Hot answers tagged

50

Digital camera sensor format-size names have their roots in television camera tubes. These were measured in inches diagonal, but for various practical reasons, the entire circle isn't used. So, from way back then, there's a concept called "the rule of 16", which says that the usable, actual sensor diagonal for a 1" tube is 16mm. (Yes, it mixes imperial and ...


50

It looks like you've got a problem with the shutter. Possibly one of the "blades" in the second curtain is missing and allowing light to strike the sensor between the time after the second curtain has completed its travel and the time the sensor is read out. Here's what a 70D shutter curtain looks like. Does the shape of the 2nd of four individual blade ...


50

From what I see this is element from the shutter. And my humble advise is to send your camera to repair shop, give it in to the hands of professional, do not try to repair it.


43

You've asked several different questions, so here goes: How effective is it? It is a lot more effective in cameras that have it than those that don't. Not trying to be a smarty-pants, but since most manufacturers adopted automatic self cleaning systems, the number of complaints regarding dusty sensors went down by several orders of magnitude. See labnut's ...


43

Quick summary Yes, bigger pixels do improve performance all else being equal, and Apple is doing a good thing by focusing on sensor size. However in this case the increase in size is so slight that the difference will be negligible, probably not living up to the level of improvement you may expect from their marketing. What does bigger pixels mean? This ...


41

There is an ISO which is not necessarily 200 that is the native sensitivity of the silicon from which the sensor is made. That sensitivity depends on the sensor itself, so will vary between cameras, but it is almost always between ISO 100 and 200. The camera amplifies the signal to get higher sensitivities. It scales down the signal to get lower ones. ...


38

Nothing Special There is nothing particularly special about ISO 1600, although in some cases ISO settings beyond 1600 have incurred less effective and efficient ways of amplifying the image signal. When you set ISO on a camera, that is simply instructing the camera to change the maximum saturation point of the sensor, from which the signal will be amplified....


36

First, understand a couple of things: Even though we call these things "digital cameras," the process of turning photons into numbers is entirely analog. Analog circuits pick up all manner of noise from their surroundings. Noise isn't one constant value, it's a range of them that top out at a level called the noise floor. The processing you did on the ...


33

The DxO Mark scores are misleading, but that doesn't mean the gap in performance isn't real! Several Nikon bodies (D800, D600 many of the D3xxx and D5xxx series) are using Sony Exmor sensors which feature a cutting edge ADC/read noise reduction system to achieve massive gains in dynamic range compared to Canon sensors, which are designed and fabricated in ...


33

Unlike a mirrored camera, there is little likelihood of the sensing system in a mirrorless camera suffering a catastrophic failure so it is really up to your "taste" to determine when a sensor is too old. The primary causes of degradation to a CMOS sensor array are heat, dye neutralization and cosmic rays. Thermal Degradation Normally thermal damage is so ...


32

Why don't cameras offer more than 3 colour channels? It costs more to produce (producing more than one kind of anything costs more) and gives next to no (marketable) advantages over Bayer CFA. (Or do they?) They did. Several cameras including retailed ones had RGBW (RGB+White) RGBE (RGB+Emerald), CYGM (Cyan Yellow Green Magenta) or CYYM (Cyan Yellow ...


28

This data was iffy then — not really enough data points, and the trendline is dubious: Source: a very timely xkcd That said, the company DxOMark does measurements of camera sensors all the time, designed to be resolution-neutral. Here's a chart of the "Sports" score, which is based on SNR, from all tested APS-C camera models from 2002 to 2018: Given the ...


26

It's very important to realize that it is not the high ISO setting itself that results in noisy image, it's that fact that using a high ISO setting means you capture very little light. Light is made up of photons which are randomly emitted by a lightsource. When the light levels are low or the exposure time very short then the number of photons you get will ...


25

Like many questions about what setting works best: It depends. The native ISO for almost all Canon DLSRs over the last few years has been ISO 100. 'Full stop' intervals, such as ISO 200, ISO 400, ISO 800, etc. increase the analog amplification of the signal readout of the sensor. The 1/3 stops in between those full stops use software adjustments during in-...


24

It is somehow true! For a moment, forget about the live view and consider the case of long exposure. While long exposing, the sensor heats up and this will cause the infamous background noise. So in reality sensor over heating can cause the noise and what happens is that in low light, warmed pixels detect light when there is none. (This last sentence is very ...


23

Maybe it represents the small variation of the temperature of the sensor. A hot sensor produces more noise than a cool one. The small temperature difference can be explained by the presence of electronic components, or the way the sensor is in contact with other parts, allowing more or less heat dissipation. Some related links : http://en.wikipedia.org/...


23

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 close from bottom to top. So it is open longer on the top side than on the bottom side, which is uneven exposure. Modern fast curtains might move about 7 ...


23

The information your friend gave you was essentially correct for most digital cameras, particularly compact digital cameras with very small sensors, made about 15-20 years ago. Digital imaging sensors were more primitive and noise reduction techniques were less sophisticated. By placing the native sensitivity of a sensor at one stop higher than what ...


22

Camera sensors (see this article for an overview) consist of a very large number of individual sensor elements, each of which can be regarded as a bucket that collects photons. These buckets have a maximum number of photons they can capture before they become full, which is called being saturated (this is when the highlights clip). This maximum capacity is ...


22

Cost. Every price raise results in fewer sales. Size. Cooling has to fit somewhere, those handgrips are already full of batteries... Weight. There's a reason P&S are popular and not lugging around a brick is one of them =) Battery Life. Cooling costs energy, lost energy means fewer shots in each battery pack. Minor Improvement: only shots pushing ...


22

Confusingly, 1" does not refer to the size of the sensor, it is instead a "type designation". The 1" refers to a certain size of TV camera tube, of which the usable image area occupied the inner two thirds. The use of such cameras is completely obsolete now but the sizing system remains. It's arguable whether this is due to doggedly sticking to tradition or ...


22

Most DSLR cameras have a sign on the top (Plimsoll mark) which looks sort of like The line indicates the position of the sensor plane. I googled for pictures of the 600D. It also has this indicator on the left side of the camera top.


22

So, why can't the sensor's image data downloaded to the processor, globally? Why is it downloaded row by row? It's a matter of physical limitations and simplicity. The physical limitation is that there's only space for a certain number of external connections -- you couldn't possibly connect every pixel to the processor and grab all that data at once ...


21

C is the correct answer. Well, actually it's A if you look at the sensor from the back, but my guess is that you will turn the camera around and access the sensor from the front. So it's C.


21

The size of the sensor does not matter, it is the size of the pixel. Having that said, bigger sensors like in full frame cameras tend to have bigger pixels. You can estimate the size of the pixel by taking the size of the sensor and divide it by the number of pixels. This calculation is not accurate because most sensors have gaps between the pixels and ...


21

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 tolerate one side of the picture being 10% more exposed than the other, so that means we allow 50μs to move the shutter back and forth. So the shutter has to ...


21

The item obstructing the sensor is a shutter blade. Your shutter has failed and needs to be replaced. There's no hack or DYI solution for this problem. This is a hardware problem and not something that can be fixed with software or some kind of hack. You should expect repairs to be in the $200+ price range. Since you can buy a used XTi for under $150, ...


19

There were economic reasons, but they were not about getting to amateur market; it was more like getting any market. The main merit seen in early digital photography was speed of delivery (no need to develop films), so news agencies were the first targets. During the dawn of digital photography, a full frame sensor would have been enormously expensive to ...


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