Help please - Studio Flash Pics too Dark

Loopy

Loopy

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Hi, sorry but all I seem to do is lurk around the edges and ask for help.

Here goes again.

I have just acquired the interfit EX150 3 head kit and being a 'total' flash novice, I'm having some difficulties. (The phrase 'all the gear - no idea' was penned for me)

Setting the gear up was a doddle, and my first attempt was to be some band photos. The intention was to light from the side and use really harsh flash so that one half of the face was almost in total shadow. However, I'm finding that when I have the flash heads on full power the shots are really dark as opposed to over exposed.
I've followed all the tutorials and set the camera to manual, f8 or f11, 1/60th -1/125th and ISO100. I'm using a 550EX (diffuser on, pointed up) on a 20D to trigger the heads.
When I put the flash heads down to 1/8th of the power the exposure is better so I can live with this and work around it.

I suppose what I'm trying to ask is 'Why does it do this?' Sorry for taking so long to get to the point.

For too long now I have been a point and shoot photographer. Now that I'm trying to really understand all the maths and physics that go with taking a good photo I'm really getting in a twist.

Thanks in advance.
L
:bang:
 
You'll get a lot more useful help with this if you can post an example pic or two to give people an idea where you're going wrong. :)
 
Maybe this will help....

Firstly, the EX150's are "only" 150 watts, so you may find that they're just not man enough. Move them closer to the subject if possible.

If that still doesn't work, wind your ISO up a bit (maybe to 400) and then start opening up the aperture a bit more if required.

If you're shooting a "band", I guess that you're in a largish room and maybe the 150's are a bit too small for the job.

Just an observation.

EDIT: I'm confused over this bit "I'm using a 550EX (diffuser on, pointed up)" I'm not sure what you are trying to do....

Steve
 
Okay, you'll have to excuse me while I figure out how to post a couple of pics.
In the meantime, the heads are definitely triggering (I'm blind). I've just taken 3 pics, all at f9, ISO100, 1/125th. Flash compensation set at 0. The first was at 1/8th of the power and the exposure was ok. The 2nd was at full power and is dark. The 3rd, with just the modeling light and on camera flash was the same as the first (1/8th).
I'm really sorry if I'm missing something obvious and wasting people's time.
Back in a mo
 
Loopy said:
Okay, you'll have to excuse me while I figure out how to post a couple of pics.
In the meantime, the heads are definitely triggering (I'm blind). I've just taken 3 pics, all at f9, ISO100, 1/125th. Flash compensation set at 0. The first was at 1/8th of the power and the exposure was ok. The 2nd was at full power and is dark. The 3rd, with just the modeling light and on camera flash was the same as the first (1/8th).
I'm really sorry if I'm missing something obvious and wasting people's time.
Back in a mo
Click to expand...



So let me get this straight then...

You're saying that you don't alter the camera settings at all, and at 1/8th power the exposure is correct, but on full power they are underexposed ???

If yes, then that's not possible :shake: so something else is wrong, and I'm in favour of them not actually firing at all - OR - (and you can't be this Loopy - Loopy !!!) that you're reading it the wrong way around and that what you think is 1/8th power is actually full power, and vice versa

If not that

No f-in idea :LOL::LOL::LOL:

DD
 
I'm guessing here, I don't use Canon cameras but...

As you're using a hotshoe flash to trigger the heads (never a good idea) I'm wondering whether it's firing a preflash that's triggering your heads before the shutter opens. If that's the case, the only flash that actually counts will be the one from your hotshoe flash.
 
Hi, I did check the dials at the back of the flash heads in case I was being that daft, but the modeling light increases in power when I turn the dial too. The flash is firing otherwise both pics would be the same whether on full or 1/8th power.

Hopefully I've sussed out how to attach pics
 
I'm a novice at this game, but found when I was playing with studio lights that although a hot shoe flash fired the main units it didn't seem to fire them properly. When I used a dedicated flash trigger I got the power I was looking for.

Do the kits come with a wired trigger, have you tried it to discount the above?

