Well, I thought I'd do something helpful here again, so here's some terminology and rules I know of in photography. It's not entirely indepth, and I do plan to write more comprehensive tutorials in the future, but you can bug me if you're curious about something RAW When I first heard about RAW, I thought it simply meant that you didn't edit it at all. I was completely wrong, but not alone in thinking this. Thankfully, I've since learned what it is and how to use it. RAW is actually what it sounds like: uncompressed and unmodified. However, it's not a state, it's a file type. Canon uses CR2, Nikon uses NEF. RAW takes slightly longer for the camera to write, but is well worth it. I've shot RAW for almost a year now, and there's no going back for me. When the camera saves a jpeg, it applies automated modifications. There's some sharpening and noise reduction applied automatically, and they tend to add a bit of contrast as well. Now, being someone who likes to control her shots completely, I hated this. But I hated something else more: when the jpeg is compressed, you lose tons of information. You don't realize how much information is tossed out until you realize what you can do with RAW. With RAW, you can recover up to one full stop of detail when it's overexposed. With jpeg, that information is gone forever. Not only that, RAW is a lossless format. Any edits you make are not permanent until you export to another file type. This is achieved by having what's called a sidecar file, which is the XMP file. The file is linked to the RAW file. As long as they're together, your edits will show up. If you separate them, you need to bring them back together again to restore your edits. If you open the XMP file in a word processor, you'll see lines of code saying what modifications you've made and by how much. The other disadvantage of jpeg is that, as you edit, you are actually removing detail. RAW handles your edits differently, so you don't lose detail like that. You can actually watch your detail disappear in the histogram in Photoshop. As you lose detail, you lose columns in the histogram. With RAW, you're not losing numbers (thus detail) as you stack your modifications on. Every edit you make is being applied to the original photo, instead of the original photo with other edits on it. --- Camera Raw is a program built into Photoshop that allows you to edit these RAW files. You can change color temperature (oops! You shot everything in daylight when you meant to do tungsten!), exposure, black levels, fill (brightens shadows), recovery (darkens highlights), contrast, vibrance, certain lens flaws, etc etc. All of this is lossless, and the program opens automatically when you click on a CR2 or NEF (RAW) file. Camera Raw is relatively new, so each version has more and more options to it. CS4 Camera Raw is fairly amazing, and is what I based that previous list off of. The other program you can use is called Adobe Photoshop Lightroom (2.3). Lightroom is more for the professional, as it allows you to easily edit and organize a large volume of photos. However, it has more features than even Camera Raw, has automated things like coding a web gallery for you, and has an excellent sorting system. Lightroom organizes photos into one catalogue and then has folders within that catalogue. For me, I just click 20090529_Freeze in my library and it takes me to the folder for that entire event and I can get editing. Basically, it's Bridge and Camera Raw combined into a photographer's best friend. --- RAW opens up so many possibilities. It gives you more options for your photos and fixes some very basic but key problems like that white balance issue. With jpeg, the white balance you shoot with is what you get. You have to lose detail in order to correct the colors. With RAW, you can always change the white balance after the picture is taken without harming your file. ________________________________________________ Stop Measurement of the amount of light. Going up one stop will double the light, dropping down one stop will half the light. Stops are measured using aperture and exposure. They don't tell you what the exposure is, rather how to adjust the exposure. "The photo was overexposed by one stop." "Close down your aperture one stop." Aperture is spaced using stops. Digital cameras commonly will measure aperture every third stop. Old lenses only measure full stops, and sometimes half stops. Aperture Full-Stops: F/1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 45 Going from F5.6 to F4 is opening up one stop (double light). Going from F11 to F22 is closing down, two stops. Your shutter speed also has full stops. 1", 1/2", 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, 1/2000, 1/4000 These numbers are essentially doubling each time (except in two cases: 1/8>1/15 and 1/60>1/125). Go from 1/125 to 1/500, you are moving two stops. ISO is your third factor. It's very simple, and cameras only have ISO in full stops. Each time you move your ISO up or down, you are changing it by one stop. ISO 50 to ISO 100 is one stop. Why is it important to know this? Well, photographers measure their calculations in stops. In the studio, you use a lightmeter to measure the light. Without the meter, you won't get the light to the power level you want (you change the lights to get proper exposure instead of your own camera). If my meter says that my light is F11.7 @ 1/125", and I want it to be at F8 @ 1/125", then I need to know how many stops to drop it down, and I need to know that F11.7 is rounded to F16. Stops also have other uses, and make it easier to estimate the correct exposure without any sort of meter. The second most common use this knowledge has is identifying equivalent exposures. ________________________________________________ Equivalent Exposure More important than I could ever express with words. Let's say you figure out that your exposure for one shot