Saturday, February 2, 2008

The Making of Moondance

Yet another entry in the Making Of series.

Moondance was my submission for the fourth (and last) semifinal of the Last Photographer Standing competition. I have admired high speed water photography for some time and had wanted to shoot some of my own. For the competition my initial idea was simple--high speed water mixed with creative light. Beyond that, I assembled a small army of DIY tools for the genre and started playing.
First of all, to create a splash. For that, I reached back in history to a medieval siege engine and modified it slightly for photography. I present to you the Martini Trebuchet. No photographer's kit is truely complete without it. The table top is 3 feet long, made of 1/4" black acrylic and reinforced with two ribs of square acrylic tubing. The base is cobbled together from scrap 3/4" ply, the hinge is a cheap but effective 8 inch long 1/4-20 bolt and the 10 pound counterweight provides sufficient range for a seige of loud party next door should the need arise.
Attaching the martini glass was a particular challenge. The bond had to be temporary, nearly invisible and strong enough to keep the glass firmly on the table under significant duress. The solution is four small holes drilled in the table top and two crossed loops of 65 pound test fishing line. Underneath, the loops are hooked over squeeze clamps attached to the support beams making them easy to tighten down and lock in place. This system performed exceptionally well; holding the glass solidly in place for several hundred shots while, when needed, letting me remove the glass in seconds.

There were three strobes: one on the left with a blue gel for the sky, one on the right with a grid and a yellow gel for the lemon, and the third shot through a hacked slide projector for the moon. Each take I would hold the table level and fill the glass. With the room lights off I opened the shutter for a 1.6s exposure and released table. As the table rose, the clamp on the left edge would break the beam on a HiViz Photogate/Delay kit and trigger the strobes (through Pocket Wizards) after a delay of about 3/4 second. Full power pops on the strobes were not fast enough to stop the motion; after some testing I concluded that 1/4 power was the highest power I could use with an acceptably sharp result.
I used fishing line to hang the lemon from a boom stand. To the right I placed a backstop and a catch tray for the water. Even with 30 pounds of weight holding it down, the trebuchet would move enough during the launch that I ended up using masking tape to mark the proper location and realigning it each shot.
Once I got the setup right, the shot only needed minor cloning and other cleanup in Photoshop to produce the final version.

Friday, January 25, 2008

Projected Backgrounds

I was looking to project a background for a project I was working on recently. For this particular project, I needed more light than the halogen in a slide projector could provide so an alternative was in order. After a little research I found the perfect solution to my problem, the Norman TL-2000 looked like just the ticket. After a quick look at the price tag, I suddenly found myself inspired to try a little DIY. So I called around to the local camera repair shop and found that they had a few broken slide projectors in the repair queue. After a conversation with the repair guy I came home with this beauty.

Now this projector is quite easily reparable (the ceramic bulb mount was cracked) which is why I was charged an exorbitant $60 for it but are we going to repair it? I thought not. Where's the fun in that?

I sat her down on my operating table and went to work. Looking in bulb compartment I found just the opportunity I was looking for. The light path comes straight to the back of the case where it is reflected off a mirror to the bulb which is mounted to the right. This means there are only two things in the way preventing me from pumping my own light in the back. First the easy one; the mirror comes out with just two screws. Next the back panel. I removed all 4 screws and took off the base plate. Then as I started working on the back panel I discovered that the little insert just pops out all on its own and, get this, the hole left behind is an almost perfect match for the lens in a speedlite. Coincidence? I think not. This mod was destined to be.
I popped out the insert and put the base plate back on. Finally there is one other parts we can remove. If you look at the optics in the body there are lenses just behind the slide mount. The first is a condenser; we want that. However the other is just a flat glass heat shield. Its important in close proximity to a halogen bulb, but when using a speedlite all it does is suck up light and add a greenish color cast so out it comes. Assembled again and back on her feet, you can see our leaner, meaner speedlite charged slide projector along with the removed parts and my sole instrument of torture.
Finally, some action. I used my 430EX (triggered by a Pocket Wizard) to project a photo of the moon on a white seamless. There is a softbox on the left spilling light on to my background which is hurting my contrast a bit but with better light control the contrast is great. Even without the heat shield the projector adds a bit of a greenish cast so white balance is a bit funky. Probably a pale windowpane green gel on the rest of your lights is in order. After a bunch of screwing around to get good focus I discovered that my little LED flashlight make a great modeling lamp.

Thursday, January 10, 2008

Why Strobes?