Sorry if this is obvious stuff, it's just something I noticed when using flash heads. (y)
 
I've just remembered that I'm going out this evening, so I apologise if I don't reply until later.
Thank you for your help so far.

Just one more... Why's it not a good idea to use the flash to fire the heads. I thought they were designed for this?
 
sorry maddog, put above post before yours appeared.
 
maddog.mark said:
I'm a novice at this game, but found when I was playing with studio lights that although a hot shoe flash fired the main units it didn't seem to fire them properly. When I used a dedicated flash trigger I got the power I was looking for.

Do the kits come with a wired trigger, have you tried it to discount the above?

Sorry if this is obvious stuff, it's just something I noticed when using flash heads. (y)
Click to expand...
That's what I said, it's a classic case of a pre-flash firing the lights before the shutter opens.
 
Loopy said:
I've just remembered that I'm going out this evening, so I apologise if I don't reply until later.
Thank you for your help so far.

Just one more... Why's it not a good idea to use the flash to fire the heads. I thought they were designed for this?
Click to expand...

Because they frequently produce enough light to affect the shot, because a lot of not too well designed cameras (no, of course I didn't mention Canon:LOL:) fire a pre-flash that can't be turned off and because radio triggers do it so much better.
 
I've had a blinding glimpse of the obvious - which is probably wrong but may be worth mentioning...
The likelyhood of the pre-flash setting off the studio flash before the shutter opens is obvious, but leaves the question of 'Why are the pictures darker when the flash is on full power?'
Well, maybe the pre-flash is reading the flash from the studio flash and adjusting the power of the 550EX flash to 'suit'.
Or maybe I't just talking nonsense, I know far more about studio flash than I do about Canon cameras, in fact I know far more about most things than I do about Canon cameras:LOL: Maybe there are some knowledgable Canon users who read this forum?
But whatever the reason, I think the only way you're going to solve this one is to buy a radio trigger or a synch cord with, if you need one, a hotshoe adapter to plug the synch cord into. Maybe there's a photographer in your area who could lend you something to try out?
 
Hi, thanks for the above. I haven't been able to test the synch cable as the ones supplied don't fit the canon directly. (I did ring the supplier before I bought the kit and asked specifically if they would (rolls eyes)) so as suggested I need an adaptor to use them. All part of the learning curve I suppose.

You are all correct about the flash being set off before the shutter was open. I've used the built in flash to trigger the studio heads and these give the same exposure regardless of the power setting on the heads. So your explanation of why the shots were underexposed on full power using the 550EX makes sense. Thanks - this was the bit I couldn't get my head around.

As a final test I took a couple of shots with an exposure of 1 second and fired the flash manually, once on full power, then on 1/8th. Bingo. This gave the exposure I had expected if the flashes had fired as they should have.
So, until I can get hold of an infra-red trigger it's still life for me.

Can I just say thanks again to everyone who's contributed. I started knowing next to nothing about studio flash and I feel a whole lot more educated now. All that remains is for me to produce some acceptable pics.
(y)
 
Glad that's sorted then. I strongly recommend that you get a radio trigger, much better than infra red or a synch cord.
But, if it's any help I've got one of those hotshoe gizmos that you can plug a synch cord into. I'll never use it again so if you want it just PM me with your address and I'll put it in the post
 
Thanks Garry, will do.

I realise that I'm changing the original subject of the thread, but why are the radio triggers better than the infra red. This is all new to me obviously as I thought that using the flash as a trigger was the chosen way.
 
Loopy said:
Thanks Garry, will do.

I realise that I'm changing the original subject of the thread, but why are the radio triggers better than the infra red. This is all new to me obviously as I thought that using the flash as a trigger was the chosen way.
Click to expand...
old technology that's been replaced by something much better.
Basically infra red is just like a TV remote - very short range and it needs line of sight to work. That isn't strictly true because the waves can bounce around a bit, but if your flash head is behind you, or behind the subject then you really will run into problems of them not seeing the signal and not firing. And some of them take a long time to recharge between shots, unlike radio triggers which always take less time than the flashes to recharge.
 
