Wednesday, September 2, 2009

New HVL-F20AM flash and a DIY (Do-It-Yourself) IR Filter Switch

Oh happy day!  My biggest complaint about the A900 - mainly, its lack of a pop-up flash for triggering wireless - has essentially been solved by Sony, who has just started shipping its HVL-F20AM flash which is actually more versatile than a normal popup flash.  No longer must I attach a big, heavy, and expensive "58" flash just to control my wireless flashes!  Furthermore, unlike a purely infrared wireless flash controller (the usual manufacturer solution to the problem of triggering wireless flashes without a built-in flash), the "20" flash can do fill-in flash as well, something I love to use when shooting portraits outdoors.

I've been playing with this flash for about a week, and the more I experiment, the more I like it.  Here's what I like:

  • You can shoot at your camera's maximum shooting speed (5 fps on the A900) with this flash in either wireless mode or fill-flash mode - whether or not the flash is fully recharged!!!  Is this a design flaw?  Regardless, I like it.  When shooting people using a fill flash (where the built-in flash is only there to lighten the shadows; not to provide all the illumination), sometimes it’s more important to get the right expression than for the fill light to be perfect. I’d rather the camera shoot when I press the button, even if the fill flash isn’t ready. Never before have I used a modern automatic camera that allowed me this option.
  • But for how long can the flash keep up when shooting at 5 fps?  Well, in wireless flash controller mode, it seems infinite - I blasted through about 30 images straight, and the flash seemed to output something each time.  The same was true when in fill-flash mode.  When examining the pictures on the camera, however, only the first five or so came out properly in either mode - the rest were too dark.  Now we all know that nobody would use the flash this way in the real world, but as an engineer I like to know the limits of my equipment.  Compared with my A700's built-in flash (which would never fire faster than every 0.7 seconds, and would prevent me from shooting if I wanted to do it faster), this new 20 flash will certainly be a more responsive tool in the field.
  • The flash tube sits higher than most pop-up flashes, reducing the incidence of red-eye (when it's the only source of light, and shame on you if you if you ever use it this way! :-) ), and also is less likely to cast a shadow on your subject when shooting things close-up.
Things that aren't so remarkable:
  • There's a mechanical switch that allows the flash tube to point UP instead of forward for bouncing the flash off the ceiling.  The flash might be too weak for that; on the other hand it might be a handy feature if you're keen on attaching a light diffuser on top.
  • It has a built-in wide-angle diffuser.  Twist the knob, and the diffuser moves in front of the flash tube.  Twist the knob again, and it retreats.  Now in my experience flash photography and wide-angle lenses generally don't go together.  And that goes double for tiny flashes - there just may not be enough power to illuminate everything, and besides, when shooting a group of people with a wide-angle lens, the distance between the flash and the subject in the far corner is greater than the distance between the flash and the person who’s at the center, meaning the people in the corner will receive less illumination. The wider the lens, the darker the corners.
That's OK; I'm actually glad that Sony designed-in the wide-angle diffuser, for I was able to take the flash apart and affix an infrared filter to that diffuser, turning the 20 into the world's most convenient and versatile Infrared Wireless Flash Controller on the planet.  (Recall from my books that I have always advocated attaching a piece of exposed and developed color negative film to the pop-up flash to prevent the wireless flash controller signals from ever appearing in the shot.  This is essential if you're shooting up close and wide open.)

So now, a twist of a knob will turn the 20 flash from a nice little fill flash to an infrared wireless controller!  I explain how to do it in detail (plus provide a more thorough review of the 20 flash) in my next article to be published in Photoworld, a magazine which I highly recommend.  (In fact, you can click here to get a discount on a subscription!). 

P.S. - These images are actually animated .gif files.  To see the animation have a look at the original article at .
Florida and Nova Scotia seminars are open for enrollment!


  1. Hi, Does the HVL-F20 use the 'older' flash protocol when on an A850?
    I have older minolta 56 & 36 flashes I would like to use as the slaves.
    Thanks for all your advice.

    1. Yes, it does and that combination should work just fine. GF

    2. 6 years since my 2016 post and I was setting up the same flash combination but the wireless flashes don't fire. They do show chl 1 and red light flashes. Is it possible the 20am flash is faulty? It works as fill flash. The 2 big flash's work wirelessly when using old 7D camera.


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