Focal length is the distance (measured in mm) between the surface of a lens and the focal point. Smaller focal lengths indicate wide-angle lenses, larger focal lengths indicate a telephoto lens.
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How can a 18-55mm lens focus on objects beyond 55mm?
I guess this is a total noob question, but doesn't 18-55mm mean that it can focus only up to 55mm?
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What is the formula for percent of frame filled at a specific distance and focal length?
I am thinking about buying a new lens specifically to take photos of distant targets (birds, bears, etc). I currently own the Canon 70-300 IS USM, which is a nice lens, but I find that if I want to ...
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EF-S lens focal length [duplicate]
Possible Duplicate:
Does my crop sensor camera actually turn my lenses into a longer focal length?
If I have an EF-S lens with a focal length of 10mm on an APS-C camera (i.e. with sensor ...
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What is a parfocal lens and how beneficial is it to photography?
I heard someone say that after using a parfocal lens for the first time, they would never switch back. What is a parfocal lens, how is it different from any other lens, and what are the advantages and ...
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Is the difference between a good 50mm vs 85mm lens just your distance from the subject?
I was wondering: is the difference between a 50mm f/1.8 lens and a 85mm f/1.8 lens just your distance from the subject? Let's assume that distortion is minimal; both lenses are of high quality. Does ...
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Why does the maximum aperture change with focal length? [duplicate]
Possible Duplicate:
Why do zoom lenses and compact cameras have varied maximum aperture across the zoom range?
It is rather common with zooms that the maximum aperture changes (in fact, ...
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If I have a 28mm f/1.8 lens (on a crop body), do I still need the 50mm f/1.4?
I have the Canon 60D and a Canon 400D (my original camera). I have two lenses a Sigma 50mm 1.4 HSM and a Canon 28mm 1.8 USM. Both lenses are incredible performers. I've noticed the bokeh I receive on ...
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In what situations should I use which lenses while traveling to Paris?
I'll be travelling to Paris and I'll be bringing me with a Canon T2i/550D, a Canon EF-S 18-200mm f/3,5-5,6 IS and a Tokina 11-16mm f/2,8 (I could also bring a Canon EF 50mm f/1,8 II). I bought the ...
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How do I calculate the distance of an object in a photo?
If I took a picture of a windmill on the horizon — given that I know the sensor size and the focal length of the lens and other factors to do with the shot — could I calculate how far away an object ...
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How can a prime lens focus on more than one plane?
By definition, a prime lens is a fixed lens system with a fixed focal length.
Then, simple physics tells us that it should be able to focus only on one plane (at a fixed distance) in front of it. But ...
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How can I get the same image with the same 50mm lens on both FF and APS-C?
First things first, I'm talking ONLY about framing here. No light sensitivity, no bokeh quality, no pixel quantity, etc.
A 50mm in a FF camera will give a certain composition and framing. How can I ...
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Is an EF 50mm f/1.4 the same as 50mm with an EF-S lens on a Canon 550D?
I have a Canon 550D with the standard 18-55mm kit lens. The 550D has a 1.6× crop factor.
My question is very simple but whenever I've asked before (Yahoo Answers) I always got overly-complicated ...
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4answers
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Is there construction-agnostic term for a lens with a long focal length?
Turns out that telephoto refers to a specific construction of a long-focal-length lens, i.e., one where the lens is physically shorter than the focal length.
Is there a generic term for referring to ...
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3answers
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Is the kit lens focal length specified for APS-C or FF?
I have the 18-55mm kit lens for my Canon 50D and was wondering if they're still specified against full frame 1:1 crop? Would my 18mm actually be 1.6x?
I ask because I doubt anyone with a full frame ...
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How useful is image stabilisation below 200mm, really?
Image stabilisation is all the rage, and hardly a new lens from Nikon or Canon is missing this "crucial" feature. To me this seems to be the new megapixel race (like when the manufacturers tried to ...
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Does changing the focal length change focus?
When using manual focus or back focus on D60, I sometimes zoom in the lens, set the focus, and then zoom out. Does changing the focal length (zooming out), also change the focus?
In case the answer ...
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How can I visualize or simulate the effect of different focal lengths?
I have seen many camera review sites illustrate the effect of using different focal lengths on the same photograph using frames. There are also similar illustrations to compare different sensors (full ...
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What else changes with zoom?
Let me start with the general question:
Consider the following situation. I want to take a picture of a particular object (that is, not a scenic shot). I can alter my distance from the subject ...
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What differences between point and shoot zoom versus DSLR zoom cause the price disparity?
I'm just getting into the world of photography, stepping up from a point-and-shoot. I've just purchased a Nikon D3100 and it should be here in a couple of days.
I've done lots of research, but ...
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4answers
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Estimating focal length range required for shooting scenario
Is it possible to estimate (or calculate), in advance, the range of focal lengths you might need for shooting in a given scenario?
For instance, suppose you will be going to the zoo (with your APS-C ...
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Why do we talk about focal-length when frame sizes are different?
I keep seeing people talking about focal-length of lenses without saying how large the frame is. Is there a more sensible way to talk about how much a lens “zooms”?
(I have seen so many adverts ...
