With F-values, you have to understand that when F-values are lower (1.4) the camera requires less light. The lens acts like your eye. If your eye was f-1.4, they would be VERY dilated, letting in lots of light. However, during high f-values (16), the camera requires much more light.
Aspect 2 – Shutter Speed
The below 3 pictures are all shot in f-4. In the first picture, we are focused on a candle holder. The shutter speed is balanced with the f-value to create a clear picture. (f-4, shutter speed 1/3 second)
In this picture, the shutter speed was open too long, allowing too much light to enter the camera. (f-4, shutter speed 3 seconds)
As stated earlier, the higher your f-value, the longer your shutter must remain open. (Look at “Aspect 1” again and how f-values relate to shutter speed). The longer your shutter is open, the easier it becomes to have blurry pictures (without a tripod). So, when in lower light where a slower shutter speed is required, how do I keep my pictures from being blurry by trying to hold the camera still for 2, 3, or 8 seconds? For starters, try a tripod. If not, there is one more aspect we can discuss.
Aspect 3 – ISO
ISO is like the old time film speeds. Basically, the way I see it is that the lower the ISO (100), the more detailed a picture is but requires slower shutter speeds. It basically allows the camera to “capture” as much detail as possible. The below image is shot at an f-4, with a shutter speed of 1/2 second, and an ISO of 100. Notice how clear, detailed, and smooth it is.
This last image is shot at f-4 with a shutter speed of 1/100 second. This is a much faster shutter speed than both the previous pictures; however, notice it’s grainier and definitely not as smooth. Basically, Higher ISO = faster shutter speed = decreased chances of blurry pictures due to movement in darker rooms, but = less detail in the picture.
I hope this helps all you bloggy friends out there. Many of you have asked how I take my pictures…the best way is to get out there and practice! Feel free to ask me any questions and I’ll do my best to answer! A great resource that I found was Ken Rockwell’s site and more specifically his pages on “Taking Better Pictures”.