Plainplane From United States of America, joined Mar 2008, 850 posts, RR: 1 Posted (4 years 10 months 3 days 12 hours ago) and read 4761 times:
I have a Canon EOS 7D and I want to start using it for cockpit shots, and to make them perfectly exposed I want to use an external directional flash that would mount on the top of the camera. The plan is to focus on the outside, while aiming the flash at the overhead panel to bounce back onto the rest of the cockpit for a perfectly exposed shot, a method that I learned about in other forum topics that is supposedly the best way to do it.
How do I determine what flash would better suit this need though? Would something like the fairly inexpensive Speedlite 270EX suffice, or would I need something like this one?
dazbo5 From United Kingdom, joined Mar 2005, 2936 posts, RR: 2
Reply 1, posted (4 years 10 months 3 days 10 hours ago) and read 4736 times:
The 270 might not be powerful enough for your needs and only has mimimal adjustment for bouncing the light. A 7D deserves more really! The guide number (first two digits of the model on Speedlites) gives you an idea of the brightness (effective distance) at ISO100, f/1. The 270 would only give you an effective range of 9ft at ISO200, f6.3 for example or 18ft at ISO400, f6.3. Always go for the most powerful flash you can afford, on the basis that you can always use a powerful flash at 50%, but you can't use a less powerful flash at 150%. Bear in mind you need extra power when bouncing light. I use a 430EX with Stofen diffuser and it's always done what I've asked of it. The 580 might be a bit much for what you need but if you can afford it, go for it otherwise the 430EX II is a good choice and not much more than the 270 if you shop around.