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Old May 3, 2005, 9:19 AM   #1
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Please help me understand "Sports" mode. I have a Canon a70 and am looking to upgrade because I want more zoom and mp to photograph soccer games and wildlife. My a70 has a Sports mode which I use in these situations. Generally I know it has a faster shutter mode than other settings and it allows me to set up continuous shooting (not available in all modes for some reason.) What else does it do?

I am asking this because the newly announced Canon S2 iS (12x optical zoom, 5 mp) seems to be a great solution to what I need but it doesn't have a "sports" mode. You can see specs at http://www.steves-digicams.com/pr/ca...5_s2is_pr.html

It has the following modes though: Auto; creative zone: P, Av, Tv, M, C; image zone: Portrait, Landscape, Night Scene, Special Scene (Foliage, Snow, Beach, Fireworks, Indoor, Night Snapshot), Stitch Assist, Movie, My Colors

Will using the Tv mode and selecting a fast shutter speed ( the camera can do 15 - 1/3200 sec) do the same thing as a "sports" mode? Should I program a "sports" mode? If so, what other settings would I use to mimic a sports mode? Is no sports mode a reason to keep shopping?

Thanks!
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Old May 3, 2005, 9:42 AM   #2
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Most of a time, a sports mode in a consumer model is only instructing the Autoexposure Algorithms to prefer using a larger aperture (represented by a smaller f/stop number) with a faster shutter speed, versus using a smaller aperture (represented by a larger f/stop number) with a slower shutter speed.

For example, any of these settings would give identical exposure in the same lighting:

f/8, 1/30 second

f/5.6, 1/60 second

f/4, 1/125 second

f/2.8, 1/250 second

So, if you wanted your camera to prefer using faster shutter speeds, you could use Av (Aperture Priority) Mode and set it to a larger aperture (smaller f/stop number). Then, the camera would use the fastest shutter speeds possible for the lighting and aperture selected (while still maintaining properly exposed images). In some conditions, you may need to select a smaller aperture (because the light is too bright for the fastest shutter speed the camera supports at the largest aperture).

Or, if you're pretty sure of the lighting conditions, use Shutter Priority (Tv) Mode instead, setting it to a fast enough shutter speed for preventing motion blur, and letting the camera pick the appropriate aperture. Of course, if you pick a shutter speed that's too fast for the lighting, then you can get underexposed images if the aperture is already at it's largest opening. Most cameras will give you a warning if this happens.

Basically, you want to balance the aperture and shutter speed used so that you don't get motion blur, but have acceptable depth of field. A larger aperture gives a shallower depth of field (less of a scene in focus as you get further away from your focus point); and a smaller aperture gives more Depth of Field (more of an image in focus as you get further away from your focus point).

You can also effect the shutter speeds a camera can use via the ISO speed settings. Each time you double the ISO speed, the camera can use shutter speeds twice as fast for any given aperture and lighting condition. But, increasing ISO speed increases noise levels. So, don't do this any more than necessary.


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Old May 3, 2005, 10:23 AM   #3
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Thanks....so taking in what you explained, it sounds like I will be missing out by not having a sports mode. The sports mode algorithm would balance shutter speed, aperature setting and ISO to give me a good photo without me having to think much about it.

On the other hand, it sounds like you think I can compensate by using the other settings as long as I understand how they work (as you nicely laid out for me) and if I don't mind having to think about it.
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Old May 3, 2005, 10:38 AM   #4
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norava wrote:
Quote:
Thanks....so taking in what you explained, it sounds like I will be missing out by not having a sports mode. The sports mode algorithm would balance shutter speed, aperature setting and ISO to give me a good photo without me having to think much about it.

On the other hand, it sounds like you think I can compensate by using the other settings as long as I understand how they work (as you nicely laid out for me) and if I don't mind having to think about it.
To be frank, I'd prefer doing it using other methods.

Also, you have to take lens brightness into consideration when shopping. For example, at a 105mm equivalent focal length (full zoom setting) with your A70, the maximum available aperture is f/4.8.

Well, with a model that had a maximum available aperture of f/2.8 at the same focal length, you'd get shutter speeds almost 3 times as fast using Av Mode with f/2.8, versus using sports mode with your A70.

