Brightness and exposure

Hi all ,

I made this app in order to avoid manipulations on the field mounting different ND filters before choosing the good one , but it can be very useful for preparing you photo session ( 2.8/4.0 zoom , prime lens , tripod ? )

With this app , first , you have to get the right brightness index :

- you can get a calculated one , you get parameters from exifs of pictures on your HD representing already done shooting light conditions , you can get values read from your camera screen while already on the field as well .( before mounting filters )
- or , you can go manually and put the value read from a cell or just because you already know ( sunshine is 15 , blue hour around 11 …. )

When confident , you validate the value and go to the next page .

On the second page , you can play with all parameters , included ND filters to reach the validated brightness .

Example 1 : you expect a night shooting in a city .

You have on your computer a picture taken in similar conditions with a 2.8 zoom : exifs 1/15s f/2.8 iso 2000

The app gives you brightness index : 2.6

Put 1/8s (stabilized sensor) f/2.0 for DOF and sharpness ( f/1.4 prime lense ), you shouldn’t go over 500 ISO , but you could open wide for ISO 250 , it’s up to you .

You can also read you can reach ISO100 at 1/3s ( with a tripod ) .


Example 2 : you want to shoot a 30 seconds picture on a sunny day ( brightness 15 , manually implemented )

You want ISO 100 which is the native value for your camera , best sensor quality .
You want f/8.0 for best sharpness and sufficient DOF .

Suggested value for ND filter is 14 , you take 15 ( 2 filters 10 + 5 ) , you can adjust f/5.6 or 60s …


You can play , close aperture , make do with owned ND filters , choose faster speed and make compromises …

Ultimately , put 3 out the 4 parameters ( A/S/ISO/ND) , you will be advised the 4th parameter to reach the goal , you can’t or don’t want to take it , just adjust and make compromises

Regards

Christophe