A fast shutter speed freezes action. Conversely, a slow shutter speed can make things that move look blurry.
A quick reminder of the technical fundamentals
This Appendix is designed to refresh your memory about the basics. (It will probably not be effective if you never learned these in the first place. ) But as I said in the book’s introduction, it’s unlikely that a person with no knowledge of the basics would spring for this camera.
A fast shutter speed freezes action. Conversely, a slow shutter speed can make things that move look blurry. |
The shutter speed can make a moving subject appear frozen and sharp, or can make it appear to be moving and blurry. The A6300 can let in as little as 1/4,000th of a second of light, freezing a moving subject, as in the left photo above. Or it can let in as much as 30 seconds (or longer) in manual mode, which is guaranteed to blur anything unless the camera is mounted on a tripod and your subject is just as steady.
If you know what shutter speed you want to use to achieve a certain effect, put the camera into either S(hutter priority) exposure mode, or M(anual) exposure mode and use the rear control wheel to set the shutter speed.
A slow shutter speed means that anything that moves relative to the camera will come out blurry. So, to get a blurred background, a slow shutter speed was used (about 1/8th of a second) and the camera was moving in sync with the passengers. This technique is called “panning” and does take some practice. |
TIP: Like to take time exposures? There’s a shutter speed that keeps the shutter open for as long as your finger is on the shutter release button. It’s called “Bulb”, and can only be accessed in Manual Exposure mode. Select the shutter speed that’s one lower than “30 seconds”. It’s recommended that trigger the shutter with something other than your shaky finger, using either a wired cable release or an infrared one as discussed in Section 3.10. |
“F/stop” (also “aperture”) is photo jargon meaning “the lens opening”. The f/stop controls how much light enters through the lens, and in doing so also determines how much of the picture is sharp in front of the focus point and behind the focus point. A wide-open aperture (small numbers, like f/2.8) means very little is in focus beyond what you’ve focused on; whereas a small aperture (large f/stop numbers, such as f/22) means that things in front of what you focused on and behind what you’ve focused on will be sharper.
If you know that you need to use a particular f/stop to achieve a particular effect, put the camera into A(perture priority) or M(anual) exposure mode, and you can adjust the f/stop via the rear dial.
The nice thing about the E-mount architecture is that when using native lenses you can see what will be in focus before you shoot, just by changing the value of the f/stop and watching the background change. (No need to invoke a "Depth-of-field Preview" like you do with most DSLRs!)
Sometimes you want EVERYTHING to be in focus. A small f/stop (like f/11) is the answer. (Left) Sometimes you want a fuzzy background so it will not draw attention away from your subject (like this photo of actor Joe Mantegna, right). A large f/stop (like f/2.8), coupled with a long zoom and a goodly distance between the subject and background, is the answer. (Yes, "Goodly" is a word. :-) ) |
When using small f/stops, typically it’s best to focus 1/3rd of the way (rather than halfway) between your closest and furthest subject in order to squeeze the most out of that aperture’s depth-of-field. |
ISO is: how sensitive the sensor is to light. The higher the number, the more sensitive it is. (This corresponds almost exactly to the ISO ratings of film.) The tradeoff is the higher the ISO, the more noise appears in the picture. The A6300 has native ISO settings going from 100 all the way up to 25,600 (and then the camera can amplify that even further to a whopping 51,200! (As you might expect, though, such a high number can result in quite a bit of noise.)
Shutter speeds, f/stops, and ISO are all tied together; if you increase one you must decrease one (or both) of the others to get the right exposure. The fourth variable doesn’t employ such tradeoffs:
