Photog Chris's Blog

got a camera and photoshop, fun times

Shutter Speed

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Up till the other day I thought everyone knew about shutter speed. Turns out I was wrong, so let me tackle this.

There are two primary reasons to think about your shutter speed, and one advance reason. Lets worry about the advance stuff later. The two primary reasons have to do with blur: camera blur and object blur. Ready for some math?

Camera blur is when you are shooting so slow that you hand movements are causing a blurry picture. This becomes more of a problem the longer your lens (focal length) gets. The classic way to avoid this was to take the focal length you are shooting at and use it as a fraction of a second. For example, if you were shooting at 50mm your shutter speed should be at least 1/50 sec. But that was in the old days of film.

Today most people have a camera with a crop sensor. Many DSLRs have a crop factor of 1.6(Canon) or 1.5(Nikon and Sony). So you are supose to multiply your focal length by that number to get your speed. That is a pain. I just double the focal length and use that. So if I was shooting at 85mm it would be 1/ 85×2 or around 1/200sec. See that, I rounded up big time! You don’t need any complicated math!

Some Examples:

50mm 1/4th sec - Blurry

50mm 1/40th sec - Better

50mm 1/100th sec - Sharpest

You may need to view the images full size to see the difference 1/40th and 1/100th. Look at the high lights and you’ll see the 1/40th are not crisp, even though I did steady myself before the shot. That being said, these numbers don’t always mean anything. I have successfully shot at 300mm and 1/25th sec with little to no camera shake, hand held. Positioning yourself to be stable, controlling your breathing, propping your elbows on a solid object. All these can steady your shot. As can using a tripod.

300mm at 1/25th sec, elbows braced on table

Object blur (subject blur) pretty easy. Most people can be frozen in time at around 1/200 sec. Many animals too. Birds, cars and other things that can move fast may need to go up to 1/500 sec. Water and splashes look pretty cool at 1/2000 sec. But the easiest thing to do, if you can shoot multiple shots, is to take a test shot. Set your speed for your focal length. If the subject has motion blur, speed it up some.

1/80 sec, motion blur

1/1000th sec, no motion blur

That is the easy stuff, the stuff I know. When you are using a flash, there are more things to consider. The shutter speed controls the amount of ambient light in the picture. The faster the shutter speed the more the flash will take over. Say if you wanted a portrait with a darken sky, a fast shutter speed would help do that. Check out lightenupandshoot for more info on using a flash.

As always, if I am not clear and need to expand on anything, please let me know.

Chris

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Written by photogchris

May 15, 2010 at 11:46 pm

One Response

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  1. […] 15, 2010 by photogchris A new tutorial on shutter speed over to the right of the page, or here. This time I am talking about shutter […]


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