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Focal length is the distance (measured in mm) between the surface of a lens and the focal point, when the lens is focussed at infinity. Smaller focal lengths indicate wide-angle lenses, larger focal lengths indicate a telephoto lens.

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243 views

How can I tell what focal length a zoom lens was set to for a photo of the moon?

It appears that neither the Sony 55-210 mm f/4.5-6.3 nor the Canon EF-S 55–250mm f/4–5.6 reports the actual focal length to the camera: both cameras' metadata show the lens but report the focal length ...
6
votes
1answer
240 views

What prevents a f/1.8, 24 mm - 70 mm or similar range zoom lens from being made? [duplicate]

I see that it is common to have professional grade lenses such as 24-70mm lenses made at f/2.8. After using a 50mm/1.8, I was wondering what would prevent a more versatile zoom lens to be made that ...
4
votes
5answers
486 views

What focal length is used in photos that both model is zoomed in and the background is open

It is easier to explain my question just by a sample photo from Lyndsey Adler: See the models are so big in the photo and still that big RV is also in the image. What focal length do I need for a ...
6
votes
4answers
501 views

How is actual focal length greater than focal range of lens?

This image (not shot by me) is shot using 70-300mm f/4.5-5.6 lens, but the EXIF shows the focal length to be 302 mm. How is it possible to be shot at a focal length (302 mm) greater than the ...
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2answers
132 views

Where is the image sensor located in a camera with a fixed-focus lens?

I am working on some research on the Kinect for XBOX One. I am looking into the depth measurements of the device. I have read that the depth values are calculated from the devices focal plane. So i ...
5
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6answers
463 views

What do the mm numbers on lenses mean?

I'm confused about lenses and numbers. Why are some lenses ex. 50mm-300mm Different sizes? Some lenses with the same mm numbers are huge and some are small... What's the difference? Also the prices ...
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3answers
6k views

Is the formula for object image size given focal length, etc. independent of sensor size?

I am trying to figure out how big an object of, say, 50cm height at 100m distance and 600mm focal length would appear on a camera's sensor. The ubiquitous formula object size in image = focal length *...
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6answers
165 views

What is the shortest focal length before a black ring appears?

I know it depends on brand to brand and model to model, but in general terms, what is the shortest focal length I can have before the black zone (A) starts to form, or it is barely noticeable? (B) ...
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4answers
727 views

Why do two zoom lenses set to 200mm on the same camera produce different fields of view?

I've been testing out a Nikon 18-200mm F3.5-5.6 against a Nikon 55-300mm F4.5-5.6 I took two pictures of a door knob from an equal distance of about 3 meters away with the same Nikon d7100 DX camera ...
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5answers
3k views

Why image at 400mm is LARGER THAN DOUBLE of image at 200mm? (according to lens formula)

Like most of us, I thought it was yes. Until I really look into the Lens Equation: (1/subject distance) + (1/image distance) = (1/focal length) http://en.wikipedia.org/wiki/Lens_%28optics%29#...
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4answers
188 views

Which focal length lens generally has the sharpest lens? 24, 35, 50 or 85?

Context I realize that the above four focal lengths lend to having a different perspective that make them all unique. It might be possible to use one as the other but that isn't always true with the ...
3
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1answer
94 views

General rules when compression in the background looks good (like with longer focal lengths)?

Is there any general set of rules or guidelines on when would the background compression generated by a long focal length look good in a picture? Example : in a headshot, I really like the background ...
2
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1answer
148 views

Possible to lock focal length on zoom lens? (SELP1650)

(This could turn out to be a bone, practical, product-specific query, but this is the internet so the worst that could happen is a 0 rather than a 1.) Anyhoo: is it possible to lock a zoomable lens ...
2
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2answers
125 views

Do I need the 18-55mm lens that comes with the camera, or should I instead get a 55-250mm lens?

I'm a novice so don't know whether I need the 18-55mm lens that comes standard with the Canon EOS Rebel T6i or should I instead get the 55-250 mm lens - or both? I'll be using the camera primarily ...
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2answers
653 views

Effective focal length of kit 16-50mm lens on A6000 (APS-C 1.5x crop factor) [duplicate]

This is likely a tedious question for you guys but, as a camera noob, I'm miffed, so please bear with me. I have a: Sony A6000 (APS-C 1.5x crop sensor). With kit lens: SELP1650 lens (16-50mm) So, ...
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11answers
17k 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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4answers
475 views

How do manufacturers come up with focal lengths for lenses?

There are a lot 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 the specific focal length numbers. For example, ...
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2answers
270 views

Panasonic Lumix FZ1000 - How does it compare to binocular magnification?

I know almost nothing about photography. But I am interested in learning. My dad just purchased a Panasonic Lumix FZ1000. I own a pair of Leica 10x50 binoculars. I asked him how the maximum zoom or ...
3
votes
1answer
96 views

Which lens size will generate more detail for equivalent field-of-views in an image snapshot?

We are getting ready to purchase a 3 megapixel IP camera. It comes with either a 4mm or 6mm lens. We will only be using the camera for still image snapshots on a specified interval. Basically, it's an ...
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4answers
365 views

Are wide angle lenses suitable for portraiture of children?

Wide angle lens tend to make faces more "chubby" than they appear otherwise, and are therefore not used often for portraits, unless the landscape is an important part of the frame. I'm curious as to ...
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3answers
203 views

What focal length is recommended for photography for social media, like groups of people in weddings?

I want to get a lens for social photography (groups of people in weddings, or a close up for a bride). What focal length range would be recommendable? Also would it be good to get a wide angle lens ...
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1answer
129 views

What's the ranges of ratios of Focal Length to Sensor Height to approximate a human eye's view? [duplicate]

Given this formula for calculating the distance to an object as long as you have a picture of the object and know the actual height of the object... distance to object (mm) = focal length (mm) * real ...
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2answers
2k 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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3answers
439 views

Is the Canon 70-200mm or 24-70mm better for convention photos? [closed]

I've decided I want to upgrade to a better lens, but I'm really torn between the Canon EF 70-200mm f/2.8L IS II USM and the EF 24-70mm f/2.8L II USM. I like to take convention photos, where space is ...
2
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2answers
264 views

How do you calculate the focal multiplier of a non-full frame camera?

I'm currently using a Sony RX100 Mark 3 camera and want to buy a Canon 6D + 24-105 F4 L lens from an online retailer, which is not in my country. (before continuing I'd like to state that there are ...
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9answers
25k views

Do professionals really never use a 24-70 lens?

I was reading lens reviews on the Rockwell site — mostly because it came up as first result in Google search — and he was saying professionals don't need and don't use mid-range zoom lenses like 24-70 ...
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3answers
230 views

Why isn't my computation of the actual size of an object in a photograph matching the expected value?

Let's say I have a full frame camera (Sony A7) with a 50 mm lens (Canon FDn 50mm f/1.4) mounted on it. At a given object (a plane) distance I should be able to compute the size of the image in real ...
4
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3answers
630 views

Does focal length change when I adjust the focus? [duplicate]

When I adjust the focus of my camera, in general, does this affect the focal length? I have heard that it does.
3
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2answers
145 views

55mm on an 18-55 lens versus 55mm on a 55-250mm lens

I have two canon kit lenses which came with my 1100D. While experimenting casually with my lenses, I came across something that I find peculiar. When I am focused at an object at a certain distance on ...
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3answers
194 views

Do lens hoods need to be matched to focal length?

Is it true that not all generic lens hoods work on all lenses (provided the filter diameter matches, of course)? I read that the focal length plays a role in it - but I cannot find such readings on ...
17
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9answers
62k views

What lens focal length most closely resembles the perspective of the human eye?

For example, if I have a lens that is 16mm-50mm, which focal length would be the closest to the human eye's view? (I don't have a camera yet, so I'm just curious.) Would 50mm be more zoomed in than "...
4
votes
1answer
374 views

What are the advantages and disadvantages of zoom lenses with a wide range of focal lengths? [duplicate]

Are there some disadvantages of a zoom-lens with wide range focal length compare to a lens with narrow range both having the same max. aperture? For example, if we have two lenses: Sigma 18-55mm f4 ...
0
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1answer
40 views

Focal length of the sony DSC-H20 [closed]

I am working in finding the distance of the objects in a video taken using a Sony Camera model DSC-H20 and suppose that any lens or zoom distortions were applied. In order to know the position I need ...
0
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6answers
194 views

Is the wide aperture and bokeh of a 50mm prime more important than getting to the 70-90mm range for portraits?

I've a Pentax K-30 with the following lens: Pentax-M 50mm 1.7 manual focus Tamron 17-50mm 2.8 autofocus Pentax 55-300mm 4-5.6 autofocus Considering that : Pentax 50mm has the nicest bokeh and ...
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4answers
262 views

Given the same sensor size lens, will a higher megapixel sensor give more “reach” then a lower one?

I've been wondering this for a while now, and I can't seem to find a straight answer about this. If we are talking about the exact same sensor size, (lets say FX) and we are using a 50mm lens. ...
0
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1answer
186 views

How do lenses focus? (and zoom?) [duplicate]

My understanding of focal length is that it is the distance from the lens to the sensor; in my observations: higher focal lengths make for longer lens. Then I started thinking about how a lens ...
25
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6answers
10k 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 ...
60
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6answers
21k 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
27k 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 ...
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2answers
209 views

What is the relationship between focal length and minimum focus distance?

If I know the focal length of a lens, How can I know the minimum focus distance? I have checked several webpage, but I am still wandering is there a formula? I know there is mark in the lens, but ...
27
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4answers
76k 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 ...
0
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1answer
183 views

I have camera specifications but don't know the actual focal length

I'm trying to figure out the focal length of my camera. I'm trying to figure out the distance from my camera to an object using the equation listed here (How do I calculate the distance of an object ...
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0answers
32 views

Tamron 18-200mm super wide angle lens [duplicate]

I purchased this lense, it says that it is a wide angle lense also. I would like to know hiw i can tell for sure, is it a wide lense or not?
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6answers
459 views

Why does Sony say that a 35mm lens is “35mm equivalent when used with an APS-C camera?”

I'm thinking of getting a Sony A6000 with a Sony SEL35F18 Lens. I'm a little confused about the actual focal length (and/or field of view) of the lens when attached to an APS-C sized sensor. The ...
0
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1answer
741 views

Camera sensor size vs pixel size and focal length [closed]

I've already seen the answer about the crop factor. I'm writing a small software for motion tracking (from two cameras, videos) in 3D space and research. To do that, I need some information about ...
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1answer
90 views

how to calculate “FocalLenIn35mmFilm” with limited metadata

Im creating an app that uses "FocalLenIn35mmFilm" to calculate feild of view(FOV). unfortunately not all photographs contain this property in their meta data, the Motorola Nexus 6 is an example. The ...
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0answers
23 views
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3answers
2k 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 ...
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1answer
137 views

Why don't all zoom lenses have variable f-numbers? [duplicate]

As I understand it, the f-number is a ratio between the focal length and the aperture diameter. A zoom lens can change focal length, but shouldn't the maximum aperture be a fixed size? If so, that ...
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2answers
6k views

How can I calculate focal length from a 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 ...