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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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2answers
867 views

How far away can I be and still get a sharp subject with a 100mm lens?

If I have a 100mm lens, how far away can I shoot the subject? If I am shooting basketball, how far can I shoot the subject and still get a sharp picture?
4
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3answers
2k views

What is the meaning of single focal length?

The Nikon AF-S DX Nikkor 35mm f/1.8G is described as a single focal length lens: http://www.nikon.co.in/products.php?categoryid=1014. What does that mean? What are its disadvantages as compared to ...
26
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3answers
3k views

What does it really mean that telephoto lenses “flatten” scenes?

This is another perspective distortion question. I understand that perspective distortion is primarily a function of capture and viewing distance, but I am still working on fully understanding the ...
8
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6answers
3k views

How do I get the 'equivalent' focal length for a DSLR lens for my camera?

On my Nikon D3000, how do I figure the focal length equivalence? In other words, if I want a lens that is just like a 50mm lens on a 35mm film SLR, I need to multiply by a factor. What is the factor, ...
4
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3answers
6k views

What mm lens for distance shots?

If I am looking to take landscape and wildlife shots and some of those shots being from a decent distance what mm lens would I need? I am not sure what else I should be adding here, I am just looking ...
6
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1answer
348 views

Does focus breathing make a lens slower when close focusing?

I've heard that focal length of some lenses will become noticeably longer when focusing to a close distance, an effect called "focus breathing". Since f-number is focal length divided by diameter of ...
4
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2answers
269 views

How rapidly does the focal length-equivalent image change by physically moving the camera?

I have recently begun moving from a Nikon APS-C DSLR to the Micro Four Thirds camera while also transitioning from using a viewfinder to using the LCD screen for framing my shots. Because of the size ...
9
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2answers
653 views

Does the size of the front glass mean anything?

Considering the Nikon lenses: Prime lenses: AF Nikkor 14mm f/2.8D ED has a huge front glass (●₃), AF-S Nikkor 50mm f/1.8G has a tiny little front glass, deep inside the body (∙₁), AF-S VR Nikkor ...
4
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3answers
7k views

What does “the telephoto end” and “the wide angle end” of a zoom lens mean?

In the Canon Rebel T3i Manual, page 59, it's mentioned that "If you have a zoom lens, use the telephoto end to fill the frame with the subject from the waist up." Same note on page 61 and another one ...
4
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4answers
2k views

When would one choose a 50mm f/1.4 over 85mm f/1.8 (or vice versa) for portraits?

Say you are using a crop body, and you have both 50mm/1.4 USM and 85mm/1.8 USM lens in your bag. Now, you want to take a portrait where there is adequate light and space, and you have decided to take ...
2
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3answers
376 views

Should I upgrade my camera or lens to shoot pro hockey games?

I've gotten the opportunity to shoot pro hockey games. My current gear doesn't cut it: Nikon D70 Nikon 18-70mm F/3.5-4.5 Kit lens Nikon 70-300mm F/4-5.6 D Nikon 50mm 1.8D Monopod From where i'm ...
4
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2answers
3k views

Does using a lens adapter change focal length?

Does using a lens adapter change the field of view? I recently bought a Sony NEX-5, an extra Minolta MD 50mm 1.7/f lens and a MD to E-mount adapter and I was wondering, as the adapter increases the ...
4
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2answers
1k views

Is it normal for focal length to change while focusing?

When I change the focus distance on my Pentax 55-300mm lens, the focal length appears to change. More specifically, the lens appears to zoom in as I focus towards the minimum focusing distance. This ...
10
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2answers
2k views

Why is depth of field affected by focal length?

As the focal length decreases, the depth of field increases as well. Why is this? I'm not so much interested in a physics lesson as I am interested in a simple, down-to-earth explanation.
10
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1answer
738 views

Does focal length affect diffraction, in addition to aperture?

The reason I ask is that f/18 on a 24mm lens = 1.5mm, and f/18 on a 180mm lens = 10mm. I thought diffraction is due to the small physical size of the aperture, rather than the f-ratio, yet I only ever ...
3
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1answer
837 views

Which famous photographers used mostly one lens throughout their careers? [closed]

Which famous or outstanding photographers did use mostly only one focal length throughout their career and what focal length did they use? For medium and large format photography, please indicate a ...
8
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3answers
793 views

How can a 24-70mm and a 10-22mm both be “wide angle” lenses?

