Use the "Modeling Flash" function to your benefit

Did you know that you can preview your lighting / shadows cast using your speedlites? It is amazing what the flash user manual can teach you. The majority of people don't read user manuals and think they know it all or they rely on Youtube to take them quickly into a quick reference mode. Believe me you are missing a lot!

The other day I bought the Canon 600EX-RT speedlite and like usual downloaded the PDF manual on my Dropbox and started reading it on my iPhone (whenever I have the chance). To my surprise I found an interesting tool that all speedlite users miss; which is modeling the light to preview where shadows are casting; an inherent advantage of continuous studio lighting.

So what is Modeling Mode? Well, according to the Canon manual; when the camera’s depth-of-field preview button is pressed, the flash fires continuously for 1 second. It enables you to see the light casted on your subject and most importantly the shadows produced in addition to the lighting balance during wireless flash shooting.

What is really neat is also the fact that you can use this feature when using your flash as master in wireless shooting. This is achieved through the test flash button instead of the depth-of-field preview button. You can refer to Canon manual custom function C.Fn-02 on page 95 to see how to customize this functionality in master / slave modes.


  • To avoid damaging your flash head due to overheating, do not fire the modeling flash more than 10 times continuously. After firing it 10 times continuously, allow it to rest for at least 10 minutes.
  • If the modeling flash is fired more than 10 times continuously, the safety function may activate and restrict flash firing. If this happens, allow a rest time of at least 15 min.


  • Modeling flash is not possible with EOS REBEL 2000/QD, EOS 300/QD or a Type-B camera.
  • Although possible in slave mode, modeling flash is not possible from a slave unit with cameras released up to 2011.
  • Modeling flash is available on the following Canon speedlite units: 600EX-RT, 580 EX-II, 450EX-II (I know because I have read all three manuals)