I received this question via Flickr mail (phrased somewhat differently) and I thought I would answer it here. Without question, strobes are difficult to use and many photographers shun them. They are expensive, hard to visualize and to the beginner metering strobes appears to be an arcane art. So why do we put up with them? Here’s a few reasons:

1. Power. They are the most powerful light sources available. Even small AA battery powered units can exceed the brightness of the sun at close range and high powered studio units can turn noon into midnight. A battery powered strobe can easily give you f/11 at ISO 100; with a comparable battery powered continuous light you are lucky to get f/2.8 at ISO 800.
2. Efficiency. High powered continuous lighting generates a lot of heat. High powered strobes can be used without the risk of fire or overheating your model.
3. Color. Strobes have a consistent color temperature near daylight resulting in lively full spectrum color in the final image.
4. Portability. The high energy efficiency of strobes means one (or several) small battery powered units can go with you anywhere.

I certainly spend many years as a photographer terrified of strobes. I had one, but the moment I put it in the hot shoe, I put the camera in full auto mode and hoped for the best. Today, though, with the instant feed back of digital cameras it is easier than is ever has been to learn how to use strobes. If you haven’t done so, pick up a strobe with manual power controls and take some time to play with it. There is no better way to learn than setting both your camera and strobe in full manual mode and experimenting. A little bit of reading and a few hours with the camera and the mysteries of the strobes will start to make sense.

To get started and an infinite amount of inspiration, here are some great resources:

Strobist 101
EOS Flash
Light, Science and Magic
Master Lighting Guide for Portrait Photographers

Tuesday, August 7, 2007

Canon 5D self timer and mirror lock up.

Back in the old days when I was shooting flim, both my EOS-3 and the T90 before it had two self timer modes: a 10 second mode for when you wanted to be in the picture and a 2 second mode for tripod shooting. When I got the 5D, I was very disappointed to discover the lack of a 2 second timer mode. Ten seconds is a long time to wait, so mostly I have used my TC-80N cable release instead of the self timer when the camera is on a tripod.

So then a few weeks ago I was shooting in Fort Point, San Francisco and I discovered that I left the cable release in my other camera bag. Oh, well, I guess a 10 second wait it is. So I turn on mirror lockup and the self timer and hit the shutter. Up goes the mirror, two second wait, and snap goes the picture all automatically. What's that? I try it again. Sure enough, not only does MLU automatically reduce the self timer to 2 seconds, the self timer automatically lifts the mirror, waits two seconds and takes the picture. Halleluia! The perfect tripod mode. I'd swear I've read the entire 5D manual and never found this, but suddenly a year after I got the camera it has become standard operating procedure.

Monday, August 6, 2007

Lighting Glass Bottles

My friend Nikolai who runs the Technique Assignments on the Digital Grin forums asked me to write up a brief technique discussion of how to light glass bottles. Well, I have always said "everything worth doing is worth overdoing," so over time I plan to turn this post into and expanded discussion on lighting glass. Note that much of the material I am discussing here starts from the book Light, Science and Magic: An Introduction to Photographic Lighting by Fil Hunter, Steven Biver and Paul Fuqua. I am not going to assume you have read this book, but if you are interested in this topic, you should read it.


First things first: this is an essay about studio lighting. If you are not used to studio work, be prepared for a change in mindset. You are not capturing a scene, you are creating it. Studio photography means taking full control of everything the camera sees and particularly in the case of glass photography this will require 360 degree control of the space you are shooting in.

Generally the way I work is this: the camera goes on a tripod with a cable release and then I set up the camera to frame my working space. Next I set up my background. Then build my scene by placing my subjects in the scene. After that I try to determine the proper aperture and focus point to get my entire scene sharp. Almost always this means using manual focus to pick the focus distance which allows the widest possible aperture; the shutter speed is set to the fastest sync speed the camera allows and the ISO is set to 100. At this point, the camera work is done; the remaining work is done entirely with the lights. In particular, I usually adjust for proper exposure by changing the flash power rather than with settings on the camera; this is always done by chimping the histogram with the flash set in manual mode. I never use any form of auto exposure for studio work and flash meters work extremely poorly for glass and other reflective objects; it is possible to get the exposure right with a spot meter but in this day and age its not worth the effort. In the circumstances where the flash is not powerful enough, to get the exposure I want I will set the flash on full power and bump the ISO for proper exposure.

Light and Glass

Diffuse reflection is the most common form of light we photograph. It is an idealization, but for many materials a good one; incident light meters are calibrated to it, much of lighting theory is based on it, and we often use circular polarizers eliminate other forms of light. In a nutshell what makes glass challenging it the complete lack of diffuse reflections. Because of that we have to completely rethink our instincts both for exposure and lighting. If your goal is to show the three dimensional form of the glass there are really to major approaches: refraction and reflection. In a nutshell, glass usually behaves both as a mirror and as a lens. Of course flat glass is a rather boring lens and the lenses in your camera are coated to make them poor mirrors. None-the-less, most pieces of glass you are likely to be interested in photographing are like to exhibit both properties to some degree. The true key to lighting glass is to really look at the lens-like and mirror-like properties of your subject and decide how to exploit them to create the image you want.

