Speedlite 580EX II underexposure problem

[Solo]

My speedlite has recently started to produce underexposed photos in E-TTL mode. Compared with previous photos the difference is about 2/3 - 1 full stop.

I have conducted a number of tests using my EOS 40D and a 24 - 105 EF f4/L IS USM lens.

I have used fully-charged batteries in both the camera and the speedlite (both alkaline and NiMH in the flash). I have checked the exposure compensation and flash exposure compensation settings as well as all other camera menu settings and the custom functions in both the camera and speedlite. All is in order and there is no conflict between the camera and the speedlite.

I shoot in RAW and as a test I have taken a number of photos in manual, Tv and Av modes, both without flash and using the camera's on-board flash. All were well-exposed (with no exposure or flash exposure compensation).

I tested the speedlite's recycling time on full power several times - about 5 seconds. So, it seems that the batteries were working well.

I then conducted a number of tests in manual, Tv and Av modes at various shutter, aperture and ISO settings to compare the on-board flash with the speedlite's performance in E-TTL mode. Each of the photos taken with the on-board flash was well-exposed with a good histogram. Each comparitive photo with the speedlite was under-exposed, with a poor histogram and smaller file size. With some experimentation, it was necessary to set a flash exposure compensation of +2/3 to + 1 stop to obtain results broadly comparable to the on-board flash.

However, this workaround did not produce satisfactory results for subject distances greater than 20 feet (speedlite only), even at high ISO and slow shutter speeds. The output of the speeedlite was far too low. These tests were all carried out indoors.

I then conducted tests with the speedlite in manual mode with the output set to full. At a range of shutter speeds, apertures and ISO settings the photos were completely blown out. The same result was obtained with the speedlite in manual and with high-speed sync selected if the shutter speed was at or below 1/250 second (the max shutter speed setting available for the on-board flash).

As a workaround I set the speedlite to manual with high-speed sync and set shutter speeds faster than 1/250 second and

tried exposures at various subject distances. Broadly, the high-speed sync kicked in. I have not yet checked performance at subject distances greater than 30 feet but full exposure was obtained in all the tests so far,(mostly better with flash exposure compensation of -1/3). However, depending on ambient light, autofocus was sometimes impossible.

From these tests, it seems that the camera works well, that the speedlite is able to generate full output and that in manual/high-sync mode it will produce correct exposures with high shutter settings.

Whilst both workarounds - E-TTL mode with flash exposure compensation and manual/high-speed sync - do work, some experimentation is required and both have their drawbacks. There are times when I will wish to shoot with the speedlite in manual but, for the most part, I have been satisfied with the results in E-TTL mode and I wish  to be able to restore my speedlite to full working order.

I wonder if anyone can throw light on the fault (sensor/transistor???) and the remedy.

I am sorry to have provided so much detail but I wanted to avoid unnecessary questions, or solutions that I have already tried. Any help from members who are aware of this problem would be greatly appreciated.

[ebiggs1]

Well...............I don't know if I followed all that but instead of trying different settings I suggest you set the camera back to factory defaults and try again. It is always best to go back to square one instead of trying different settings. You may have something set you forgot about. Go back to default and try again. 

Also, dump the rechargeable batteries and get fresh brand new AA's. Rechargeables in a flash is not a good idea.

[Solo]

Many thanks for the suggestion. I did try that initially, both for the camera and the speedlite. The results were the same.

[Solo]

P.S.  As for batteries, I use Energizer Precision NiMH. Whilst they are rated at 1.2 volts they retain the voltage even as power is used up, which is not the case with alkalines. And recycling is very fast with the NiMH batteries. I remove the batteries when the speedlite is not in use and I've never had an issue with over-heating. Maybe I'm not taking enough photos; need to get out more!

[ebiggs1]

Some Energizer rechargeable AA batteries come built in with what they call “PTC” (built in thermal protection). Once the batteries hit around 25-30 flashes the thermal protection kicks in and limits the battery output.

I do mot recommend rechargeable in any flash. A fresh set of alkaline and/or lithium is best.

[amfoto1]

"dump the rechargeable batteries and get fresh brand new AA's. Rechargeables in a flash is not a good idea."

Sorry, but this is completely incorrect. I've used both extensively and decent quality rechargeable AAs will give you faster recycling and more shots per charge than you'll get with alkalines. I only use alkalines when I just need a few shots... or as a last resort after draining all the 50+ rechargeables I've got (including quite a few of the Energizers). I don't use lithiums because they are too expensive.

Solo, I answered your questions in your other post here.

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM 

[TCampbell]

Do use rechargeables.  AA alkalines will cycle slower (and ultimately single-use batteries are more expensive.)

