Hot answers tagged

60

From my understanding, higher ISO gives a more grainy photo I'm afraid your understanding is incorrect. High ISO doesn't necessarily give a more grainy photo as there are other factors involved. In some circumstances it can be the case that lowering ISO increases noise. I did an experiment a while back to prove this: http://www.mattgrum.com/ISOcomparison/...


54

It would be wrong to think that increasing ISO results in no "physical" change in the camera at all. The problem with ISO is that people often call it sensitivity. That is really a misnomer...sensitivity is a fixed attribute of any given sensor, and it cannot be changed. Sensitivity is really more synonymous with the quantum efficiency of the photodiodes, ...


48

The ISO function on most digital cameras amplifies the analog signal prior to readout and digitization, which itself is a source of noise. If you just apply the correction digitally you amplify the read/quantisation noise as well as the signal. Increasing ISO in camera to account for lack of light actually reduces the overall noise seen the image. Here's ...


46

Hardware ISO control exists to amplify the signal before readout to maximise the signal to noise ratio. Without read noise you wouldn't need ISO if you had a high precision ADC as you could simply shoot everything at the native sensitivity, and if the image was too dark just apply digital gain (multiply the pixel values). It's easy to demonstrate 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....


32

The mountain and the valley obviously are static -- even more from that distance. The clouds, however, move. If you chose a low ISO value, e.g., in the range of 50 to 100, the exposure time might be enough to get washy/faded/blurred clouds. If I calculated it correctly, an ISO value of 100 with the other settings (exluding shutter speed) staying the same ...


29

In general, photos at lower ISOs will have less noise. This means that they compress better (remember that RAW files have lossless compression) and so, on average, you'll be able to fit more images onto the card. The other important thing to remember is that the number shown is only an estimate - how many images actually fit depends on what you take photos ...


29

So I first shoot with ISO 1600 and shutter speed set to 1/125 second and then I shoot with ISO 3200 and shutter speed set to 1/250 second. The amount of light should be identical and indeed both shots look properly exposed and exposed the same way. The amount of light is not identical. You let twice as much light into the camera at 1/125 second than at 1/...


29

The easiest way to solve this problem is to use a neutral-density filter. They are essentially neutral grey filters that cut down on the light reaching the film or digital sensor. Good ones are fairly expensive, because they are surprisingly hard to manufacture. Another option is to shoot in more favourable conditions, like overcast days or really early ...


27

The look you are going for is known as low key lighting. It is not necessary for the room to be dark. You just need to put enough light on your subject that there is a large enough difference between the shadows and the highlights. I took this self portrait by shooting into a mirror in a fully lit room. By using a good amount of flash power I could use a ...


26

This is a perfect example of "expose to the right" — that is, even though you want the final result to be low key (largely dark), take the initial exposure as bright as you can (without blowing out the brighter part of the sky, reflections, or any more subtle brighter areas). When you expose so that dark areas are really dark — either because you are ...


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-...


25

I think "several fluorescent fixtures that I use to light my studio" is the key here. I'm guessing that the very high ISOs are accompanied by very short shutter speeds. Fluorescent lights cycle, and there are color variations within the cycle. Repeat your test with incandescent light or sunlight (or a strobe with high-speed sync). See Do fluorescent ...


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 ...


21

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 ...


21

Let's try this as a very different explanation: Imagine that you have been asked to record a piano recital at the local school. It will occur in the auditorium, and it will be full of parents and friends to hear the work of the pianists. You are not a studio technician, but are doing this as a favor to a friend. You bring your laptop, and you have an old ...


19

Just because the image is mostly black doesn't mean the scene is dark. With a flash positioned on the left pointing at the subject (he's facing the flash) and a black backdrop you could possibly even pull this off in daylight. Start with a low ISO, a middle of the road aperture and the sync speed for shutter speed (probably 1/200th or 1/250th). The point ...


18

The Factors There is an equation, and by convention, it's set up to be really simple. There are basically five factors to consider together: Aperture — the size of the opening which lets light in, Shutter Duration (or shutter speed) — the amount of time the sensor (or film) gets that light, Sensitivity (or ISO, or sometimes "film speed") — how quickly the ...


16

Some of the following suggestions will depend on your camera (I have a Nikon so I'm not sure about Canons). Rather than press the shutter button directly, try using a remote shutter release or alternatively there may be a timer function which delays the shutter - this will allow (at least some) vibrations to settle down. Look in your camera manual to see ...


16

There were several techniques: Carry extra film backs (MF) or camera bodies (35mm) with different film loaded Push process lower ISO film to sacrifice fine grain in favor of perceived higher ISO Rewind the film already in the camera until just the leader is outside the canister, noting what frame you are on, then load a different roll. You can then reload ...


16

Being a man of science, I did some scholar-googling and came across some articles. Too long, didn't read: None of the scientific articles I found give a clear definition of "high ISO". However, they all link high ISO with higher noise levels. Therefore, I would say that high ISO is completely dependent on subjective criteria and the camera in question. My ...


15

Analogue amplification (pre-digitization) is the best way to implement a variable ISO sensitivity. When you do so you are only amplifying the photon noise. When you amplify the digital data (i.e. by multiplying all the values by a fixed amount) you amplify the photon noise, the read noise and the quantization noise, leading to more noise overall! Most Canon ...


14

I think you might be confusing a few issues here. The terms "Base ISO" or "native ISO" are often used to refer to the unamplified sensitivity of the camera. In addition to this digital camera sensors have built in amplifiers to amplify a weak signal (such as you get in low light) before it is digitised in order to reduce read noise and increase signal to ...


14

1600 is not a magical number, but with today's current technology many DSLR's commonly produce poor results above ISO 1600. On the other hand, you could argue that many still produce fine results at 3200 and 6400 - it depends on the audience and what technology they are familiar with. If you are reading this on a forum with many users of consumer level DSLR'...


14

The base ISO of all Canon cameras is ISO 100. This is the ISO with the lowest gain, without any in-camera magickry to achieve the setting (like ISO 50, which mucks with the actual exposure settings behind the scenes). There is a lot of conjecture and misunderstanding about Canon's ISO settings because they use a "real/push/pull" model for ISO settings, ...


14

The concept of light sensitivity is related to speed in that a faster film (higher ISO value) requires less time exposed to light than a slower film (lower ISO value) for a single exposure. Fast film achieves this by having larger crystals of silver salts than slower film, thus collecting more light and creating larger "grain". "ISO speed" might better be ...


14

How to disassemble / take apart Fujifilm X-T1 and how to disable ISO Dial lock switch. It is relatively easy to take apart FujiFilm X-T1. You only need one type of screwdriver, although the screws themselves are different. So as usual, make sure to have several small containers and a piece of paper to write down/draw where a particular screw came from. It ...


13

You young'ns have it too easy with your digital cameras that let you adjust ISO at whim. This is how you overcome it: Technique: breathing, bracing, practice, practice, and more practice. (Honestly, I think the high ISO capability of DSLRs has made many people very lax in this area.) Monopod or tripod. Or a tree, doorjamb, car -- anything you can lean ...


Only top voted, non community-wiki answers of a minimum length are eligible