Rebel XT with 550ex flash, exposure not correct...

HI,

I have a question about a problem that has been bugging me. I have
experianced this problem even when using a different lense, which I think
happens to be less tham 5.6 at its max.

I am finding that to get a good photo with this flash on the xt that I have
to use flash exposure compensation on the camera and over stop it one to two
stops. Then my photos turn out well, if I don't over stop the flash setting
on the camera, then I end up with under exposed photos.

I am shooting people / pets / objects, within a range of say 5 to 20 feet or
so. I seem to get the same results wether I use bounce or have the flash
aimed directly at the subject. I am in rooms with a celing of no more than
9 feet if I am using bounce. I still have to over stop the flash setting on
the camera to get a decent exposure.

Here are a couple photos to show you what I am talking about. Theses
examples were with bounce flash, with Flash exposure compensation set to one
full stop +.

(These are full resloution files)

http://www.dolanhosting.net/jamiedol...es/f562187.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f562187.JPG
(JPEG VERSION)
http://www.dolanhosting.net/jamiedol...es/f692107.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f692107.JPG
(JPEG VERSION)

This one was with flash exposure compensation set to +2 full stops:

http://www.dolanhosting.net/jamiedol...es/f178123.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f178123.JPG
(JPEG VERSION)

I look at these photos, and I dont think the exposure is as good as it could
be on any of them, but when I shot test photos in this same room without
using flash exposure compensation, it was very very clear that the photos
were underexposed.

Thanks in advance for any 'light' you can shead on the situation.

-Jamie

First off, flash compensation is because no all equipment syncs with
all other equip just way it is supposed to and also because sometimes,
you just need to do it. Just because you are using flash comp, doesn't
mean that it is "wrong".

Second, fix the dog's freaking eyes. I think you shot so much flash
they poor things eyes went in different directions -- just like in the
cartoons.

Third, some of the highlights look like they are on the verge of being
blown out, so you definately don't want more flash.

Fourth, the higher flash is allowing higher f-stop, so your focus is
better so the pic looks better.

Fifth (booze?), if you aren't adjusting the camera and just the flash,
I believe the camera will then "correct" the exposure. That's why it
isn't blowing things out, too bad. It is just giving you a bigger
f-stop. Try setting the flash to normal and setting the camera to
overexpose by one stop. That might work better.

Sixth, what color is your ceiling.

Seventh, put a card on the flash to give some highlight to the eyes.

Eighth, fix those damn eyes. They're freakish.


Jamie Dolan wrote:
HI,

I have a question about a problem that has been bugging me. I have
experianced this problem even when using a different lense, which I think
happens to be less tham 5.6 at its max.

I am finding that to get a good photo with this flash on the xt that I have
to use flash exposure compensation on the camera and over stop it one to two
stops. Then my photos turn out well, if I don't over stop the flash setting
on the camera, then I end up with under exposed photos.

I am shooting people / pets / objects, within a range of say 5 to 20 feet or
so. I seem to get the same results wether I use bounce or have the flash
aimed directly at the subject. I am in rooms with a celing of no more than
9 feet if I am using bounce. I still have to over stop the flash setting on
the camera to get a decent exposure.

Here are a couple photos to show you what I am talking about. Theses
examples were with bounce flash, with Flash exposure compensation set to one
full stop +.

(These are full resloution files)

http://www.dolanhosting.net/jamiedol...es/f562187.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f562187.JPG
(JPEG VERSION)
http://www.dolanhosting.net/jamiedol...es/f692107.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f692107.JPG
(JPEG VERSION)

This one was with flash exposure compensation set to +2 full stops:

http://www.dolanhosting.net/jamiedol...es/f178123.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f178123.JPG
(JPEG VERSION)

I look at these photos, and I dont think the exposure is as good as it could
be on any of them, but when I shot test photos in this same room without
using flash exposure compensation, it was very very clear that the photos
were underexposed.

Thanks in advance for any 'light' you can shead on the situation.

-Jamie

I have a question about a problem that has been bugging me. I have
experianced this problem even when using a different lense, which I think
happens to be less tham 5.6 at its max.

I am finding that to get a good photo with this flash on the xt that I
have to use flash exposure compensation on the camera and over stop it one
to two stops. Then my photos turn out well, if I don't over stop the
flash setting on the camera, then I end up with under exposed photos.

