Under exposed with the 580EX

Yesterday I shot a wedding with my 5D and had a 580EX cabled from the hot shoe to a Custom Bracket. I used the 24-105 IS 4 Flash .I shot the flash in ETTL and the camera in Manual
F8 1/60 sec. I has the camera set for 400 speed film.
I also had the flash power supplied with a Battery 1+
The problem I had was most of the photo's were under exposed.
It seemed that when I had the lens zoomed out to 35mm and the flash said 35mm I did not get as good of light exposure as I should have. I was told this flash will do as good as my Quantum T4D, but I am now wondering if that
was true.
I would appreciate any suggestions or tips you can give me to help eliviate this problem
THanks
Ron

Did you check your flash exposure compensation?

Can you post a small sample along original EXIF data?

Did you check your histogram at the wedding to see if your shots were appearing to be coreectly exposed? I always keep the histogram visable in the LCD with the picture so I can monitor exposure. I use the 20D with the 580 flash also. I have found I have to monitor the histogram and adjust the flash compensation for different indoor conditions. Outside has not been an issue so far.

Post an example of course with exif.

But, was your head zooming? When your batteries are low or one has a dead cell (rechargables) the head will not zoom but will fire ETTL no problem.

Was your head zooming with focal length changed? Were you paying attention to that?

The head was zooming with the camera and I was not using any FEC.
Also, my battery 1+ was fully charged. How can I post an example of one of my photo's for you to look at. I don't know a lot about histograms, but I can tell you that the little white lines on the historgram were barely up from the bottom. However , when I looked at the photo in the view finder, they seemed to be ok. Then when I got home and down loaded them to the computer, then was when I was disappointed.
I had the flash pointing directly at whomever or whatever I was going to shoot.

Tip 1: Never trust your viewfinder for exposure.
Tip 2: That's what the histogram is for. As a 5D shooter, you really need to do some reading on exposure and digital cameras. These are the basics. IMO, these are issues with your settings and not the flash.

Read the sticky threads in the photo sharing forums for how to post photos. If we see some examples, we can help.

When shooting weddings, one of the most common problems, is shooting the white gown or light dresses, and underexposing. Aso of concern, is shooting the black tux, and overexposing. This will happen with all flash units, that I have used, unless compensation is used. Watch your histogram! Study exposure!

Can you tell me what the historgram should look like and what I should be looking for?

Mod, Move to Flash Forum?

papathree wrote in post #2772086
I was told this flash will do as good as my Quantum T4D...

As a happy user of QFlash and Canon EX, who gave you that bit of wisdom? All hot shoe flash, by definition, is "fill" flash. Fill flash only. You can't "make" ambient light. Qflash is a parabolic flash head with easily 2-3 times more bounce power than a Canon 580EX.
In a dark scene, a Canon EX (or any hotshoe) illuminates a foreground subject either direct or by bouncing. But it can't make up for really low light; it can't make light nor illuminate a scene. QFlash can make light if you need it too.

You can tell if your Canon EX has sufficient output by putting the camera in Center Weighted Metering Pattern, popping FEL (center of viewfinder) over a subject mid-tone, then exposing the photo with flash. If it looks good, then you just need some E-TTL/FEC tutorials (many good ones here and other places). If it still too dark, you need to raise ISO, slow shutter, or get out the QFlash.

QFlash in Auto Thyristor Mode is not confused by light or dark clothing or scenes with open backgrounds vs. closed ambient backgrounds. Canon E-TTL flash metering behaves in way making it essential master continually "riding" FEC at events. Once a person masters the arcance nature of E-TTL using FEC, it is great. But it can't make light like a QF!

Recently, I've been on lighting hog heaven since I upgraded my QF to the QFlash T5-d-R for $99 and bought a QNexus for $150. Now, my QF behaves 100% as an E-TTL Wireless Slave. I use the 580 over the camera on a Custom Bracket as Fill and the QF on a pole as Main Key light, with E-TTL Ratios of 1:4 +/-.
I did a little write-up for myself on using both together here:
http://postit.rutgers.​edu …FWirelessCanon%​5FETTL.pdf
No guarantees this will make sense to you.
Good luck. Jack

PS: Judging flash exposure by histogram is NOT the same as judging exposure of complex outdoor scenes where scenes have more tones. Flash scenes have few tones, and I have many many good flash exposures that go no where near the the right side of histogram. The best way to judge quality of a flash exposure on a person is open the image in PhotoShop and do a "Facemask Histogram" check on it (Google Will Crockett Facemark histogram). That's how you really tell. Can't do it in camera well.

Thanks for the information Jack,
I have been doing some reading today on reading Histrograms and after looking at the pictures I shot yesterday, most of the information on the graph was on the left side indicating low light. There was hardly any information in the midtone areas. And the right side of the graph, well there was nothing. Some of the shots it did slope up from the left, peak in the middle and then slope down to the right. Sounds like this might be better.
I still don't understand why I could set my QFT4d on auto with my 645AFD and it gives me great pictures (film)
I could set my 5600 HS flash on TTL with my Minolta SlR (film) and get great pictures.
I DIDN'T HAVE TO DO ANY COMPENSATING WITH THESE TWO FILM CAMERAS AT ALL.
Now it sounds like for me to get those same great pictures at a wedding I need to shoot the shot, look at the historgram and decide whether the exposure is ok. If not retake the shot. Sounds like a lot of wasted time that I usually don't have at a wedding.

Uhh, let's take a shot with my opinions shall we...
1. Because 400 ISO negative film has a 1+ stop latitude in developing at the lab and making prints while digital exposure is similar to slides. There is only 1/3 - at most 1/2 - stop tolerance latitude for successfully exposing with slides and digital being able to make good prints. Like slides, digital is unforgiving and intolerant. Think Astia/Provia, not Portra in terms of exposure tolerance. Digital ain't like shooting negative film. The lab did the compensating for you.

2. Becuause old Auto flash was not fooled much by subject tone reflectance and metered fill flash is fooled by reflectance. On Auto, once we got distance and f/stop nailed at an event, we bang away with confidence, changing f/stop as we change flash distance to subject. With matrix meters (film and digital), metering HAS to send out a low power pre-exposure metering flash. Flash is being metered separate from the ambient exposure. But just like camera ambient metering, this flash metering is affected by tonal reflectance from subjects. White dresses, table cloths, etc, lead to under exposure without FEC. That's why "event" Canon Flash users learn to lean on FEC bigtime, just as we use EC on auto exposure cameras.

3. Because QFlash is a better flash system for event work.

The histogram IS a great and wonderful exposure feedback and learning tool on the fly. Truly "the 21st Century light meter." It doesn't slow you down. Having the histogram, along with changing ISO on the fly, and RAW, are conveniences that help kill film quicker for people like us.
I just think you're vexed by No. 1 and No. 2 above; lack of exposure tolerance in digital and Auto vs. metered flash.

Jack

So Jack, you are saying that for my weddings and other events, I am better off to use my T4D or my T2d for a flash rather than using my 580EX. If that is so, I am disappointed in the people who sold me the flash and adapter cord. I asked them about it verse the Quantum flashes since I already had one and they assured me it was more than ample for what I do now.

J Rabin wrote in post #2772938
If it still too dark, you need to raise ISO, slow shutter, or get out the QFlash.

...shutter speed doesn't affect flash exposure...

bieber wrote in post #2776533
...shutter speed doesn't affect flash exposure...

He might have been talking about background exposure (which depends on ambience light) rather than the foreground subjects.