DiddyDave said:
So let me get this straight then...

You're saying that you don't alter the camera settings at all, and at 1/8th power the exposure is correct, but on full power they are underexposed ???

If yes, then that's not possible :shake: so something else is wrong, and I'm in favour of them not actually firing at all - OR - (and you can't be this Loopy - Loopy !!!) that you're reading it the wrong way around and that what you think is 1/8th power is actually full power, and vice versa

If not that

No f-in idea :LOL::LOL::LOL:

DD
Click to expand...

One possible explanation for the pics being darker when using full power is that the capacitors in the strobes are being completely discharged and thus require more charging to reach the ready state again. Using 1/8 power requires less charging and may, indeed, leave the capacitors with enough charge for another shot straight away. The time between pre-flash and main flash is not enough for the capacitors to recycle at full power, but the remanent charge at 1/8 power could allow the strobes to fire.

One little trick is to hit the 'splat' button to do an FEL and wait for the strobes to recycle before taking the shot. This will effectively separate the pre-flash from the main flash (of the 550, that is).
 
mr_pants said:
Using 1/8 power requires less charging and may, indeed, leave the capacitors with enough charge for another shot straight away. The time between pre-flash and main flash is not enough for the capacitors to recycle at full power, but the remanent charge at 1/8 power could allow the strobes to fire.
Click to expand...

Hi, thanks, but that wouldn't explain the dark pics when I took a shot on full power straight after 1/8th.

I think I'm sorted. Just need to find the correct radio trigger now.

If the jack plug is the right size for the head, can I use any manufacturer or will I need to stick to interfit?
 
Loopy said:
Hi, thanks, but that wouldn't explain the dark pics when I took a shot on full power straight after 1/8th.
Click to expand...

Often, the pre-flash of the on-camera unit causes the optical slave of the strobe to trigger. The time lag between the pre-flash and main flash is so short that it is often not noticeable. When the main flash of the on-camera unit fires, it is asking the strobes to fire again. At full power, the strobe capacitors will be fully depleted and will not be able to provide enough power to fire the strobe (indeed, as the charge has not reached the point it should be at, the strobe won't even attempt to fire). At 1/8 power, the strobe could well have enough charge left to fire again so quickly.

As an experiment, it's worth trying the FEL button (which should trigger the strobes) and waiting for the strobe to recycle before taking the shot. This should work, at the expense of being a little clunky. Another alternative might be to put the 550 into manual, which should avoid a pre-flash altogether.
 
Right. I'll give that a go when the New Year hangover wears off.
Thanks
 
Loopy said:
Right. I'll give that a go when the New Year hangover wears off.
Thanks
Click to expand...
I wouldn't bother if I were you - flashes don't even start to recharge in 1/5000th of a sec at any setting.
Your hotshoe adapter is on the way, will post in the morning.
 
mr_pants said:
At full power, the strobe capacitors will be fully depleted and will not be able to provide enough power to fire the strobe (indeed, as the charge has not reached the point it should be at, the strobe won't even attempt to fire). At 1/8 power, the strobe could well have enough charge left to fire again so quickly.
Click to expand...
The significance is that it simply doesn't work. I've tested this theory with 2 flash heads, an Elinchrom Style 1200, a Lencarta ElitePro 300, and an Elinchrom 101 Rapid (incredibly fast recyling) generator unit and none of them had any residual power after firing them at reduced power, nor were they able to fire again immediately after being fired.
If you know of a flash head or a flash generator that it does work with, please let us know.
 
Garry Edwards said:
The significance is that it simply doesn't work. I've tested this theory with 2 flash heads, an Elinchrom Style 1200, a Lencarta ElitePro 300, and an Elinchrom 101 Rapid (incredibly fast recyling) generator unit and none of them had any residual power after firing them at reduced power, nor were they able to fire again immediately after being fired.
If you know of a flash head or a flash generator that it does work with, please let us know.
Click to expand...

Thanks for explaining that. My experience with studio strobes is limited. I thought that they might operate a little like speedlights, but I seem to be wrong on that count.

