Exposure and F lock

k60sgb

New member
Hi,
I'm a neewbie, howevrer in P mode i seemed to have somehow locked my shutter an F stop so when i try to change say the shutter the F stop range changes as well, how can i disengage this....thanks
 

WayneF

Senior Member
Hi,
I'm a neewbie, howevrer in P mode i seemed to have somehow locked my shutter an F stop so when i try to change say the shutter the F stop range changes as well, how can i disengage this....thanks

Welcome to the forum.

If I understand your question, that is just what P mode does. It sets BOTH shutter speed and aperture automatically. Then when you change one, it changes the other to keep it constant exposure.

P mode is a little like full Auto mode, but Auto also sets Auto ISO and Auto white balance and Picture Color Controls. P mode does not, it uses them however you set them (on or off).

Try camera A, S, or M modes.

In A or S modes, you set one, and it sets the other.

In A, S, or P modes, if you want to deviate from that exposure, you use the Exposure Compensation to tweak it to be little different (that may be your question?)

If you want to set Both, use M mode. In M mode, Exposure Compensation then only affects the meter reading, but does NOT change the camera settings (unless Auto ISO, which can).
 

nickt

Senior Member
Just to add to what Wayne said, you are demonstrating to yourself how the exposure triangle works. To get a correct exposure, shutter speed and f stop must work together. P mode is giving you a correct exposure. You turn the wheel in P mode and you get alternate combinations of shutter and aperture that will give the same correct exposure. You would need to be in manual to set both shutter and aperture on your own. You also need to be very mindful of creating a 'correct' exposure in manual or you will get bad results. You can't just pair any shutter with any aperture. I am over simplifying this somewhat, ISO also factors in and flash is a whole different lesson.

Aperture priority or Shutter priority mode will behave in a very similar way to what you see in P mode. Shutter and aperture will track together. In Aperture mode, you pick the f stop, the camera meter will calculate the shutter speed. In shutter mode, you pick the shutter time and the camera will calculate how much to open the aperture. A and S mode give you more specific control of shutter OR Aperture than P mode. But still, if you change one, the other will automatically change. There are reasons and tradeoffs why you may prefer to have an exact shutter speed or exact aperture. In most cases of simple daylight shooting, we pick a shutter OR aperture, which ever is most important to us and the camera picks the other based on how much light there is.
This video might help:
https://www.youtube.com/watch?v=F8T94sdiNjc
 
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