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 do I choose among the following lens of 55-250 IS, 70-300 IS and VS 75-300?
Sorry by this specific question, but I'm pretty crazy here looking for a difference.
I've got to buy a lens tomorrow (I leave my country in 2 days)
I could see the difference between 55-250 and ...
3
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1answer
108 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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2answers
112 views
How to simulate different focal length and sensor size on an image?
I like to simulate different focal length and sensor size based on an image i have taken. I have a full frame body so I like to know how the picture would look like if I have taken with a cropped ...
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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 ...
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3answers
178 views
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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11answers
2k views
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 ...
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4answers
245 views
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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1answer
105 views
How can I find a compact camera with an ultra-wide lens?
I'm looking to buy a compact camera, and having a very wide angle is important to me. I know that review sites often list the real focal length of the lens, but what I'm looking for is something that ...
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1answer
160 views
What is the focal length on your typical cell phone camera?
Now, let me clarify (or...divulge) a few things.
I know cell phone cameras are generally wide angle, which makes sense because hey, people wanna go out to dinner, or a show, or at the park with their ...
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3answers
209 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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2answers
198 views
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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1answer
242 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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1answer
159 views
Relationship between camera sensor size and lens focal length [duplicate]
I am choosing a camera and lens.
I want to buy a Canon EOS 650D, as this camera seems to be a good point of entry into the world of SLR.
My question is in the following:
The EOS 650D has a cropped ...
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10answers
2k views
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 ...
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3answers
126 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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3answers
4k 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 ...
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4answers
180 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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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. ...
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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: ...
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2answers
115 views
What happened to multi-focal lenses?
Apparently multi-focal lenses such as the Tri-Elmar 16-18-21mm went out of fashion but I was wondering if the reasons for that were technical or commercial.
Are multi-focal harder to build compared ...
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3answers
136 views
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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4answers
5k 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 ...
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3answers
711 views
50mm lens=75mm on DX camera? [duplicate]
I'm looking for a 50mm lens for my nikon d3100 and I just came across an AF-S 50mm f/1.8G lens and it says in the description that if it's used on a DX camera, the angle of view is going to be 75mm. I ...
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1answer
115 views
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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4answers
1k views
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 ...
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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, ...
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2answers
177 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 ...
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 ...
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 ...
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2answers
252 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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3answers
207 views
Will a short focal length cut it for indoor event photography? (Context: It's Crowded, Dark, Has Mixed Lighting, and Requires Walking Around.)
Short version: What primes are good walk-around lenses for an indoor, dark, crowded environment where you'll be taking pictures of individuals or small groups ad-hoc, walking around and stopping in ...
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2answers
240 views
What is the benefit of a dedicated wide angle zoom vs a superzoom?
I am considering buying a Sigma 10-20 mm F3.5 wide angle lens for my canon 550D, but not sure what the benefit would be compared to using the wide angle end of my existing Sigma F3.5-6.3 18-250 mm ...
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1answer
132 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
193 views
Is it possible to calculate focal length if you know the aperture?
I need focal length (for my IA homework), but I didn't know that in real world I would only get the aperture.
Ok, my camera is an Olympus X-21, and manual says:
-----Olympus lens: 6.3 to 18.9 mm, ...
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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 ...
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3answers
200 views
How to get focal length from a camera specification which gives a value like “4.5-22.5”?
I am using a Sony W520 camera. The specifications mention
Focal Length (f= mm) 4.5-22.5. What number should I take? The lower value or the higher? And if not both of them, then how to calculate actual ...
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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 ...
11
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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 ...
18
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5answers
25k views
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 ...
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3answers
509 views
Does sensor size affect lens distortion?
There was recently a video posted about how different focal lengths affect portrait photography, specifically how distortion at smaller focal lengths have more distortion and are less flattering.
So ...
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2answers
184 views
What does different focal length offer me?
I have a beginner photographer and I have spent a lot of time learning the basics (exposures, lenses, focal lengths, crop factor etc). It's all good except I'm not so sure when I need to buy lenses of ...
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2answers
458 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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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 ...
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3answers
176 views
What is the difference between shooting with different (but similar in quality) lenses at same focal length?
What are the theoretical and/or practical differences between shooting with different lenses at same focal length? For example, if we are shooting with a 24-70mm f/2.8 lens at 70mm focal length vs ...
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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 ...
21
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5answers
3k 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 ...
4
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2answers
359 views
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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1answer
1k views
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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1answer
147 views
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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2answers
622 views
What are the technical camera specs for the HTC Wildfire S?
I am trying to do some CGI manipulations on pictures I've taken. In order to fake reality with some 3D object inserted in the picture, I need some information to configure my virtual camera so it can ...
