Photography

[asterroc]

I have heard it's possible to take multiple photos at different light exposure levels and combine them, and thereby get an image closer to what the human eye sees (since we can perceive both the bright things and dark areas at once, while a photo meters for only one or the other). I've seen these done by otheres, the prime example being the inside of an unlit church w/ light streaming in through stained glass windows; let me know if you know the artist's name.

Anyone have a suggestion on how to do this in P-shop or a similar program? What I have is a series of three photos that my camera took automatically bracketting one f-stop (or shutter speed) up and down, one right after the other. I'm thinking along the lines of having a background that's solid white (or black, or gray), then adding three semi-transparent layers, one for each image, and then adjusting the amount of transparency for each until I get something pretty. To make the issue more complicated, some of the images I'm thinking of playing with are of flowers that were swaying a bit with a breeze, so a good combined image might not be possible at all, or will require offsetting of the three images so that the flower looks good but the background does not.

Comments

[framefolly.livejournal.com]

Dunno any of the science behind it, but I know that film (the kind with emulsion, not digital) has a lot less range for brightness and hue than human eyes do. Someday I should learn how digital image capture works...

As for Photoshop or similar, I suspect that in addition to adjusting transparencies, you'll need to make a series of mattes and play a bit with the curves -- but you probably already knew that.

[zandperl.livejournal.com]

you'll need to make a series of mattes and play a bit with the curves -- but you probably already knew that.

Um, no. Why will I have to make mattes? And I really hope I don't have to play with curves, that's a pain.

[framefolly.livejournal.com]

That was my first thought -- hence the "I suspect." Mattes and curves together can get a lot done, pain or not. But clearly a lot of your respondents have better ideas, so no need to go through the hassle.

[zandperl.livejournal.com]

Someday I should learn how digital image capture works...

http://en.wikipedia.org/wiki/Photoelectric_effect
http://en.wikipedia.org/wiki/Charge-coupled_device

In short, each pixel is a material where when a photon hits it, an electron pops out (the photoelectric effect, and the only one of Einstein's three pivotal papers to actually win him the Nobel Prize). Put together a bunch of them and you get a CCD (astronomy) or CMOS (commercial digital cameras). Everything other than the sensor is identical in film and digital.

[framefolly.livejournal.com]

Thanks!

> Everything other than the sensor is identical in film and digital.

Ahh -- but it was the nature of the sensor that I wanted to understand better, and I'm afraid I don't have enough physics in my pocket to be able to get quick explanations :( .

Someday -- sometimes I already look forward to retirement...

[zandperl.livejournal.com]

Hee, me too, so much I can do then!

In B&W film, what happens is a photon hits the paper and causes a chemical reaction in the silver atoms that makes them turn dark after more chemicals (developer) are applied to them. In a CCD the photon knocks an electron off of the atoms in the material, and a moving electron == current.

[framefolly.livejournal.com]

Thanks! That makes enough sense to me that I think I can fudge it to myself now ;) .