34 votes

Why isn't my camera body white?

This is purely speculation, so take it with a grain of salt. But the outside of a camera can benefit from being black for the same reason the inside does, to prevent light bounce. This may not be as ...
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  • 2,942
30 votes
Accepted

Are there any secrets in lens design?

In general there are no secrets to lens design. Everything important, all breakthroughs, etc., are shared publicly or semi-privately with modification through patents, conferences, papers, etc. ...
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  • 2,377
23 votes
Accepted

In what way does the lens mount limit the maximum possible aperture of a lens?

There are two hard limits on how fast a lens can be: The first is a thermodynamic limit. If you could make a lens arbitrarily fast, then you could point it to the sun and use it to heat your sensor (...
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  • 3,335
22 votes

Is a two-prime lens possible? E.g. 35mm and 50mm

Yes, it is possible and a "Lens Turret" is one way of accomplishing it. It was very common to use a "Lens Turret" on film and movie cameras in the 1950's before zoom lenses became practical. Source:...
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  • 11.4k
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
Accepted

Why is my large format lens so much smaller (in length) than my 35mm-format lens?

The focal length is the distance from the (theoretical) center of the lens to the image plane. On the large format camera, there's a lot more camera between the lens and the film. The lenses are also ...
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  • 140k
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
19 votes
Accepted

Why do prime lenses have multiple lens elements?

Single lenses with real thickness refract the different wavelengths of light at slightly different angles. For anywhere other than the exact optical center of the lens, this causes a prismatic effect ...
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  • 168k
18 votes
Accepted

How do apertures which seem too large to physically fit work?

Your observations of the lens leads you to both a correct, and incorrect, conclusion. Correct: the aperture (i.e., mechanical iris) of the lens is substantially smaller than the 10 cm it supposedly ...
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  • 31k
18 votes

Why isn't my camera body white?

From a marketing perspective, black tends to be a safe colour to choose because it's the least offensive and most subdued. From an manufacturing perspective, if a pigment is involved (such as the case ...
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  • 291
17 votes

Why did manufacturers stop including DOF scales on lenses?

Short answer: The digital photography revolution has pretty much eliminated any idea of a standard display size and viewing distance. Depth of Field calculations are always based on several variables ...
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  • 168k
16 votes

What is the difference between the Canon 55-250 IS II and 55-250 IS STM lenses?

First, let's get a bit of nomenclature out of the way: EF-S means a lens in the Canon EOS system that will only work on cameras with APS-C or smaller sensors (if any smaller than APS-C EOS sensors are ...
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  • 168k
15 votes
Accepted

How does an apodization filter improve bokeh?

Bokeh is formed by many points of light spreading out, passing through the aperture and being projected onto the image plane as series of overlapping discs (assuming a round aperture). This can lead ...
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  • 117k
15 votes
Accepted

What is a pump zoom lens?

It just means you push / pull the front of the lens to zoom, rather than twisting a zoom ring. The mechanism is simpler to design/manufacturer but is less precise and has a reputation for sucking ...
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  • 117k
15 votes

Does a large mount diameter really allow design advantages for large aperture lenses?

First: Sony doesn't necessarily disagree with Nikon's claim. It's just that Sony designed their 'E' mount with a throat diameter of 46.1 millimeters at a time when it appeared it would be an APS-C ...
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  • 168k
14 votes

How do manufacturers get to high (83x) zoom levels on hybrid cameras?

I think the use of the term 83X while true, is most misleading. The Coolpix does a remarkable job when it comes to its optical range which is 83X. This is actually called the zoom range. The math is: ...
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  • 36.2k
14 votes

Why we can't use telephoto lens for macro objects?

There is no direct relationship between Telephoto focal lengths and Macro capability. There are some fixed focal length prime lenses that fall into the Telephoto range in terms of focal length and ...
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  • 168k
13 votes

I am getting a complete vignetting on my new canon 6D but only with the 18-270mm lens

From the "Recommended For" tab of the Tamron web page for that lens: Tamron Di-II lenses are engineered expressly for digital SLR cameras with image sensors commonly referred to as APS-C, measuring ...
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  • 1,123
13 votes
Accepted

What motivated lens makers to now use 1/3 f-stops rather than say 1/4 or 1/2 stops?

Historically, the unit of exposure was a doubling or halving of the exposing energy. This is the origin of the f/stop. Initially, this adjustment was made by inserting a thin metal plate with a ...
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  • 36.2k
13 votes
Accepted

What's the opposite of a fisheye lens?

The opposite of a fisheye is a rectilinear lens. You probably did not find one because your definition is wrong. Distortion of a fisheye lenses is not barrel distortion, it is that a different ...
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  • 101k
12 votes

How would a curved sensor change camera and lens design?

Digital image sensors used in modern cameras are essentially silicon chips: Sensor dies are produced in large batches on silicon wafers. The wafers are cut into many pieces with each piece housing a ...
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11 votes
Accepted

Is a two-prime lens possible? E.g. 35mm and 50mm

Yes it is technically possible. The question is whether this will have practically same limitations as a zoom or not. There are two objectives from Leica with stepped focal length adjustment: the 16-...
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11 votes

Canon 18-55mm lens giving err01 after it fell down

whether lens could be repaired without loosing big amount of money? Whatever the damage, repairing the 18-55 almost certainly isn't worth it. People upgrading sell them for not very much, just get a ...
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  • 19.8k
10 votes

Why did manufacturers stop including DOF scales on lenses?

Not including a DOF scale can make the lens barrel smaller and allows the use of different focusing mechanisms such as linear motors instead of the traditional helicoid (which is where the DOF scale ...
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  • 117k
10 votes
Accepted

What are STF lenses?

STF stands for "Smooth Transition Focus", and is a Sony-specific* term indicating that the lens includes an apodization filter to create smooth bokeh (out-of-focus blur) — and smooth bokeh is ...
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  • 140k
10 votes

Why there are so few lenses with small minimum focus distance?

Because most interchangeable lens cameras typically use larger-format sensors than 1/2.3"-format. The close-focusing capability of most small-sensored compacts comes from the fact that small sensors ...
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  • 49.1k
10 votes
Accepted

What is the advantage of a lens with a curved focal plane?

The distinct "look" it provides. In addition to adding more pleasing bokeh blur to background objects near the edges of the frame, it also allows objects on the periphery that are in the same plane as ...
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  • 168k
10 votes

Is a two-prime lens possible? E.g. 35mm and 50mm

It is possible and Canon has done it, although in a different way than you'd expect - their EF 200-400mm f/4L IS USM Extender 1.4x. It's a zoom lens with a built-in teleconverter that could be toggled ...
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  • 2,024
10 votes

What's the opposite of a fisheye lens?

A fisheye lens isn't designed to have extreme barrel distortion -- the distortion is the result of trying to map a sphere onto a plane. A regular lens follows the equation image height = focal length ...
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  • 2,377
10 votes

Why do lenses for larger sensors tend to have shallower angles?

This is simply where the market is converging to at the moment. The typical kit lens is still 18-55mm on an APS-C sensor but most people find wider angle more useful, so some manufacturers made a few ...
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  • 101k

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