Science or craft?

In response to my “quick portrait” instructions, a reader asks:

What do you think about’s method where he recommends adjusting shutter for ambient and aperture for flash, by “chimping” (no light meter).
Just interested in your response.
As the two methods have similar results, yet dramatically different philosophy.

Great question.

David Hobby (the Strobist) and I (the Speedlighter) sometimes differ – he says “don’t use TTL”, I say “do” – but it is never a case of “you don’t know what you are talking about” – it is more “personally, I’d do that differently”.

First, I think for ambient you set both aperture and shutter. Clearly, changing aperture affects foreground as well as background.

The table of “what affects what” is as follows:

  • Shutter: Changes mainly the background.
  • Flash power setting (including distance of flash to foreground subject): Changes mainly the foreground.
  • Aperture – changes both.
  • ISO – changes both.

So first off, I’d change the two boldfaced properties above.

But secondly – I like to meter, since it takes guesswork away. Then I finesse.

Yes, my experience tells me I can just choose 1/4 power on the flash, say, and with f/5.6 this will give you a good picture at standard ISO and distance. But it’s still guesswork so you need to iterate. When I use my meter I am objectively sure I’ll get that good starting point with less iterating.

That said…

  1. I will not go to extremes and set my light meter to tenths of stops. No way. The last bit may be chimping, not metering to 1/10th stop which I will never see anyway.
  2. I set the values I know will work to get close enough before I even meter. You will see that with a little experience, this will work just fine.

So taking into account 1 and 2, David and I are not that far apart after all, are we?


4 thoughts on “Science or craft?

  1. Wow thanks – great response Michael. You both deserve accolades and respect for all the volunteer time you spend teaching others.

    Do you use the miniTT1 or Radiopopper to overcome the infrared limitations of TTL?

    The last time we met, you were using the Plus II which was just for manual flash.

    I was playing around with off-camera flash yesterday outside and the off-camera TTL wasn’t working very reliably (not firing when it was supposed to).

    I wonder if the sunlight was interfering with the infrared or I wonder if the system was sensing enough light in the scene in the pre-flash and thus not firing. In the first case I’d have to spring for more expensive radio slave equipment!

    I was trying to take a photo where the background (dark clouds, sunlight hitting a bush of bamboo) was exposed -1 stop and the foreground (my daughter) was way underexposed in ambient but I wanted to light her face with a flash+snoot. The 60D popup didn’t activate my 430EX about 90% of the time.

    I walked back inside put the 430ex on the table, walked across the room, and hit the shutter a few times, and the 430EX fired 100% time indoors – so other variables like battery and equipment failure were unlikely the cause.

    Many thanks,

    • So. Here’s the long and short.

      1. You need line of sight. The red thing on the 430 needs to see the pop-up flash straight on. Turn the head to achieve that. Was that OK?

      2. You need power. If there was too much sun, you may need a 580EX on your camera instead of the very small popup.

      3. You need to avoid direct sun falling onto the red thing on the front of your 430. That will help too.

      Does that help?

  2. Ahh… I see.

    #1 was okay. I had the body swiveled so IR sensor faced my 60d popup.

    #3 probably not okay. Sun was hitting the IR sensor on 430EX.
    Maybe I needed to gaffer a flag to the IR sensor so it could point towards me but not get sunlight? haha…

    #2 – I am not sure. I may be wrong, but I thought the flashes of the popup doesn’t contribute to exposure, just sends IR signal to 430EX (with built-in flash wireless control set to speedlite only)


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