Looking at the RAW files (camera-produced JPGs are irrelevant in this
regard, the camera has tried to compensate for the underexposure during the
JPG conversion), the "normal" images are underexposed by maybe half of a
stop. Looking at the +2 FEC images, you'd expect to see overexposure
(supposedly being two stops brighter) - but you don't. They're *barely*
properly exposed at best, and realistically, still a little underexposed.
My Rebel XT would have done a much better job, and so would have every
functional Canon body that I've worked with.

I am shooting people / pets / objects, within a range of say 5 to 20 feet
or so. I seem to get the same results wether I use bounce or have the
flash aimed directly at the subject. I am in rooms with a celing of no
more than 9 feet if I am using bounce. I still have to over stop the
flash setting on the camera to get a decent exposure.

This is similar to a problem I saw on one of the original Digital Rebels
(300D) - the camera, with a hotshoe flash, would consistently underexpose
all scenes by about two stops. I tested a number of flashes on the camera,
all tested reliably on other bodies, and the camera would always
underexpose. The body went back to Canon.

Now, that was about two stops - yours are only underexposed by half a
stop, give or take. The interesting bit is that when the flash is set to +2
FEC, the exposure does NOT go up by two stops. Are you setting FEC on the
body, or the flash? Setting it on the body will only affect the onboard
flash, you need to set it on the 550ex. But still, the underexposure is not
typical of that combination of body/flash. You could try ISO 400 or 800 to
rule out a power issue, but since the same is reproducable when you aim the
flash directly at the dogs, that's not likely the problem.

Assuming that the body does a better job of exposure without the flash,
I'd start by trying the flash on a different body, and/or a different flash
on that body, and see what happens. By the way, good job on posting the RAW
files, they're much more certain in diagnosis than JPGs.

steve

Steve Wolfe wrote:
I have a question about a problem that has been bugging me. I have
experianced this problem even when using a different lense, which I think
happens to be less tham 5.6 at its max.

I am finding that to get a good photo with this flash on the xt that I
have to use flash exposure compensation on the camera and over stop it one
to two stops. Then my photos turn out well, if I don't over stop the
flash setting on the camera, then I end up with under exposed photos.

Looking at the RAW files (camera-produced JPGs are irrelevant in this
regard, the camera has tried to compensate for the underexposure during the
JPG conversion), the "normal" images are underexposed by maybe half of a
stop. Looking at the +2 FEC images, you'd expect to see overexposure
(supposedly being two stops brighter) - but you don't. They're *barely*
properly exposed at best, and realistically, still a little underexposed.
My Rebel XT would have done a much better job, and so would have every
functional Canon body that I've worked with.

I am shooting people / pets / objects, within a range of say 5 to 20 feet
or so. I seem to get the same results wether I use bounce or have the
flash aimed directly at the subject. I am in rooms with a celing of no
more than 9 feet if I am using bounce. I still have to over stop the
flash setting on the camera to get a decent exposure.

This is similar to a problem I saw on one of the original Digital Rebels
(300D) - the camera, with a hotshoe flash, would consistently underexpose
all scenes by about two stops. I tested a number of flashes on the camera,
all tested reliably on other bodies, and the camera would always
underexpose. The body went back to Canon.

Now, that was about two stops - yours are only underexposed by half a
stop, give or take.

"The interesting bit is that when the flash is set to +2 FEC, the
exposure does NOT go up by two stops. "

No it isn't. Assume you have the camera set to aperature of A and
speed of S to get an exposure of E (which is an acceptable exposure).
And assume you have the camera on any automatic exposure. If you set
the flash to +2, you then are telling it to provide more light. The
camera is still metering the scene. So the camera then either lowers
the aperature to A-2 or the speed to S-2. This will provide you with a
picture with a brighter subject in the flash area and a darker, distant
background.

If you want to increase the exposure, you have to tell the CAMERA to
increase the exposure by 2 f-stops. That will then tell the flash to
increase it's light.

For true flash compensation (not just increasing the power of the
flash) such as photographing a person in the shadow with a brightly lit
background, you meter the background and set the exposure in manual
mode. Then set the exposure to underexpose by 2 f-stops. Then tell
the flash to overexose by 2 f-stops. That will balance the person and
the background. But it should be in manual mode to work right.

Good luck with it.

Are you setting FEC on the
body, or the flash? Setting it on the body will only affect the onboard
flash, you need to set it on the 550ex. But still, the underexposure is not
typical of that combination of body/flash. You could try ISO 400 or 800 to
rule out a power issue, but since the same is reproducable when you aim the
flash directly at the dogs, that's not likely the problem.

Assuming that the body does a better job of exposure without the flash,
I'd start by trying the flash on a different body, and/or a different flash
on that body, and see what happens. By the way, good job on posting the RAW
files, they're much more certain in diagnosis than JPGs.

steve

Now, that was about two stops - yours are only underexposed by half a
stop, give or take.

