Digital Photography One on One Video Tutorials

DP 1on1 E001 – Key Shifting and Shutter Speed

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In this episode of Digital Photography One on One, Mark Wallace [] explains Key Shifting and how your shutter speed affects exposure when using an external flash.

Questions Answered:
1) To get the best results when using a Canon 580 flash unit on a 20D, should I stick to ISO100? Would you ever change the ISO for some reason? -Nigel

2) Can you please explain Key Shifting to me in regards to outdoor portraiture? Once I establish a meter reading on my subject of say f/8, what do I have to do to lighten and darken the background?

Digital Photography One on One is a video question and answer tutorial format from and You can submit questions for us to tackle on the show by contacting us.

We’d love to hear what you think of this video tutorial format. Be sure to stop by the LightSource Flickr group and tell us what you think.

Visit to learn more about Mark Wallace and his educational workshops on photography and studio lighting.

24 thoughts on “DP 1on1 E001 – Key Shifting and Shutter Speed

  1. Lawrence

    new to lighting photography so i sometimes struggle understanding your guests techniques. So these video podcasts are great and should be used to supplement the audio podcasts more often. But great podcast guys and keep it up.

  2. jesus ali

    I’m not sure if your DIGG link was setup correctly. it asked me if I wanted to start a topic, thinking one didn’t exist already to simply add a digg to. so I started one. then it said it seemed like it was a duplicate entry. I continued and started it anyway.

    great tutorial. perfect for beginners and hobbyists. well done.

  3. Andrew Smith

    This is one of the most important techniques for people to learn when they first take an interest in lighting. It took me six months to finally understand all of this! People who write/produce tutorials often forget how confusing this information can be to people who are trying to learn it. Once we know it, it seems to simple, but it’s the steepest part of the learning curve. Mark you have provided a great service for new photographers and this video is an absolute must-see for anyone interested in taking their lighting to the next level. Brilliant work!

  4. Raghu

    That was beautiful illustration. Cant go wrong after seeing this lesson. A question with balancing ambient light. In real life, when we cannot afford to experiment with different shutter speeds, how do we capture the right moment at right exposure? In other words how do I use the exposure meter in the view finder and play with Flash exposure comp/ambient exposure compensation? I always over or under expose even with TTL :-(
    Any thumb rule?

  5. Tony

    Strobist recommended your site, so i thought i’ll give it a shot (no pun intended)…very nice. Your first podcast is simply awesome and very well done. I’m a pro, so it was kind of basic for me…however, i’m looking forward to others. There’s always something to learn. Learning light is a life long process. Keep it up. So, how long do we need to wait for the next one?

  6. troy

    awesome tutorial.

    however i think it is a little unclear that when you slow your shutterspeed down that the softboxes flash is not outputting as much light as it was in the previous shot.

    does your softbox pro light have ttl? or are you manual just stopping it down between shots?

    looking forward to the next one.

  7. Mark Wallace

    Troy said:

    “however i think it is a little unclear that when you slow your shutterspeed down that the softboxes flash is not outputting as much light as it was in the previous shot.”

    The softbox is putting out the same amount of light on each exposure. The amount of light from the strobe doesn’t change from shot to shot.

    If you were using an on camera TTL flash head (like a speedlight) then the light may change from shot to shot, but not with an external strobe.

  8. Kevin H. Stecyk

    Terrific tutorial.

    One question though, let’s say you are shooting at an Æ’/8 and initially shoot at 1/250 of a second, your sync time.

    You decide to allow more time to bring in more ambient light. You decide to use 1/4 of a second. If Meghan were to move at all during that 1/4 of a second, does she cause blur in the picture? Or because the flash has “frozen” her image, it doesn’t matter what she does after the initial 1/250 second flash?

    In other words, is it imperative that you subject remain motionless if you use a longer time to capture more ambient light?

    Again, great tutorial!


  9. Mark Wallace

    Great question Kevin,

    Then answer is… it all depends. :)

    The more ambient light that you have the more likely there will be blur. The subject will be frozen, but may have a soft “ghost” around them. You can see that in many photos. Some photographers actually do this on purpose to give a sense of movement.

    Another item that I didn’t address in the video is that the aperture may need to change with very long exposures. So f/8 at 1/250 may become f/10 at 3 seconds. Your light meter will let you know when that happens. :)

  10. Charlie

    Wow, please keep producing these great tutorials! I’ve been shooting for about a year now, but still didn’t understand how the shutter actually functioned and why I was getting black areas when I went above sync speed.

    Your tutorials are very professionally done and easy to watch and learn from. You are improving my photography!

    Thanks so much and keep up the good work!

  11. Potion61

    Thank you so much for these tutorials.
    The explanation in them is very easy to understand and they are very informative.
    Looking forward to watching more of them.

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RARE ONE OF A KIND WILART 35mm ANTIQUE Motion Picture Camera C. 1919. HAND CRANK