550EX Speedlite Underexposures

[Ishred2]

Hi, all-
I'm wondering if my new 550EX is broken, or if I'm suffering from some of the problems other users have run into, using the 550 on the D-Reb.

Regardless I read the manual, as well as a bunch of posts (here/other places) that go way back to 2001, discussing how to use the 550 with the D30... then applying that (i think) to my picture taking of people... individually or posed in groups... my pics are mostly (75%) underexposed.

But what's really goofy, is I can take one picture that turns out perfect... and move over about 45degree to the next person to shoot (same distance and lighting... and after waiting for the 'ready lamp' to light) and this next pic will be severly underexposed.

I've set the flash for E-TTL and have tried full auto (green) and "P" mode, with simailr results (Canon 35-70 lens on autofocus. Never tried 'manual focus').

Q: Have there been any RECENT Canon, or other publications... on how to either operate this darn flash properly ...or at least test it? Or has anyone out there had same problem.. and successfully fixed it?

I spent way over what I should've for a flash... and I want to get my money's worth. Am I the only guy too dumb to properly use this thing? (maybe!)

Thanks much...

:?:
Shredder

[robertwgross]

But what's really goofy, is I can take one picture that turns out perfect... and move over about 45degree to the next person to shoot (same distance and lighting... and after waiting for the 'ready lamp' to light) and this next pic will be severly underexposed.


I can't prove this, but there is a strong suspicion in my mind about the ready lamp. I've shot mine too many times when the ready lamp had just turned on, and then I got a half-assed exposure. But, when the ready lamp turns on and then I wait a few seconds more, it seems to work better. This whole condition seems to have something to do with using batteries for too many flash shots, so they are getting weak. In other words, when the batteries are weak, the ready lamp might not mean "really ready".

This is easy to work around by using fresher batteries. During the course of one wedding, I generally rotate through about three new sets of AA alkalines (for the 550EX).

---Bob Gross---

[RichardtheSane]

I've noticed that about the ready lamp....
After a bit of use on one set of batteries if I listen to the whine of the flash I can hear it raising pitch after the lamp has come on, indicating that it is still charging some more. Maybe that is the problem... :)

[Arnie]

Hmmm maybe thats the reason why i always get differently exposed flash shots of the same subject/same composition/same distance taken second/s apart.

[droosan]

I have noticed that the batteries can get very hot. Could it be that they don't work properly if they get too hot?

[Ishred2]

All-
Thanks for the feedback, I'll definitley make sure I wait a bit after the lamp lites 'red.'

BTW: When I experineced this problem, the batteries were fresh out of the box.

And besides the good advice received, so far.... does anyone know the BEST method to avoid problems with underexposure with DREB & the 550?

For example- Are you folks saying that you don't have consistent underexposures... where waiting a bit longer to charge the flash SOLVED your problems?

Re; DREB folks: Are you also avoiding that 'single focus point, narrow exposure metering' the camera does? i.e.; Are you using by multiple/camera selected points and/or all "manual" with the 550?

I've read what some critics deem a slight 'negative' with respect to DSLRs; less forgiving latitude exposure than even slide film. Doe this, combined with what I read is a very narrow exposure ('tiny spot?') metering area inside the DREB, tied to the focus point, make proper flash exposure a tough challenge??

Sorry for all the questions- Just trying to get a good handle in understanidng/operating my new toys! :?

[droosan]

Are you folks saying that you don't have consistent underexposures...


I have a 10D and a 550ex and I don't get consistent under exposure. The 550 is an absolutely necessary part of any job where flash is needed and I need a decent end result. Sure, I make mistakes with it sometimes and blow out things I shouldn't. Being able to review pictures is great.

I've read what some critics deem a slight 'negative' with respect to DSLRs; less forgiving latitude exposure than even slide film. Doe this, combined with what I read is a very narrow exposure ('tiny spot?') metering area inside the DREB, tied to the focus point, make proper flash exposure a tough challenge??

