Thursday, July 2, 2009

The subtle art of lighting

For a while that I've been willing to gain some serious experience with off-camera flash(es). However, the concepts of automatic flash or (P- or E- or A-) TTL have always seemed a bit awkward to me. In other words, I just wasn't having much fun using those "advanced" features. Besides, the TTL and P-TTL modes on my Pentax flash don't even work with the "manual" lenses I'm using now (no electronic communication between the lens and the camera body).

That's when I started perusing over the "Lighting 101" and "Lighting 102" archives at the Strobist blog, by professional photographer David Hobby. That's an extraordinary place to learn how to properly light a scene, using small flashes, a few props and a lot of excellent ideas. Most of all, it sparks one's creativity with well conceived examples and challenges. If you know that blog already, reading the rest of this post will not teach you anything new, but if you don't, then please don't click on that link yet! Before I loose you to the addictive world of strobing, let me describe what I've done so far.

Thank you! One of the things that I enjoy in David's approach to lighting is that he uses the flashes in manual mode, dialing down the appropriate power ratios based on the feedback from the camera's display. Perfect! He also suggests the use of several accessories, some improvised and inexpensive, like "plant-cookies" (check it out yourself), others more specific and a bit more costly, like radio triggers or umbrella diffusers. My family is not yet prepared to see me assemble light stands, diffusion boxes and umbrellas around the dining room, so I'll be using some simple, low profile and improvised gear for a while. At least until I'm taken a bit more seriously on my photographic endeavors...

There was one gadget I could not improvise: the remote trigger/receivers. Off-camera mounted flashes are essential if you want interesting lighting results. My Pentax AF-540 flash can be remotely actuated by the K10D, via an optical signal, but this feature is disabled when using manual lenses. So I got a Cactus V2s system, composed of one trigger and two receivers. This way I can use both my Pentax AF-540 and my old Contax TLA-30 simultaneously. The Cactus radio trigger/receiver sets are much cheaper than the more professional alternatives, like the Pocket Wizards. However, they have been getting some bad publicity for being unreliable. I've had no problems so far, even on outdoors use, but I haven't tried large triggering distances yet.

Let's talk about my first experiments. I decided to attempt a low-key photo of a complex subject, rarely seen in still-life work: an apple.

Pentax K10D + Zeiss Sonnar 85/2.8 + extension tube + Pentax AF-540 flash off-camera

OK, I'm kidding, everybody and his cousin has already taken close-up photos of apples... But I really like the painting-look of my photo. The only post-processing consisted on contrast adjustment, mainly to make the background uniformly black. I used a single flash, placed about 20 cm (8 in) to the left, slightly higher than the apple. I covered the flash head with an open white plastic bag, which worked as a diffuser. This way I got a soft light wrapping and avoided a harsh highlight reflection on the curved surface.

After deciding where to place the flash, I could manage the light intensity using three factors: flash power rating, lens aperture and ISO sensitivity. In this case I set the aperture to f11, in order to get an appropriate depth of field, and the sensitivity to ISO 100. Then, after a few trials, I found that the best power ratio was 1/32. The shutter speed was 1/180 sec - the maximum sync speed on the K10D - and the camera handheld.

The background must be kept strongly underexposed, so it is a good idea to stay away from walls and other light surfaces that may reflect stray light. By the way, the room lights were kept turned on, to help focusing and composing. At 1/180 sec and f11, the camera can't really capture the ambient light.

Another example: an image of a hydrangea flower lying on top of a water-filled glass. I didn't want any direct light to hit the glass, since this would create several distracting reflections. So this time I used a snoot instead of a diffuser. My snoot was a black cardboard cylinder slipped onto the flash head. This way the light can be directed to fall only on a very small area. This was my favorite image:

The flower gets most of the light, as intended, and the glass is not intrusive at all, being reduced to only a few subtle reflections, which I find quite beautiful.

This is simple stuff, really. Most of it has to do with experimenting and keeping a few key guidelines in mind. OK, thanks for bearing with me. Now you can go to the Strobist and learn with the pro!

1 comment:

Tyler Monson said...

I like the apple image.