Serene Life

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59

Fluorescent lights can flicker at twice the frequency of the current feeding them, which implies an entire cycle of the flicker will take between 1/100 and 1/120 second. During each cycle the light's intensity and its color temperature can change. Thus, if you're using a shutter speed of 1/100 second or faster, you might observe exactly these phenomena: ...


28

It is important to understand that different types of lighting will produce different ‘color casts’ to the light in a photograph. While the eye is great at correcting for color ‘on-the-fly,’ our cameras aren’t very good at the task of adjusting in mixed environments at all. This can result in severely yellow/orange pictures, or sickly green ones, depending ...


26

The white balance setting doesn't affect the image data in the RAW file, but the setting is recorded in the meta data in the file, so you can still use it to process the RAW image if you like.


24

Different light sources have different color temperature and when you want natural colors, you need to correct them for that particular light source. Basically white balance says what is rendered as neutral gray. You can find a more thorough explanation here: http://www.cambridgeincolour.com/tutorials/white-balance.htm. Wikipedia lists different light ...


24

White balance is all relative. Light (natural or artificial) varies in colour and your eyes are used to adjusting it. It's amazing how an image can seem fine until you see another image with a different white balance and it suddenly looks wrong. Even the background colour of the page holding the image or frame can influence how colour balance is perceived. ...


22

Fluorescent lights are terrible news for photography, and this is just one of the reasons! They give out light which is missing a big chunk of the red spectrum, which can make skin tones look greenish and unhealthy, they are usually different colours from each other even if the tubes are the same type, and they change colour during the power cycle! Your ...


21

mattdm has it spot on - it's not the colour temperature that matters, it's the width of the spectrum. Here are some examples that illustrate the difference nicely. Here's an image I shot a while ago at a bonfire. Straight of camera, without the white balance set it looks massively orange: And here's an image shot just now under sodium vapour streetlights ...


21

No. If you shoot in RAW, there is nothing lost. In fact, in RAW, the white balance you set in-camera is nothing but advisory information to the post-processing software. A different multiplier is applied differently to the red, green, and blue channels during RAW conversion depending on the setting, and if you're doing that conversion from a RAW file, you ...


21

The white balance should be indicated on the box and the datasheet for the film. There aren't too many choices though. Most films are daylight balanced for shooting in sunlight. If you were shooting in open shade, you were expected to use a slight warming filter to get rid of the blue cast. If you shot daylight-balanced film under tungsten light, you could ...


19

For myself the easiest way to understand UniWB was the following. Most current digital cameras have twice as much green light sensors as they have reds and blues (referenced as RGBG). Now to achieve neutral gray by changing white balance, usually the red and blue channels need to be amplified more than green. Just a few examples (for Canon 350D): ...


18

Let's consider the image captured by the sensor (RAW) as calibrated and neutral. The equation is the following to generate a color balanced JPEG is: JPEG = RAW * T where T is the color balance transformation Normally to apply a different color balance to a JPEG, you would need to apply the inverse of as-shot transformation to the JPEG (to restore the ...


18

The problem with fluorescent lighting isn't the color temperature, exactly. You can generally adjust white balance to account for that. If there's a green tint, that can usually be compensated for with manual white balance. But the poor color rendering is harder. The problem is that by their nature fluorescent tubes only produce light in narrow ranges of ...


17

This can be a complex answer, and quite often, the outcome is that it depends what you print on, meaning you might need to change it or recalibrate often. On White Point White point from the perspective of the human eye is a very subjective thing, as the eye automatically "recalibrates" itself to differing white points depending on the kind of light that ...


16

Ideally, you're shooting in an environment with controlled lighting (a single light source, or several tuned to same color temperature), your subject and black or white surfaces only. In this case, the angle does not matter - just take care that its exposure falls somewhere in the middle in your test shot (so you're not accidentally clipping a channel). In ...


15

When you have already set your exposure parameters, white could be clipped in some single color channel (but not all, so your camera won't show it as blown), therefore not being very good basis for color balance adjustment. Also, paper will turn yellow during time. And just looking at the sheets currently on my desk, there's three different tones of white ...


