Home · Register · Search · View Winners · Software · Hosting · Software · Join Upload & Sell

Moderated by: Fred Miranda
Username   Password

  New fredmiranda.com Mobile Site
  

FM Forums | Canon Forum | Join Upload & Sell

  

Archive 2013 · Fast sync flash Q
  
 
stanj
Offline
• • • • •
Upload & Sell: On
p.1 #1 · Fast sync flash Q


I know in general how high speed sync works. But I still don't know the answer to this:

Given a scene, and a constant aperture, from purely a battery life perspective, am I better off with 1/500s at ISO 400 or 1/1000 at ISO 800? Solely flash battery life.

Thanks for any insights!



Feb 28, 2013 at 05:45 PM
gpop
Offline
• • •
Upload & Sell: On
p.1 #2 · Fast sync flash Q


I don't know, but I'd guess it may have to do with the batteries used, and how they react to different rates of power draw. but again, I don't know.

interesting question.



Feb 28, 2013 at 06:18 PM
AmIgone
Offline
• •
Upload & Sell: Off
p.1 #3 · Fast sync flash Q


Well Iím guessing 1/1000 @ 800 would use less juice. At 1/500 you be pulsing more, with more output do to the ISO 400.


Feb 28, 2013 at 06:41 PM
RobDickinson
Offline
• • • •
Upload & Sell: Off
p.1 #4 · Fast sync flash Q


Aye.

Longer shutter time to have to pulse over + twice as much light needed.



Feb 28, 2013 at 07:43 PM
stanj
Offline
• • • • •
Upload & Sell: On
p.1 #5 · Fast sync flash Q


RobDickinson wrote:
Aye.

Longer shutter time to have to pulse over + twice as much light needed.


Yes but only half the power or you would over expose by a stop.



Feb 28, 2013 at 07:54 PM
 

Search in Used Dept. 



RobDickinson
Offline
• • • •
Upload & Sell: Off
p.1 #6 · Fast sync flash Q


hmm 1/1000th ISO 800 is 2 stops more sensitive than 1/500th ISO 400 already...


Feb 28, 2013 at 08:47 PM
Cicopo
Online
• • •
Upload & Sell: Off
p.1 #7 · Fast sync flash Q


I may be wrong but I think the real answer will depend on whether or not the flash had to fully discharge to properly light the scene. It's my understanding that we basically charge up a capacitor which discharges into the strobe, and if all that energy is used you re start from scratch. Shooting something distant will require all the power, while something close may not. If the capacitor retains part of it's charge it will require less energy (battery power) to rebuild to full charge again.


Feb 28, 2013 at 08:55 PM
stanj
Offline
• • • • •
Upload & Sell: On
p.1 #8 · Fast sync flash Q


RobDickinson wrote:
hmm 1/1000th ISO 800 is 2 stops more sensitive than 1/500th ISO 400 already...


I may be completely dense, but can you explain that math? They are identical to me.



Feb 28, 2013 at 09:01 PM
AGeoJO
Offline
• • • • • •
Upload & Sell: On
p.1 #9 · Fast sync flash Q


If there is any difference, it wouldn't be that much from each other, I would say.


Feb 28, 2013 at 09:05 PM
RobDickinson
Offline
• • • •
Upload & Sell: Off
p.1 #10 · Fast sync flash Q


stanj wrote:
I may be completely dense, but can you explain that math? They are identical to me.


Duh your right , need more coffee...



Feb 28, 2013 at 09:12 PM





FM Forums | Canon Forum | Join Upload & Sell

    
 

You are not logged in. Login or Register

Username   Password    Retrive password