Why do we say "shutter speed"
After running a couple of "be brave - turn off the auto" introduction courses recently, I'm increasingly irritated by having to explain the term shutter speed when the values we use are not speeds at all but times. Speed is distance per unit time. 1/200s is a time not a speed.
Canon at least marks the dial Tv for shutter priority which suggests T for Time, but apart from that we are lumbered with "speed" pretty much everywhere.
What about a campaign to adopt "shutter time" as a more appropriate term ?
Grumpy retired engineer in Nouvelle Aquitaine.
Canon at least marks the dial Tv for shutter priority which suggests T for Time, but apart from that we are lumbered with "speed" pretty much everywhere.
What about a campaign to adopt "shutter time" as a more appropriate term ?
Grumpy retired engineer in Nouvelle Aquitaine.
Agreed.
I've been using the term "exposure time" in its place for some considerable time.
Trouble is, a lot of people don't know what I mean!
I've been using the term "exposure time" in its place for some considerable time.
Trouble is, a lot of people don't know what I mean!
But the shutter does travel - therefore it is surely a speed?
Quote:therefore it is surely a speed?
No.
Speed is formulated as a distance covered in a specified period time; ie. 60 miles per hour.
1/25th. (of a second) is simply a description of a unit of time. For it to relate to a specific speed, you'd need to include the distance covered during that 1/25th. (of a second).
Quote:Agreed.
I've been using the term "exposure time" in its place for some considerable time.
Trouble is, a lot of people don't know what I mean!
Yes, "exposure time" that's even better.
I started off with a Canon A1 SLR which had Tv on the top dial. I had to look up the instruction manual to find out what it meant because everyone was talking about shutter speed. I have used Canon cameras since so i am used to it now but it is confusing.
Does the "Tv" on Canon cameras actually stand for anything?
Quote:But the shutter does travel - therefore it is surely a speed?
Yes, the shutter does travel and, as you say, it therefore has a speed, a certain number of mm of movement in a certain time. But that's not what we are interested in as photographers, what matters to us is not how fast it moves when opening and subsequently closing, but how long it remains open. The "exposure time".
Quote:Does the "Tv" on Canon cameras actually stand for anything?
Think it’s “Time Value”....?
Quote:Think it’s “Time Value”....?
OK. Thanks.
This reminds me of an eccentric physics lecturer we had at college. He said you shouldn't go into a butcher's shop and ask for a pound of mince, because it was actually a pound force of mince you wanted. Hey ho, good luck with changing every photography book that was ever written. 
