speedlite question

Started 4 months ago | Discussions thread
OP Doug Haag Senior Member • Posts: 2,512
Re: speedlite question

Richard Hopkins wrote:

kli wrote:

It depends on the speedlight. Most of the time, it will be for full frame.

But, as Richard Hopkins stated, sometimes it will be adjusted for a different sensor format based on a custom function in the flash.

For example, my Godox TT350-O, which is for Olympus/Panasonic four-thirds cameras, which use a 4/3"-format sensor with a 2x crop format, there's a C.Fn 43. If I set it to OF, then the widest angle when I pull out the wide angle diffuser panel, displays as 14mm (full frame equivalent FoV). If I set that function to ON, it then displays as 07mm. This is not in the manual, as the feature was added by a firmware update. [eyeroll].

Similarly, on a Nikon SB-900, there is a custom function (C-23) to switch between FX and DX.

Generally speaking, the cameras don't communicate sensor format size to the speedlight, so this setting has to be done explicitly on the speedlight itself. However. Most of us don't bother to worry about the specific mm being used, since that type of field of view coverage, like guide numbers, is really only accurate for direct on-camera flash. Most of us bounce, or do off-camera flash, at which point, the scene coverage you would have had with the flash on-camera pointed directly forward isn't going to matter that much. And the zoom setting on a flash is simply how focused the beam is.

All the setting really does is position the flash tube forward or back inside the head, with the longest "focal lengths" having the tube all the way in the back, and the widest angle (typically 24mm) with the tube at the front, just behind the fresnel panel.

Apologies if this has already been said, but the auto-zoom function only works for direct, on-camera flash.

If you tilt/rotate the head, or remove the flash from the camera, auto-zoom is disabled (as it should be). AFAIK this applies across the board.

Thanks for the clarification even though it doesn't apply for someone like me who almost always uses bounce flash.

But the main reason for this reply is to tell you how much I liked your "Practical Photography" magazine.  I have owned a camera for 63 years and been a serious hobbiest for approximately 50 of those.  Back in the day before the internet, photo mags were my main source of knowledge about techniques, etc.  And Practical Photography was one of my favorites.

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