I prefer Sanyo Eneloops -- these are particularly good if the flash can sit unused for a while between uses.  Eneloops are "Low Self Discharge" (LSD) batteries.  Once charged, they can sit for a full year and still have 90% of the original charge remaining (when you buy them they are actually pre-charged because they are so good about retaining a charge.)

[ebiggs1]

"I tested the speedlite's recycling time on full power several times - about 5 seconds. So, it seems that the batteries were working well."

The problem with using rechargeable on any equipment that isn't working properly, is you never know if it is the device or the batteries. It is the same even when it is the camera that is suspect. The first thing to replace is the batteries with known good ones. 

As a amateur or hobbyists I guess rechargeable are fine but as a pro, who has time to monitor 50+ batteries to make sure they are charged and good? Then keep track of them at a shoot? Not for me and I still do not recommend rechargeable to anybody. I am retired now but even now all my equipment gets brand new batteries at each shoot. Too risky.

[TCampbell]

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@ebiggs1 wrote:

"I tested the speedlite's recycling time on full power several times - about 5 seconds. So, it seems that the batteries were working well."

The problem with using rechargeable on any equipment that isn't working properly, is you never know if it is the device or the batteries. It is the same even when it is the camera that is suspect. The first thing to replace is the batteries with known good ones. 

As a amateur or hobbyists I guess rechargeable are fine but as a pro, who has time to monitor 50+ batteries to make sure they are charged and good? Then keep track of them at a shoot? Not for me and I still do not recommend rechargeable to anybody. I am retired now but even now all my equipment gets brand new batteries at each shoot. Too risky.

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That's why I'd use "low self discharge" batteries.  Once you charge them, you can generally depend on the fact that they'll be fully charged and ready for use (they still maintain 90% of their charge after sitting for a full year).  Regular rechargeables can lose that much just sitting for a day.

The strobe itself is powered by capacitors in the flash.  The batteries build up the charge in the capacitors.  The better the batteries, the faster the capacitors will recycle -- but regardless of how long it takes, once you get the "ready" indicator, the flash is ready to fire.

Alkalines decrease their power output as they drain.  Many (probably most) rechargeable technologies tend to put out a near-consistent power output until they run out of power and then have a huge drop-off in power.  This means rechargeables tend to give you faster recycle times throughout the day (but it also means they can die pretty much without warning... you know it's time to swap your alkalines when it's taking 10-15 seconds for the flash to recycle.)  The point here is that as long as you have fresh replacements ready to go (and you would regardless of if you're using single-use vs. rechargeables) the rechargable batteries tend to give better performance.

I think you might be surprised at the number of pros who rely on rechargeables.  I started stumbling across guys who would give the "what's in my bag" list and found that many of them will point out that they use rechargeable batteries for their strobes and they'll tell you what brand they use (that's how I found out about Sanyo Eneloop batteries, btw.  I had never heard of them before that.)

I use a battery storage caddy ("Storacell" by a Powerpax) and it's designed to let you put batteries into the holder either +tip up or down.  So I put them in with the postive tip facing up when they are charged.  I pull a fresh set of charged cells (I know they are charged because the tip is "up") and then put the dead batteries in tip "down", so I know those are the cells that need to be recharged when I'm back home.    Incidentally... I use a "smart" charger (La Crosse BC1000).  With the smart charger, I can actually charge just ONE battery at a time if I need to (the battery in the Canon GPS is a single AA but most chargers insist that batteries by charged in "pairs" so this gets me around that problem or having to wait to go through 2 batteries before I can recharge them.)  Also you can set the amount of power applied during the recharge.  Fast chargers are stressful on the battery.  If I'm not in a hurry, I set a fairly slow charge rate so that it takes all night to bring them back up... but I can set a charge rate that will bring them back up pretty quickly if I want.

[ebiggs1]

I don't, or I should say didn't, have the time to keep refreshing batteries and go through all the maintenance that they require.

I need batteries that work when I want them and when they die I replace them with new AA's. Plus making sure I get back home with the dead ones. Way more safer to just get new ones and discard as needed.

Like I say if you are a hobbyists or amateur, I suppose rechargeables are OK, I guess. But when I am under the gun, they are not for me and I don't recommend them to others.

I have to admit I have never tried or used Eneloops. Maybe they are better but you still have all the maintenance. I just don't see "busy" pros doing it. Too much wasted effort for pennies. We never used them at Hallmark.

I'll ask around my buddies this weekend and see if I am still in the Dark Ages, or something.

BTW, I do have external battery packs for my old 283's and 285's. They work great. I don't have or even know if Canon makes one for the 580's.