February 6, 2010

Aperture Controls Flash Exposure - PLUS Behind the Scenes - lightenupandshoot.com

Andy and I cover the basics of how aperture controls flash exposure. Simply put, aperture controls the exposure of whatever your flash is hitting. For example, if your subject is over exposed by one stop at f5.6 you are going to close down your aperture to f8.  Andy and I demonstrate how to get proper exposure of our subject while taking pictures of a model in the studio.  Also,  shutter speed controls the ambient light or any continuous light source, i.e. sun, candle, light bulb (watch the Speed Light Series on this site for more detailed information.)  As always,  lightenupandshoot!

Photo examples after the break!

Above, is a picture of Carina taken in the studio at an aperture of f5.6.  She is over-exposed.  The solution is to stop down or use a small aperture.

Andy adjusted the aperture by two stops, f11, to see if he could get the proper exposure.   The picture is under-exposed.   What is the solution?  Open the aperture up.  

Alright!  Carina is properly exposed at an aperture of f8.  See how easy that was?  By simply adjusting aperture you can obtain proper exposure of your subject.  note:  notice the dark shadow on the right side of the model's face.  She turned her head.  One solution would be for her to turn her head or add a second light for fill.  

The above picture was featured in the behind the scenes footage of the video.  There are three light sources, the sun (for back light), a bare SB28 (for fill camera left) and an Alien Bees B1600 shot through a Westcott 28"Apollo softbox (main light camera right.)  Normally I would have used just one flash to get a very contrasty look.  But, the model needed shots for her portfolio;  in Colombia clients like to see their models evenly lit.  So,  I added a second light to fill in the shadows on her face camera left.  The second flash also added some nice rim light on her boots and hair.  Camera settings are:  ISO 200, f9, 1/320 sec.


  1. You shot the last image at 1/320 sec but the sync speed for most DSLRs is 1/250 sec. How did you compensate? Camera setting? Flash setting?

    Great stuff here guys. Where else can we go for photography demos AND leaf selection? I'm sure NO ONE else is combining the two skills!

  2. Robert,

    Yes, my max sync is 1/250, but I have found that I can push my max sync speed to 1/320 without getting that little black line in my photo. Try it! It doesn't always work, but works most of the time.

  3. Guys, put some TP in your BP Studio!

    Nice gag tho.

  4. Mikey, you looked like you lost a few pounds after your pit stop in the woods:)

    By the way, I asked the same question about the sync speed during the last video post. I tried pushing the SS to 320 and up and it worked great.


  5. Mikey you didn't tell us if the leaves worked or not. Did Andy tell you there was a bano 50ft from where he was?? Your model is beautiful in any light!

  6. Sherry,

    Thanks for the tip! "TP for the BP." Jajajajja. I love it!


    The leaves worked awesome. Quick tip: Smooth leaves are a waste of time. You need a leaf with a little grab.

    Lighten up and shoot!

  7. Bahhahahahahaha my father used leaves before when he "really" had to go...except, it was poison ivy or sumac *LOL* ...needless to say , he had to go the the hospital, doctors and nurses where LAUGHING in the halls! LOL at the time, he didn't thnk it was funny but a few months later, he was laughing about it like everyone else...So, be careful with your "leaf" of choice when desperate! *LOL*

    Great tutorial guys!!! :)

  8. Great post guys. Simple yet helpful. Haha, great bonus features too.

  9. Thank you both so much for your great videos. They're great fun and have taught me loads. I have a question but please excuse me if it sounds dumb - I'm just a noob with this off-camera flash stuff. If you change the aperture to control the flash, won't you also need to change the shutter speed if you want to keep the same ambient exposure? Thanks again for the fun teaching & please come do a workshop in the UK. Tim

  10. Holy SHIT. Where are thou now?