Because the A70 is already at it's maximum aperture (f/4.8 )in the same conditions and zoom amount, you can't get shutter speeds any faster without increasing ISO speed. Lens brightness is the main thing I'd worry about if shutter speeds were a large concern. I personally consider Sports mode to be a "gimmick" (since you can control these things yourself with other modes), but I'm sure others disagree.

It's not really that much trouble. In most lighting conditions where you need to worry about it, the autoexposure algorithms are already going to select the largest available aperture anyway. In better light is when it's usually a problem requiring you to use a larger versus smaller aperture with Av Mode, to change the camera's behavior. Even then, it may not be an issue, depending on how bright the light is.

Also, depth of field is not as much of a concern with non-DSLR models, since it's dramatically greater at any given aperture, focus distance and 35mm equivalent focal length compared to a camera with a larger sensor.

IOW, don't buy a camerajust because it has a sports mode (especially if the lens is not as bright). If you can find one that does what you want that happens to have a sports mode, fine. But, if you need to choose between a camera with a sports mode that has a lens that's not as bright, versus a camera without a sports mode (but still with an Av Mode) with a brighter lens, go with the model that has the brighter lens (if everything else about them meets your needs).

This is because the model with the brighter lens will help you get faster shutter speeds in less than optimal lighting (which isgenerally why most users think they need a sports mode to begin with).
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Old May 3, 2005, 12:12 PM   #5
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P.S.

To give you a better idea of how this works, a zoom lens will have two ratings for aperture. One is the largest available aperture at it's wide angle zoom position, and the other is the largest available aperture at it's full zoom position.

Some higher quality lenses can maintain a constant aperture throughout their focal range, so you'll only see one number for these. The Panasonic DMC-FZ20 is an example of a non-DSLR model that can maintain an f/2.8 aperture throughout it's focal range.

Your Canon A70 is rated at f/2.8-4.8 (f/2.8 is the largest at wide angle, with the largest available aperture becoming smaller as more zoom is used, down to f/4.8 at it's full zoom position).

The Canon S2 IS you're looking has a lens rated at f/2.8-3.3. So, it's largest available aperture at wide angle is f/2.8 (just like your A70). But, as you start using zoom, the Canon S2 IS lens will have larger available apertures (able to let in more light, allowing faster shutter speeds in the same conditions). It only stops down to f/3.3 at it's full zoom position (which is much longer than full zoom on your A70, too).

Aperture is a ratio, and is determined by dividing the focal length of the lens by the size of the iris opening.

The aperture scale (in one stop increments) goes f/1.0, f/1.4, f/2.0, f/2.8, f/4.0, f/5.6, f/8.0, f/11, f/16, f/22, etc. With each one stop move to a smaller aperture (represented by larger f/stop numbers), you will need shutter speeds twice as long for proper exposure.

So, a lens with a larger available aperture is desired to get fast enough shutter speeds to reduce motion blur (either from camera shake or subject movement) in many conditions.

So, if you have a camera with a sports mode, but it's lens is not very bright, it will be handicapped by it's lens design compared to a model with a brighter lens.

Here is achart you can use to get anidea of the shutter speeds required for any EV and Aperture (but make sure to use your camera's metering, as lighting can vary -- this is only to give you an idea of how it works). It's based on ISO 100. So, each time double the ISO speed, you can use shutter speeds twice as fast:

http://home.earthlink.net/~terryleedawson/dcnotes/tables.htm

The term "faster" lens is because you can get faster shutter speeds with it, and it's synonymous with the term "brighter lens".

Here is a handy online exposure calculator that lets you see how this works in 1/3, 1/2 or 1 stop increments (you can change this via check boxes at the bottom).

http://www.robert-barrett.com/photo/exposure_calculator.html


A brighter (a.k.a., faster) lens also helps a camera to "see" better for Autofocus Purposes. Many cameras won't be able to focus with a slow lens in some lighting conditions.

Understanding how exposure works (how light,ISO speed, aperture, and shutter speed interact) is probably one of the most important things you can learn about to get the most out of your camera (and a knowledge of exposure can help you pick a camera/lens combination better suited to your needs, too).



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