Friday, November 5, 2010

How to get a black background without a backdrop

Today's post is a guest post by one of our readers, Mohammad Shafik (aka mshafik), about how to get a cool-looking black background in a natural environment, without a backdrop, transforming your backyard into a studio.  Without further ado:


ABOUT THE AUTHOR

Hello everyone, this is my first guest post on this blog and thanks to Mic for the opportunity.

I believe an introduction is in order, my name is Mohammad Shafik, I am Egyptian and I consider myself an advanced amateur photographer, I used to take pictures a long time ago using my father's Yashica Electro 35 GN rangefinder camera with a 50mm f/1.7 fixed lens, back then I was using it as a point and shoot camera. A few years back I got myself a Sony DSC-T10 P&S thinking that it was the best camera in the world.

Recently when Canon released the G11 and the S90 point and shoots, all of the different blogs were raving about the large sensor (for a P&S), the image quality and that Canon has finally listened to their customers and reduced the sensor resolution from 14 MP down to 10 MP which resulted in a much better high ISO noise performance. I was starting to get interested. A few reviews later I wanted to make sure I understood the difference between the aperture and the focal length correctly, that's when I started looking for online photography tutorials.

When I thought I understood enough, I went back to my Sony T10 only to discover that it was severely limited in comparison, that's when everything really started for me. I spent months comparing the S90 and the G11 until I finally settled on the G11 because of how it felt when I tried it in the shop; the S90 was too small and slippery for my taste.

Not to make this any more longer, that's when I really started learning about photography, I can safely claim that I have read all of the free online tutorials, well, at least 90% of them. I started learning about lighting from the strobist (a highly addictive site, you've been warned), as a side effect I got myself a couple of Canon speedlites (430EX and 580EX), some wireless triggers, umbrellas, modifiers, light stand, etc...

In this stage I was (as they say) on steroids, I had an intense and a very quick learning curve, and just as quickly I hit a limit with my Canon G11. I wasn't able to get all of the shots that I thought I would get of my little daughter (wretched focusing speed + shutter lag), so I got myself a Canon 550D, but more on that later; the introduction has already dragged out enough. Check this link for a quick impression about my 550D versus the G11. If I do further posts; hopefully; I will talk more about the differences between both
cameras. Oh, and by the way, the strobist has a G11.

ABOUT THE SHOT

Today's post is about the Spider Lily picture you've seen at the top of this post, you thought you'd directly get to the shot? Hah! Anyway; here's the rundown of how I shot this picture.

My father was the one who drew my attention to this flower, we have a small garden at home and this is where I took this photo. He (my father) told me that this flower only flourishes twice a year, and that each time it stays open for a week or so.

I quickly fetched my G11, a couple of speedlites (Canon 430EX, 580EX, equivalent to the Nikon SB-600 and SB-800), wireless triggers and my brother to help me. I started taking a few trial shots with one flash lighting the area, but I didn't like all of the distractions around the flower, there were too many objects near the flower that getting a good composition required using a much tighter field of view (105mm instead of 28mm).

Next step I moved further away, zoomed in all the way and tried to get a clean angle that shows the flower without all of the distractions behind, but still it didn't look good enough. That forced me to think about the inverse square law.

INVERSE SQUARE LAW SIMPLIFIED

Now if you know what that means then skip to the next paragraph. If you don't, here's a very simple explanation (in English, no less) without actually stating that law, the effect of this law is that when you have your light source (in our case the speedlite) very close to your subject (the flower), you can reduce the output power from the speedlite just to illuminate just the flower and the light will fall off quickly without illuminating all of the objects behind that flower. Now if you move the light source farther away from your object and increase the power output to match the same illumination on the flower as you did when you were close, then this stronger light will illuminate the flower AND the objects surrounding it as well, and you won't get the same isolation.

Now that I decided what to do, I had to make sure before turning on the speedlites that I won't have any of the ambient light affecting my exposure, so I started taking several shots (without flash) and increasing the shutter speed (no problems here since the G11 is able to sync with the flash up to 1/4000 sec, actually only up to 1/800 because of the delay of the wireless triggers) until the histogram told me that I had a completely
black picture, this is represented by just one vertical line at the very far left side of the histogram. The aperture was around f5 and the shutter speed was 1/250, and I used ISO 80 as well to get the lowest noise possible.

After that I turned the power way down on both of my speedlites (1/128 for the 580EX and 1/64 for the 430EX) and tried several lighting positions until I found one that I like.  I was holding one light just to the left of the camera with my left hand (the camera in the right hand, obviously), and my brother was holding the other one directly above the flower just out of the frame, this produced the best look. Next step is to dial in the exposure.

The most important part of dialing in the exposure was not to blow out the highlights.  Since the flower was white I had to check the histogram and the resulting image for any blinking highlights, I was trying to get the histogram positioned just before the right edge, and this meant that the white on the flower was actually white and that I preserved the textures as well. This dialing in was done by moving the hand held speedlites away or close to the flower until I got the desired result.

Check the next two pictures as well to see how it actually looked like around the flower.  The first shot was taken at the same time by moving the speedlite farther away from the flower and increasing the power slightly. The other one was taken the next morning while going to work, I know it's awfully blurry because of handshake but I had only 5 seconds to take the picture while carrying a heavy bag on my shoulder.




POST-PROCESSING

The final part is post processing since I usually shoot in RAW. In these shots I used the lowest ISO possible so the noise was not an issue, however I had to increase the blacks a bit to increase the contrast and make sure that the background is still 100% black. That's how I got the shot at the top.

I hope you enjoyed this quick rundown, so please let me hear it in the comments.