WIDE ANGLE AND TELEPHOTO LENSES:

Generally, a normal lens (around 30mm) is used for…. normal everyday use. Photos of the family, the dog, the cat, the things around the house.

A wide angle lens is most popular for landscape or scenic photos, to get the whole picture into the frame.

And the telephoto is generally used to bring objects in closer to you. The most common use is for wildlife, sports, and things from afar.

NEXT SET OF NUMBERS:

CANON ZOOM LENS WITH ALL THE NUMBERS.

THE “APERTURE RANGE”

Every lens has an aperture in it. It controls the amount of light getting through the lens. This has another major function that photographers really use and that is the “depth of field”. That has been discussed before in a previous blog. JUST : CLICK HERE

It is usually expressed in f-stops such as f/1.4 and stated on the name of the lens. For example, the Nikon 35mm f/1.4G lens has a maximum aperture of f/1.4, whereas the Nikon 50mm f/1.8G has a maximum aperture of f/1.8.

One lens, and several different aperture openings:

Here is where it can get interesting and you can see why the price of a lens goes up. Listed below is a list of Nikon lenses. And they are all 50mm lenses. You can see the Nikkor lens 50mm F1.8 lens lists for only $134.95. Now go to the second lone on the list: Nikkor 50mm 1.4D lens. It sells for $369.95. And go to the top one: the 50mm f1.2 lens sells for $724.95.

50mmf/1.2NIKKOR 50mm f/1.2FXM$724.95Get a quick view for the NIKKOR 50mm f/1.2
50mmf/1.4AF Nikkor 50mm f/1.4DFXAF$369.95Get a quick view for the AF Nikkor 50mm f/1.4D
50mmf/1.4AF-S NIKKOR 50mm F1.4GFXAF-S$449.95Get a quick view for the AF-S NIKKOR 50mm F1.4G
50mmf/1.4NIKKOR 50mm f/1.4FXM$469.95Get a quick view for the NIKKOR 50mm f/1.4
50mmf/1.8AF Nikkor 50mm f/1.8DFXAF$134.95

The difference between each 50 mm lens is that the f1.4 lens lets in almost twice the amount of light through it than the f1.8 lens. I don’t know how many actual lens elements are in each lens, but, say they have 14 elements in the lens. That would mean the f1.4 lens elements, all 14 of them have to be made larger than the f1.8 lens. But if you are a person who wants the lens to be able to shoot in lower light, then the f1.4 lens is a better choice. Better still, the f1.2 which doubles the amount of light transmission would even be better. But you would end up paying for all those elements in the lens housing to be bigger than the previous version.

So, in summary on this number, the lens with the smallest number, let’s a lot more light through the lens than a lens with a bigger number. And that allows you to also have a depth of field even smaller, but, the usual case for having a lens with a lower aperture number is usually to allow you to shoot in lower light.

THE LAST IMPORTANT NUMBER:

Most lenses have this important number on it. It is a 2 digit number with a circle and a line through that circle.

THE FINAL IMPORTANT NUMBER TO KNOW IS THE FILTER SIZE THE LENS TAKES.

On this photo above, all lenses (at least I think almost all lenses) have a number to tell you what size filter this lens takes or the size of the lens cap. If you are a photographer who uses filters (and I think all photographers should use filters), you will appreciate knowing what size filters you would need to enhance your photography. On this lens above, the filter size is a 72mm. That is a big filter, but certainly good to know. If you would like to learn more about using filters, CLICK HERE AND one more link: CLICK THIS ONE TOO

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