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

Started Jan 10, 2013 | Discussions
Glenn Veteran Member • Posts: 7,893
Re: How much light does CNTL flash "spill" into scene?

This flash is set off wirelessly. It should work but it might cast a shadow of the lens with the ring on it if you don't filter out the visible light in a macro situation. It would be interesting to try it might not male any diference depending on the angles.

FramerDave Contributing Member • Posts: 663
Re: sybersitizen is right (again) — the ANSWER

Glenn wrote:

William, 1 more quick test for you to satisfy this HSS question. Take your flash and trigger flash into a room with a mirror and shoot a self portrait with and without HSS enabled.

This is what it looks like.. (and by it I didn't mean me)

Without HSS

Wireless without HSS

With HSS enabled

HSS Enabled, Note the main flash is in the exposure and the pop up isn't. The triggering pulse begins and ends entirely before the exposure.

Did a little testing with my A99, F60M as CTRL and F58AM as RMT, ratio set to "-":4:4.

I found that with HSS enabled (which also means no bouncing on CTRL to get HSS), S mode or M mode 1/300 or faster on the A99 I will get same result as aove bottom pic.

I guess if you want shutter speed of 1/250 or slower on the A99, you will have to use the exposed film/IR only method. It was shown here on this forum that if you use F20AM as trigger, the proctective bag works great as light blocker but lets the IR through.

Just for curiousity I tested FEL lock to avoid the lag in above setup and yes, no delay and same results as before. So if your subject is in front of floor to ceiling windows your trigger flash does not have to show up in the picture!

Glenn Veteran Member • Posts: 7,893
Re: sybersitizen is right (again) — the ANSWER

FramerDave wrote:

Just for curiousity I tested FEL lock to avoid the lag in above setup and yes, no delay and same results as before. So if your subject is in front of floor to ceiling windows your trigger flash does not have to show up in the picture!

Just to be clear. Using FEL eliminates the flash delay on wireless in the A99 either at sync or in HSS mode? Or just in HSS?

William will be glad to hear this I'm sure.

William Porter
OP William Porter Senior Member • Posts: 1,730
Re: sybersitizen is right (again) — the ANSWER

Glenn wrote:

Just to be clear. Using FEL eliminates the flash delay on wireless in the A99 either at sync or in HSS mode? Or just in HSS?

William will be glad to hear this I'm sure.

Yes, indeed, I would. So (I suspect) would Gary Friedman.

And I'm wondering also about FramerDave's reference to using a bit of exposed film (or the F20's protective bag) to block the light leak. Why does this work-around keep getting mentioned? Is there really something to this after all — is this really necessary?

It seems to me now (i.e. as a result of what I learned in this thread) that there really is little or no light leak, even when the shutter speed is slow. In my most recent tests, the shutter can be quite slow — 1/60th sec, 1/80th sec — and yet no light from the controller leaks into the scene captured, provided that EITHER (a) the aperture is stopped down sufficiently AND/OR (b) the ISO is low like 100 or 200. In other words, under normal flash shooting conditions. So if one or the other of those settings that most control flash (aperture or  ISO) is set to reduce the camera's "vulnerability" to the flash, then there seems to me to be no need for any "muffler" on the controller.

Or is the muffler necessary in one special circumstance only: to obviate any reflection from the control such as we see in your tests, Glenn, when you're shooting towards a window or mirror? I just did some tests in my dark (late night) kitchen. Using an un-muffled F20AM as control, shooting into a nearly pitch black kitchen, with the F43 pointing down into the porcelain sink, I get this result:

  1. Basically, no light leak from control — an eerie light issues from the porcelain sink, but the kitchen is otherwise pitch dark; but
  2. I do see a very slight specular reflection in the window I was facing when I shot and this has to come from the F20.

My settings were 1/60th sec, f/3.2, ISO 100.

So is the muffler designed simply to help when you're shooting towards something reflective? Or do people still think it's necessary in some other circumstances?

Will

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FramerDave Contributing Member • Posts: 663
Re: sybersitizen is right (again) — the ANSWER

William Porter wrote:

Glenn wrote:

Just to be clear. Using FEL eliminates the flash delay on wireless in the A99 either at sync or in HSS mode? Or just in HSS?

William will be glad to hear this I'm sure.

Yes, indeed, I would. So (I suspect) would Gary Friedman.

I commented on Gary's blog on the delay and he confirmed it already:

Gary L Friedman December 28, 2012:

I hope he does not mind I quoting him here.

philbot Contributing Member • Posts: 846
Re: sybersitizen is right (again) — the ANSWER

I sometimes use on-board flash (A77) to trigger my F58's for portraits at weddings, and up close, you can find the control flash adds a small unwanted extra catchlight to the subjects eyes, but I just put my hand in front of the on-board flash, it still bounces off the ceiling and triggers the slaves, but no unwanted catchlight...