"The interesting bit is that when the flash is set to +2 FEC, the
exposure does NOT go up by two stops. "

No it isn't. Assume you have the camera set to aperature of A and
speed of S to get an exposure of E (which is an acceptable exposure).
And assume you have the camera on any automatic exposure. If you set
the flash to +2, you then are telling it to provide more light. The
camera is still metering the scene. So the camera then either lowers
the aperature to A-2 or the speed to S-2. This will provide you with a
picture with a brighter subject in the flash area and a darker, distant
background.

What planet are you living on?

Perhaps things work as you describe under some other camera system, but
that system would be sufficiently badly-designed as to be considered broken.
In the EOS system, when you dial in FEC, the camera does *NOT* alter the
shutter or aperture, those values stay the same, and the flash emits a
greater or lesser amount of light according to the FEC value.

Not only is the scenario you mentioned wrong, it would also be completely
useless. If FEC didn't result in an underexposure or overexposure from the
flash, then it would do no good whatsoever, and all of the people who set
negative FEC to keep fill flash subtle, or positive FEC to overcome backlit
situations would suddenly be in a lot of trouble.

Just because it seems so odd to me that someone would spout as much
incorrect information as you have, I decided to do a sanity check, so I just
threw my flash on my XT, and gave it a try. Yes, I'm right. Dialing in FEC
does, indeed, alter the exposure from the flash. Go try it. Afterwards,
read http://photonotes.org/articles/eos-flash/index3.html , particularly the
section titled "flash exposure compensation".

steve

"Jamie Dolan" wrote in message
. com...
HI,

I have a question about a problem that has been bugging me. I have
experianced this problem even when using a different lense, which I think
happens to be less tham 5.6 at its max.

I am finding that to get a good photo with this flash on the xt that I
have to use flash exposure compensation on the camera and over stop it one
to two stops. Then my photos turn out well, if I don't over stop the
flash setting on the camera, then I end up with under exposed photos.
Jamie,

First it seems that Canon deliberately underexposes flash shots. Why? I
don't know but it's a consistent comment in threads like this.

Second, I flat gave up on my wife's 550ex (she uses very successfully with
her Elan 7ne) and bought a 580ex. I never could get decent results on both
my 300D and 20D with that flash. The 580, and also a 420 I bought in a
pinch, works great but with the FEC set to 0 it still underexposes.

You'll find many threads which will suggest using a manual exposure and
setting the FEC to +1/3 - +2/3 for proper exposure. This is the method I
use for all my indoor flash exposures. I will often just ignore the meter
and set the shutter speed to something around 1/30 - 1/50 (slower the
shutter = more background exposed,) the aperture for desired results and FEC
to +2/3 shoot and then adjust. Your mileage my very... This is what works
for me.

--

Rob
"A disturbing new study finds that studies are disturbing"

First off, flash compensation is because no all equipment syncs with
all other equip just way it is supposed to and also because sometimes,
you just need to do it. Just because you are using flash comp, doesn't
mean that it is "wrong".

ok, This is good to know, because I was assuming that something was wrong
that I was having to use FEC.

Second, fix the dog's freaking eyes. I think you shot so much flash
they poor things eyes went in different directions -- just like in the
cartoons.

I shoot some new photos tonight, and I did a few things differently. They
dogs eyes are much better in the new photos.

Third, some of the highlights look like they are on the verge of being
blown out, so you definately don't want more flash.

I saw that, but I also noticed that areas of the photos where being under
exposed as well.


Fifth (booze?), if you aren't adjusting the camera and just the flash,
I believe the camera will then "correct" the exposure. That's why it
isn't blowing things out, too bad. It is just giving you a bigger
f-stop. Try setting the flash to normal and setting the camera to
overexpose by one stop. That might work better.

I have only been adjusting the FEC on the camera itself, not the flash at
all. Do you mean to try and run the exposure its self on the camera + one
stop?


Sixth, what color is your ceiling.

The celings in the rooms I have been usings are While, or very slightly off
while, matt.

Seventh, put a card on the flash to give some highlight to the eyes.

Do you mean like a Lumiquest 80/20? I have one, and I got it out and tried
it on some new photos...

Eighth, fix those damn eyes. They're freakish.


I got out the lumi quest, Set the FEC to 1+ and I got out a 4 foot gold
reflector that I have. I used these things together and I think that the
photos turned out better..

