AVECOL
Sponsored by the
Museum of Natural Science, Louisiana State University
Date: Mon, 3 Feb 2003 23:02:21 -0800
Reply-To: Bulletin Board for Bird Collections and Curators <AVECOL-LLISTSERV.LSU.EDU>
Subject: Re: [AVECOL-L] photographing specimens
To: AVECOL-LLISTSERV.LSU.EDU
Hi Jack and all-
Photographs for technical illustration-
Use a plain contrasting background so you don't lose the edges of importantsubject matter. If shooting color and the final illustration will beprinted on color, then that will be easy to do. Don't put a brown subject onbrown background, or if you do, make it a much darker or lighter brown,etc. If shooting black-and-white, avoid tonal mergers by lighting thebackground so the light parts of the object are against a somewhat darkerbackground, and the dark parts of the object are against a somewhat lighterbackground. Or at least make sure that the tones are distinctly differentat the edges of important subject matter. When using b&w film, this isharder than it sounds. You must never forget that the colors you arelooking at will be transformed into tones on a gray scale. A gray subjecton the same tone gray background will not be visible. This may sound sillybut look at a few black-and-white photos and you will easily find placeswhere the shapes of objects merge into the background. :-(
Use traditional "Rembrandt" type lighting. The main light source shouldbe in front of and to the side of the subject, and higher than the cameralens. The exact position is important depending on what you want toillustrate, Moving the light stand a few inches, raising the lamp a fewinches, or tilting/swiveling the lamp a few degrees can make a bigdifference, so move things around but stay within the position rulesabove, and take a lot of pictures. Don't use up-lighting, where the mainlight comes from below, and stay away from back-lighting if it's for aformal paper in a journal. (Back lighting is sometimes nice if it's for anarticle in a magazine.) If you want to accentuate texture use a pointlight source (spot light) and move the main light more toward the side ofthe object rather than at side of the camera. If that's too harsh, broadenthe light source (flood light) or diffuse it with a white photo umbrella,or reflector (white foam core from any art supply store).
After you set the main light set the fill light. Use a largish piece offoam core to lighten the shadow side of the subject. If you can fit a fulla full sheet of foam core into the set up you can back up more and stillcatch enough light for natural looking fill light.
The general rule of thumb lighting ratio for black and white is 3:1, Isometimes shot as low as 2:1 for a technical illustration. 2:1 means thereis two times as much light falling on the light side of the subject as thedark side. In technical illustration the priority is to present as muchinformation as you can, not to make a pretty picture. Imagine putting awhite cube in the setup with a edge toward the camera. If the face that islit by the main light reads f16 from the camera position, then for 2:1, theface lit by the fill light should read f11 from the camera position, ...remember each f stop is a factor of two, so f16 / f8 (two stops) would be a4:1 lighting ratio. This is easier than is sounds. If you don't have aspot meter, squint at your subject. Important detail in the dark side(anything you want to see in the final picture) should still bevisible. Squinting is a very useful technique but it isn't exact, so shootvarying lighting ratios, lighting angles, camera angles and bracketexposures for each. The combinations may require a few dozen or moreshots. If you have to do a big series of similar subjects, shoot a testroll of one subject first to nail down the lighting and exposure, thenshoot the rest.
Editors sometimes ask for "shadowless" photographs. I generally ignoredthat instruction because the proper use of shadows is important. Theycreate form (three dimensionality), texture, and provide setting(orientation). Use the fill light described above to lighten up shadowscast by the object on itself as well as shadows on the background. Do itright and it will rarely be rejected. Even if an editor has backgroundshadows retouched out, important tonal gradation of the subject willremain.
Make the background look seamless.
It used to be that transparency film was almost required for publishingcolor, I don't know what format publishers prefer these days, but whetherit will be black and white or color, use the slowest "regular" film youcan get. You don't need speed for table top photography, and sometimes aphoto will be published again in a larger form, so you'll you want thehighest quality possible, especially when shooting with the teensy 35mmformat. Oh, .. don't forget to use a tripod.
Here's another way to light a table top shoot. It limits the possibilitiesbut it's easier, and is much more forgiving. Find a window facing a sunlitwhite wall ( white is important if it's a color shoot). Or hang a whitesheet over a window where the sun will fall on it. The larger the windowthe more forgiving the light. Make a fist and hold it at arm's length infront of you. Now turn around, move around, and move side to side, in front ofthe window until the light on your fist looks great. Now you know,roughly, the camera/subject/light source angles to use. Put yourbackground and subject on a small table so you can easily move it if youneed to fine tune the set up. Have your assistant hold up a foam corereflector somewhere to the side of the camera opposite the window Moveit/tilt it , up/down, in/out, sideways until the shadows are filled in anatural looking way and shoot. You can ignore the no-up-light-rule withthe fill reflector and use it below the lens. Sometimes photographers willend up poking the lens though a hole cut in the foam core. As above, shoota lot and use a tripod.
uhm, one last thing... If the nests or any subjects are small, try to usea, hopefully longish, macro lens, and use as much available negative (film)space as you can. Normal lenses work best at some considerable distance,some many multiples of their focal length out to infinity. Macro lensesare optimized to work best much closer, at fewer multiples of their focallength. You want a longish macro so you can get a big image of a smallsubject without having to get too close to it. Getting in too close startsintroducing perspective problems. Within reason, make use of as much filmarea as you can, it can make a big difference in the quality of the image.
When shooting in close, you need to stop way down, especially with atelephoto "micro" lens to get adequate depth of field. Hopefully f32 orclose to it will be available. Focus 1/3 of the way into the importantsubject matter. Use long exposure times if you have to, and use your mirrorlock up feature with a pneumatic (not a cable) shutter release. I neverused a remote control release, I suppose one of those would work .....maybe, if it was compatible with B shutter setting. Note: At over onesecond exposures reciprocity failure starts to kick in, so bracket heavilyto the upside. If the meter says f32 at 1 second, also shoot 3 seconds, 6seconds, and 12 seconds just in case. This little bit of esoterica savedmy butt on several deadline days.
Well three vodkas down the hatch now and I don't think I can reread thisthing again, hope it's readable......
Have fun!
Sam Sumida
(net pole maker and former freelance photographer)
______
At 05:42 PM 2/3/03 -0500, you wrote:
>Avecol readers...
>I need to photograph some bird nests and specimens for publication. Any>suggestions as to backgrounds, lighting and film speed? I am using a Nikon>35mm.
>Jack Eitniear
>CSTB Inc.
>Bull. Tex Ornithol. Soc.