Although these days, I tend to use cheap radio triggers and manual set the flashes for exactly the conditions I want.. Or I bounce the control flash and use that as soft fill light, and use the F58's ratio control to get the more controlled lighting I want..

Glenn Veteran Member • Posts: 7,893
Re: sybersitizen is right (again) — the ANSWER

you hear people talk about it adding a catchlight to the eyes and things, If you want to eliminate that for example. Or if you can't avoid being too close to your subject like in a macro shot where a beetle shell can get a hot spot.

tom Senior Member • Posts: 2,724
I think Minolta/Sony deliberately added the ratio when they went to digital

The old Minolta wireless system for the film cameras had 2 choices.  One was normal wireless where the control flash had almost no contribution (small highlight in reflective scenes).  The second was a 2:1 ratio where the control flash (built in or on camera) added a fill.  Many times the 1st setting resulted in shots like William's photo of the dog with deep shadows.  When shooting portraits the contrast was too much.  If you have an old Minolta manual, they show the effect of direct, wireless with no control contribution, and wireless with 2:1 ratio.  On the example shown, the 2:1 looks much better than the others.

There were also ways to use their wireless controller to set the ratio of two off camera flashes.

The way the 2:1 worked was the lower ratio flash fired first.  When the camera read the off-the-film exposure value met the lower ratio, it shut that flash off and started the main flash which fired until the correct total exposure was met.  When they went to digital, they no longer had off-the-film flash metering and had to rely on preflash metering.  Probably the preflash from the built in couldn't give them the accuracy they needed for the ratio flash so they just dropped that option.

But that would have left them with the non-ratio wireless and its harsh shadows.  For most general users that would have been a problem making wireless essentially useless.  So they added a constant amount of exposure from the controller to fill in the harsh shadows.  That results in better shots for the general user, but takes away control from the specialized user.  For cameras that are designed to appeal to a wide range of users, that was probably the best decision.  More experienced users will try different techniques to get the response from the controller that they want (IR filtering with exposed film - that's what I use, putting a reflector in front of the flash, etc.) or just switch to using radio controls.

Tom

JohnD2000 Forum Member • Posts: 64
Re: How much light does CNTL flash "spill" into scene?

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.

robert614 Senior Member • Posts: 1,563
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

JohnD2000 Forum Member • Posts: 64
Re: How much light does CNTL flash "spill" into scene?

Thanks Robert.  That's by far the clearest explanation I've heard.

William Porter
OP William Porter Senior Member • Posts: 1,730
Re: sybersitizen is right (again) — the ANSWER

Brilliant, FramerDave. I'm very glad to learn of this workaround, which will help me a great deal. About the only time I use multiple flashes is when I'm doing a "formal" portrait and in those situations the subject is pretty much always stationary. I'll give this FEL thing a try.

Of course it would still be great if Sony could fix this problem with a firmware update and I hope they do.

Will

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William Porter
OP William Porter Senior Member • Posts: 1,730
THE ANSWER SUMMARIZED

Okay, thanks to Glenn and philbot for following up.

So, to summarize:

  • "Most of the time" or in "normal flash shooting conditions" the controller contributes a negligible amount of light to the scene as captured, so the wide reports of this being a serious problem are, basically, wrong. 
  • However there are a couple of margin situations where the small amount of light from the controller that's still there when the picture is captured can be a problem, particularly when you're shooting towards something reflective (window, mirror, the back of a beetle).

I put "most of the time" and "normal flash shooting questions" in quotes because I understand these are vague terms with no universally accepted meaning. What I basically mean by "normal" conditions is: (a) low ISO and/or stopped-down aperture; (b) you're not shooting towards a reflective surface; and (c) you're at least five or six feet from the subject.

And as a bonus (not strictly part of my original question):

  • The problem on the A99 of flash lag when triggering remote flashes can be worked around by using FEL.

Thanks to all those who helped me with this one!

Will

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WaltKnapp Forum Pro • Posts: 13,857
Re: How much light does CNTL flash "spill" into scene?

Bart7D wrote:

Actually I had hoped that the control flash would have ended before the actual shutter opening occurred.

Bart

Nearly all the control information is sent to the main flash via a coded flash before the shutter is even open. At least it was with Minolta's protocol. Only the smaller amount of control flash code to turn the main flash on occurs after the shutter opens.  Yes if by having the aperture wide open, the ISO way too high you can make it so the control flash is near the intensity of the main flash thus showing.  But if you are doing that you have abandoned good practice and the aim of the main flash is compromised.

Knowing how expert Sony is at messing things up and that a sony designed flash was used, it's easily possible that Sony got it wrong. But assuming Sony did not mess it up and you had some clue as to how to do flash photography most all the light from the control flash is long gone before the exposure begins and even that is many stops lower than that from the main flash under correctly used conditions.

Remember when you aim that control flash off somewhere else you are messing up the camera's exposure readings too. It's you that's messing up by not understanding the exposure and flash control system and misusing it.

