It's a bird

by Vian Esterhuizen

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

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.

learn more… | top users | synonyms

1
vote
1answer
72 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 ...
17
votes
3answers
14k 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: ...
5
votes
2answers
4k 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 ...
0
votes
1answer
30 views

Comparing focal length [duplicate]

Hello I want to move from my compact camera to a dslr. I am fan of landscape photos so I want to buy an ultra-zoom lens. My camera supports 14x optical zoom. I know that for compact cameras it's just ...
1
vote
3answers
1k views

How far away can I be and still get a sharp subject with a 100mm lens?

If I have a 100mm lens, how far away can I shoot the subject? If I am shooting basketball, how far can I shoot the subject and still get a sharp picture?
4
votes
2answers
7k views

How to calculate the FOV in degrees from focal length or distance?

How does one to calculate the field of view (or angle of view) in degrees from the following details: sensor size (for example, 1") distance to target (for example, 7 feet) focal length (for ...
5
votes
6answers
3k views

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 ...
4
votes
1answer
148 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 ...
13
votes
9answers
35k 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 ...
1
vote
2answers
141 views

How can I know the focal length and sensor size of my webcam?

I have this webcam: QHM495LM WEB CAMERA and I need to know its focal length and its sensor size, but in the specs of the webcam, it only gives me this information: • Inbuilt sensitive microphone and ...
2
votes
3answers
125 views

If the zoom number doesn't tell me magnification, what does? [duplicate]

I've read How do I convert lens focal length (mm) to x-times optical zoom?, and learned that the times-zoom number doesn't tell you much. So, how do you determine the magnification — the amount a lens ...
37
votes
5answers
129k views

How do I convert lens focal length (mm) to x-times optical zoom?

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 ...
1
vote
3answers
107 views

Will a macro extension tube eliminate the cropping of an APS-C lens on a full-frame sensor?

I understand using an A-mount lens intended for APS-C sensors on a full-frame camera results in cropping of the image. According to a tech at Sony, you lose 1/3 of pixels (APS-C is a 2/3 sensor so it ...
1
vote
1answer
152 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 ...
23
votes
5answers
7k 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 ...
0
votes
3answers
977 views

How do I convert focal length to maximum distance?

I would like to know whether there is any relation between focal length and distance. For example, what is the max distance I can shoot from a 55mm-300mm lens?
0
votes
1answer
63 views

How do I measure the distance from an object to fit it in the screen? [duplicate]

I'm curious if there is any math formula for this. Let's take a close-up of a human face for instance, given the human face is about 20cm/8 inches, how do I choose the right focal length and from ...
50
votes
6answers
15k 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 ...
0
votes
1answer
73 views

I want to know about the relationship between focal length and aperture [duplicate]

I have Nikon D7000 and I know the basic relation of shutter speed, aperture, and iso. All I want to know is focal length and aperture relation. As I zoom in the camera the f/stop increases (e.g. it ...
37
votes
9answers
13k 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 ...
1
vote
1answer
192 views

How do I calculate the maximum aperture at each focal length on a 35-200mm lens

I am looking for the linear maximum aperture of a 35-200mm 3.5/4.5 Nikon manual focus lens. I already know the max & min of the 35 & 200mm it's the 50, 70,105, & 135 that I am interested ...
4
votes
5answers
2k 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 ...
7
votes
5answers
2k views

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 ...
1
vote
2answers
132 views

What is the importance of the back focal length of a lens?

What is the effect and importance of the back focal length of a lens? For instance, if I look at these two lenses by Ricoh, they have the same focal length and aperture, but their back focal lengths ...
0
votes
1answer
85 views

How do I find the focal length that will fit a poster in the frame from across the room?

If suppose I want to take a photograph of a poster on the wall of the room, so I can't back away any farther than 5.0m to take the shot(max dist of the room). The poster is 0.80m wide and 1.2m tall, ...
15
votes
4answers
2k 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 ...
31
votes
5answers
8k 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 ...
0
votes
5answers
261 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 ...
4
votes
5answers
1k 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 ...
1
vote
3answers
156 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 ...
1
vote
2answers
89 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 ...
0
votes
1answer
58 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 ...
6
votes
5answers
4k 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 ...
2
votes
4answers
372 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 ...
1
vote
2answers
10k 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 ...
0
votes
1answer
114 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)
1
vote
1answer
191 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 ...
1
vote
4answers
99 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 ...
2
votes
2answers
456 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 ...
0
votes
2answers
94 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 ...
4
votes
2answers
1k 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 ). ...
0
votes
3answers
242 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 ...
5
votes
4answers
307 views

Can a telephoto lens have a wide field of view?

85mm-135mm lenses are great for portraits because of compression perspective distortion, meaning they flatten facial features. However at those focal lengths, you have to step back a few meters from ...
0
votes
2answers
500 views

How does focal length change perspective? [duplicate]

@MichaelClark answered a question I posted about zoom using focal length (emphasis added): You are correct that a focal length twice as long (2X zoom) as the original one will make objects appear ...
0
votes
1answer
76 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 ...
25
votes
3answers
51k 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 ...
4
votes
5answers
13k views

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 ...
1
vote
2answers
316 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 ...
2
votes
4answers
344 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 ...
0
votes
1answer
117 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 ...