74 votes

Why is there "single" in the term DSLR (Digital Single Lens Reflex)?

A picture is worth a thousand words, here. This is a Twin Lens Reflex camera: The two lenses are linked together so they focus as a set (either the whole front panel moves, or the lenses are linked ...
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  • 140k
54 votes
Accepted

Why is there "single" in the term DSLR (Digital Single Lens Reflex)?

Single lens means that there is only one lens attached to the camera at once. This is to distinguish it from a twin-lens reflex camera, which has two lenses - one used for the viewfinder and one used ...
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  • 19.7k
40 votes
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Why can't my custom camera body focus to far distances?

If I have built my device with the correct distance between the flange and the optical plane, does this mean the (inexpensive) lens I am using is bad? If you had built your device using the proper ...
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  • 167k
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
28 votes
Accepted

Why do even high-end cameras often still include normal (non-cross-type) AF sensors?

In actuality, a cross type AF sensor is just two "normal" AF sensors, one with the lines oriented in a vertical direction and the other with the lines oriented in a horizontal direction, that are ...
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  • 167k
25 votes
Accepted

Why don't people care any more about shutter speed accuracy?

Shutters are probably more accurate/reliable now, but more importantly with digital photography you get instant feedback so you can tell right away if there are any exposure problems, you're not going ...
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  • 117k
25 votes

Why do DSLR cameras still use monochrome LCD as their top displays?

The main reason is that it is low powered. An raster LCD - color or not - requires much more power and most of them need a permanently on back-light. New OLED display do not need the back-light but ...
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  • 101k
23 votes

Why do cameras use a slit between two curtains rather than exposing the entire sensor instantly?

As was said, the mechanical shutter has speed limitations. As to the slit, try to imagine without it. Suppose the shutter opens by moving from top to bottom of frame. And then of course, it has to ...
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  • 12.5k
22 votes
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Is there a DSLR/mirorless camera with minimal options like a classic, simple SLR?

There isn't. Once you have the basics needed to make a digital camera work, the incremental cost of additional features is very small, so there is a very strong incentive to cover at least the most ...
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  • 140k
21 votes

Why do cameras use a slit between two curtains rather than exposing the entire sensor instantly?

Thought experiment time. Assume we'd like a minimum exposure of 1/2000 of a second (500 microseconds) on a 35mm full frame camera. We have a single 'shutter' to move out of the way, and back. We'll ...
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  • 1,848
18 votes
Accepted

What does the pentaprism/pentamirror do?

It's important to realize that you don't actually look directly through the lens with an SLR! If you did, a periscope style arrangement would do just fine. What you are actually doing is looking at ...
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  • 117k
18 votes

Why do we need a DOF preview button?

Hitting the DOF preview with a stopped down aperture should make it obvious: what you see can be very dim, dim enough it can be very difficult to compose and focus. That's why cameras have the lens ...
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  • 1,174
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
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How do SLR lenses connect to the body?

if I use the auto-focus, does it adjust the lens focus, or is there a secondary lens in the body that gets adjusted? No, there's no secondary lens. The lens attached to the camera contains a motor ...
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  • 31.2k
14 votes

Why do you need a viewfinder in MILC?

Pros of using an EVF as opposed to the rear LCD screen: It is easier to see in direct sunlight. Holding the camera to the eye increases stability and comfort (especially with heavier lenses). EVFs ...
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  • 117k
13 votes
Accepted

Why is the IR filter present when there is already the Bayer filter on an image sensor?

The Bayer filter passbands are designed to be make the sensor have a reasonable match to the human eye, while not costing too much. They're fairly leaky even in the visible part of their stop band, ...
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  • 3,602
13 votes

Why do we need a DOF preview button?

Why do we need a DOF preview button? So that you can see how much depth of field you'll get when the shot is actually taken. Why not just show the effective depth of field, by default? Because ...
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  • 31.2k
12 votes
Accepted

Will a pinhole camera work with instant film?

You definitely have to change the design of the camera. This HowStuffWorks page explains how instant film develops well enough. Essentially, the film cassette contains rollers that roll out the ...
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  • 20.3k
10 votes

In-body neutral density (ND) filters?

Just a guess, but I don't believe that ND filters are so widely used as you assume. A very large share of the users of a specific camera will never need an ND filter and therefore not be interested in ...
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  • 2,809
9 votes

Why is there "single" in the term DSLR (Digital Single Lens Reflex)?

The more important letter in DSLR is the R, which stands for reflex. What differentiates reflex cameras from others is that the image is made to appear on a screen that's positioned in a way that's ...
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  • 5,392
9 votes

Why can't my custom camera body focus to far distances?

If not, do I move the lens away or closer to the optical plane to fix the problem? If the lens will focus on near subjects, but not on a subject at "infinity," then that means that the lens is too ...
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8 votes

Why do DSLR cameras still use monochrome LCD as their top displays?

Segment LCD is a technology with the lowest power consumption of all available display technologies and those are more than visible on sunlight or any kind of strong light without any need for ...
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8 votes

How do SLR lenses connect to the body?

As Caleb pointed out, all focus and aperture-related functions (as well as optical zoom when relevant) happen inside the lens, not in the body (in terms of lens components moving at least, not talking ...
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  • 317
7 votes
Accepted

Is it coincidence that Nikon F lenses can fit a Canon EF body (with an adapter)?

If you read Canon's public statements at the time the EOS system/EF mount was introduced in the late 1980's, they spoke of the longer 44mm registration distance and larger diameter flange of the EF ...
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  • 167k
7 votes
Accepted

Are there any DSLRs that are only manual mode?

No. The incremental cost in actually providing modern features including priority and program modes is very, very small — but the reduction in potential market would be enormous. Because of this, ...
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  • 140k
7 votes
Accepted

Is it technologically possible for a sensor to run two ISO's at once?

It should be possible but may require a specific hardware design to do so. Magic Lantern does something similar (but not the same) on standard Canon sensor with dual ISO, which means every other line ...
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  • 196
6 votes

Why don't people care any more about shutter speed accuracy?

In most of old cameras (film) people are concerned about shutter speed accuracy at all speeds Shutter speed has a direct bearing on exposure. With digital cameras, you find out more or less ...
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  • 31.2k
6 votes
Accepted

Why are rangefinders not directly above the lens?

Rangefinders use two "viewports" in order to get the split image to aid in focusing. If you look closely you will see the second little window usually near the lens itself. It would be possible to ...
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  • 11.4k
6 votes

Can we improve phone cameras using separate sensors for each of RGB?

Your idea is very interesting. But there are some very serious problems. Parallax. Because the sensors will be shifted to each other they will "see" different picture. And the process of creating one ...
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  • 9,253
6 votes

Is there a DSLR/mirorless camera with minimal options like a classic, simple SLR?

The closest thing might be the Epson R-D1 (only available pre-owned), a manual focus, manual shutter cocked digital rangefinder camera. Also, there are some similarly designed cameras from Leitz. ...
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