Saturday, March 28, 2009

A New Level

I got a new and, to me, really cool toy that I've been playing with and I wanted to share it. Even if you can't fully appreciate it, you can appreciate that I do. :)

Look at this picture

First of all, isn't it just the cutest? These two are just the most wonderful little girls in the world. But actually the photo is noteworthy for more reasons than that.

We've lived here for some time and have had persistent difficulty getting good photos in certain parts of the house. Like our room. It's just not light enough in there. We have these little bedside lamps but they only put out a few watts of light (like 10 each or something) and their diffusers are really dark orange-brown, and we have blackout curtains. You can light up the room with a flash, but the light from the flash is blue by comparison with the lamps, and of course causes harsh reflections and shadows that make people look terrible. Recent pictures have not been as bad as my pictures used to be when I used a normal point and shoot camera (back then people actually got redeye), but it is still pretty bad. The solution?

Bam. My new toy. An external flash that you attach to the top of the camera. The little red panel at the bottom sends out a low red beam that allows the camera to focus in the dark, and then the flash part you point wherever you want (it rotates and tilts up and down). For this shot I pointed it at the ceiling, which lit up the whole room without creating any harsh shadows. In fact it kind of looks like the light in the room came from the lamps. The flash can put out a variable amount of light from just a little to a blinding amount. When it goes off it looks to us like one flash, but actually it sends out two really quick flashes: one to determine how much light will be needed to light up the room optimally, and the second one after the shutter opens to do the actual lighting using the amount calculated by the first flash. This allows us to point the flash head up, to the side, down, behind us, or anywhere we want and still get a properly exposed picture---it just puts out way more total light when it's pointed at the ceiling instead of the people. Neat huh?

Of course, the light from the flash is pure white, which is blue compared with the orange light from the lamps. Having two different types of lights (unintendedly) in a scene is the bane of photography. With digital photography it's really easy to redefine white in the post processing, but if one light is bluish, like sunshine, and another is orange, like a lamp, you have to choose which one you let be white. For example in this post we have some pictures lighted by a lamp in front and a window behind. To get the skin tones right, you have to let the window become blue. There are a few of those here on our blog.

The solution is to change the color of your flash so it matches the ambient light. The result in this case would be a completely orange picture, but in post processing you redefine orange as white and it looks like a nice white photo. You do this using my latest latest toys, some color correction gels. A gel is a transparent piece of plastic that you put over a light source to change its color. They use them in theater for spotlights and stuff. I have a bunch of "color correction gels," which are for making the light from the flash match the ambient light. I have various shades of orange for taking pictures in rooms with incandescent lighting, green ones for taking pictures under flourescent, and blue ones for sunlight that is not mid-day light (at noon the color of the sun is almost exactly the same as a flash).

Anyway, an orange gel on an external flash (let's call it a strobe to stick with the language of the growing movement of flash lighting enthusiasts) pointed at the ceiling are what's wanted. Here's the picture as it came out of the camera

Then you take a picture in raw format instead of jpeg. Our sweet, sweet camera will do this. A jpeg file is an image...an array of pixels of defined colors. You can kind of edit it but you are actually changing the image as you do so and after a lot of changes it looks really unnatural. A raw file is a record of how much light each pixel in the sensor got, there are no colors per se. It's like the digital equivalent of a negative. With a film negative, you can get a different print of it by shining a different intensity or color of light behind it, without changing the negative. That's what I did with the raw file that created this picture. I developed it with a different definition of white and now it looks like the scene did to my eyes when I took the picture (the human eye is annoyingly good at compensating for differences in colors of white. To us a white paper looks the same under flourescent lights, sunlight, or tungsten lights. Not so with film or digital sensors).

The one remaining variable is the colors of our computer monitors. This picture was "developed" and optimized on my screen. Well, some screens are bluer than others, so the picture may look bluer or yellower (or lighter or darker) on your screen than it does on mine. What I've tried to do is calibrate my monitor so it conforms to some absolutes of color temperatures, but it's hard to do without calibration equipment.

