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Old Apr 23, 2005, 10:31 AM   #1
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Wow. There is so much knowledge here. I'm impressed. I'm quite a newbie compared to the rest of you here.

My parents bought a Casio Exilim EX-Z4 U for the family to take pictures. It's great for them because it's generally point and shoot. (I get the blame if it turns out otherwise :roll But I've gotten to the point where I'm really experimenting with photography in general. I'm looking for a way to manually set the shutter speed, or to "suggest" to the camera to set it faster. The specs say that it's automatic up to, I believe, 1/4000 sec, but most of the time it uses 1/8 of a second. I've taken pictures though up to 1/2000 that came out very nice. Taking action shots with a 1/8 sec. shutter speed doesn't quite do the trick. If anyone can help me with this particular camera, I greatly appreciate it.

Summary: Manual shutter speed on Casio Exilim EX-Z4 U?
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Old Apr 23, 2005, 11:01 AM   #2
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No, you don't have the ability to manually set the aperture and shutter speed with your model.

Even if you did, it wouldn't help you in the conditions you're talking about (where the camera is using a1/8 second shutter speed).

Even if you could set it manually to a faster speed, you'd just get underexposed (dark) images.

A camera must keep the shutter open long enough for proper exposure.

This depends on the available light, the ISO speed, and the aperture used.

If you try to use a faster shutter for any given aperture and lighting, you'll get underexposed images. If you try to use a slower shutter speed for any given lighting and aperture, you'll get overexposed photos.

Your camera's Autoexposureis already going to be using it's largest available aperture (smallest f/stop number) in low light anyway.

So, with your camera, you're left with controlling the light (which may not be possible), and controlling the ISO speed.

Each time you double the ISO speed, the camera's autoexposure can use shutter speeds twice as fast for any given lighting condition and aperture.

But, this will increase noise (similar to film grain). There are some products to reduce the appearance of noise if you go this route. Here are a few:

Neat Image

Noiseware

Noise Ninja

If you are unable to use a flash and shutter speeds are too slow, shooting at your model's wide angle lens position will also help (since several times as much light can reach the sensor through the lens at it's wide angle position versusfull zoomwith your camera).

To get a better idea of how aperture,ISOSpeed (shown as film speed with this calculator),and light impact exposure, see this handy online calculator:

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

Note that the largest available aperture with your model is f/2.6 (only available at it's wide angle lens setting), dropping downto a largest available aperture of f/4.8 at full zoom.


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Old Apr 23, 2005, 11:24 AM   #3
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P.S.

In addition to using a higher ISO speed, you can also use Exposure Compensation to get faster shutter speeds with your model. It's settable from-2EV to +2EV (in 1/3EV steps).

So, if you used a setting of -1EV (or probably -0.9 EV with your camera), you'd get shutter speeds around twice as fast in low light.

But, your images would be underexposed by a stop, too.

This feature is designed to control exposure (if you have conditions where the camera is not metering the scene correctly). It's not designed to speed up shutter speeds (but can be used for this purpose, if you have no other options and can correct the exposure in Post Processing).

Using a +EV setting will lighten the exposure (by using a larger aperture and/or slower shutter speed). Using a -EV Setting willdarken the exposure (by using a smaller aperture and/or faster shutter speed).

Since your camera's Autoexposure Algorithmswill be using the largest available aperture in low light for the focal length selected anyway, a -EV setting will cause it to use faster shutter speeds than it would normally use.

However, noise tends to be worse in underexposed areas of an image (just like using a higher ISO speed).

But, if you set your ISO speed to it's highest value, and still need faster shutter speeds, this technique (deliberately underexposing an image) can work.

Chances are, you will not want to do this (the noise would probably be unacceptable if you've already increased ISO speed).


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Old Apr 23, 2005, 11:26 AM   #4
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Thank you for the speedy response. After reading this article, I think I understand what you're saying. Apparently I have more to learn that I thought I did. When I begin to need it, I'll look into a more user-adjustable camera to learn on. Until then, I'll have to stick with landscapes and still subjects with this camera for now.

Again, thank you for your response. It is greatly appreciated.
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Old Apr 23, 2005, 11:35 AM   #5
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Again, you can set your ISO speed to a higher value with your model, and staying at your lens' wide angle position (using your feet for zoom) will also help.

What you think is "well lit" (for example, average lighting in a home), is actually very low light to the camera.

The problem you're describing is very common (shutter speeds too slow), even with more advanced models that do allow you to control aperture and shutter speed.

If low light shooting without a flash or tripod is something you need to do more of, you'll want a model with a brighter lens (larger available apertures, represented by smaller f/stop numbers), as well as the ability to shoot at higher ISO speeds without noise being too objectionable.

This tends to put you into the DSLR class of camera (making sure you buy a bright lens(es) to go with it for this purpose. Most DSLR models can shoot at up to ISO 1600 (or even ISO 3200) now. Of course, you'll want to keep ISO speeds set lower when possible (to reduce noise), and will still want to use noise reduction tools when higher ISO speeds are needed.

Of course, there's always flash (making sure you stay within the statedflash range).


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