What you need is to learn better how to use wireless flash.  There is a nice intro in how to do it here:

http://www.friedmanarchives.com/flash.htm

How much of the good stuff was lost when Sony switched to it's (video oriented) new (Not) ISO shoe is unknown.  The problems showing up with the a99 say a lot was lost.

WaltKnapp Forum Pro • Posts: 13,857
Re: How much light does CNTL flash "spill" into scene?

sybersitizen wrote:

BTW, the 'huge' amount of light you're seeing from the flash controller is because you're shooting at f/2.8 and ISO 800/1600. Don't do that if you don't want so much extra light in the image. Use normal flash parameters by lowering the ISO and/or closing down the lens.

The "huge" amount of light clearly came as a bounce flash from the main flash pointed up. Note it in the tailing of the exposure on the wall, the sharp cutoff line on the hall floor. Not too surprising the exposure metering system got it pretty close to right on the exposure. That should have been a hint as to what was going on.

Yep, wide open and way excessive ISO is very foolish and wastefull in flash work. Using flash means you don't have to do low light stuff like that.

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WaltKnapp Forum Pro • Posts: 13,857
Re: sybersitizen is right (again) — the ANSWER

William Porter wrote:

sybersitizen wrote:

BTW, the 'huge' amount of light you're seeing from the flash controller is because you're shooting at f/2.8 and ISO 800/1600. Don't do that if you don't want so much extra light in the image. Use normal flash parameters by lowering the ISO and/or closing down the lens.

I would make a bad testing engineer, as this thread proves conclusively. I've been hearing these conflicting claims for a year or two and wanted to see for myself. I opened the aperture up precisely because I wanted to call as much of the "slop" as possible. Bart7D asked if this problem occurred in real life, and I tried to test that — but that test (with my dog) was done with wide aperture and high ISO. Anyway, I posted here hoping for correction. Seemed like the right thing to do. But not everything that seems like a good idea, actually is.

In short, YOU ARE RIGHT.

There is one reason why you might want to use a wide aperture in flash photography, and that is DOF control.  A limited use as in flash photography you are more likely trying to get things to be seen, including in focus.  More likely to want more rather than less DOF.

Can't see any reason to use higher ISO. But then that's true in nearly all photography.

Here's a shot taken in my office, with basically no light other than that supplied by the two flashes. Before I hit the shutter I was sitting in the dark. Aperture is wide (f/3.2) but the ISO is down to 200.

I don't see any light spillage or slop here from the control flash. I would expect to see some light on the near side of the chest of drawers on the right if the control were having an impact and I don't.

It does show how much light can reflect all around off surfaces. And those surfaces reflecting even more.  All part of the complexity of lighting control.

One last question: Why do people keep talking about using a piece of film to cover the triggering flash?

Shows that they are way out of date to still have film around? And probably engage in film thinking rather than digital. (BTW, you can buy synthetic filters that will do the same thing if you are paranoid.)  I have been DSLR digital since the early 90's when the RD-175 came out, no unexposed film or the chemicals around to develop it here. And I tossed all way overexposed shots in film long, long ago.

WaltKnapp Forum Pro • Posts: 13,857
Re: THE ANSWER SUMMARIZED

William Porter wrote:

  • The problem on the A99 of flash lag when triggering remote flashes can be worked around by using FEL.

It is probably a indication that Sony has done some major messing with the Minolta protocols and coding.  It needs to be tested just how far off the reservation they went.

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WaltKnapp Forum Pro • Posts: 13,857
Re: sybersitizen is right (again) — the ANSWER

Glenn wrote:

you hear people talk about it adding a catchlight to the eyes and things, If you want to eliminate that for example. Or if you can't avoid being too close to your subject like in a macro shot where a beetle shell can get a hot spot.

Where Minolta's 1200 macro ringflash with MFC1000 is a good prescription. It does not go funny even at a few mm distance. (not necessarily so for 3rd party ringflashes)

The twin macro can also be set up to deal with a hot spot.

IanML Senior Member • Posts: 1,654
Re: How much light does CNTL flash "spill" into scene?

WaltKnapp wrote:

How much of the good stuff was lost when Sony switched to it's (video oriented) new (Not) ISO shoe is unknown. The problems showing up with the a99 say a lot was lost.

The shoe is a red herring.  It changes nothing as regards flash control.  The four pins for the camera and flash to communicate are still provided to carry the same signals.

The problem with the delay when a shoe-mounted flash is used as controller is due to poor firmware design and slipshod development testing.

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Ian

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Edward Sargent
Edward Sargent Veteran Member • Posts: 4,693
Re: How much light does CNTL flash "spill" into scene?

William Porter wrote:

Edward Sargent wrote:

... it works great on the A77 and A700 but it will not work on the HVLF43 which the OP needs to use on the A99.

Sarge,

Have no plans to buy a ring flash but just curious: Why wouldn't this Metz ring flash work with the A99?

Will

It will, it works wirelessly but has a sync cord option. Which I have used.

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