India Point Park

India Point Park
by matt-ball                

Submit your Photo
Hall of Fame

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, when the lens is focussed at infinity. Smaller focal lengths indicate wide-angle lenses, larger focal lengths indicate a telephoto lens.

learn more… | top users | synonyms

4
votes
4answers
3k views

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 ...
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 ...
4
votes
2answers
258 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 ...
4
votes
1answer
254 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 ...
4
votes
2answers
6k 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 ...
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 ). ...
4
votes
2answers
1k 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 ...
4
votes
1answer
8k 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).
4
votes
1answer
230 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 ...
4
votes
3answers
333 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.
4
votes
4answers
156 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
votes
4answers
440 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 ...
3
votes
2answers
740 views

Image size of the Sun / Moon from a telephoto lens

I'm interested in taking a picture of the Sun / Moon using a telephoto lens. For example like this. It would be very helpful for me to know what the approximate image size of the sun / moon would ...
3
votes
2answers
394 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 ...
3
votes
1answer
255 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 - ...
3
votes
2answers
1k views

28mm vs. 24mm (wide angle) for selfies?

I know that selfies are an "evil" of this generation, and you're never going to get a good picture when taking one of yourself, let alone when you are unable to compose it bc you can't see the ...
3
votes
3answers
361 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?
3
votes
1answer
285 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 ...
3
votes
2answers
7k views

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 ...
3
votes
2answers
1k 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 ...
3
votes
4answers
233 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. ...
3
votes
1answer
1k 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 ...
3
votes
1answer
2k 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 ...
3
votes
1answer
78 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 ...
3
votes
4answers
4k views

35mm vs 40mm: Does it matter?

I want to buy the lens Voigtlander Nokton 40mm F1.4, $449 Voigtlander Nokton 35mm F1.4, $629 I am asking, why the slightly difference in focal length, the price difference in so much as $180? ...
3
votes
2answers
137 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 ...
3
votes
2answers
348 views

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 ...
3
votes
1answer
368 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 ...
3
votes
3answers
598 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 ...
3
votes
1answer
340 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 ...
3
votes
2answers
2k 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 ...
3
votes
1answer
86 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 ...
3
votes
1answer
251 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 ...
3
votes
3answers
840 views

Phone camera (Samsung S4): is it possible to determine the distance to the object in focus on jpg picture?

I took a picture with Samsung S4 phone. Is it possible to determine the distance to the object on the picture? The object is in focus. I looked at the JPG picture properties but could not find ...
2
votes
2answers
597 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 ...
2
votes
4answers
6k views

What is the relationship between focal length and shutter speed?

I am very new to photography and am trying to grasp the basics of it these days. Can someone please help me understand the relationship between focal length of a lens and shutter speed of camera?
2
votes
2answers
1k 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 ...
2
votes
3answers
1k 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 ...
2
votes
3answers
660 views

What do the specifications mean on the Canon G15's lens?

I am quite new to photography, but spent some days understanding aperture, timing, zoom and ISO. Now I see the values printed on the Canon Powershot G15´s lenses, and I can´t interpret them. I ...
2
votes
3answers
153 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 ...
2
votes
3answers
748 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 ...
2
votes
2answers
159 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 ...
2
votes
3answers
1k views

Is 50-200mm (APS-C) a good zoom range for a single lens for people, buildings, and distant objects?

Assuming I do want to take pictures of things like people, buildings and things further away, but not too far away. Does it sound reasonable to buy a 50-200 mm lens, when just considering the distance ...
2
votes
4answers
331 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. ...
2
votes
4answers
340 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 ...
2
votes
3answers
410 views

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 ...
2
votes
2answers
118 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 ...
2
votes
3answers
437 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
votes
2answers
576 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 ...
2
votes
3answers
8k views

What is the relationship of aperture, focal length, and ISO in a SLR?

I was using Nikon digital camera, and recently bought a Canon 550D. I am totally new to SLR. I am not familiar with SLR terms: Aperture, focal length and ISO, and their relation to one another. What ...