However, for completeness, I thought that you were referring to the latter part of my post, where I suggested using FEL first and waiting for the strobes to recycle. AFAIK, there's no reason why this shouldn't work. I've tried it with a couple of studio strobes and an external flashgun, optically-triggered. It is, indeed, clunky, but a suitable workaround (until a dedicated flash trigger becomes available :D ).
 
Loopy, if you set the 550EX to Manual and a low power output (1/64 or 1/128) then it will trigger your studio flashes just fine as it doesn't preflash then...
 
Richardthesanehas it correct, you need to read the Canon flash bible here

The EX550, 580 Mk1&11 can be set in manual to avoid the preflash and thus trigger your strobes.

Phil
 
:agree:

I used to have this problem using my bowens lights and a 430EX. If you leave the flash to ETTL it doesnt work too well when firing the lights, however set it to manual and to 1/64 then it works just fine.

If I used the PC sync cord then there was never a problem so thats what made me think it was my flash causing the problems.
 
Well, I've just received the adaptor from Garry this morning (thanks) so I'm going to give both a go this afternoon.
Cheers
 
Hi, sorry it's taken so long to post my response.

I've tried all the methods. Setting the flash to manual did work. Sorry Mr Pants I realise that you did say this but it wasn't as idiot proof as how Paulmack put it. Also, and this is where I feel very sheepish, the synch cable does fit directly into the canon body, but it's very tight and I didn't want force it. It was only when I compared the fitting to the adaptor that I had the confidence to use a bit of pressure. So it did do the job - sort of. Garry, do you want me to send it back, or keep a hold of it until someone else needs one?

Anyhoo, these are a couple of the photos I took at the weekend. Only been cropped, no editing yet.

We did 2 sittings. One on Saturday evening with 7 people (3 of whom were desperate to get to the pub) and one on Sunday morning with 3 peeps and a dog. They had to be the shortest photo shoots ever. The studio was set up in a room above a friend's shop, no heating, unwilling subjects. Not good for a first attempt. Fortunately, the first flash setting I used (1/2 power) seemed okay so I rattled off 200 frames in total in the hope of getting maybe a dozen good ones. I think that most were slightly fuzzy because of the shivering.

I realise that there is much room for improvement. Ideally, I would've liked more time to compose the image, focus better and play around with different positions of the flashes etc, but it was so cold. Even so, I learned an awful lot from just a short shoot.

Now that I've figured how to put the actual photo into the thread I'll be boring you with a lot more.

Thanks for all the help (and patience)

CraigScottresized.jpg


HayleyLucyresize.jpg
 
Loopy said:
Garry, do you want me to send it back, or keep a hold of it until someone else needs one?
Click to expand...
I don't need it, so if you could keep hold of it until someone else does...
 
Garry Edwards said:
I'm guessing here, I don't use Canon cameras but...

As you're using a hotshoe flash to trigger the heads (never a good idea) I'm wondering whether it's firing a preflash that's triggering your heads before the shutter opens. If that's the case, the only flash that actually counts will be the one from your hotshoe flash.
Click to expand...
You are correct in every way. The only flash on the subject is the hotshoe flash.That is why the shot is dark when you stop down. I designed and made a preflash eliminator to plug into my studio flash. Canon cameras will always fire two flash`s no matter how you set the camera up. As a matter of interest I purchased a compact camera that fires three flash`s,so it was back to the drawing board. :bonk:
 
Forgot to mention , Remember that Canon state that their max trigger input is 5v. So using your sync socket direct to studio flash is dodgy. My studio flash heads have a trigger voltage of 20v which is iffy.
 
Glad to see you got sorted. It is rather confusing to begin with but when you play about with it you get to find out whats going on in the end.
 
oldfella said:
Forgot to mention , Remember that Canon state that their max trigger input is 5v. So using your sync socket direct to studio flash is dodgy. My studio flash heads have a trigger voltage of 20v which is iffy.
Click to expand...

I thought that the newer Canons were good for up to 250V.
 
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