Tuesday, January 26, 2010

Wednesday Word of the day! ISO

What is ISO? ISO measures the sensitivity of the image sensor, the lower the number the less sensitive your camera is to light and the finer the grain and vice versa. Lower # = less noise.

Depending on your camera’s make and model will play a HUGE roll in how high you can go and still remain “safe”. When I started out with my Canon Digital Rebel, I couldn’t even think about going over 400ISO without grain. My 50D worked well up to about 800ISO.

Play with your camera and find your “max”.

There are of course instances when you will have no choice but to go above what you are happy with. Indoor sporting events, a wedding perhaps, maybe even a dim clients home.

Because ISO is part of the triangle of light, changing your ISO greatly effects the two other key points, as will adjusting any or all of the points Aperture, Shutter Speed, and ISO.

Let’s setup a mental situation with poor light. Your local high school has asked you to shoot the Championship Basketball game Friday night. You know that the lighting is pretty poor and there is going to be a ton of quick moving action. Let’s determine which point of the triangle will be most important to us. I’m going to go with shutter speed. We are not going to want Jim Three Pointers to be blurry as he take that game winning shot. We want to capture that moment in time. Let’s bump the shutter speed to 1/500, maybe even 1/1000. You haven’t touched your aperture yet, it’s set at f/7 and your ISO is at 100 (haven’t touch that yet either). Shoot. WAY to underexposed. Remember that we want to leave ISO as our last ditch ever, so lets bump the Aperture down a whole lot. We can take that down to f/4 or even f/2.8 Wow! What a difference. MUCH more light coming in to the camera but still not perfectly exposed. Last resort, ISO…bump the ISO from 100 to 400. HUGE difference. Now shoot away!!

If you are in a low light situation that does not require a super fast shutter speed, get yourself a tripod! I know, its yet ANOTHER piece of equipment that you just don’t feel like lugging around, but you will be so thankful you did! Situation: Maternity session, clients home little light coming through the small itty bitty windows on a dark, stormy day. That small bit of light is hitting mom’s belly just right. Camera settings: Shutter Speed: 1/125 Aperture: f2.8 ISO: 200. You need just a bit more light coming into your camera. First thought, bump the ISO to 400 or higher, say a prayer and hope for no noise. IF you had your trusty tripod, you could easily break the hand held shutter speed rule (remember never put your shutter speed less than your aperture length or you risk some nasty shake blur). Hook that bad boy up to your tripod and you can drop the shutter speed down to 1/30 without any shake (as long as mom-to-be is a good listener and can sit still) ISO remains at a safe no-noise level.

The only way to get the hang of these tips and tricks is to get out the camera and play. Eat, Sleep, Breathe the triangle. When you get on location, take a big deep breath, review your surroundings, set your camera settings, check your settings, check ‘em again and start shooting, making adjustments as you go.

Aperture, Shutter Speed ISO. Aperture, Shutter Speed, ISO. Just keep saying it, out loud if you have to. You’ll be shooting manual in no time…with PERFECT exposure!

Taken from PropInsanity

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