Hey, fancy meeting you here, too!
c/p of my reply on that other board:
jpld wrote:
I want to shoot my daughters' dance recitals and stuff at Disney World with the telephoto lens that the stabilizer would be useless in this case.
It depends on how much you're zoomed in. On the wide end ("zoomed out") of those lenses, you should be fine without stabilization. But zoomed in, not so much. If you want the details: in order to freeze motion of dancer, you'd probably want to use a shutter speed of 1/200 or faster. There's also a rule of thumb that stabilization will start to factor in when your shutter speed drops below the reciprocal of your lens' focal length multiplied by your camera's crop factor (which, for your T3i, is 1.6). e.g. 1 / 100mm x 1.6 = 1/160 Since 1/200 is faster than 1/160, you should be OK without stabilization when shooting with a focal length of 100mm (or less). But since 1 / 200mm x 1.6 = 1/320 and 1/200 is slower than 1/320, you would probably see the benefit of IS when shooting with a focal length of 200mm (or more). (Or you could increase your shutter speed to 1/320 or faster and shoot without IS.)
My concern is that, at f4.0-5.6, both of those lenses are rather slow, especially for what I'm assuming will be an
indoor dance recital. I would strongly recommend a lens with a max. aperture no larger than f2.8 and ideally, f2.0 But telephoto lenses with large apertures are very expensive, and if your budget is $200, you're going to have a difficult time. So I would try to get as close to the stage as possible and use a shorter lens. (e.g. 50mm f1.8 II can be had for around $100.) You're going to have a similar issue shooting either indoors or at night at Disney World. Although, outdoors in broad daylight, you should be OK increasing your shutter speed as needed to shoot without IS.
If you need more reach than 50mm and can increase your budget to around $400, you might check out the 85mm f1.8 or 100mm f2.0 (And although neither is stabilized, remember, from above, that with a shutter of 1/200, you shouldn't need stabilization for focal lengths of 100mm or less.)
Mark
{edit}To add a bit more here and make things a bit more straight forward...
I would approach an indoor dance recital by:
Setting my shutter speed to 1/200.
Setting my ISO as high as I'm comfortable with. (I would suggest 1600)
Setting my aperture wide open.
If the pics are underexposed, increase ISO (be aware that this will mean more "noise" in the pics) and/or decrease (slower) shutter (be aware that this will mean more motion blur).
If there's too much motion blur in the pics, increase both shutter (faster) and ISO (higher) in steps to maintain exposure.
If the pics are overexposed, (Yay! But not likely.) decrease ISO.
Oh, and shoot RAW (or RAW + JPEG) so you can adjust exposure and white balance in post. (Exposure because the pics will probably be underexposed, and white balance because (colored) stage lights can cause problems for auto-white balance.)
{/edit}