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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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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10answers
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What is the relationship between focal length and crop factor?
I'm reading that a 50mm lens is recommended as a first prime lens for DSLR owners as it's supposed to give a 'natural' perspective, but when used on (most) DSLRs, the view is cropped, as if you were ...
28
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4answers
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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 ...
26
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10answers
4k views
Which focal-length lens is usually used for portrait photography, and why?
What focal length or range of focal lengths are usually used for portraits?
What is used by professionals? Why would one select a certain focal length? What are the advantages and disadvantages of ...
24
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3answers
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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 ...
23
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3answers
3k 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 ...
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5answers
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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 ...
21
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4answers
970 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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3answers
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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 ...
20
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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?
19
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4answers
1k 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?
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5answers
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How do I convert lens mm to optical zoom times?
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 ...
18
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5answers
642 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 ...
18
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4answers
1k 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. ...
17
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4answers
2k 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 ...
16
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4answers
369 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 ...
14
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5answers
2k views
What focal length gives a “normal” field-of-view on APS-C cameras?
I wish to purchase a "standard angle-of-view" prime lens for my Canon Rebel, which has an APS-C sized sensor. Various articles note that the popular "nifty 50mm" lenses are a little too much of a ...
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 ...
14
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11answers
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Will a 50mm f/1.8 work for general outdoor photography?
I want to know if it's advisable to use 50mm lens for general outdoor photography. I'm torn between 35mm and 50mm primes, and have read all the pros and cons. I understand that 50mm could be tight in ...
14
votes
2answers
15k 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 ...
14
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1answer
900 views
Why does a 50mm lens appear to give a human perspective, rather than a normal lens?
I grew accustomed to the notion that what one sees through a normal lens equates (or is close to) what can be seen with the naked eye (although that is not the "pure" definition of a normal lens, ...
12
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4answers
3k 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
1k 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 ...
12
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4answers
1k views
What is a normal lens?
I've heard people call 50mm lenses "normal lenses".
For a lens to be considered normal, does it have to be exactly 50mm or is there some leeway? Does the normal focal length depend on crop factor of ...
12
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5answers
774 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 ...
12
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2answers
570 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 ...
12
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4answers
323 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 ...
11
votes
2answers
663 views
How do people shoot very large moon views?
I see pictures of the moon that looks like it is very close to the earth; I am wondering whether they are real or is there a trick to show the moon that big?
Here is an example: ...
11
votes
4answers
1k 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 ...
11
votes
4answers
608 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 ...
11
votes
2answers
993 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 ...
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9answers
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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 ...
10
votes
5answers
395 views
What are the different focal lengths of macro lenses and their advantages?
I am interested in macro-photography. I see there are macro telephoto (zoom?) lenses (e.g. 200mm), or smaller macro lenses (e.g. 40mm) ...
What are the different types of macro lenses and their ...
10
votes
3answers
2k views
How does changing focal length affect depth of field?
I'm curious about how my "area of acceptable focus" changes when the focal length of the lens I'm using changes as I zoom (or switch lenses). In particular, I'd like to know how the front & back ...
10
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1answer
514 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 ...
9
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2answers
1k 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.
9
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2answers
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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 ...
9
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2answers
490 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 ...
8
votes
3answers
643 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 ...
8
votes
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 ...
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4answers
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What lens focal length most closely resembles the human eye perspective?
For example, if I have a lens that is 16mm-50mm, which focal length would be the closest to the human eye view? (I don't have a camera yet, so I'm just curious).
Would 50mm be more zoomed in than ...
7
votes
2answers
1k 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 ...
7
votes
3answers
305 views
How much distance should one move so that a shot that can be framed at xx mm be framed at yy mm?
Is there a website / app that will tell you approximately how much distance a person should move so that they are able to frame the same shot at different focal lengths?
Say for example, I'm ...
7
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3answers
868 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 ...
7
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1answer
856 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, ...
6
votes
6answers
1k 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, ...
6
votes
3answers
209 views
Must I allow for crop factor in the viewfinder when shooting with a Nikon DX format camera?
Will a Nikon D5100 (dx format) viewfinder show me what the captured image will be, or do I need to allow for "crop" factor? Will that depend on/alter with using a DX lens or an FX lens? I don't have ...
6
votes
1answer
307 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 ...
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7answers
2k 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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6answers
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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 ...