Some of what may be taken as narrow exposure latitude, results from the fact that when you mess with the files your camera produces, you are looking at the picture the camera actually took. If, in the days of film, you were accustomed to messing with prints, you were seeing the pictures AFTER the lab had adjusted the exposure to make the print, that is, AFTER they had attempted to fix what they saw as an exposure problem.

The pictures you take with your digital can be light-adjusted afterwards, too. This is especially true with RAW.

[robertwgross]

I have noticed that the batteries can get very hot. Could it be that they don't work properly if they get too hot?

Batteries have an internal series resistance. Think of that as loss. When you charge up a rechargeable battery, the charger must force current through that resistance, which shows up as heat. If a battery gets too hot during charging, then that is a sign that something is not optimal, but they usually get warm.

When batteries are being used, the power drain into the flash unit must pass through the same series resistance (going the other way). If you are really hitting it hard, then the batteries will get warm again (more power lost as heat). In some cases, this might mean that you are using batteries with a different chemistry as compared to what the flash unit was designed for. In other cases, this might mean that your batteries are getting old and funky.

---Bob Gross---

[droosan]

In some cases, this might mean that you are using batteries with a different chemistry as compared to what the flash unit was designed for.
---Bob Gross---

Now that I think about it: The one case that I noticed the batteries getting extremely hot, and the flash temporarily stopped working properly, was with, I think, those new 'e3' batteries that are supposed to last longer. Could it be that they should not be used with the 550?

[ggustafs]

Hi, all-
I'm wondering if my new 550EX is broken, or if I'm suffering from some of the problems other users have run into, using the 550 on the D-Reb.
...

I've set the flash for E-TTL and have tried full auto (green) and "P" mode, with simailr results ...

:?:
Shredder

I believe the primary problem may be caused by using "auto (green)" or "P" mode with the 550... In the kind of circumstances you are describing (moving from person to person...event-type photography with the 550-EX flash) I believe you should use either "AV", "TV" or manual mode. I have best results when I take some sample photos to get exposure correct and then once I've established that optimal exposure range, I use manual mode.

[robertwgross]

Now that I think about it: The one case that I noticed the batteries getting extremely hot, and the flash temporarily stopped working properly, was with, I think, those new 'e3' batteries that are supposed to last longer. Could it be that they should not be used with the 550?

I don't know what 'e3" batteries are.

Find the package label and tell us (e.g. ordinary alkaline, rechargeable NiMH, primary lithium, or whatever).

I think that just about every type of AA battery can be used in a 550EX flash, but some are better than others. Some batteries are better for high-current (quick usage), and others are better for low-current (long usage). I think the 550EX would classify as a moderately high current load. That is why an old feeble battery will crap out. It will still maintain its voltage somewhat, but it can't keep up trying to produce that much current repeatedly.

If you are really good with a multimeter, you can determine the value of the internal resistance of each battery, and you can tell when they are ready to die. However, with the modest cost of good batteries these days, few bother to fool with them.

---Bob Gross---

[santa]

People that suspect batteries as a problem could try getting an external battery like the Digital Camera Battery or Quantum battery, which would provide a good power source. I've long suspected that many of these complaints are related to battery issues.

[droosan]

Now that I think about it: The one case that I noticed the batteries getting extremely hot, and the flash temporarily stopped working properly, was with, I think, those new 'e3' batteries that are supposed to last longer. Could it be that they should not be used with the 550?

I don't know what 'e3" batteries are.

Find the package label and tell us (e.g. ordinary alkaline, rechargeable NiMH, primary lithium, or whatever).

---Bob Gross---

Sorry, it is e2, not e3. "e2 lithium"

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=243772&is=REG

This shows General Brand but I am pretty sure the type I had were one of the name brands: duracell or energizer.

Thanks for the ideas.

[robertwgross]

The B&H page certainly doesn't say much about it.

If it is AA type, and 1.5 volts, and lithium, then it is a lithium primary battery. So, I would expect long shelf life, high energy density (low weight), and moderately high current output capability.

Something like that usually lasts about 2.5 to 3.5 times as long as an alkaline equivalent.

---B.G.---