Canon IS Lens

Discussion in 'Beyond the Basics' started by berrisj1, Jan 4, 2007.

  1. berrisj1

    berrisj1 TPF Noob!

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    Looking for some info. I am going on vacation next and taking a friends 28-300 canon lens. I know that the IS will give you a couple of stops down. This enables you to shoot at a shutter speed or ISO less than you otherwise would in order and still avoid shake. My question is whether this is something that only applies to manual controls. On full auto or other programs where ISO or shutter speed is set by the camera will it recognize the lens and automaticlly set a slower shutter, lower ISO to take a better picture? Any answers or advice on how to best utilize this would be appreciated. Thanks in advance.
     
  2. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    Welcome to the forum.

    Image Stabilization has no effect on the settings of the camera. The camera behaves exactly the same as it would with any other lens on. The difference is that the lens is stabilizing the image...so that you can get less blurring from camera shake. The thing to watch for is the shutter speed.

    The rule of thumb for camera shake, is as follows...to avoid blurry images from camera shake, use a shutter speed that is the reciprocal of the focal length or faster. So with that 28-300 lens, when zoomed to 300mm, you will want to use a shutter speed of at least 1/300. Many people think that if you are using a digital SLR with a smaller sensor (Rebel, 10/20/30D) then you should apply the 1.6 crop factor to the rule. So at 300mm...you would want to use a shutter speed of 1/480. You would need a good amount of light and/or a higher ISO to get that shutter speed, especially with that lens.

    So now we turn on the IS...which is said to give you 2 or 3 stops of extra hand-hold-ability. So rather than 1/480...you could use a shutter speed around 1/60 to 1/125...and still expect to get reasonably sharp images. That's pretty good. Without IS, you may have had to turn up the ISO to get a faster enough shutter speed...but then you have to deal with more noise in the images. With IS, you hopefully won't have to turn up the ISO.

    The rule of thumb is just that...it's not certain. Some people are steadier than others and some people have better technique, which allows them to get sharper images at lower shutter speeds. I'm sure a Google search could turn up some tips and tricks for holding a camera steady.

    Take note that IS will not prevent blurriness from subject movement. A moving subject still needs a fast shutter speed to freeze the action.
     
  3. berrisj1

    berrisj1 TPF Noob!

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    Thanks for the info.
     

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