Focus lock button

[gabrielh]

Hello!
I was wondering what the use was of a focus lock (on D300 and above). When pressing that button, is it the same as pressing the shutter halfway? And say you go into the menus and tell the camera only to focus when the focus lock button is pressed, what use would the halfway pressed shutter have?
Just wondering...
Thanks for any answers!

 

[rdompor]

As a personal preference, I like to separate my focusing and my metering from each other. I set the back button to activate the auto focus and a half press of the shutter locks exposure. This is useful in Av or Tv modes when the camera decides correct exposure. By separating the two functions, I can focus on one area (like on someones eyes) and then meter for another area (like their skin/hair/clothing).

 

[gabrielh]

Thanks rdompor!
Anybody any more comments welcome!

 

[MikeBcos]

As a personal preference, I like to separate my focusing and my metering from each other. I set the back button to activate the auto focus and a half press of the shutter locks exposure. This is useful in Av or Tv modes when the camera decides correct exposure. By separating the two functions, I can focus on one area (like on someones eyes) and then meter for another area (like their skin/hair/clothing).

Thank you, you just made me read a section of my manual I hadn't got to yet, my D40 is now set the same way, up to now I have been setting the focus then switching the lens to manual before metering a different area.