Measuring the amount of light in a picture?

Off-topic Chatter
1

I've got a series of pictures taken during a runtime test.

i was wondering if perhaps there was a way to measure the amount of light in each picture? As in the initial picture is 100% brightness the 2nd is xx% and so on?

2

If you’re shooting with manual settings that haven’t changed across the pictures, you’re shooting at a white surface (makes things easier) AND you can directly translate the tint of your light into a hex number to put into Adobe Photoshop you can most definitely measure the light.

But… the last step is pretty much impossible so usually we just use light meters.

EDIT: Also it can’t have any oversaturation.

3

I have all but the tint… Hmm.

Any way to get a rough estimate? I don’t need a lumen measurement just 100-75-50-25 would be okay.

I may have to just cave and finally get a lux meter. :stuck_out_tongue:

4

You can use the histogram tool in Photoshop or similar to give you an idea. Here is an explanation:

5

Lock the iso at a high setting, noise is not a problem here, use aperture mode at whatever setting it takes to get the shutter speed over 1000th and take a picture with the light at 100%, note the shutter speed, then take one at each of the lights lower settings, leaving everything else the same
Now compare the shutter speeds to the first one.
If you don’t want the images then don’t even take the photo, just look at the shutter speed :wink:
Rough and ready, yes, however if you have a camera with manual it costs nothing.
oh, and you can leave the white balance at whatever it is on, you are only interested in the amount of light not the tint or the quality of the photo.

Cheers David