Refractive Lighting
What I mean by Refractive Lighting is lighting the subject in a way that reveals its form because of how the light passing through it is refracted. Curved glass is refractive which means it bends light and distorts any image which passes through it. As the glass gets thicker and more curved this effect gets stronger. The general strategy for using refraction to show the form of glass is to light the glass from behind with a high contrast pattern. The most common approaches for mildly refractive subjects are either to use a white backdrop with a black border or a black backdrop with a white border. In either case the border is placed just outside the camera's direct view so that is is only visible via refraction in the glass subject. With some highly refractive objects (like dewdrops and full wine glasses) it possible to actually use the subject as a lens to reveal a secondary subject in the background.

Reflective Lighting
By Reflective Lighting I mean revealing the form of the subject through specular reflection off of its surface. Glass usually has a polished surface which makes it reflective. It is possible then to show the form of the glass in how it reflects its environment. If the glass is clear, it is best to make sure that the background is black so that the transmitted light doesn't compete with the reflections. Specular reflections from point light sources are very bright and will blow out so you should use large diffuse light sources. If you don't have a soft box use either a bounce card or a white diffuser sheet. Umbrellas aren't a good choice for reflective subjects because the ribs will show.

There are many other ways to light specific glass subjects. For instance tinted subjects can reveal form through density and dirty, impure or frosted glass can reveal form through scattered light. However, for this article we are going to stick to just two, reflection and refraction, because they are quite commonly useful for solving some difficult lighting problems.

Before you start lighting your subject, it is best to decide up front whether you are going to use reflection or refraction for your lighting strategy. Generally, if the subject highly refractive (i.e. behaving like a fish eye lens it is best to use a white field refractive approach (with white directly behind the subject and black outside the camera's field of view) because otherwise you will have a hard time controlling reflections off the subject. If the subject is not refractive enough you may have to put your border too close to your subject to get the framing you would like which would indicate using a reflective strategy. If your subject is darkly tinted or translucent in a way that will obscure light transmission you should again choose reflection. While many subjects will force your hand to pick one strategy or the other, there are also some subjects where either will work and the choice is personal taste.

Lighting Bottles

Now for a few samples just to get you thinking about it.
Empty Clear Bottle
Empty bottles typically bend the light passing through their edges enough that you can create an outline around the bottle using refractive light. The effect gives you a two dimensional look as the center of the bottle is not curved enough to pick up the contrasting border. Reflective lighting is possible on a clear empty bottle but it takes extremely careful background control to provide a sufficiently dark background for good contrast.
Empty Tinted Bottle
If you want to show the color of the glass, you must shine light through it. With light colored glass it is probably best to use refractive lighting. With dark colored glass it is possible to show the color with a back light and still have sufficient contrast to use reflections to show form.
Clear (or lightly colored) Full Bottle

The strong refractions of a full bottle make refractive lighting a better choice here and controlling reflections will put the emphasis on the contents of the bottle.
Dark Full Bottle
A dark full bottle is similar to a darkly tinted bottle. To show form it is usually best to use reflections. Again a back light can sometimes be used to show the color of the bottle contents.

Monday, July 9, 2007

The Making of On Edge

Yet another entry in the Making Of series.

On Edge was my submission for the fifth qualifying round of the Last Photographer Standing competition which had themes of Translucent or Silhouette. The theme I had in mind for this shot was translucent and when I was planning it I had in mind to show the translucence of the pepper by using a strong enough back light to make the pepper apparently glow from inside. However, many people who saw the shot picked up first on the silhouette of the knife.

The set up for this shot was really quite simple. I used two sheets of white foam core and a couple sticks of scrap wood I had sitting around the shop. The sheet of foam core I used for the floor had a hole cut in it (it is black on the other side and its normal use it to hang over the lens when I want to hide the reflection of the camera in glass or metal subjects). I then slid the flash under the floor so it fired up through the hole. Normally I trigger the flash with and ST-E2, but in this case I had it shoved down where the IR don't shine so I ended up using a cable trigger instead.

The one flash is the only source of light in the shot. The gradient in the background is scatter off the knife and the pepper; the glow of the pepper is light transmitted through its flesh from behind; the light on the stem comes directly from the flash. Yep, some people use tupperware as a lighting modifier, I used vegetables. The knife, along with being a player in the scene is also serving as a gobo to hide the flash from the camera.

Thursday, May 10, 2007

The Making Of series.

The posts Making Of series are thoughts about, lessons learned from, or technique discussion of the process of creating some of my more difficult photographs. Many of these were shot for the Digital Grin Last Photographer Standing competition.

  • The Making of On Edge
  • Lessons Learned from Strut
  • The Making of Incandescent
  • The Making of Lemonscape
  • Lighting for On the Rocks