Friday Flash Flash Types • On Camera • Off Camera How Long Is A Flash? Shutter Open Flash ~1/1000 s So, any exposure time below 1/1000s will work? Focal Plane Shutter Flash Synchronization • The physical arrangement of the focal plane shutter limits the exposure times that will work with electronic flashes. • Cameras usually allow flash synchronization times of up to 1/60, 1/125 or 1/250 of a second. Nikon’s D40 can use up to 1/500 s • Anything faster than that will lead to a partially lighted image. Control the Light • We cannot control how much flash falls on the sensor with the shutter speed. • What are our options? Aperture Control Flash by Aperture Guide Number • Every flash comes with a “Guide Number” • GN = distance × f-number at given ISO • Example: GN 100 - Object is 20ft from the camera - We need an aperture of 100/20 = 5 • 4 Times the ISO (e.g. from 100 to 400) doubles the guide number On Camera Flash • GN for EOS 60D is 43 at ISO 100 • GN for Nikon D40 is 55 at ISO 200 What’s the Problem with the Pop-up Flash? • Too small - does not have enough power for larger distances or large rooms • It sits right on top of the lens, which leads to flat pictures, harsh shadows and red eye problems. When to use the Pop-up Flash? • During the day for fill flash • In emergencies • To trigger a bigger, off-camera flash Flash Exposure Compensation • Just like with our regular exposure compensation, most DSLRs allow for flash exposure compensation • Control flash output up to +/- 2 stops Play Time Which images look better? The ones with or without flash? Rear-Curtain Sync Why Is That? • Pre-flash - Shutter opens - Flash - Shutter remains open (object moves) - Shutter closes • Pre-flash - Shutter opens - Shutter remains open (object moves) - Flash - Shutter closes Remember Two Things • Use a shutter speed not faster than the flash synchronization speed your camera supports • Only aperture will allow you to control the amount of light provided by the flash Composition Take a Class! • The “Learn to See” class at the Community Darkroom is a great way to improve your composition skills • I’ll only list a few tips Check the Edges • Before you push the shutter, check the edges of your view finder for “stuff” that’s getting into the shot • The view finder is only showing you about 95% of the final shot, but you can usually crop out what creeps in. Frame the Shot • Look for elements that can frame your shot (tree branches, …) Horizon is Horizontal • Keep the horizon horizontal • Otherwise everything in your shot will look like it’s tilted Lines • Use lines to guide the viewer’s eyes Rule of Thirds • Place important elements on the 1/3 lines crossing the frame, or on the intersections of two of those lines Foreground Interest • If you have a stunning background and mid level (e.g. landscape), add something interesting in the foreground to balance the composition to add a sense of depth Negative Space Patterns Contrast Pay Attention to the Background Break the Rules!.