lately, several people have asked me how to "use their new cameras" to take better photos. I have attempted to explain the relationship between shutter speed, F-Stop, and Film Speed to no avail. I have realized that I am a better photographer than teacher (which isn't saying much!). Do any of you Apuggers know of a site on the web, or have a handout that explains this all important relationship in plain english?
Use the sunburn thing for film speed too. Faster film burns fast, just like blue eyed, blond haired, fair skinned people. Slow film burns slower like dark haired, dark skinned people.
I'm looking for more along the lines of caculating exposure. Such as F8 at 125 is the same exposure as F11 @ 1/60, etc.
The way that I relate exposure to people is to explain that a given film will require a given "quantity" of light to expose it. There are in photography two different "controls" to affect this quantity of light. The first is the size of the aperature or "opening" through which the light passes. The second is the length of time that the opening is open "Shutter speed".
The important thing to remember is that the measurement of apertures and of shutter speed is a ratio of doubles and halves. Thus if one reduces the opening by one half the offsetting factor would be to allow the opening to be open twice as long. This effectively gives the same quantity of light. Conversely if one opens the opening by twice as large, then the offsetting factor would be to allow the opening to be open only one half as long.
Once the quantity of light is determined by a light meter, either in camera or hand held, the user determination is one of "depth of field"or of shutter speed (ability to stop photographed subject movement). The more the opening is restricted the greater the depth of field (near to far plane of focus). The more the opening is increased the faster the required shutter speed to compensate. (Higher shutter speeds stop movement). I hope that this helps and gives you some idea of how to present this to your friends in your own words. Good luck.
you need a diagram! two scales, one for shutter speeds, one for apertures. Explain how the camera determines how much light is needed to expose the film (has a device to measure the quantity of light) , line up those settings and show how all the other combinations are equal in the quantity of light using Donald's explanation. Once they have a grasp of that, add in filmspeed and how that moves the reference point back and forth along the scales, then explain high/low shutters speeds, big/little aperture effects and how you need to stay with matching 'pairs' of shutter speed and aperture. For the moment, I'd let them believe their camera's meter! If they come back again, then you can try to explain that!!
Reminds me of trying to explain the game of cricket or Aussie Rules football to a foreigner... Seems simple enough having been brought up on them, but really quite complicated to explain, where one thing implicates on another.. and another... etc!
I use a faucet and pail analogy with a full pail representing proper exposure.
Say it takes one minute to fill a pail with water. If you open the faucet (Aperature) to double the flow and then you cut that time (shutter speed) in half to thirty seconds, You'll have exactly the proper amount water. You don't even have to look. Conversely, if you halve the flow it will take twice the time, two minutes to get the same amount.
This analogy can be extended futher in either direction and the consequences of abandoning the rules of reciprocity are obvious, either not enough water (underexposure) or wet shoes (overexposure). http://apug.org/forum/html/emoticons/smile.gif
The real pisser is trying to explain how to determine "proper" exposure.
When all else fails show them the program button and the auto focus setting - then help them understand:
have a subject
draw attention to the subject
simplify the image
Some people were made for auto cameras - they can still learn to see a good image and compose it well. That would be a big service to them. ---- of course if simplifieing the image means to through the backgound out with a long lens and a large aperature ,,,, well - I guess they may as well go digi - at lease that way they can erase the bad ones! - Frank
I tried posting this yesterday, but somehow, the message must have gone to "bit heaven".
Hasselblad (of all people) produced an excellent explanation of f/stops and shutter speeds by relating f/stops to pipe diameters and shutter speeds to time, with "exposure" being the amount of water that has flowed through. Excellent analogies, with the intensity of light related to water pressure. All in one slim "freebie" book.
Contact Hasselblad USA - I'm sure they'll help.