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.

[Solo]

Thanks to everyone for your interest. I've resolved the speedlite issue.

I use low-discharge NiMH batteries and found their performance superior to alkalines.

[amfoto1]

"...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..."

Yes, Canon offers CP-E4 auxiliary battery pack for 550EX, 580EX, 600EX flashes. The earlier versions (CP-E, CP-E2 and CP-E3) all also work fine with any of those flashes. There have been various improvements to the battery packs over the years, but they all put 6 or 8 additional AA batteries at the flash's disposal (the flash still needs to have 4 AAs installed as usual, too). They make for faster recycling and many additional shots.  

I shoot professionally and rechargeable AAs make for a lot of savings, after the initial purchase and setup costs. I don't find it any more of a problem to recharge a bunch of AAs, than I do recharging the LP-E6s (or whatever) that power the cameras themselves. Over the years I've accumulated enough chargers that I can recharge overnight sufficient AAs for a full day's shoot. But I also keep a bunch of alkaline AAs handy, just in case.

***********
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 

[digital]

Good thread. I ased alkaline batteries at one time but when I got more serious with flash my local mom and pop camera shop explained this to me. They also mentioned the Alkalines not only recycle slower but do not have the power low discharge batteries have. That may have been mentioned as well. After getting new rechargeables I never looked back.

Also it is a good idea to get a good quality recharger that conditions the batteries.       

[ebiggs1]

I did speak with two of my full time pro buddies last weekend. Well one was by email. These are guys that make 100% of their income from their camera. It puts groceries on the table. Likely nobody on this forum is in that situation.

One said, "No way." Actually that isn't a direct quote. You can add the explicative. 

But the other told me he had switched.   It was not Eneloop but was some other brand that I have quickly forgot. I'll have to see him again. He said these charge in two hours but will quick charge in an hour.

For now I will stay with my use of regular AA's. I just don't want the extra effort of another thing to keep track of.

Right now I have eight camera batteries to make sure are charged and in good condition. Adding 16-20 AA's to that mix is just something I don't want. Especially when you are talking about pennies. Plus the PITB of making sure you get back home with all of them.

And if you have a malfunctioning flash, like all this started out, I firmly recommend you get a brand new set of regular AA's to make sure it is not the batteries. So, dump the rechargeables.

[Solo]

Interesting, but not surprising to see strongly-held but opposing viewpoints.

I think I will stick with rechargeables. "Chacun a son gout" as we say where I come from.

Solo

[digital]

Yes. I'm going to stick with my rechargeables as well. I keep pack of Alkaline as a backup but never use them. I'm not sure about ebiggs friends asseccment based on everything I have read but I live in an each to his own world. Whatever works for you.    

[VOF]

I have the same problem with my 580 EX and have done similar tests with my flash.  I have multiple flash units and the problem is only with my 580 EX.  Tomorrow I am bringing the flash into the Canon Service Center in Irvine, CA.  I will let you know what Canon claims is the problem when the flash is repaired.

I am a pro photographer for over 40 years and would not hesitate to use my Eneloop rechageable batteries in my Nikon or Canon flash units or any other piece of equipment in which the batteries fit.  I have never had any problems using rechargeables.

[VOF]

I found the problem to my 580 EX underexposure and I hope this helps you if you haven't fixed your problem yet.  I recently brought my camera into Canon for sensor cleaning and after that came a consistent flash underexposure.  Before taking the camera and flash into Canon tomorrow, I decided to go through everything on the camera again.  I discovered that the Flash Exposure Compensation in the camera's menu had been set to -2.  When I set it back to 0, the camera and flash functioned perfectly.  I have a 5D Mark III but your menu cannot be too different from mine.  Find  External Speedlite Control in your camera's menu, look this up in your manual to find where this is in your camera's menu.  Scroll through the various sub menus under External Speedlite Control until you come to Flash Exposure Compensation.  Set this back to zero if it is not already at zero.  Hope this works for you.

[Solo]

Thanks for your interest. I went through the same exercise as you, my settings were fine.

I now get good results, I tend to shoot in manual rather than ettl, sometimes with + flash exposure compensation.

[Skirball]

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@ebiggs1 wrote:

And if you have a malfunctioning flash, like all this started out, I firmly recommend you get a brand new set of regular AA's to make sure it is not the batteries. So, dump the rechargeables.

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Or you could just put another set of rechargables in to check.  It's not rocket surgery.

Your information on rechargables is dated, at best.  NiMH rechargeables offer quicker recycle time, longer lasting, economically cheaper, and creates less waste.   Your claims that it’s ok for the hobbyist, but beneath Pros, is just arrogance.  Do a search for flash battery recommendations and you’ll see evidence of thousands, if not millions, of professional photographers that are using rechargeables without logistic difficulty.  You charge them the night before, put them in a marked case, and it’s no different than pulling out a brand new set of alkalines.