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Old May 19, 2007, 11:06 AM   #1
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Posting my own specific, "which lens" question, I AM doing research and learning. A post from 2005 went down a debate of IS versus a faster lens such as 2.8. The discussion then quickly went WAY OVER MY HEAD and efforts as it began pasting and linking charts.

Can anyone cover quick opinions on IS versus faster lens. Situations. Benefits. For context, my of my shooting is in lower lit, indoor situations. Filming children so speed is key. Often rolling on floor into position or grabbing camera and JUMPING INTO ACTION to capture precious or funny moments.

In my short time in the hobby/obsession, I've got some GREAT shots but then been curious why others came out blurry.
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Old May 19, 2007, 1:47 PM   #2
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Lee,

Here's the basics of the discussion:

IS will keep the image steady for anywhere from 2-3 stops below what you could normally hand-hold without camera shake showing up in your images. So, if you could normally hand-hold 70mm at 1/60 and not see camera shake, IS will allow you to hand-hold at 1/15 or 1/8.

The advantage of wider apertures is two-fold: you gain faster shutter speeds in a given lighting situation: So a 5.6 lens may give a shutter speed of 1/30 while a 2.8 lens gives a speed of 1/125 (two stops faster), an f2.0 lens will give a speed of 1/250, a 1.4 lens will give you a speed of 1/500 in the same light. The other benefit of wider apertures is producing a shallower depth-of-field. So you get more isolation of your subject from it's background.

So, IS is most beneficial when you are taking low light shots of non-moving subjects. wider apertures are more useful when you're taking low light photos of moving subjects or when you want subject isolation. Both have their place.

Now, on to your specific case: toddlers. i think you'll find that neither IS nor a 2.8 lens are going to be the right solution for your indoor shots. The IS won't prevent motion blur from your kids moving and the 2.8 aperture won't be wide enough to give fast enough shutter speeds to freeze the motion either. In fact I might go so far as to say a 1.8 lens might not be fast enough. More often than not the best bet for moving kids indoors is a bounced flash.

The blur can come from a number of things - camera shake, subject motion or both. In general you need 1/500 shutter speed to stop hand motion (hands move pretty fast - even on toddlers), 1/250 can stop trunk motion of normal movementbut you'll see blur in hands/feet.

For portrait type shots - both IS and wide aperture have great benefit when shooting children - but once they're moving IS is useless and even wide apertures may not be enough - that's when flash is the best bet. It really depends on how well lit your house is and whether you can get the 1/250 or 1/500 shutter speeds I mentioned.
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Old May 19, 2007, 5:52 PM   #3
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JohnG,
Great answer as always. Thank you. I may have to read and re-read a few times, but...

What I love about this site is that what may seem like common sense and old news to some, or "Go read a book to others..." is a great, quick, specific education to others' very specific needs. The books may cover everything from fields of flowers in Amsterdam, to running water, or shooting the old guy in a half lit doorway in Mexico, etc.

Thanks again. Much of that I understood but it leads to another question. So, IS would not be all that useful in Sports shots??? Fast action, etc. I may think this question through a little further as I'm racing out the door.

Also, you may have answered this question months ago, but, with your new young one, what is your favorite lens? Wish list with your 20d???
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Old May 19, 2007, 10:47 PM   #4
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leeraff wrote:
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So, IS would not be all that useful in Sports shots??? Fast action, etc. I may think this question through a little further as I'm racing out the door.

Also, you may have answered this question months ago, but, with your new young one, what is your favorite lens? Wish list with your 20d???
IS can be useful for certain sports like cycling or certain car races where you use a panning technique to show motion and end up using slower shutter speeds. It could also be beneficial at any time for other sports where you desire motion blur for a specific shot - but that is the exception and not the rule.

Now, when you get to very heavy lenses like a 300mm 2.8 then IS can be beneficial for hand-holding even when trying for shutter speeds like 1/500. But that's a $4000 l ens. For any of the 70-300, 70-200 or similar lenses, IS will not help a bit for stop-action photography. Even with heavier lenses I recommend a monopod over IS. IS doesn't prevent muscle fatigue - I wouldn't want to handhold my 120-300 2.8 for 3 hours shooting a sporting event. Outside of ego, there really isn't a good reason to do so. Even those that use the 300mm 2.8 or it's big brother the 400mm 2.8 almost always use a monopod if they're using it as the primary lens.

As for my son, I've gotten a ton of use out of my 85mm 1.8 and 50mm 1.8. But equal amount of use out of my Sigma 500 DG Super flash. At some point in the future I'll probably invest in a wider 1.8 prime - 50mm can get a bit tight - fine for now but I'm guessing in another year I'll need a new, wider lens.
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Old May 23, 2007, 3:26 AM   #5
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To IS or not to IS, that IS the question!

I was going to post something similar. But about wildlife photography; for wild birds and zoo.

There is sometimes good price on a used canon 300 mm f2.8 NOT IS. (Around 2700$US and with the possibility of no tax / custom.)

Would the IS version have any advantage for wildlife?

If yes, then what to pick between, the 300 f4.0 IS vs the 300 f2.8 not IS?

Will there be a big difference? I have money for any of those, but it it's a big expense! The price of the f2.8 IS makes my teeth's grind a bit:roll: and we all like to spend wisely :-)

Thanks!








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Old May 23, 2007, 8:06 AM   #6
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Isn't 300mm too short for wildlife?

Anyway, I vote for f2.8 non IS version, because you can easily mount 2x and 1.4x teleconverters, which will make it capable 600mm f5.6 and 420mm f4 lens.

Offcourse, get a monopod right before tcons.
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