Anyway there's a lot of detail I've skipped over, but the bottom line is that I'm really enjoying the capabilities of my new strobe. It's given me a lot of creative flexibility to make pictures I want to take look like I want them, and then I take the raw files and there is a lot of fun hacking behind the scenes to finish the job (I had to nab a color profile file from the inner workings of some of canon's software that has information about how my particular camera percieves light and then plug it into a linux program that manipulates raw files, etc.). It's been a lot of fun, and I now have all the goodies to do a lot of really fun things. The first order of business is to make sure all the photos I put up on the blog are color balanced, well lit, and lacking harsh shadows (unless desired for effect). I'm eventually going to get a cable that connects my strobe to my camera so I can hold the strobe off to the side and take a picture from the front...but I have to become a pro with what I have first. For now even my raw file editing skills are not what they will be when I'm done optimizing and honing my skills. The resulting images are of correspondingly lower quality. It kind of makes me want to save the raw files so I can re-develop them later to more exacting specifications.

Anyway, I've been wanting to get a shot like the one at the top of this post for a long time and my efforts have not been real productive until now.

Everyone has to have a hobby, and this one has been more rewarding than most.

8 comments:

Ashley said...

Dear readers,

If all that went over your head--you're not alone. He talks to me about this stuff on a daily basis and I still have no clue in the end. But, he LOVES it and it's a less-creepy hobby than tarantula-keeping.

And as a result, he's able to give you increasingly better pictures of our pride and joy for your baby-ogling pleasure.

Sincerely,
The Wife.

Ketchesons said...

How fun! I got Dave one of those babies for his Birthday. We love it!
So, if I understand right, you do NOT save your RAW files? you save them as jpeg's? would you mind explaining why?
Another question, if you don't mind, these gel things you talk about. In my poor country we just bought the clear plastic paper called "celofan" and cover our lights, when performing. Is that what you do or did you buy them?
I'm sorry to just use your knowledge,I'm looking for a good graduation present for Dave but I don't really know that much about the topic. I am making progress though, I am playing with Lightroom, I really like it.
Thanks, I love that picture :-)

Grant said...

Yeah I actually don't save my RAW files. I guess it's because it's kind of overkill. Once you get a jpeg that's nice and works it's good enough. I will be unlikely to want to redevelop it differently in the future. Jpegs are way smaller and work with all sorts of software on all computer, and ultimately only a few pictures will be printed, and they won't be looked at all that much. I might start saving super important RAW files. Like if I had raw files of our wedding or something I might have saved those because I might want to redevelop them later.

My gels are made of cellophane I think. It's clear, colored plastic. It's specially made to be heat resistant and reproduce specific colors. I'm guessing it's the same stuff you used down there. It turns out that flashes are so much smaller than stage lights that free sample swatches from stage lighting companies are sufficient, so you don't have to pay more than a couple of dollars for shipping. I attach them to my flash with little circles of velcro. LIke this http://strobist.blogspot.com/2006/03/lighting-101-using-gels-to-correct.html

Jacqueline said...

So, I don't really understand it but the subjects of your pictures are certainly worthy of your expertise. Such a useful hobby. And we get the benefit of it. How satisfying.

Michelle said...

And Ashley is like, "You had to use the picture of me yawning so big you could stick an apple in my mouth? Really?" Even though I don't understand what the heck you're talking about, that picture is still really cute. ;)

Laura said...

That. is. amazing! I'm coming up to take lessons, Grant!!! First I have to buy an SLR (which has been on my wish list for some time now) and then I have to figure out how to make a shot in a room that is too dark look like you took it in broad daylight with no flash at all. That's so awesome. You're my hero. Seriously. I want to be able to do what you're learning/doing.

Ketchesons said...

Awesome, Thanks,
they are the same thing I used to work with.
The link is great,thanks again.

Kristina said...

Do you know that we still have one of your very first cameras from your long long camera obsession? Ya, it's not so great. But Seth is going to buy me a new one before the baby is born. But I'm a point and shoot kind of gal so I'll be happy with a nice 8mpx or so :)