Go Back   Steve's Digicams Forums > Digital Cameras (Point and Shoot) > Canon

Reply
 
Thread Tools Search this Thread
Old Jul 2, 2006, 11:15 AM   #1
Junior Member
 
Join Date: Mar 2006
Posts: 6
Default

When I'm using Av mode, no matter what aperture I set it on, the shutter speed stays at 1/60.

In Tv mode, I try to set the shutter speed at 1/500 to get bird pictures, and the pics are practially black.

This is all in open shade in the yard, ISO set at 50 or 100.

Actually, I really can't get good pictures in any mode, not even in P. The shutter speed is always too low, IALWAYS get the camera shake icon and flash icon in the viewfinder.

I've tried using the landscape and foliage settings and have to use the flash every single time. I cannot get good pictures with a fast shutter speed at all.

I'd like to take stop-action pictures of birds at the feeder. Any ideas what I'm doing wrong?

I'm ready to return it to the store.


JJG2006 is offline   Reply With Quote
Sponsored Links
Old Jul 2, 2006, 11:35 AM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

JJG2006 wrote:
Quote:
When I'm using Av mode, no matter what aperture I set it on, the shutter speed stays at 1/60.
That doesn't sound right. Are you half pressing the shutter button again and watching it change? I could see it not getting any faster than 1/60, depending on the lighting and ISO speed. But, it should go slower than 1/60 at smaller apertures (higher f/stop numbers), unless you've got the flash popped up.

Quote:
In Tv mode, I try to set the shutter speed at 1/500 to get bird pictures, and the pics are practially black.
Just because a camera has faster shutter speeds available, doesn't mean you can actually use them if the light isn't good enough.

The camera's got to keep the shutter open long enough for proper exposure.

If you try to set the shutter speed to 1/500 second in Tv Mode and the camera needs an aperture larger than the lens has available to it, it will underexpose (and most models will give you a flashing aperture in the viewfinder to let you know that you're exceeding the largest aperture available).

If you try to use a shutter speed that's too fast for the lighting, ISO speed and largest available aperture, you'll get underexposed (dark) images.

If you try to use a shutter speed that's too slow for the lighting, ISO speed and smallest available aperture, you'll get overexposed (bright, washed out) images.

Unless lighting is very good, and you know you're not selecting a shutter speed that's going to exceed the capabilities of your camera, you're probably better off sticking to Av (Aperture Priority) mode when you want faster shutter speeds in lower light, selecting the largest available aperture (smaller f/stop numbers).

Your lens has a largest available aperture of f/2.7 on it's wide end (least apparent magnification), dropping off to a largest available aperture of f/3.5 at it's max telephoto zoom setting.

Quote:
This is all in open shade in the yard, ISO set at 50 or 100.
It's probably darker than you think in the shade. The human eye won't perceive the same difference in lighting that a camera will.

Open shade typically has an EV (Exposure Value which is one way light is measured) of around 11.

At ISO 50 and f/2.8 (close to the largest available aperture on the wide end of the lens with your Canon), you'd need shutter speeds of around 1/125 second for proper exposure. At ISO 100 (twice as sensitive to light as ISO 50) and f/2.8, you'd need shutter speeds of around 1/250 second for proper exposure.

That's just typical open shade. You may have much darker areas, requiring even slower shutter speeds.

If you're zooming in much, the largest available aperture will be even smaller (higher f/stop numbers), requiring even longer exposures for the same ISO speed and lighting. Fortunately, your Canon has a relatively bright lens (only losing a half stop to f/3.5 on it's long end).

Here is a handy online exposure calcualtor that may help you understand the relationship between lighting, ISO speed, aperture and shutter speed.

This calculator applies to both film and digital. Note that Film speed in the calculator is the same thing as ISO speed. But, always use your camera's meter to judge exposure (as there can be a huge variance in lighting that may not be obvious to the human eye).

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

You may also want to check out a book on basic photography at your local library. What you read about exposure will apply to both film and digital.

If your shutter speeds are too slow for what you're trying to shoot, increase your ISO speed (each time you double the ISO speed, the camera can use shutter speeds twice as fast for the same lighting and aperture for proper exposure). That's why film camera users often use ISO 400 or even faster film when faster shutter speeds are needed. ;-)

Using higher ISO speeds will mean a bit more noise, similar to the way using faster film can mean more grain. But, noise/grain is often preferrable to motion blur.

BTW, there are some pretty good tools like like Neat Image, Noiseware or Noise Ninja that can be used to help reduce the appearance of noise when higher ISO speeds are needed (and all 3 products have free and/or trial versions available).

P.S.

If you're using any filters, I'd remove them in lower light. For example, a Polarizer will typically cost you about 2 stops of light (requiring shutter speeds about 4 times as long for the same lighting, ISO speed and aperture).

JimC is offline   Reply With Quote
Old Jul 2, 2006, 2:49 PM   #3
Junior Member
 
Join Date: Mar 2006
Posts: 6
Default

Thanks very much for your ideas, JimC. I think I might be able to get the hang of it now, and that calculator is very helpful. I've saved it for future reference.

I'm still not getting a sharp focus, but at least the exposure is better now. Thanks again!



JJG2006 is offline   Reply With Quote
Old Jul 2, 2006, 3:03 PM   #4
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

I wouldn't try to use it to set your camera by. But, it can give you an idea of the relationship between lighting, aperture, ISO speed (film speed in the calculator) and shutter speed.

Often, what we think is very bright is dim to a camera's lens. ;-)

JimC is offline   Reply With Quote
Old Jul 3, 2006, 8:32 AM   #5
Junior Member
 
Join Date: Jul 2004
Posts: 23
Default

if flash is ON the shutter speed stays at 1/60 every time
if flash is OFF the shutter speed may have any value
plop is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 7:37 AM.