20D and 580ex dark images

[mchivers]

been taken taken some photos today with the above camera and flash.some have come out very well but some(mainly indoor shots)have come out dark.camera is set on program mode.our other camera and flash has a similar problem(10d and 420ex).

the flash is going off but obviously not at the correct time.

thanks in advance

martin

[mchivers]

any ideas at all?

[rent]

please post a sample and exif. -alex

[mchivers]

File Name
202_0271.JPG
Camera Model Name
Canon EOS 20D
Shooting Date/Time
5/28/2005 1:11:59 PM
Shooting Mode
Program AE
Photo Effect Mode
Off
Tv( Shutter Speed )
1/60
Av( Aperture Value )
4.0
Metering Mode
Evaluative
Exposure Compensation
0
ISO Speed
100
Lens
17.0 - 40.0 mm
Focal Length
40.0 mm
Image Size
2336x3504
Image Quality
Fine
Flash
On
Flash Type
External E-TTL
Flash Exposure Compensation
0
Red-eye Reduction
On
Shutter curtain sync
1st-curtain sync
White Balance
Auto
AF Mode
AI Focus AF
Parameters
Tone Curve Standard
Sharpness level 0
Color tone Normal
Noise reduction
Off
File Size
1929KB
Custom Function
C.Fn:00-0
C.Fn:01-0
C.Fn:02-0
C.Fn:03-0
C.Fn:04-0
C.Fn:05-0
C.Fn:06-0
C.Fn:07-0
C.Fn:08-0
C.Fn:09-0
C.Fn:10-0
C.Fn:11-0
C.Fn:12-0
C.Fn:13-0
C.Fn:14-0
C.Fn:15-0
C.Fn:16-0
C.Fn:17-0
Drive Mode
Single-frame shooting

[robertwgross]

Ha! You fell into the standard wedding photography trap.

What is the dominant item in the photo? The white dress.

What did the camera do? It made the exposure right to make the dress look gray. That is what it is supposed to do, oddly enough. The camera's metering doesn't know that the dress is supposed to be bright white.

The photographer should have been thinking that this might happen, and he would have fired a test shot to see what the histogram looked like. Well, it is slumped way over to the left. Try it again, and add exposure compensation or else flash exposure compensation to goose it over to the right, possibly so that the histogram data stops just before it hits the right edge.

Otherwise, shoot RAW and you can do some of that after the fact.

---Bob Gross---

[scottbergerphoto]

Bob is exactly right! To make white look white in flash exposure as in ambient exposure, you need 1-2 stops +FEC.
Way to go Bob.

[rent]

ditto. also shooting in RAW might have allowed you to save this shot in post process. -alex

[robertwgross]

Way to go Bob.

I've been down that road before.

It took me until about halfway through my first wedding shoot to learn that.

---Bob Gross---

[glangston]

The B&G's expressions might be good for an out-take but it doesn't seem likely to be a keeper. Maybe they knew how grey the dress was looking.... :)

Thanks for the example and the explanation of the fix for this situation.

[Mike H]

...
Otherwise, shoot RAW and you can do some of that after the fact.

---Bob Gross---

If you're going to use flash, you absolutely should shoot RAW, even if you learn to compensate for automatic metering pitfalls. RAW gives you more ability correct for faulty exposures. There will be many faulty exposures using automated flash metering, especially if you don't use flash often enough to be able to spot the potential problems and correct as Bob does.

The same problem (metering off of white and getting underexposure) exists with non-flash photos. Yet, the problem seems worse with flash shots. I don't have a good explanation for that. I do know that the metering systems are different for flash and ambient light photos. My best guess is that the reading is more heavily weighted on the auto focus point for flash metering, so if that point lands on something white (or black) you're cooked.

There is a custom function with the 1D Mark II and (I think) the 20D that will allow you to change the flash metering pattern to center-weighted. A few people have claimed better results with the camera set up that way.

Mike H

[mchivers]

thanks for the response guys.why does it also turn out dark even if its a photo without the bride in it.

[rafiki]

When I brightened up your picture it was also evident that it would have benefitted from a bounced flash because there are hard shadows of the couple on the wall behind.

[LiquidDye]

Another trap you might fall into is even if you have allowed for exposure/flash compensation is if you need to shoot quickly/instantly after a shot and the flash hasn't completely re-charged it puts out a half powered burst and if you haven't checked cos you're in a rush.

[tim]

I always shoot RAW, and it really helps. I took a wedding photo before the flash was ready, the shot was 3 stops underexposed at ISO200, with EC+3 in CS2 RAW the shot was salvagable.

[photography By Evangelos]

I hate to tell ya but you need to manually control the camera and the flash. Program mode just will not cut the ham with digital!! This is ware your level of skills comes in to play. Try it next time in manual mode and bump up the flash a bit. Also ISO 100 may have not been the best bet in Auto mode. Better luck next time. I shoot the 20D with the 580EX all the time at my weddings and it is wonderful.

Angelo

[triangle]

Even if that shot came out, what was the bride making that face for? :rolleyes:


I will be attempting a wedding in a few months with the same set-up (different lens), is it best to shoot in M? Also, I have read several times about the preferable shooting in Raw for weddings. If that is the case, do I need to set custom white balance at all?

[scottbergerphoto]

My best guess is that the reading is more heavily weighted on the auto focus point for flash metering, so if that point lands on something white (or black) you're cooked.

There is a custom function with the 1D Mark II and (I think) the 20D that will allow you to change the flash metering pattern to center-weighted. A few people have claimed better results with the camera set up that way.

Mike H
There are 2 misstatements here:
1. ETTLII is never AF Point biased. That is the major difference between ETTL and ETTLII. ETTLII is subject based in Evaluative mode. It determines where the subject is by measuring the reflected pre flash and figuring out where the most and least refleted pre flash comes from and then throws out the extreme values in calculating flash output. That's why pictures like the one above usually come out better in ETTLII then they did in ETTL. ETTL is active AF Point biased.

2. ETTLII is never Center Weighted. In Averaging mode, ETTLII takes readings off all the flash sensors equally and gives an output based on the average of all the sensors. There is no overweighting to the center sensors. You can accomplish this in ETTL by switching to Manual Focus.

[robertwgross]

Another trap you might fall into is even if you have allowed for exposure/flash compensation is if you need to shoot quickly/instantly after a shot and the flash hasn't completely re-charged it puts out a half powered burst and if you haven't checked cos you're in a rush.

We've probably all made that mistake once.

---Bob Gross---

[robertwgross]

I hate to tell ya but you need to manually control the camera and the flash. Program mode just will not cut the ham with digital!!

Program mode works fine with flash. You just have to be able to finesse it.

---Bob Gross---

[PacAce]

I hate to tell ya but you need to manually control the camera and the flash. Program mode just will not cut the ham with digital!! This is ware your level of skills comes in to play. Try it next time in manual mode and bump up the flash a bit. Also ISO 100 may have not been the best bet in Auto mode. Better luck next time. I shoot the 20D with the 580EX all the time at my weddings and it is wonderful.

Angelo
Are you referring to manual mode for the camera or the flash? Or both?

[mchivers]

bump the flash up a bit as bob said earlier.bounced the flash off two plant pots,two walls and a mirror and came up with this.

still struggling to attach files!!!!

[Mike H]

Thanks for the clarifications, Scott. I had forgotten about the E-TTL/E-TTL2 changeover.

The flash metering system is basically a sophisticated guessing game on the part of Canon about what will work in typical situations. The ambient metering systems are also making educated guesses, but they tend to be more successful because there are fewer variables to guess about. That's why I love incident meters so much. :-)