K10D - Green button in TAv & M

[Snapac]

What would be the case to choose Program Line over Tv Shift or Av Shift? or maybe a better question is how does this impact your shot?

[jgredline]

i have found that TAV is my best friend. You have total control of both AP and Shutter speed, while the camera will choose the proper ISO. What is cool about that little green button is that you can press it anytime and the camera will choose what it believes to be the proper exposer...In other words, it resets it back to Auto mode...It has bailed me out many times. Learning to use this with your cameras histogram will be a great help to you.

[Snapac]

thanks...yeah I have to need to learn how to use the histogram, but before that, I need to get a better understanding of it's function.