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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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382 views

Does the X-Pro 1's “Lens Focal Length Setting” do anything with automatic lenses?

In the X-Pro 1's custom menu, one of the options is Focal Length Setting. The manual says: FOCAL LENGTH SETTING (Defaults to 50mm) Enter lens focal length when using a lens that does not ...
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3answers
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How does using a lens with some focal length on a full frame camera differ from using a lens with “equivalent” focal lens on a crop camera?

As an example, a 35mm lens on a crop body (such as Nikon DX) is said to be "equivalent" to a 50mm lens on a full frame body. Equivalent here means that they will have the same field of view, but what ...
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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 ...
6
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2answers
396 views

Can I get better image quality with a higher focal length or by cropping an image from a sharper lens?

Two well known ways to get better image quality are to use a sharper lens, and to zoom in to fill the frame (as opposed to zooming out and cropping in post). Sometimes there is a give and take between ...
20
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4answers
3k views

What is focal length and how does it affect my photos?

What is focal-length? Are focal-length and zoom synonymous? How does the focal length of a photo affect it?
8
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3answers
1k views

Does the shutter speed and focal length rule of thumb apply to cropped sensor cameras?

So, the rule of thumb for shutter speed is that it shouldn't be less than 1 / focal length. Well, that's straight forward on full frame cameras, but what about cropped sensor cameras? Is it going to ...
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1answer
1k views
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4answers
2k views

What is the reference point that the focal length of a lens is calculated from?

I understand the idea of a focal length for a single lens, i e the distance from the lens to the point at which parallel rays of light converge. However, in the case of a photographic lens with ...
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2answers
433 views

Why are the area of aperture, focal length, and amount of light specified in these terms?

So I'm looking at the wikipedia article on Aperture, and I'm a bit confused. I understand aperture to be the diameter of the hole that lets light in. In the article, someone states that The ...
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4answers
1k views

Do bigger focal lengths capture more light?

I never understood what the f really stands for in the f-stop values, like f/1.8. Wikipedia explains it in various articles, but I still find it very confusing. What I understand, though, is that it ...
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3answers
3k 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 ...
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3answers
788 views

How to compare the focal length of a 50mm prime lens with the default lens of a point and shoot camera?

To imagine the 50mm focal length of a prime lens 1.4F, can I simply zoom the lens of my point and shoot camera up to 50mm? Will both the focal lengths be same? Any other way to imagine the focal ...
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5answers
10k views

If I have an 85mm lens for portraits, is a 50mm useful as well?

I recently got my Canon EF 85mm f1.8, after lot of thought over if I should buy Canon EF 85mm f1.8 or Canon EF 50mm f1.4, I decided on 85mm so that I can shoot portraits of people even from a ...
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2answers
2k views

DX 35mm vs FX 50mm

Will the picture taken from AF-S DX NIKKOR 35mm f/1.8G and AF-NIKKOR 50mm f/1.8G be one and the same because of the DX and FX format??
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2answers
995 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?
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3answers
3k 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 ...
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6answers
5k 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, ...
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4answers
348 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 ...
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4answers
4k 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 ...
4
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3answers
9k 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 ...
12
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2answers
764 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 ...
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2answers
302 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 ...
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2answers
805 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 ...
12
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4answers
4k views

How can a lens like a 18-55mm have more than one focal length?

How can a lens have a range of focal lengths? Shouldn't it be a single number? Isn't focal length supposed to be fixed for a lens of a particular shape and geometry? What am I missing? How many ...
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3answers
392 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 ...
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2answers
3k 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.
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1answer
905 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 ...
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1answer
946 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 ...
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6answers
2k views

Is crop-factor a bad thing?

It seems to me that there is a preference for full-frame sensors rather than cropped sensors, and I'm curious as to why. It seems to me, that the cropped sensor means that I get more bang for my buck ...
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3answers
6k 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?
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3answers
1k 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 ...
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3answers
839 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 ...
14
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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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2answers
5k 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 ...
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1answer
2k 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, ...
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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 ...
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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 ...
7
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2answers
3k 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
512 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 ...
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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 ...
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3answers
554 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 ...
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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 ...
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3answers
3k 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 ...
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7answers
5k 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 ...
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5answers
862 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 ...
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4answers
2k 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 ...
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5answers
1k views

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 ...