14

The problem is that the exposure meter in the camera does not know whether the subject itself is bright or not. It simply measures the amount of light that comes in, and makes a guess based on that. The camera will aim for 18% gray, meaning if you take a photo of an entirely white surface, and an entirely black surface you should get two identical images ...


14

For creative photography I dont bother. The "correct" white balance (if it even exists, many scenes with different coloured lightsources have no single white balance) is rarely the one that looks most pleasing so I pick the balance in post that looks best. White balance alters the emotion of a scene from cold stark blues to happy warm oranges and is part of ...


14

The original assumption is that the average scene should be color neutral and therefore by computing the average color in the scene and then applying the same correction to every pixel you would get a scene whose average color is neutral which should have the correct white-balance. This will fail when there is a dominant color and the scene. Algorithms got ...


14

There are a few ways. Here are the main two I use: before you start shooting a scene/pose have someone hold the card in your primary light and hit it with your in camera meter. (in spot meetering mode, ideally with the card fully filling your spot meter area, even if that means zooming in.) set your exposure such that that is "properly exposed". Now remove ...


14

The issue with these sorts of light sources isn't the color temperature, but rather the spectrum provided by the light. A camera (or your eyes) can only record colors which are reflected from the objects in the scene (not counting objects which have fluorescent properties). If the light shining on the object doesn't contain a certain color, it can't bounce ...


14

This is actually fairly easy to test, and so I did. I used my Pentax K-7, so this doesn't speak to all cameras, but I think at least many work the same way. I worked in a dark room, lit only by an iPad app which simply turns the whole screen a certain color. I put the camera close enough to the screen that the color filled the entire frame, and, although I ...


14

The camera can not alter the spectral sensitivities of the sensor, those are baked into the chip. What actually happens depends on what format your saving files in. If it's a Raw file format, what happens is the cameras white balance setting is recorded in the raw file for a raw file processor to use to create that white balance. If you're writing ...


13

I've also tried using CFLs in clamp lights for photography, and I've also been disappointed with the color rendering. Color temperature is a measurement that properly only applies to black body radiators, which produce a continuous spectrum. CFL bulbs aren't black body radiators and don't output a continuous spectrum, so the color temperatures claimed for ...


13

It is in the EXIF data, but the info is under Canon tag. For any EXIF-related tasks, I wholeheartedly recommend ExifTool by Phil Harvey. Here's an example of a real file (which coincidentally was shot with Canon 450D) $ exiftool -canon:"WB_RGGB*" -canon:"*temp*" MG_5366.CR2 WB RGGB Levels As Shot : 2270 1024 1024 1520 WB RGGB Levels Auto ...


13

Don't use auto white balance - choose a color temperature that looks well and stick to it (or use a gray card if the color accuracy is important) Close all the windows - the daylight color changes based on weather, if possible use only flashes and photographic color balanced lights, if you must use normal indoor lights try not to change light bulbs, if you ...


12

White balance tools (like those in Lightroom or Photoshop) will tell you the color temperature of the neutral card essentially directly, based on the color temperature data in the RAW file. More theoretically, if you're shooting with a known color temperature (even approximately known), then the color of the neutral target is directly related to the color ...


12

Color-temperature is a way to describe the color of light along a spectrum that goes from warm colors (measured as having a lower temperature) to cool colors (measures as having a higher temperature). Color-temperature is measured in Kelvin degrees and corresponds to the temperature at which a certain metal must be heated to emit light of that color. That ...


12

For all the discussion about which camera white balance setting to use, I think it is important to note that, if you are shooting RAW, the simple answer should usually be "Always use AWB". The reasoning for this is because white balance is an easily correctable thing in post processing when you shoot in RAW. Even if you do use the "Manual" or "Custom" white ...


12

Try sunlight. That'll give you a fixed setting which will assume a relatively "hot" light source, which will render the more-yellow light sources as yellow in your image. (Conversely, if you shoot actual sunlight in incandescent-wb, you'll get a strong blue cast.) If your camera (or RAW processing software) allows you to set color temperature in Kelvin, try ...



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