I've been looking at a 10-22mm lens for my Canon T2i. I've also come across some other "wide angle" lenses, like the Sigma 24-70mm F2.8. I don't understand how a wide angle lens can have such high ...
5
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3answers
853 views

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 ...
2
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3answers
656 views

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 ...
12
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3answers
2k views

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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3answers
2k views

What does the millimeter measurement of a macro lens mean?

I understand that the millimeter measurement on a lens is, for lack of a better term, how far it can "zoom" in or out, but what about macro lenses? What does the millimeter measurement signify? How ...
5
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2answers
4k views

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 ...
8
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1answer
1k views

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, ...
28
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5answers
61k views

How do I convert lens focal length (mm) to x-times optical zoom?

What is the rule to convert the 'mm' notation to the 'optical zoom' notation? I searched a bit and found this one: optical zoom = maximum focal length / minimum focal length For example a 18-55mm ...
4
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2answers
2k views

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 ...
18
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4answers
2k views

How to test actual focal length?

From Matt Grum's comment to my previous question, I learned that manufacturers may casually "round" actual focal length of a lens to some nice number that gets printed on the box and stored into EXIF. ...
5
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6answers
2k views

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 ...
19
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2answers
25k views

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 ...
11
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4answers
809 views

What does 'Equivalent to 1.6x the focal length of the lens' mean?

In the specifications of Canon 550D, about the lens the following is mentioned LENS Lens Mount EF/EF-S Focal Length Equivalent to 1.6x the focal length of the lens Now this is really ...
7
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2answers
2k views

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 ...
4
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3answers
486 views

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 ...
4
votes
5answers
2k views

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 ...
23
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4answers
3k views

Does my crop sensor camera actually turn my lenses into a longer focal length?

So, I mount a 200mm lens on my Canon 450D. It effectively becomes a 320mm lens. Is this the equivalent of 320mm on a full frame camera? That is, from what I've figured out I get an equivalent field of ...
23
votes
3answers
2k views

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 ...
12
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4answers
342 views

What is it called when an object appears to be the same size with the eye and through the camera viewfinder?

I have a Canon 18-135 lens. I am looking into the camera viewfinder with my right eye and not through the viewfinder with my left. I start from 18mm and keep zooming in till I see a particular object ...
5
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7answers
4k views

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 ...
21
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5answers
4k views

How to capture the scene exactly as my eyes can see?

What settings of my DSLR camera will emulate the scene exactly as I can see through my naked eyes? I think it's not possible to get the contrast and colors exactly as my eyes can see, and it may vary ...
8
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2answers
2k views

Does a Nikon DX lens on a FX camera get subjected to the 1.5X crop factor?

My friend has a Nikon 35mm DX lens that I want to use on my FX camera. If I use his lens on my camera in DX mode, does the effective focal length of the lens become 35mm * 1.5 = 52.5mm, or does it ...
12
votes
2answers
699 views

Does a crop sensor affect closest focusing distance? Why does it not affect focal length in EXIF data?

Since I am considering to buy the Nikkor 105mm micro VR, I wondered if the cropped sensor does affect the closest focusing distance of 0.31m? Thinking about this, the following additional (and ...
29
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4answers
5k views

What software can show my most frequently used focal length?

Many people recommend a focal length of 35mm, 50mm, and sometimes even 85mm and upwards for those interested in purchasing a prime lens. I, however, would like to figure out what focal length(s) I use ...
11
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2answers
1k views

When I use FX lenses on a DX camera, does the focal length or minimum aperture change?

If I put a Nikkor 35mm f/2 FX lens on a DX camera, is it still 35mm f/2, or has the effective focal length or minimum aperture changed, because it is being used on a smaller format than what it was ...
14
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5answers
4k views

Can I use my APS-C kit lens as a reference for choosing between 50mm or 35mm prime lenses?

I'm looking at getting a second lens in addition to my Nikon D7000's kit lens. I want to know if it's possible to use my 18m-105mm kit lens to get an idea of the focal length for a 35mm lens vs. a 50 ...
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9answers
2k views

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 ...
37
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4answers
9k views

What is “angle of view” in photography?

I read on the Lens Buying Guide @ neocamera: Focal-length determines the angle-of-view seen through a lens for a given sensor-size. With a full-frame sensor a lens gives the same angle-of-view ...
12
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2answers
3k views

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 ...
21
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3answers
5k views

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?
18
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4answers
478 views

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 ...
22
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4answers
1k views

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 ...
18
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5answers
789 views

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 ...
3
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3answers
454 views

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 ...