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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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134 views

How can I get a 12ft wide field of view at 3ft distance?

Is it possible to get 12ft wide image from a 3ft distance? I am a beginner and have very little knowledge on the field of view of cameras. I calculated that a Go Pro would need a lens with 1.5mm ...
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1answer
50 views

What's the full frame equvialance of this phone lens?

I took a photo with my phone, and here is the EXIF: F/2 4mm 1/14s ISO-1250 I searched on the Internet and found that the sensor is Sony IMX134, 1/4 inch. Then how to calculate the equivalent focal ...
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2answers
68 views

How does “designed for APS-C” affect focal length? [duplicate]

If a lens is designated by manufacturer as "designed for crop sensor" (i.e. DC in Sigma, DX in Nikon, DT in Sony), how would that affect the calculation of practical focal length (equivalent focal ...
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5answers
236 views

Is it worth getting a zoom lens which overlaps with lenses I already have?

I want your experience in choosing a new lens. I already have a couple of lenses with focal lengths as follows: 18-55mm, 70-300mm (MF), and 55-300mm (AF) - regardless the 18-55mm. All my zoom ...
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1answer
85 views

How do prime lens allow variance of focal length when focusing? [duplicate]

If the definition of prime lens says that their focal length is fixed, then how come you can still alter the focal length when focusing? (either MF or AF)
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1answer
104 views

How to calculate the focal length of cell phone cameras when none of the required parameters are available?

There are many camera phones for which the focal length, aperture size, and sensor size are not available. Is there a formula to calculate these parameters or a site which provides these details for ...
2
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4answers
339 views

What kind of lens is typically used for these type of night street shots?

I've been trying to duplicate the depth of field like in these photos on snowy nights and I'm not getting comparable results. I'm using a 35mm prime lens at f/1.8 on a D3100. So my question is: Are ...
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2answers
400 views

How does physical aperture size relate to f/stop?

There are two lenses on the market I am comparing AF Micro-Nikkor 60mm f/2.8D AF-S VR Micro-Nikkor 105mm f/2.8G IF-ED If I use the formula for calculating apertures of both the lenses I will use ...
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4answers
69 views

Does the crop factor affect the field of view (FOV)? [duplicate]

I'm working on smartphone cameras. I want calculate Field Of View of different smartphone cameras using the formula : FOV = 2 arctan(SensorSize/2f) where: f is the focal length sensor size is the ...
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2answers
69 views

Actual Focal Length on APS-C cameras [duplicate]

I'm aware that actual focal length of a lens on APS-C cameras is longer than what is written on the lens. My question is, for lenses that are specially designed for APS-C cameras (like a Nikkor DX ...
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1answer
67 views

Do I get more detail from a shorter focal length by being physically closer?

Let’s say I want to shoot a static scene and have a free hand regarding the focal length. If I ignore the geometric distorion for a while, do I get some image quality advantage by shooting from a ...
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3answers
213 views

Is an 18-200mm lens sufficient for an Alaska trip? [closed]

I am an amateur photography enthusiast, mostly for vacation shots. I have a Nikon D80 body and the 18-200mm lens which I use as my "walking around" lens. I have a trip to Alaska coming up this ...
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2answers
292 views

What type of lens is more suitable for this type of portrait shot on railroad tracks?

Posted on FaceBook looking for volunteers to model for me for free and I give them the photos for free and some people agreed to that so I want to be prepared and at least take the right gear to the ...
3
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5answers
524 views

What is a good focal length for street photography?

With a long lens you don´t disturb people but you are left "out of the scene", while with a short focal lens you are "inside the scene" but you may disturb people. What is a better alternative for ...
2
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4answers
318 views

Will a 50mm EF lens give the same result as a 50mm EF-S lens? [duplicate]

edit: ^^ the answer to that question talks about the lens being the same and but not how or why this is the case, and does not answer the question about resultant image, First of all, to let you ...
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1answer
55 views

camera mobile phone takes pictures at constant focal length if 3.5 mm.supposed to have autofocus and touchfocus [duplicate]

This is a cheap Chinese landvo l200 Android mtk65xx mobile The onlything it keeps Changing is IS0 from 150 to 800 + And exposure time I wondered how can it autofocus and touch Focus when it keeps ...
6
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1answer
361 views

Why doesn't exposure change when changing focal length?