is this: ISO400 F/16 @ 1/60" You want to have a narrow depth of field, but F16 won't give you that. You want your aperture to be at F2.8. The only way to figure this out is to understand stops, and equivalent exposure. It's really very simple and just takes practice. Equivalent exposure is changing your exposure settings to achieve a different effect without actually changing your exposure. (I can provide examples, if you want). So, if I want to shoot at F2.8, here's what I'd do: ISO400 F/16 @ 1/60" <- original exposure ISO200 F/11 @ 1/60" <- that's one stop ISO200 F/8 @ 1/125" <- that's two stops ISO200 F/5.6 @ 1/250" <- that's three stops ISO200 F/4 @ 1/500" <- four stops ISO200 F2.8 @ 1/1000" <- five stops Every single one of those exposures will look the same. Every time I changed a factor other than my aperture, I also opened my aperture up by one stop. So, in the second one, I changed my exposure by one stop (to 1/125"), then I changed my aperture from F11 to F8. When I half the light by changing the shutter speed to 1/125, I'm doubling the light by opening up the aperture to F8, canceling out all the changes. For something like this, I generally would count how many stops I need to move my aperture to get to 2.8, and then I'd do it all in one step. Ask me questions about this so I explain it better too. ________________________________________________ Open up Adding more light/increasing the exposure ________________________________________________ Close down Subtracting light/decreasing the exposure ________________________________________________ Histogram Bar graph displaying # of pixels at what luminosity. Based from 0-255, 0 being absolute black, and 255 being white. 128 is middle (50%) gray. The histogram is used to determine if you have a proper exposure, and/or clipping in your blacks and whites. There is no correct histogram; it's all based off of the variations you see and what you want. However, LCD screens don't display the colors and values correctly, and the histogram is something you absolutely need to understand for serious photography. If you want to know more about it, ask me and I'll get some things together to explain it better. ________________________________________________ Clipping Detail being lost because of improper exposure, or it exceeds the spectrum of light that a camera can capture. It also happens in editing. ________________________________________________ White balance/color temperature/light temperature This is how your camera sees light. Because light is different colors depending on the source and time of day, the camera needs to know what color it is to adjust for the color shift. Your eye does this automatically for you, but the camera isn't quite that smart. If you have your white balance wrong, the photos will have a color cast you probably don't want. It is highly discouraged that you use AWB (auto white balance), no matter the circumstances. It's not that smart, and so it gets it wrong too much. Better to use presets. ________________________________________________ Kelvin This goes hand in hand with your white balance. Kelvin is what white balance is measured in. 1800K is candlelight, 3200 is tungsten, 5500 is daylight, 6500+ is overcast, and shade is somewhere above there. The lower the number on the scale, the more blue is being added. The higher the number, the more yellow is being added. So if you have a shot that is overcast and your white balance was set to 3200K, you will find that your photo is very very blue. Likewise, shooting in tungsten light with your WB set to 6500, you will have an extremely yellow photo, since the light itself is yellow, and you're adding even more yellow to it. When you're editing the color temperature in a RAW photo, it's measured in kelvin. ________________________________________________ Focal length Focal length is how far your lens elements are from your image sensor. This is why my 300mm lens is far longer than my 50mm lens; the elements are further away from the element, requiring a longer lens. Those interested in macro lenses should not only be looking at focal lengths, but that the lens is actually a macro lens. Macro lenses can be wide angle, or be telephoto. The defining factor is actually how close the lens can focus, not the focal length. My 300mm can only focus on objects at least 5.5ft away from me. If it were macro, that number would be significantly smaller. ________________________________________________ ISO An acronym for a name you never need to know (and I applaud you if you memorize it, since I can never remember it). ISO is slightly different than shutter speed and aperture, since it doesn't affect the amount of light coming in. Instead, ISO is changing the sensitivity of your image sensor. The reason you get noise at higher ISOs is that you make the sensor more and more sensitive to the light, which is affecting how well the sensor receives and converts the data. Certain cameras can shoot higher ISOs than others. The optimal ISO for Canon is 100, and Nikon is 200. ________________________________________________ Depth of field This is controlled using two factors. The first one is your aperture. Opening up your aperture will give you a very narrow depth of field. If I shoot someone's face at F1.4, it's likely that I'll have the nose and ears out of focus and the eyes sharp. Shooting with a closed down aperture will give you a very wide depth of field. For the same shot, if I change my aperture to F16, I'll have the face and background sharp. The second factor is focal length. The longer the focal length, the narrower your depth of field. If you shoot at 300mm, you'll have a narrower depth of field than if you shot at 24mm. It is preferred that you use aperture over focal length to control this in portraits, as a longer focal length will also flatten your image, an unflattering effect on someone's face. Will add more as it comes.
