Understanding the MM in your lenses, and what you might need:

When you first own your new dslr camera, most people buy it in a kit form, where it comes with one lens, strap, bag, camera, etc. And at first, most people don’t really understand all the numbers on their lenses. Today, I wanted to talk about 1 of the numbers on your lens, so that you understand it, what it can do, and what you might need next.

person holding film strip
35 mm film….. Photo by Markus Spiske on Pexels.com

Back when we had 35mm film, the standard lens was then: 50mm. What defines the standard lens, or what I liked to call it, the “normal” lens? When I worked at a camera store, the one thing we used to tell people was, “your 50 mm lens, is about the same as what your eye sees. We would take the camera with the 50mm lens, hold it up so the customer could look through the lens, then bring it down, and look with your eye at the same subject, and then back with the 50mm lens on the camera, and you found that the lens was the same as your eye, as far as magnification. There was none with the 50 mm lens.

Today we have the digital camera. And the 50mm lenses you had for your 35mm film cameras are just not the same. Every time you change the format of a camera, you change the “standard lens” or normal lens. So, the normal lens for a dslr camera is: approximately 28mm. Why would I say approximately? Because it depends on the format of your new digital camera’s sensor. Ha, you thought they were all the same, but, they are not. There is an APS-H sensor, An APS -C sensor, a FoveonX3 sensor, and a Four-thirds sensor. You would have to look at the specs of your camera to find out which one it was. But, the normal lens for a APS-H sensor, for example is roughly 30- 38 mm, where a normal lens for an APS-C sensor is: 25-32, and so on.

For sake of making things easy, let’s say all cameras’ normal lenses are 28mm. So, when you look through this 28mm lens, it looks about the same as what your eye sees: no magnification, just the same thing. Now, let’s play with this number:

Anything greater than this 28 mm, will be a telephoto lens. Everything smaller than the 28mm lens, will be a wide angle. Now, look at this:

A 56 mm lens (or closest to that number) is double the magnification of your normal lens (28mm). Or in other words, the 56mm lens will pull something that you would normally see, twice as close to you now.
Architectural Photography on M4/3 - 9-18mm vs OM 28mm with shift adapter:  Micro Four Thirds Talk Forum: Digital Photography Review
If 28mm lens is the new normal lens, then at 50mm (56mm is close enough), you also will lose the area that you would see, but, it would enlarge that area by double. And at 18 mm, or even 14mm, you would see twice the area as your normal lens.

Now, let’s look at other lenses. I have a lens that is 75-300mm. If we go by that magnification scale, it would be a lens that brings things closer by 3X to 9X magnification. At 300mm, that lens is now hard to handhold and get a sharp picture, unless I increase the shutter speed significantly. But, I have got used to putting my camera on a tripod when using this big lens.

Just for giggles: Olympus just announced a lens that will go from 300mm to 1000mm using the teleconverter it comes with.

The Olympus 300 – 1000mm lens is not for the faint of heart. The new super lens for sports and wildlife.
Focal Length and Angle of View — The Photo Video Guy

Notice in the diagram above, that by going from 28mm to 14mm you get twice the area in your image as the normal lens, even though the degrees of what you can see is going from 75 degrees to 114 degrees. Have you ever heard of a “Fish-eye” lens? Now, that is a super wide lens, and you get about a full 180 degree view. But, the lens may look like this:

Fisheye-Nikkor 6mm f/2.8 mounted on a Nikon F2 in the Nikon Museum.

You know what would make me nervous about using this lens, is you cannot protect the front element of your lens with a UV filter or Skylight filter. There is no way that it will fit.

The Squirrels 0048.jpg
And this is what your picture would look like with a fish-eye lens. A full 180 degrees. You can see the same sidewalk on both sides of the image.

Most camera manufactures today, make something called: A full-frame fish-eye lens:

Sigma 10 mm F2,8 EX DC HSM Fisheye.jpg
This is a “full Frame” fish-eye lens.
Image shot with a 16 mm full-frame fisheye lens before and after remapping to rectilinear perspective.
Conclusion:

A 28mm, is your normal lens, anything larger in number is a telephoto. A telephoto pulls things closer to you, much like binoculars do, only this is a single lens, pulling the image closer to you. A 280mm lens is 10X magnification.

Anything of a smaller number than 28mm is a wide angle, meaning it gives you “more angle” in your lens, and by so doing, pushes it back further. So, a 14 mm, would, theoretically give you twice the angle as your normal lens, but pushes your main subject back twice as far in order to get that angle.

Tomorrow: we will talk a bit about those other numbers on lenses, and why some are very desirable to have.
17-24mm
A wide angle lens is usually the best for scenery or landscape photos.

Published by 123photogo

I have been a photographer for many years. Worked in retail selling cameras and accessories for over 20 years. Taught many photo classes, and have even been a judge in several county fairs. Now, I want to share photo instructions and entertainment with all other photographers around the world.

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