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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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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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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295 views
Is there a difference between using a telephoto or wide-angle lens for portraits? [duplicate]
Possible Duplicate:
Which focal-length lens is usually used for portrait photography, and why?
Assuming a similar aperture, what difference would you see using a 50mm, 85mm, or telephoto ...
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812 views
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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417 views
Should my flash zoom match my lens focal length or its 35mm equivalent?
I have a camera with an APS-C sized sensor. Should my flash zoom match my lens's actual focal length or its 35mm equivalent?
I am hoping that someone can shed some scientific light to this matter.
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Where exactly would the focal length of a lens in the ray diagram fall?
If a lens is specified as (EF 50mm f/1.8), where exactly is the 50mm distance if I were to show it in a ray diagram? Considering that a lens is made up of multiple elements, I could not find a ...
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217 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 ...
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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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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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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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Why doesn't the background become blurred when I change the aperture on my Fujifilm S4000?
I am sorry if my question is too naive, but I am a complete beginner in photography, and I think I still need to understand well what aperture is. I have a Fujifilm S4000 camera, and I know I can't do ...
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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 ...
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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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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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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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How do they come up with focal lengths for lenses?
There are a lots of lenses for each camera and I understand that each lens caters to a different use case but my question is on how they arrive at these numbers.
For eg: there are prime lenses which ...
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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 ...
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What factor determines the largest usable sensor size with a certain lens?
Reading this excellent answer about field of view, focal length and sensor size a new question came to mind.
From the drawn diagrams it is clearly visible that for the same focal length an increase ...
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2k 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 ...
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Why does calculated distance of an object in an image vary when zooming?
I would like to calculate the distance of an object from my camera, so i used the formula given in this question and I got a very good answer, but I've found that when I zoom and take the picture and ...
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How can lenses with different focal lengths have the same angle of view?
I always assumed that there was a fixed relation between focal length and angle of view. But compare the technical data for the following lenses, all from the same manufacturer:
Canon EF-S 15-85mm ...
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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 ...
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Why do Canon EF and EF-S lenses exhibit the same crop factor?
I have a Canon 7D, which has a crop factor of 1.6x.
When using a Canon EF-S lens I get the focal length stated on the lens, when using a Canon EF lens I get the focal length times 1.6 when used on ...
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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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Calculating focal length from photograph
I posted this question over on Stack Overflow, but someone suggested this site might be of more help to me.
I'm doing a college project where I'm trying to calculate the focal length of a camera ...
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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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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 ...
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142 views
Why is there no apparent relation between focal length and physical lens size?
Why is there no apparent relation between focal length and physical lens size?
For example, the Nikkor 20mm lens has a physical length of 42.5mm! That's more than twice the focal length! And if you ...
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360 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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What is the conversion between focal length and times zoom? [duplicate]
Possible Duplicate:
How do I convert lens mm to optical zoom times?
What is the conversion between focal length in mm (e.g. 50mm) and x zoom (e.g. 20x) commonly used in compact cameras? Is ...
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116 views
Do crop sensors on SLRs changes the depth and flatness of the objects as well? (in comparison to same focal length on full frame sensors)
1- I know different focal lengths change the depth and flatness of an objects in the picture. For examples longer focal lengths make objects appear flatter so they will be appropriate for portraits. ...
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How do I find a camera's focal length in pixels?
I am working on camera pose estimation. For this, I need the focal length of my smartphone camera in pixels. (My phone is HTC Wildfire S, with Android 2.3).
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377 views
Taking pictures with fixed/full focus camera
I have got a fixed focus, 5 MP camera with 3.3mm focal length (not sure what it means) on my phone. I want to know what's the best way to take pictures with since it's missing auto-focus feature. Is ...
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How much versatility does a 85 mm lens have?
Can it be effectively used for landscapes as I am not a portrait shooter?
This may be first "prime" lens so I need to understand what it's usable for.
How far of a "range" does it have as far as ...
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223 views
What does it mean that a lens is x millimeters?
Every lens has different focal length in terms of millimeter so if I have a 100mm lens, what does that refer to? Does it mean the length of the lens itself is going to be 4 inches long, or does this ...
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1answer
246 views
How do I properly understand what f-stop is? [duplicate]
I don't quite understand why most lenses seem to have approximately the same diameter aperture regardless of focal length.
F-stop is, by definition, a ratio of focal length to diameter, so a 20mm ...
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188 views
Is lens focal length specified considering the effect of barrel distortion on field of view?
Given a NIKON 14mm f/2.8D ED AF Ultra Wide-Angle Nikkor Lens on a full-frame sensor, in theory the field of view is HFOV: 104° x VFOV: 81°. However this lens exhibits noticeable barrel distortion ...
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1answer
141 views
Why 5-50x focal length for autofocus micro-adjustment?
When we do an AutoFocus Micro Adjustment session, the general opinion is to set the focusing target at 25 x focal length (or somewhere in the range of 5-50 x focal length).
Why is so? What happens if ...
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3answers
142 views
Does lens metadata from crop-sensor cameras factor in the crop?
I use a Canon 60D, which is a crop-sensor DSLR. Does the metadata found in Lightroom or Bridge report the actual focal length or the crop-sensor equivalent?
For example, if the metadata says the ...
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4answers
188 views
At what focal range does it make sense to have Image Stabilization turned on when using a Tripod?
I was always under the impression that one should turn off the Image stabilization when using a tripod but when I see lenses with long focal length (300mm, 600mm etc...) comes with IS on them. ...
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3answers
457 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 ...
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2answers
224 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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Are there specific use-cases in mind that make the 70-200 F2.8 worth its weight/size?
I've been looking to upgrade my Mark iii's kit lens, and am comparing lens strategies. The 70-200mm canon F2.8 seems like an enduring and very popular lens. After holding one, i am left wondering why?
...
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1answer
135 views
EOS M focal length conversion to cropped frame and full frame camera
I am thinking about EOS M .. it looks appealing to me ... especially for Hiking .. the thing i want to know is if I use my 18-55mm Canon lens (that normally come with 550D, 600D series) on EOS M with ...
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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
572 views
Zoom Lens and Prime Lens Photo Comparison
Are there any examples comparing the picture quality of prime lenses and zoom lenses with the same scene and shot at the same focal length? I have not seen anything that shows me why a prime is better ...
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1answer
704 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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1answer
595 views
Is it worth to buy old Sigma lens instead of Nikkor?
I'm amateur and I want to try something new. I have Nikon D3100 with Nikkor AF-S DX VR 55-200/4,0-5,6 G ED and I'm shooting everything - animals, landscape, people, sport, ... (like real amateur :D ). ...
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477 views
How to calculate the size of the image circle at infinity focus?
How can I determine the diameter of the image circle (i.e. the diagonal size of CCD required to fully utilise a telescope's optics) at near-infinity focus? I have looked around online and found this ...
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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 ...
