Concerning Exposure/Depth of field:( for point and shoot 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

Regards, Ken