Jump to content


Photo
- - - - -

Pre Flashes?


  • Please log in to reply
2 replies to this topic

#1 SMY

SMY

    Sting Ray

  • Member
  • PipPipPip
  • 205 posts
  • Gender:Male
  • Location:Germany
  • Interests:photography, diving, hiking in the mountains and everything with an Apple on...

Posted 11 February 2018 - 03:19 AM

Once again I need your support. I read always in flash manuals 'if your camera supports/makes pre-flashes do this or that'.

 

So my question: when does a SLR like Nikon D850 makes per flashes and when not?

 

Thanks and best regards, Sascha


Nikon D850, Nauticam NA-D850 housing, Nauticam TTL-Converter 26308, 2 x INON Z330, Sigma 15mm Fisheye, Nikon 17-35mm, Zen 170 Port, ULCS arms with StiX floats

#2 Pavel Kolpakov

Pavel Kolpakov

    Wolf Eel

  • Industry
  • PipPip
  • 132 posts
  • Gender:Male
  • Interests:UNDERWATER PHOTO

Posted 11 February 2018 - 07:00 AM

Hello Sascha,

 

Camera rates reflected Pre-flash to determine main flash duration, for TTL automatic lighting control.

Pre-flashes are emitted by external uw strobe using TTL-Converter, or by pop-up camera flash. In communication protocol of camera and flash, camera sends special commands regarding Pre-flash beginning and necessary Pre-flash duration.

 

In common case, Nikon sends 2 Pre-flashes of different duration, Canon sends 1 Pre-flash of fixed duration.

 

Yes, user can go to Manual mode (without Pre-flashes) at camera side, switch off Pre-flash camera commands for pop-up flash on both Nikon and Canon systems, very easy, - set M mode in pop-up flash partition of camera menu. Nikon and Canon, both have the same partition in camera menu for pop-up flash control. You can use it, if you have optical synchronization by camera pop-up flash.

But for external land strobes control (or other TTL devices on HotShoe), only Canon can switch off Pre-flash by camera menu directly, Nikon traditionally does it by external devices. That is why Canon TTL-Converters use direct way, - camera command "M" mode" in menu, but Nikon TTL-Converters use indirect path for switching system to M mode by camera menu (for example "Auto FP", or other command), but final result is the same as in Canon system.

 

It makes sense to better switch off Pre-flashes from camera side, if you want to shoot in M mode by your underwater system. 

Shooting in TTL, you must have Pre-flashes anyway, this is camera standard mode. This is necessary for automatic lighting exposure control.


Edited by Pavel Kolpakov, 11 February 2018 - 08:32 AM.

  • SMY likes this

#3 SMY

SMY

    Sting Ray

  • Member
  • PipPipPip
  • 205 posts
  • Gender:Male
  • Location:Germany
  • Interests:photography, diving, hiking in the mountains and everything with an Apple on...

Posted 11 February 2018 - 07:13 AM

Dear Pavel, as always your answers help me a lot, thank you!

Sascha
Nikon D850, Nauticam NA-D850 housing, Nauticam TTL-Converter 26308, 2 x INON Z330, Sigma 15mm Fisheye, Nikon 17-35mm, Zen 170 Port, ULCS arms with StiX floats