Flash goes off but photo is dark

[Lorilou]

Hi there!  I'm sure this question must have been asked before, but couldn't find it during a quick search.  I have a T3i that's about 18 months old. Just about a month ago, the flash started doing strange things. One picture would be fine, but the next and subsequent shots are dark, even though the flash DOES flash. An example from tonight is shown below.  I've cleared all the settings, used a new memory card, checked my lens to make sure it's on autofocus.  Originally I blamed the battery because it would no longer hold a charge, so I bought a new one. No change. I'm stumped...  Any ideas?

[Skirball · Accepted solution]

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@Lorilou wrote:

 One picture would be fine, but the next and subsequent shots are dark, even though the flash DOES flash.

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That brings up an interesting point, and I'm not sure the answer.  My first thought was that it's not a recycling issue, because you said that it does flash, and it wouldn't do so if it was recycling.  But that said, I'm not sure how the flash functions with eTTL in a low battery situation.  When shooting in eTTL the camera first fires a pre-flash, measure how much light it needs, then the actual flash.  I'm not sure how the camera would react if it doesn't have enough energy for the full flash, but it makes sense that it would fire the pre-flash if it had enough energy, since it won't know how much energy is required for the actual flash until it tests it with a pre-flash.

I'm assuming you're using the flash on the camera, which means it's pulling energy from the same source it uses to power the camera.  So I'm sure there's a large recycle time.  The more I think about it, the more I think the above scenario is exactly what's happening.  Battery wear certainly would affect it, as would the conditions you're shooting in and the camera settings.  The darker the room and/or camera settings (e.g. fash shutter speed, small aperture, low ISO) the more the flash needs to compensate, and thus more power it needs.  I'd guess that the camera battery can't provide very many full power flashes.

If you're frequently using flash for your photography I would highly, highly recommend an external flash unit.  You could pick up a Yongnuo 565EX for under $100.  External units provide you with much more flexibility, better quality light, more power, more flashes, faster recycle time, and it doesn't take energy from your camera battery.  If, eventually, you decide to try "off-camera flash", you would see a significant improvement in the quality of your food photography.

[hsbn]

the flash needs time to recycle. Slow dow a bit between flash.

[Lorilou]

Yes, I've been reading that. But the thing is, it didn't used to do that. I use the camera mainly for food photos, so it always takes a moment or two to reposition between shots - maybe five to ten seconds? This is something that just started happening in the last month or so, even though I'm using the camera exactly like I was before.

[Lorilou]

I guess I should also add that I live in Costa Rica, on the ocean. I wonder sometimes if the heat and humidity can mess with the camera - it messes with everything else!!!  I plan to have it cleaned when I visit California in a few weeks.

[Skirball · Accepted solution]

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@Lorilou wrote:

I guess I should also add that I live in Costa Rica, on the ocean. I wonder sometimes if the heat and humidity can mess with the camera - it messes with everything else!!!  I plan to have it cleaned when I visit California in a few weeks.

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Humidity can absolutely reek havoc on electronics, as you no doubt know.  Unfortunately the Rebel series doesn't offer any sealing from humidity.  I would highly recommend taking a few basic steps to minimize risk from humidity.

Extreme temperature changes (e.g. going from an air conditioned room to outside in hot humidity, and vice versa) is a great way for that hot moist air to find its way inside the camera and eventually condense.  Whenever possible I'd keep the camera in a soft camera bag and let it adjust to the ambient temperature before taking it out.  I'd keep silica packs in the camera bag, and lots of lens clothes to wipe it down frequently.

[Skirball · Accepted solution]

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@Lorilou wrote:

 One picture would be fine, but the next and subsequent shots are dark, even though the flash DOES flash.

---

That brings up an interesting point, and I'm not sure the answer.  My first thought was that it's not a recycling issue, because you said that it does flash, and it wouldn't do so if it was recycling.  But that said, I'm not sure how the flash functions with eTTL in a low battery situation.  When shooting in eTTL the camera first fires a pre-flash, measure how much light it needs, then the actual flash.  I'm not sure how the camera would react if it doesn't have enough energy for the full flash, but it makes sense that it would fire the pre-flash if it had enough energy, since it won't know how much energy is required for the actual flash until it tests it with a pre-flash.

I'm assuming you're using the flash on the camera, which means it's pulling energy from the same source it uses to power the camera.  So I'm sure there's a large recycle time.  The more I think about it, the more I think the above scenario is exactly what's happening.  Battery wear certainly would affect it, as would the conditions you're shooting in and the camera settings.  The darker the room and/or camera settings (e.g. fash shutter speed, small aperture, low ISO) the more the flash needs to compensate, and thus more power it needs.  I'd guess that the camera battery can't provide very many full power flashes.

If you're frequently using flash for your photography I would highly, highly recommend an external flash unit.  You could pick up a Yongnuo 565EX for under $100.  External units provide you with much more flexibility, better quality light, more power, more flashes, faster recycle time, and it doesn't take energy from your camera battery.  If, eventually, you decide to try "off-camera flash", you would see a significant improvement in the quality of your food photography.

[Lorilou]

I'm thinking we're on the right track. Just confused about why it didn't do this for the first 12 months of ownership. I was using it in exactly the same way for the same purposes.  And once I got my new battery, it didn't solve the problem.

Most of the time, I'm shooting in close-up mode (the flower icon). I have an outdoor setup for most of my pictures, so it only does this in the evenings, and all indoor lights are on. I guess I better start learning manual mode!    I definitely agree with you that an external flash is in order. I'll pick one up on my next trip to the Motherland! And go to an SLR bootcamp... 

Thank you so much for your help!!!  Blessings...

[houseofcharm]

Hi all, in a thread-surrection, I have a t5i doing the same thing as in the OP. It's gettimg more frequent also and I'm in FL though the camera is almost always in doors. And on occasion, the flash overflashes and whites out the image. Any new info on this problem since the last posting? Thanks!