sepiareverb
genius and moron
Shutter speeds and lens openings adjust exposure in equal steps called stops. This means that when making a correct exposure there are many settings that will allow the same amount of light to reach the film. f2@1/500, f2.8@ 1/250, f4@1/125, f5.6@ 1/60 and f8@ 1/30 all are equivalent exposures. This is often referred to by an Exposure Value (or EV) on lightmeters, which shows all equivalent exposures in a given brightness of light for a given ISO film. As the lens aperture opens up to let more light through (the bigger the window the brighter the room) the shutter is open less time. If we think of light as water:
• the aperture is how forcefully the tap is turned on
(full blast is f2, a trickle is f16)
• the shutter speed is how long the tap is turned on
(on & off in an instant 1/1000, on and wait 1/2)
In this water example the ISO is represented by the size of the cup we are trying to fill to make a perfect exposure. A huge cup needing lots of water would be a low ISO film (50), needing lots of light. A small cup would be a high ISO film (1600). Once the film is loaded the size of that cup is set. Unlike digital one cannot change the ISO of the film mid-way and expect to get good results on the whole roll.
In filling any size cup we can use a trickle of water for a long time or the full blast of water for a short time. As long as the cup is filled the exposure is correct. It doesn't matter if it takes a long time or a short time in terms of correct exposure. These adjustments effect how the pictures look, but that's lesson 2. Simplest way to keep these adjustments in order is to remember if one numeric value goes up the other must go down an equal number of steps to keep total exposure equal.
Determining how much light the film needs is done most simply with a meter. Judging light by eye takes practice, but was done by many photographers for years. It involves a lot of trial end error at the beginning.
• the aperture is how forcefully the tap is turned on
(full blast is f2, a trickle is f16)
• the shutter speed is how long the tap is turned on
(on & off in an instant 1/1000, on and wait 1/2)
In this water example the ISO is represented by the size of the cup we are trying to fill to make a perfect exposure. A huge cup needing lots of water would be a low ISO film (50), needing lots of light. A small cup would be a high ISO film (1600). Once the film is loaded the size of that cup is set. Unlike digital one cannot change the ISO of the film mid-way and expect to get good results on the whole roll.
In filling any size cup we can use a trickle of water for a long time or the full blast of water for a short time. As long as the cup is filled the exposure is correct. It doesn't matter if it takes a long time or a short time in terms of correct exposure. These adjustments effect how the pictures look, but that's lesson 2. Simplest way to keep these adjustments in order is to remember if one numeric value goes up the other must go down an equal number of steps to keep total exposure equal.
Determining how much light the film needs is done most simply with a meter. Judging light by eye takes practice, but was done by many photographers for years. It involves a lot of trial end error at the beginning.
shayallen
Established
Thanks sepiareverb that was very helpful and about time you gave me something useful! By the way what does OP stand for?
burninfilm
Well-known
OP stands for "Original Poster"... as in you.
Just wanted to add again that you have some really great stuff in your gallery. Once you learn all the metering and exposure settings you need to use that M4-P, I'm sure you'll have some more fantastic images to add to your gallery. Good luck!
George S.
How many is enough?
Thankfully we didn't mention those lenses that allow for settings "in-between" the marked F stops! (ducking for cover...)
shadowfox
Darkroom printing lives
Shay, looking at your Smugmug gallery, you reminded me of my wife. When she got started years ago, she couldn't be bothered to know about the technicality of an exposure, but whenever she took a picture of our daughter, her compositions are just outstanding 
Now she's a part-time photographer on her way to being a "pro"... that took a *lot* of time reading both books and online.
Another thing, I have one Leica, an M4-P also, good choice
Now she's a part-time photographer on her way to being a "pro"... that took a *lot* of time reading both books and online.
Another thing, I have one Leica, an M4-P also, good choice
Chris101
summicronia
That's an unusual story Shay. Congrats on taking a path that is less followed.
I hope to see some of your photos posted!
I hope to see some of your photos posted!