With a Canon 550D camera and a Tamron 18-270 mm zoom lens, I tried to fix shutter time, aperture (f/8.0 to cover all zoom range), and ISO, so the exposure meter read 0.0 with 18 mm focal length and ...
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0answers
25 views

Relationship between the focal length and sensor size [duplicate]

What is a relationship between the focal length of the lens and the sensor size to achieve the same image area ?
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3answers
187 views

Which EXIF tag to set for the 35mm equivalent focal length?

For a manual lens (*Rokinon 8mm f/3.5 Fisheye) I want to add the focal length information to the EXIF metadata in the resulting pictures with exiftool. I use the lens on a Canon 60D body. Obviously I ...
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1answer
342 views

Does the Canon EF-S 24mm f/2.8 STM Lens offer any significant advantage over the Canon 18-55mm IS II at a 24mm focal length?

Does the Canon EF-S 24mm f/2.8 STM Lens offer any significant advantage over the Canon 18-55mm IS II at a 24mm focal length (the kit lens for my T3i)? I'm looking for a cheap lens that offers a wide ...
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1answer
100 views

How to calculate the correct focal length needed for a subject of a given size and distance?

I need to purchase my first ever lens. So far I've only used lenses that were built into a camera. This specific lens is for the BlackMagic Deign Pocket Cinema Camera (a video only camera, but one ...
0
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2answers
4k views

So my iPhone 6 camera lens is as wide as my full frame 35mm DSLR lens?

I am trying to understand what is the deal with "full-frame" and what difference it makes, so did a silly test: I sat at my bed and aligned the iPhone 6 camera with the door of the room and took a ...
36
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9answers
10k 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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0answers
60 views

Where is the focal point of a camera lens? [duplicate]

If the distance between the center of the lens and the film is called Focal length, does that mean the focal point of the camera lens is located on the film?
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2answers
93 views

Valid value for shutter speed based on Focal Length [duplicate]

I was listening to Ben Long videos and he was saying a safe value for shutter speed is 1/focal length So if I have a 35mm prime 1.8 lens, does that mean 1/35 = 0.02 so in my camera panel do the values ...
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1answer
42 views

Why does the FoV of adapted lenses seem to be the same as kit lenses with the same focal length?

I have a NEX-6 with a number of legacy lenses and the two NEX "kit" lenses. If I fit the 16-50 kit lens, setting it to 50mm, and view the image through the viewfinder, noting the width of the image, ...
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3answers
303 views

Will a 18-140 lens be good for basketball stadium photographs? [closed]

I am absolutely new to photography and have just started learning the basics. I have got a Nikon D-610 with a 18-140 lens for now. I just want to know if I can take this to a basketball game and get ...
2
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2answers
323 views

How to estimate camera sensor size?

I am using a smartphone for capturing photos and I need to estimate the camera sensor size (mm*mm). I have the resolution (in pixels) and the focal length (in pixels). I can also measure the size of ...
3
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3answers
210 views

How can the focal length of a lens be many times greater than the lens's physical length?

I bought a Tamron 16-300. Question is: how can it have a focal length 0f 300 mm when it is only about 30 mm long? Doesn't the lens have to be 300 mm from the sensing element?
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3answers
203 views

How to shoot/capture the droplets of water being sprayed through a spray bottle

I am trying to capture the droplets of water while being sprayed on a subject through a spray bottle. What I mean here is - when I am spraying the water on my subject, I want to capture the droplets ...
0
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0answers
19 views

How to determine the focal length needed to fill a frame with an object given the height and the distance of the subject? [duplicate]

say I want to take a picture of an object, which is 50cm tall and is 4 meters away from me. I also want that the subject fills the frame heightwise. Is there an even aproximated mathematical formula ...
0
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1answer
126 views

What focal length does Lee Jeffries use for his portraits?

I'm astonished by the portraits of an English photographer, Lee Jeffries. Does anybody knows the focal length he shoots with? The link to his flicker.
3
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1answer
189 views

Sharp, in focus portraits - analyse an example please

I have tried taking a few portraits in my living room, using studio flash. I'm still new to it, so my lighting setups may not be great. I have found sometimes that I can shoot 3 or 4 shots in a row - ...
0
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2answers
117 views

Close range stereoscopic recording [closed]

So I have some work for a client; I have never tried to shoot 3D before but I have an idea how it can be done. So the situation is: I have a wide green screen and I want to record stereoscopic videos ...
7
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4answers
2k views

Do I need other camera lenses if I have an 18-200mm or other super-zoom?

