Lighting and Shutter Priority

[kencaleno]

Originally Posted by auto-focus

Looks like you seriously over exposed...I don't believe you mentioned what camera you have. A slightly faster shutter speed, say 1/30th, and a smaller aperture setting may have helped the exposure. I know my G2 won't close down beyond F/8, and having an ISO 64 available leads me to believe it's a point and shoot, and you may not be able to close your lens down any further.

Please understand that F8 on G2 or any camera that has a circle of confusion of 0.006mm is equivalent to F22 on a DSLR

[kencaleno]

Originally Posted by bcummings88

I went on a hike today and was messing with the shutter speed while taking pictures of the river. I was just wondering why I couldn't seem to get the river and the flowing action. Was it the lighting or was the aperture set to high?




Aperture: F/8
Shutter Speed: 1/20s
Exposure Mode: Shutter Priority
Exposure Comp.: 0EV
Metering: Matrix
ISO Sensitivity: Auto (ISO 64)

Ok what you need to do is ,with camera on tripod,is to use a neutral density filter,a ND4 will slow you by 2 stops,and if you have a polarizer,attach this too an you will slow down another 1-2 stops (even a polaroid sunglasses lens will help)

Where standard books confuse is that they don't explain why the smallest aperture on compact cameras is F8,so:

Concerning Exposure: ( for cameras where you can change aperture/shutter speed)

You may be wondering why your smallest F stop (aperture) is only F8,where DSLR cameras go to F22 and beyond- the reason for this is Diffraction-Diffraction is a limiting effect concerning lens optics which affects total resolving power of your lens. Light generally travels in straight lines, but when light rays are forced to enter very small openings (small f-stops) the rays start to spread out, and converge with each other, and bend round diaphragm blades which affects your images, due to the softening that occurs. This achieves a greater depth of field, but sharpness suffers. The reason for F 8 being your smallest aperture is directly due to Diffraction.
The “F” in “F-stop” means Factor. So “F 8” translates as Focal length of camera lens divided by 8 is the diameter of the aperture. For DSLR’s with a 50mm lens focal length, F8 equals 50/8 = 6mm )approx) F8 on your point and shoot with lens set at equivalent of 50mm = 1mm,so anything smaller would be impractical, and all images made would be blurred.
Now if you can change aperture and shutter speed on your camera, you may be interested in setting exposure manually-what was known as the “Sunny-16 Rule”, But will be known to you as the “Sunny 5.6 Rule.”

Basic daylight Exposure (Sunny 5.6 Rule)

Based on “Sunny 16” Rule where at F16 shutter speed =1/ISO (14.6)EV Because of the diffraction problems of very small apertures-(re F8 being the smallest aperture of point and shoot cameras), 14.6 EV equates to 1 / (8*ISO).

DSLR Point and Shoot

F 22 = F8
F 16 = F 5.6
F 11 = F 4
F 8 = F 2.8
F 5.6 = F 2


So, at 100 ISO:

Hard edged Shadows………………………. 1/800 @ F 5.6

Soft edged Shadows…………………………1/800 @ F 4

Barely visible Shadows………………………1/800 @ F 2.8

No shadows……………………………….......1/800 @ F 2

Hope this helps, Regards, Ken