101 votes
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Do professionals really never use a 24-70 lens?

Rockwell presents his opinion as fact even when it is actually a contested opinion. Yes, professionals use 24-70 lenses. They aren't for every situation, but there are plenty where they are great go ...
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  • 34.4k
42 votes
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Is there a difference between taking a far shot on a 50mm lens and a close shot on a 35mm lens?

If you shoot from the same position with both lenses, then taking the 35mm lens and cropping it to the same angle of view of the 50mm lens will give you pretty much the same picture, other than the ...
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  • 168k
34 votes
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So my iPhone 6 camera lens is as wide as my full frame 35mm DSLR lens?

You're right that the angle of view of the iPhone camera is a little bit wider than a 35mm lens on a full-frame film camera. Up until this point, you're not really confused. But the part after that, ...
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  • 140k
32 votes
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Why doesn't the picture become darker the more you zoom in?

The answer to this question revolves around explaining how zoom lenses function because you are correct in your observation: As you zoom to higher and higher magnifications the image dims unless ...
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  • 36.2k
31 votes

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

You are not required to purchase any lenses at all. It all depends on your photography needs and what you're willing to spend your money on. Regarding range, the superzoom 18-200 mm covers the same ...
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  • 8,138
27 votes
Accepted

Do convex lenses make parallel light rays of different wavelength converge to different points?

Do convex lenses make parallel light rays of different wavelength converge to different points? Yes. The separation of different wavelengths of light is called dispersion. Different wavelengths of ...
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  • 31k
25 votes

Are lenses marked with the true focal length?

Oh, it is worse than that. Many lenses designed for still photography exhibit focus breathing, where the angle of view varies over the range of distances the lens can focus. Normally this isn't an ...
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  • 3,896
21 votes

How do zoom lenses restrict their widest aperture at the telephoto end?

The entrance pupil is limited by the diameter of the front element, and that is what usually restricts the maximum aperture of telephoto zoom lenses - not the physical size of the aperture diaphragm. ...
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  • 168k
21 votes

Is there a difference between taking a far shot on a 50mm lens and a close shot on a 35mm lens?

The proof is in the pudding – the focal lengths are not exactly the same as yours, but the differences are obvious...
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  • 813
21 votes

50mm mirror lens. Does one exist?

The mirror lens design resolves two key optical problems: All lenses suffer from chromatic aberration. This is color fringing due to the failure of the lens to refract (bend inward) all colors of ...
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  • 36.2k
21 votes

Do convex lenses make parallel light rays of different wavelength converge to different points?

Light from a far distance object, like a star, arrive at the lens, as parallel rays. As they transverse the lens, they are forced to change their direction. They bend inward, we call this refraction ...
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  • 36.2k
20 votes
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What is the shape of the focal plane?

The effect is called field curvature. A good discussion comes from Nikon. It is a lens aberration that can reduce the resolution of the lens when coupled with a flat sensor. In the old days, the ...
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18 votes

Why is the background bigger and blurrier in one of these images?

The easiest way to think of this is with an image. When you use a wider lens, you have to be closer to your subject, which emphasizes the distance between the subject and background by making the ...
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  • 480
18 votes

How does crop factor affect perspective?

When I started photography, this one took me ages to figure out, because people tend to explain it with a lot of math, or in a way that makes sense once you already grasp the principle but not before. ...
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  • 19.7k
16 votes

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

When the engineers are designing a lens, the 70-300 is a target focal range they design to, but it's not important that they hit it exactly as long as it covers the advertised range. As they tweak the ...
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  • 1,174
15 votes
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What prevents a f/1.8, 24 mm - 70 mm or similar range zoom lens from being made?

It's most likely a commercial decision based upon cost and performance. Let's take your prime at f/1.2 example. Canon makes a number of 50mm lenses. The EF 50mm f/1.8 II is about $100. It has 6 ...
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  • 49.1k
15 votes
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What is the relationship between focal length and minimum focus distance?

It depends entirely on how the lens was designed, there is no general formula or way of determining the minimum focus distance. Lenses of the same focal length can have completely different minimum ...
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  • 117k
15 votes

Are lenses marked with the true focal length?

Published focal length is rounded in some degree, normally to nearest 5 or 10, or in some short cases, to the nearest 1. More precision would not be realistic, because the marked focal length is only ...
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  • 12.5k
14 votes
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Is f/number more relevant than aperture and/or shutter speed?

The f-stop is more directly relevant to photographers because it normalizes out the focal length. It then gives you a measure of how bright the image will be on the sensor relative to the scene ...
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14 votes

Is there a difference between taking a far shot on a 50mm lens and a close shot on a 35mm lens?

Thanks to my schwifty skills in Inkscape, the rotation here is slightly off but the following shows exactly what you're comparing. These are the fields of view of a Nikon 35mm (inner) and a Nikon 50mm ...
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  • 1,412
14 votes
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Is this "tack sharp with blurred background" look done with Photoshop?

No photoshop necessary for that background. That's simply what happens when shooting a telephoto lens, f/2.8 or larger, and having the subject closer to the camera and much further from the background....
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  • 20.3k
13 votes

Shouldn't the diameter of the moon with a 600mm lens be double what it is with a 300mm lens?

Assuming both lenses are being used on the same size sensor, the area in the frame with a 600mm lens should be one quarter the area in the frame with a 300mm lens. The linear dimensions should change ...
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  • 168k
13 votes
Accepted

Is a lense with an aperture larger than f/8 useful with an EOS 80 D?

So I have a EOS 80D and supposedly it has a max aperture of f/8. That's incorrect. The aperture is in the lens, not the body. All Canon EF and EF-S lenses, including the one that came with your ...
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  • 31.2k
13 votes

Would a 50mm lens on a Canon APS-C crop produce the exact same image as an 80mm lens on a full frame camera?

Would these two photos be identical (i.e. depth of field, perspective etc.)? Depth of field: not exactly, but very similar if you also multiply the f-number used by the same crop factor. If you use f/...
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  • 168k
13 votes
Accepted

focal length and sensor width of a phone

The Redmi 6A uses the Sony Exmor IMX486 sensor, which is a 1/2.9" format sensor. Note that "1/2.9 inch" is merely a name, not its diagonal dimension (see: Why is a 1" sensor ...
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  • 31k
12 votes

How can a lens with a single focal length focus on more than one plane?

First, focal length is a property of a lens (by lens I mean a piece of plastic or glass that's inside your camera's photographic lens system). If you just have a single lens (think magnifying glass) ...
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  • 221
12 votes
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What is a good focal length for street photography?

This is very much a matter of preference and taste. Henri Cartier-Bresson was inseparable from his 50. The same holds for Jean Gaumy. On the other hand photographers like Bruce Davidson and Joel ...
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12 votes
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What focal length is used in photos where the model is zoomed in but the background appears open and wide?

Using some reasonable assumptions, geometry, and a bit of math, we can put actual constraints on the composition. Measure the height of the trailer door as a percentage of the total height of the ...
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  • 31k
12 votes

What focal length do I need to get the same field of view as an iPhone SE?

According to this the iPhone SE has an 29mm-equivalent lens, so on a Fuji with a 23.6x15.6 sensor (Fuji XT-3)(crop factor 1.53) you need a 29/1.53=19mm lens for the same field of view.
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