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Old Jul 7, 2004, 6:17 PM   #1
csi
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I just got the S7000 and I am trying to play with the shutter speed and aperature but the instruction manual is pretty vague on how to use it. I am new to the whole digital camera thing but from what I have read a fast shutter speed would be 1/4000 of a second. If I am reading the numbers correctly on my Fuji S7000 I can only get the shutter speed down to 1 (no idea what that means) and as high as 1000 (again no idea what that means. Secondly is it possible to set the Shutter and Aperature or is one automatic based on the other.Any help would be greatly appreciated.
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Old Jul 7, 2004, 8:18 PM   #2
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First of all, it's doubtful that you'll ever be in lighting conditions that you'll be able to use a shutter speed as fast as your camera is capable of. It may be limiting it, based on ISO Speed, Resolution, etc.

The shutter speed and aperture combination the camera uses is designed to insure proper exposure of the image, based on the lighting conditions you are in. So, if the camera is picking a slower shutter speed, then the light must require it for proper exposure.

For example: if it is using 1/30 second shutter speed for proper exposure, and it tried to use 1/1000 instead, then the photo would be totally black (not enough light hitting the CCD Sensor).

Think of it's electronic CCD sensor as film. It must open the shutter just long enough to properly expose the image. If it opens it too long, the image will be too bright (washing out details). If it does not open it long enough, then the photo will be too dark.

The camera must also select an aperture (iris opening for light to come through). This is like the pupils in your eyes (opening wider in low light, and smaller in brighter light). In most cases, it's probably selecting the widest aperture it can in lower light already. Then, it sets the shutter speed so that just the right amount of light enters through the iris for proper exposure.

Unfortunately, what is bright to the human eye, is not to a camera's lens.

The amount of light that can go through the lens, is based on the lens aperture rating.

Some models give you the ability to control both aperture (amount of iris opening), as well as shutter speed. Somedo not.

There is another factor for controlling exposure: ISO Sensitivity. This is a way of controlling how sensitive the CCD sensor is to the light admitted through the iris when the shutter is opened.

Think of it in the same way as buying different film. You need a "fast" film (ISO 400 or higher) usually for lower light. That way, your film camera can use a faster shutter speed. ISO 100 is typically used in very bright light. The downside of using a faster film, is that you will see more grain in your image (ISO 100 is higher quality, but not as sensitive to light). The same applies to digital cameras (image quality is better at lower ISO speeds).

Scroll down a little bit on this page, and you will see a chart that may help you understand the relationship between available light (measured as EV), aperture, and the shutter speed needed for proper exposure of an image

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

For a given lighting condition and aperture, you must use the appropriate shutter speed to properly expose an image (otherwise it will be either underexposed or overexposed).

As you can see from the chart, you can get properly exposed images, using more than one aperture/shutter speed combination, too.

To take the best photos, you need an understanding of why you'd want to use one combination, versus another.

To prevent motion blur from camera shake or subject movement is one reason you would want to use a larger aperture and faster shutter speed. However, using a larger aperture also impacts Depth of Field (the amount of a photo that is in focus, as you get further away or closer to the camera's focus point).

Also, sometimes Less Depth of Field is desired (to blur backgrounds), to help a subject stand out.

See my latest post in this thread, for a discussion how Aperture impacts Depth of Field:

http://www.stevesforums.com/forums/v...mp;forum_id=20


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Old Jul 7, 2004, 11:34 PM   #3
csi
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Hey Jim, your right down the road from me, I live in Hiram. Anyways your post was very helpful. I understand how shutter priority and aperture priority work for the most part and why you would want a larger or smaller value, my biggest questionis when I am in shutter priority, I can choose values from1 to 1000. Everything I read has shutter speed generaly listed as a fraction. I have guessed by playing with the camera that 1 is fastest and 1000 is the slowest, but I don't know what fractions they represent. The chart you posted for exposure values is great, and I can't wait to use it, however I dont' know how to set my camera for a shutter speed value of 1/125s at the moment.
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Old Jul 8, 2004, 6:20 AM   #4
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Well, actually we just recently moved to Savannah, Georgia. I just haven't updated my profiles yet.

I don't own a Fuji camera, but from what you're describing, it is far more likely that 1 is the slowest shutter speed (representing 1/1, or 1 second), and 1000 is the fastest shutter speed (representing 1/1000 second).

Even though the camera may be capable of faster (or slower) shutter speeds (outside of a 1/1000 to 1 second range), these speeds may not be available in all modes.

You should have a way to look at the image information (shutter speed, aperture, etc.) in playback mode. That way, you can easily see the shutter speed used for any image. If your Fuji doesn't show this information in playback mode, then you can access the EXIF data (embedded in image header), with many image editing packages.




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Old Jul 8, 2004, 9:46 AM   #5
csi
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Thanks, I found out I had the numbers backwards. I appreciate all the help. Thats funny you just moved to Savannah, I just moved from there to here. Thanks for the Help Jim.
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