How much light does CNTL flash "spill" into scene?

Started Jan 10, 2013 | Discussions thread
robert614 Senior Member • Posts: 1,404
Re: How much light does CNTL flash "spill" into scene?

JohnD2000 wrote:

William Porter wrote:

robert614 wrote:

Have you adjusted the ratio settings on the on camera controller flash.You can set "ctrl" to "--" so the amount of light it outputs is minimal.I have sold my F43 and F58 flashes so I don't remember exactly how to do it,but I'm sure it's in the manual.

I know how to do it, but I didn't have ratio control turned on in these tests, and unless you turn it on, you can't set the ratio. So how would that matter?

Now that you mention it, though, I'm also not sure I see why the ratio control options include numbers at all, and they do. In ratio control, you can set controller to "--" but also to 1, 2, 4, 8, etc. I haven't shot with ratio control at all yet, although I have wanted to. I'm used to putting the flashes into manual and getting things to work for me that way. I'll have to play with this next.

Will

I'm somewhat embarrassed to ask this, though in my defence I only use optical triggering very occasionally, and usually with just one RMTflashgun. My practice when doing so is to leave ratio control off and adjust the individual levels by moving each flash closer or further away from the subject.

What do the numbers in ratio control mean? I had assumed, and have been told they are power levels (so "1" is full power, "2" is 1/2 power and so on). However, this has always troubled me because a) in tests, it sometimes seems that the flash set to 2 is brighter than the one set to 1, and b) if they were absolute power levels, then wouldnt that mean its not TTL?

Can anyone point me towards a definitive explanation of how ratio control works? The Sony camera and flash manuals have hardly anything to say on the matter.

Hello John,

On page 79 of the HVL-F60M manual they use the example of 4:2:1 for ctrl:rmt:rmt2.They add up all the ratios to get the total flash output for the final image.So in this case 4+2+1=7.With this ratio the ctrl flash will output 4/7th of the total light,with the remote flashes output 2/7th and 1/7th of the total light respectively.

I too thought the higher numbers were representing 1/4 power,1/8 power,etc. with 1 being full power.But the opposite seems to be true.With higher number representing a higher % of the total light in the scene.

I hope this helps you.

Robert

Post (hide subjects) Posted by
tom
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow