Canon Flash Issues

Sam

This may not be the best place for this post so if it needs to be mover please do. I posted it here to see if other wedding have experienced this.

The gear in question is a Canon 5D II and a 580 EX. I and the primary have both had similar issues, same gear. While I find it quite normal to continually chimp and adjust the flash settings at events of any kind, I have experienced times where the flash would ether completely blow out the shot or underexpose badly. When a second shot is taken without any adjustments the exposure is fine. Primarily in ETTL mode. Under exposure could be capacitor recharging.

Weddings are so fast paced I don't have time to do a real analysis of what is going on.

Last weekend I shot some SCCA workers, social gathering, etc. with both my 5D II and 7D and the same 580 EX flash. I noticed the same exposure variation with the 5D, but can't remember any issues when using the 7D. While it's difficult to say with any accuracy how many shots the flash is not exposing properly I would guess one out of 15 or 20.

Any ideas??

Sam

ziggy53

Have you reviewed the EXIF information to see if there is a relevant setting difference?

As usual, some example images with full EXIF might help us help you diagnose the issues.

ian408

There are instances when ETTL doesn't work.

As Ziggy suggests, samples and setting info would help immensely.

Sam

ziggy53 wrote: »

Have you reviewed the EXIF information to see if there is a relevant setting difference?

As usual, some example images with full EXIF might help us help you diagnose the issues.

Sorry Ziggy...................I have deleted all of them. But the key here is there were no setting changes at all. The underexposed ones are battery, capacitor charging issues I am sure. But what would make it randomly overexpose is a mystery.

I initially thought that instead of activating a flash power compensation I had activated the flash bracketing, but I no longer think this is the cause.

Sam

tenoverthenose

ETTL by itself will cause a number of fluctuations in exposure even if the camera settings remain the same. That is the bless/curse of ETTL. Beyond that ugly issue, it could be your flash contacts are dirty.

ian408

I would add that you might take several exposures at exactly the same setting with ETTL and get different exposures.

Assuming it's not a ETTL issue, you might have under exposure if your exposures are consecutive with the flash firing at full power. The second may be under exposed if the flash has not fully charged. That could be a function of nearly depleted battery condition. Of course, this can also be the result of the way ETTL works.

Sam

Dirty, DIRTY!!!! Not my gear.

Yes not concerned with the underexposure at all, just the overexposure. If it's just an ETTL quirk, I can live with it.

Sam

ziggy53

Overexposed images can also be caused by a faulty aperture.

Was the same lens used during all of the instances with gross overexposure?
What was the aperture setting?
Exposure mode?
Portrait/landscape orientation?
Flash head orientation? (Straight ahead, bounced, etc.)
Was this a 580EX or 580EX II?

The more you describe the situation and settings the better I can guess about a cause.

mmmatt

What type of metering are you using Sam? I mostly use spot metering. I don't have this problem unless I am right next to a wall I am bouncing off or right in my subjects face with flash forward. It is also important to note that if you focus and recompose you will be metering on that focus point and not on your subject where you locked focus unless you use flash exposure lock.

Flash exposure lock (FEL).

EOS cameras (type A) which support E-TTL also support flash exposure lock when used with EX flash units. This feature lets you lock flash settings in, then optionally recompose the image before taking the final photo. This allows you to adjust the flash settings in certain difficult to meter cases. Canon first introduced FEL in 1986 with their T90 camera and 300TL flash, but dropped the feature with the first EOS cameras. It wasn’t until 1995, with the introduction of the Elan II(E)/50/55 and E-TTL, that FEL made its return.

FEL works by issuing a preflash when the AE lock button or, if the camera has one, when the FEL button is pressed. (on most EOS cameras the AE lock and flash exposure features are tied together, but top of the line EOS cameras have separate FEL buttons which allow you to set AE lock and FEL independently) The camera then stores flash exposure data, biased towards either the current focus point or the central focus point, for a 16 second period or for as long as you keep the shutter release pressed halfway. During this time you can recompose the photo or you can adjust the aperture and shutter speed (overriding AE lock, which is set when you press the AE lock button, if you like). If the flash symbol in the viewfinder flashes then you’re too far from the subject.

FEL is thus useful for taking photos in which the subject is not covered by one of the focus points or photos containing reflective surfaces which can fool flash metering or certain cases in which the subject is moving. It’s also useful for scenes in which you want to bias the flash exposure to something other than the current focus point. A major drawback with FEL is that the E-TTL preflash occurs when the AE lock or FEL button is pressed, which can confuse your photographic subjects who may think that the photograph is already taken.

If you lock focus on a scene and recompose you will likely have poor flash metering, since E-TTL biases flash metering to the current focus point. Use FEL instead to avoid this problem.

Some cameras have a custom function (CF 8 on the Elan II(E)/EOS 50/55 and Elan 7(E)/EOS 30/33/7) which lets you specify whether you want partial metering and FEL tied to the central focus point - the default - or to the active focus point instead. Remember that the flash unit has to be in E-TTL mode for FEL to function, if you have a flash unit that can also function in TTL mode.

Cameras that support FEL:
All type A bodies.

Cameras with separate FEL buttons:
EOS 3, 1V, 1D, 1Ds, 1D mark II, 1Ds mark II, 1D mark II, 1D mark IIN, 1D mark III, 1Ds mark III, 1D mark IV.

Cameras with a button that can be assigned to the FEL function:
EOS 10D, 7D.

Flash units which support FEL with type A bodies:
All EX series flash units.

The T90 and the 300TL flash unit support FEL, but only with each other. Their FEL protocols are not compatible with E-TTL, and so putting an EX series flash unit on a T90 will not give you FEL.

5d's DO have an FEL button, but I personally don't use it. Best is to adjust your focus points, however in really low light only that center point is worth a hoot on anything other than the 1d series

wave01

I will add my bit I have had the same issues with a 550d/T2i and a nissin flash. Take one shot and its blown second shot same settings and its ok.I usually find its the first shot taken with a flash after that its ok

marikris

Hey Sam! I have this issue when I do multiple shots. For example, with the bouquet toss. The first image would sometimes blow out, the second is fine, the third is dark. I figured the 3rd shot is just the capacitor not charged enough, but the first shot blowing out is kind of strange. It's an ETTL thing, I'm sure.

Glort

Have to say I shake my head at all this expensive technology that dosen't work.

I have tried about 4 different 580's on at least half a dozen different camera's and for all their modern technology, none of them were as easy to use or as reliable in exposure as my 20+ yo metz 45's. Set the apeture on camera and flash and forget.

If I ever did update, there is no way I'd be buying a Canon flash, the only things I'd look at would be a TD5 Quantum or a 54 Metz.

aj986s

X2 on checking the contacts, both on camera and flash. I've had similar misfires, but evenutally started noticing the shutter speed varying in the viewfinder; would go from 1/60 flash sync to something else. Was able to see the variations occur while jiggling the flash. Cleaning the contacts helped tremendously.

oceanthrsty

Sam:

I have to ask. Have you ever used your 580 flashes on the PocketWizard TT5 units? If you have, that would explain all your problems.

-Matt

tenoverthenose

oceanthrsty wrote: »

Sam:

I have to ask. Have you ever used your 580 flashes on the PocketWizard TT5 units? If you have, that would explain all your problems.

-Matt

???

oceanthrsty

I ask because if you put a 580EX or 580EX II flash on the Pocketwizard Flex TT5 it will blow it up. Basically causing these exact issues. It starts by causing the flash to intermittently to flash at full power in any mode. Eventually it won't be intermittent. $120 fix from canon. Pocketwizard is aware of this problem. Their claim is that too much strobing inside a sealed housing builds up ozone gas. Causing the flash tube and the metal components to arc and build up carbon. Which can be seen on the edges of the flash tube when disassembled.

Only use the 430EX or 430EX II.

jeffreaux2

I know of two things that can cause this when using ETTL.

- a loose connection with the shoe

or more likely

-Being to quick on the shutter.

I use a seperate button for focus with my thumb and the traditional shutter button is still set up for metering and shutter activation. With that set up it is really easy to see something happening....grab that thumb focus....and then jab the shutter without giving her the half press to meter the shot. The problem is that todays gear is super quick to focus and meter so some of the time you will get a successful shot. Other times you dont.

My advice. If the flash is tight.....remember the half indent for metering.

Kris...

You may be jabbing too quick on the first shot...but the camera "catches up" in metering for the second one.....then the flash cant keep up for the third. Same issue Sam is having I bet.

marikris

jeffreaux2 wrote: »

Kris...

You may be jabbing too quick on the first shot...but the camera "catches up" in metering for the second one.....then the flash cant keep up for the third. Same issue Sam is having I bet.

Jeff, that makes a lot of sense. I can see that happening specially during the bouquet toss, etc, and having to quickly shoot. I will remember to half press first next time.

jeffreaux2

marikris wrote: »

Jeff, that makes a lot of sense. I can see that happening specially during the bouquet toss, etc, and having to quickly shoot. I will remember to half press first next time.

It will meter really quick so you dont have to wait. Just be aware that this can happen and make the mental note that you need to ease tge shutter down rather than jabbing it without thought. It will make all the difference.

And really this can be blamed on us being spoiled to fast gear. If you could never jab the shutter with ettl and get a good exposure then we would all still be in the half press habit. Our good gear can pull it off most of the time, and causes us to break that good habit.

And I can see where this would be more of a problem with a shooter who primarily shoots in manual as we never need the half press unless you are throwing ettl flash into the exposure.