In addition to reading the tips below, visit the “GETTING STARTED” folder inside of Canvas for specifics on:
- Nuts and Bolts
- About the course website
- Assignment submission naming (use this EVERY TIME)
- Resizing photos – REQUIRED image sizing
- Submitting to your gallery
- Other important Start Up issues
If you haven’t done so, please make sure you read through the book and your camera instruction booklet about the effects the LENS has on your images. Right now we are concerned with Depth of Field, which goes along with both f/stop (lens hole size), and focus point.
In film photography, we mainly have two variables for each exposure. The shutter speed and f/stop. In digital we have three, as we can change the ISO at will, with every exposure if we like. We are seeking a balance of all three of these setting in order to give us the correct exposure for the image. Exposure if the amount of light we allow into the camera, changing with the amount of light in our scene (such as outdoor daytime vs. indoors, vs. nighttime), in order to achieve an image on our pixel filled digital sensor.
The shutter lets light hit the sensor for a period of time, and the f/stop is the size of aperture in the lens through which the light “flows.’ I compare this to filling a glass of water. If you think of the size of the glass as the right “exposure,’ the volume of water as the “aperture’, and how long you have to turn the faucet on as the “shutter speed’, then you can obviously fill the glass quickly with a heavy stream of water, or slowly with a thin stream. When the glass is full, you’re there- you’ve achieved the correct “exposure.’
In film though, the glass size is always chosen when we put in a certain ISO film. We have that glass the whole roll. So our only variables are the shutter speed and aperture to adjust to a given light situation. Now we can also adjust our ISO, so you should familiarize yourself with how to do that on your camera, as it will be a constant change you make.
One final note, in film the highest “normal’ ISO speed was usually about 400. In digital our cameras go as high as 6400, or some much higher. This means we can shoot digitally in much lower light. But there are losses, such as digital “noise’ that appears as we go to higher and higher ISOs. So generally you want to use as low an ISO as you need to get the lens or shutter setting you desire. We’ll learn more about this in the next few asssignments.
Some ISO suggestions: Outside in daylight use 100 or 200. Indoors in good light use 400-800. With lower light to to 1600-3200. At night, if you want to play, crank your ISO to its highest setting and see how you do.
I can’t cover every camera, though if you cannot figure out how your autofocus works, I’ll try and help you. Generally, on digital SLRs, the lenses will have an AF-MF button. On AF the lens will focus on a point indicated in the camera’s finder. Through the menu (read your manual), you can usually choose a focus point on the fly. Or you can set it so the camera chooses one for you (not a great idea). You need to learn how to choose the middle or one of the other focus points as you will want to be able to focus on a face, say, to the left of middle in some compositions. You’ll also want to be able to manual focus at time (say for the Aurora), and you need to learn how to do that as well.
In photography we talk in terms of “Stops.’ I guess this comes from f/stops. But it doesn’t mean only f/stop, it means any halving or doubling of exposure. So if I say you should open your lens one stop, it means let twice as much light into the camera. Or if I say that shot looks two stops too underexposed (dark), you might have a) used too high a shutter speed by two whole settings, b) used too small a hole (aperture), by two whole settings, or your ISO was two whole settings to high.
Digital cameras have brought us all kinds of new numbers for these things, as they provide exposure settings for 1/3 or ½ f/stops, ISOs, and shutter speeds. This is generally a setting in your menu.
But traditionally shutter speeds were, in “whole’ “stops:’
- 1/2000 (of a second)
- 1 second
- B (holds the shutter open, say with a cable release, as long as it is pressed)
Traditionally f/stops in “whole’ “stops:’
- f/1.4 (largest hole, smallest number, just to confuse things. Think of as a fraction)
And ISO’s were traditionally, in “whole’ “stops:’
Going up or down these list from one point to another doubles or halve the amount of light or sensitivity of the film or sensor setting. So f/8 lets in twice as much light as f/11. Or 1/250 lets light hit the film or sensor for half the time as 1/125. And ISO 400 is twice as sensitive to light as ISO 200.
Reciprocity of Exposure
Say you have a lighting situation where this exposure is correct:
- ISO 400, f/2.8, 1/500
Then these, and others would also be the correct exposure, due to this doubling and halving of values:
- ISO 800, f/4, 1/500
- ISO 200, f/2, 1/500
- ISO 400, f/5.6, 1/125
- ISO 1600, f/8, 1/250
Play with this idea, and try to get in in your head. The intermediate f/stop, ISO, and shutter settings on your digital cameras confuse this issue, but the principle is always operating. Three variables. Yikes! Luckily we have the camera meter, and the histogram (later), to evaluate all this without doing the math each time. But the math is there, and you should know where it comes from.
In general, you will anchor one setting for a reason, say the first assignment where the f/stop will be anchored in two different places. Then you’ll alter the shutter speed and ISO to achieve the correct exposure for those f/stops. ISO is our most malleable variable. As we’ll see as we go. Again, read the book chapters and your camera manual for more information, and look at online tutorials.