I wanted to ask that once you have purchased a lens of say 18-200mm, then is it required to purchase other lenses — say 24-70mm, 24-105mm, 18-105mm, 28-135mm,etc. Does 18-200mm lens satisfy all the ...
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0answers
39 views

Which is better for portraits: 18-55mm or 75-300mm? [duplicate]

Would it be better to use a 18-55 or 75-300 for portraits? I inherited the Canon rebel xti kit and I'm new to photography. Eventually I will expand but for now just trying to get the settings down.
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4answers
217 views

What is the equivalent f/stop for 50mm?

If f/8 And Be There is the rule for 35 mm, what is the best f/stop if I am using 50mm? Context: Street Photography Note: Though one can say that "it depends", this is a very specific question. When ...
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1answer
115 views

How does focal length determine lens quality? [duplicate]

What does an 18 - 50 mm lens mean? Are those numbers the first focal length and second focal length? How do you use this parameter to judge what kind of lens to buy? Does more equal better?
5
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2answers
496 views

How do zoom, magnification, and focal length relate?

Zoom lenses and cameras with superzooms are often sold with a times ("×") zoom number — like a 12x zoom or 30x zoom. The question How do I convert lens focal length (mm) to x-times optical zoom? ...
0
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3answers
187 views

Which lens/focal length offers the widest viewing angle without too noticable distorions/fish-eye-effect?

I am looking for a lens for my Sony Alpha 77 (APS-C), which gets me an as wide as possible viewing angle, but I also hate that fisheye effect one gets from using too low of a focal length. About where ...
4
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2answers
144 views

Understanding Lenses Focal Length with Converters

I read about APS-C sensors EOS DSLRs, that if the focal length is 300mm and as the image ratio is 1.6 then the 300mm x1.6 = 480mm focal length. So if I add a 1.4x teleconverter to 300mm lens so I ...
0
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1answer
61 views

Is there an “optimal” background distance when striving for a minimally distracting background?

Let's assume a thin lens and an object O in focus at a distance of dO from the lens. Further, let's assume there's a large out-of-focus background object B at a distance of dB. Now, we know ...
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0answers
155 views

How to get width and height of an image based on distance

I have an app to overlay the images on the camera overlay. But I need to set the width and height of the image based on the user distance. If the distance is, say 8 feet, how can I calculate the width ...
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0answers
45 views

How to overlay the image scaling based on the user distance & focal length

I'm overlaying images on the cameraView and based on the user input of room width & height. The images are displaying proportionally to width & height ratio. but i need to overlay the images ...
1
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2answers
1k views

How do I take good portraits with a bridge camera and superzoom?

I'm an absolute beginner with regards to photography. I did some research on portrait photography today. From what I learned, a long-telephoto lens (70mm-135mm or more focal length (35mm ...
1
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0answers
48 views

Which lens to use for landscapes? [closed]

I bought my Nikon D5200 camera with a 18-55mm f/3.5-5.6G lens as well as a Nikkor 70-300mm f/4-5.6 G lens. I was just wondering if you would be able to tell which lens to use in what situations. Like, ...
2
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1answer
159 views

Is 85-135mm really the best for every single kind of face?

They say that focal length around 85-135mm is the best for the head and shoulder kind portraits. I've done some tests myself, I can definitely see the differences. The face is more natural looking ...
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3answers
613 views

Which is better: a smaller f-number lens or a bigger sensor size?

When choosing a camera, which of the following options would be the best in taking photo in low light situation and cropping photo situation? A smaller f-number lens with a bigger sensor size A ...
0
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1answer
103 views

How to obtain a subject's measurement from image [duplicate]

I am trying measure real object height from an image. I'm using the below formula real height = (object px height * pixel size * distance)/(focal length) my camera is Canon_EOS_550D, my values are ...
2
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2answers
117 views

What is the real focal length of the Lytro Illum

According to Lytro, the Illum Light-field camera will have a 30-250mm equivalent focal length with a constant f/2.0 aperture. What is the actual focal length of the camera? Or, What is the sensor ...