Difference between a 50mm lens and a 25mm lens

<p>Hi, I've been asking a lot of questions lately!<br>

What is really the difference between say a 25mm lens and a 135mm lens? What do the numbers mean. Is one better for a certain type of photography than the other?<br>

Thanks in advance</p>

Welcome to Photo net.In this case google is your friend type in what does 25mm mean on a camera lens... voila answer about 10 lines down.. Try to post some of your photos as well you will get good advice and help Miken

PS try the blue tab on this page Learning click and choose online textbook. helpful material, if you get stuck please ask for help Miken

<p>In simplistic terms, the focal length of the lens is the "magnification". To keep all things equal, just think about full frame 35mm cameras for the moment.</p>

<p>There's an arbitrary agreement to call a 50mm lens "normal" for that format. A 25mm lens will funnel twice as much view onto the film, hence it's called a wide-angle lens. A 135mm lens will give you roughly a third of the area seen by a 50mm lens, so it's called a "long focus" or "telephoto" lens.</p>

<p>Another way of thinking about it: the 25mm lets you get the whole wedding group into the picture, while the 135mm, from the same distance, lets you fill the picture with uncle Jim's beaming features.</p>

<p>Kayla,<br /> The value ios what is called the focal length of a lens. The real difference between these lenses is that they are completely different designs... but the important thing is: they give a different angle of view. Assuming 35mm film, 25mm is a wide-angle lens. If you stand in front of a large building, the whole building may "fit" in one photo. On the same 35mm film, a 135mm lens is a medium-telelens. Standing in front of the same building, you'd might get only two windows in one photo. And a 50mm falls nicely in between.<br /> So, yes, one is better for certain types of photo than the other. Wide-angles are rarely used for portraits, because their large angle of view gives a perspective that is not very nice to most people. But they're great for architecture, and often used for landscapes. Medium-tele (like the 135mm) are often used for portraits, as they give a perspective very suited to that; but they're not practical for a lot of architecture work, and often still too short for wildlife, sports, where far more extreme telelenses are used (400-500mm).</p>

<p>This is the highly simplified version - but I hope it gets the base idea across a bit.</p>

<p>[ EDIT] Yep, that simulator is a lot easier than my long bla-di-bla... :-)</p>

<p>Nikon has a very useful "lens simulator" on their global site that lets you see the angle of view of any lens with a focal length between 10mm and 600mm. Just move the slider to any focal length and you can get an idea of how a scene will look through that lens.</p>

<p>http://imaging.nikon.com/lineup/lens/simulator/</p>

<p>Okay, got it. I thought so, but I wasn't sure. That simulator is very helpful. Thank You!</p>

<p>The camera lens acts much like a slide projector only backwards. The camera lens projects an image of the outside world onto a flat surface in the rear of the camera. This flat surface can be photographic film or a digital imaging chip. Lenses come in different strengths. We are taking about the projection distance lens to fiat surface (focal plane). The longer the projection distances (focal length), the larger (more magnification) the image will be. We use a super long lens (telephoto) to photograph distant objects like animals or birds or the moon or stars. We usually use a much shorter focal length for everyday pictures and a super short focal length when we want to take a wide landscape view (wide-angle). </p>

<p>When you buy a camera it will likely be equipped with a zoom lens. This allows the photographer to adjust the focal length to better fit the lens to the scene. Likely the center of the zoom range will deliver a "normal" view. We zoom in to get more magnification; we zoom out to get a wide-angle view.</p>

<p>Focal length selection is somewhat complicated; you need to know what focal length is considered normal for your camera. For the 35mm film camera 50mm is considered "normal". Different size cameras will have a different value for "normal". An example, the popular compact digitals use a 30mm as "normal".</p>

<p>When we say "normal", we are talking about, not wide-angle and not telephoto. As a rule, telephoto is longer than normal by 200% or more. For the 35mm film camera, 100mm or longer. For the compact digital 60% or longer. Wide-angle is about 70% of normal or shorter. For this 35mm film camera this would be 35mm or shorter, for the compact digital this would be 20mm or shorter.</p>

<p>Maybe this will help: Your camera is a compact digital set to "normal" 30mm. You see a bird in a tree 500 feet away. You take a picture with your zoom set to 30mm and then another with the zoom set to 60mm. The image of the bird will be twice as big using the 60mm. The bird will appear to be only 250 feet away (magnification 2x). Now you zoom to 120mm, the bird appears 4 times closer (4x), it appears to be 125 feet away. In other worlds, longer focal lengths magnify. Most binoculars operate at 8x. To duplicate with a compact digital you need to mount a 240mm telephoto lens.</p>

<p>The 'trick answer' which came first to mind was that there is no difference between a 50 and a 25 lens if the first is on a full frame camera and the second is on M4/3. That an 80mm is normal for a MF 2.25"x2.25" film camera and quite a long lens for M4/3.</p>

<p>The message here is that the angle of view of a lens also depends on the sensor size.</p>

<p>A secondary answer to your questions is that the 135 with its narrower angle of view keeps you back from the subject when taking portraits and so avoids the bulbous noses of the wider angle lense such as if you used a 25mm on an APS-C camera. The 50mm on APS-C with its x1.6 'crop' factor has an AoV of about 80mm enables you to work in a smaller area, closer to the subject without undue bad perspective. The 50mm on M4/3 gives a 100mm AoV which is very good for portraits. The 135 could be good for street photography if you don't want to stick the camera under people's noses but since I normally use a zoom lens to get the composition I want from where I am I do not really think in terms of focal length.</p>

<p>Third answer :-) It is usual these days to compare lenses less by their actual focal length but by the Angle of View that they give in terms of the lens on a full frame or 35mm film camera giving a similar view .... so a 90mm lens on a bridge camera might give a 430mm AoV. All rather confusing until you get the hang of it and then one does the comparision automatically :-)</p>

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<p>Hi, I've been asking a lot of questions lately!</p>

</blockquote>

<p>Keep asking. We're all here to share. :-)</p>

The numbers are distances. 25 mm equals one inch. 50 mm equals two inches. 100 mm equals four inches. Etc.

 

The lens projects an inane onto a sensor of a piece or film, just as a projector in a cinema projects an image onto a

screen. The distance described by the numbers is the distance of projection.

 

The projection is a circle of light as when pointing a flashlight toward the wall. The greater the distance between the

flashlight and the wall, the larger the circle. Short lenses (25mm) project a smaller image than longer lenses (50 or 100

mm). With the long lens, the sensor sees more of the middle of the projection. With the short lens, the sensor sees a

wider view of the image.

 

Shirt lenses are called wide angle lenses. They project a wide view of the scene in front of the camera onto the sensor.

 

Long lenses are called telephoto lenses. They project a more tightly cropped image onto the sensor due to the larger

image circle.

 

Zoom lenses have a variable focal length that can be adjusted between shorter and longer focal lengths.