I am processing the new photos right now (RAW's) on my computer and will
upload them shortly, and then I will make a new post containing the photo
links...

Thanks for the help,,

jamie









Jamie Dolan wrote:
HI,

I have a question about a problem that has been bugging me. I have
experianced this problem even when using a different lense, which I think
happens to be less tham 5.6 at its max.

I am finding that to get a good photo with this flash on the xt that I
have
to use flash exposure compensation on the camera and over stop it one to
two
stops. Then my photos turn out well, if I don't over stop the flash
setting
on the camera, then I end up with under exposed photos.

I am shooting people / pets / objects, within a range of say 5 to 20 feet
or
so. I seem to get the same results wether I use bounce or have the flash
aimed directly at the subject. I am in rooms with a celing of no more
than
9 feet if I am using bounce. I still have to over stop the flash setting
on
the camera to get a decent exposure.

Here are a couple photos to show you what I am talking about. Theses
examples were with bounce flash, with Flash exposure compensation set to
one
full stop +.

(These are full resloution files)

http://www.dolanhosting.net/jamiedol...es/f562187.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f562187.JPG
(JPEG VERSION)
http://www.dolanhosting.net/jamiedol...es/f692107.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f692107.JPG
(JPEG VERSION)

This one was with flash exposure compensation set to +2 full stops:

http://www.dolanhosting.net/jamiedol...es/f178123.cr2
(RAW VERSION)
http://www.dolanhosting.net/jamiedol...es/f178123.JPG
(JPEG VERSION)

I look at these photos, and I dont think the exposure is as good as it
could
be on any of them, but when I shot test photos in this same room without
using flash exposure compensation, it was very very clear that the photos
were underexposed.

Thanks in advance for any 'light' you can shead on the situation.

-Jamie

Looking at the RAW files (camera-produced JPGs are irrelevant in this
regard, the camera has tried to compensate for the underexposure during
the JPG conversion), the "normal" images are underexposed by maybe half of
a stop. Looking at the +2 FEC images, you'd expect to see overexposure
(supposedly being two stops brighter) - but you don't. They're *barely*
properly exposed at best, and realistically, still a little underexposed.
My Rebel XT would have done a much better job, and so would have every
functional Canon body that I've worked with.

Do you think that there is a possiable issue with the rebel XT body?

This is similar to a problem I saw on one of the original Digital Rebels
(300D) - the camera, with a hotshoe flash, would consistently underexpose
all scenes by about two stops. I tested a number of flashes on the
camera, all tested reliably on other bodies, and the camera would always
underexpose. The body went back to Canon.

I saw this exact problem on the origonial rebel, it was far far far worse on
the origonal rebel. It was all over the place in its exposures, under,
over, etc. The problem on the rebel xt is very mild compared to what
happened on the origonal rebel.

Now, that was about two stops - yours are only underexposed by half a
stop, give or take. The interesting bit is that when the flash is set to
+2 FEC, the exposure does NOT go up by two stops. Are you setting FEC on
the body, or the flash? Setting it on the body will only affect the
onboard

On the body.

flash, you need to set it on the 550ex. But still, the underexposure is
not

When I set it on the body, it deffinatly is making a difference,, I didn't
try it on the flash yet, but I can do that..

typical of that combination of body/flash. You could try ISO 400 or 800
to rule out a power issue, but since the same is reproducable when you aim
the flash directly at the dogs, that's not likely the problem.

Assuming that the body does a better job of exposure without the flash,

Day light exposures are very good, no problem at all...

I'd start by trying the flash on a different body, and/or a different
flash

I will have to stop into the camera store to test this...

on that body, and see what happens. By the way, good job on posting the
RAW files, they're much more certain in diagnosis than JPGs.

Thanks,, Thats easy, I have been shooting raw, and doing the conversion on
the computer...

Thanks,
Jamie

steve

"The interesting bit is that when the flash is set to +2 FEC, the
exposure does NOT go up by two stops. "

No it isn't. Assume you have the camera set to aperature of A and
speed of S to get an exposure of E (which is an acceptable exposure).
And assume you have the camera on any automatic exposure. If you set
the flash to +2, you then are telling it to provide more light. The
camera is still metering the scene. So the camera then either lowers
the aperature to A-2 or the speed to S-2. This will provide you with a
picture with a brighter subject in the flash area and a darker, distant
background.

If you want to increase the exposure, you have to tell the CAMERA to
increase the exposure by 2 f-stops. That will then tell the flash to
increase it's light.

For true flash compensation (not just increasing the power of the
flash) such as photographing a person in the shadow with a brightly lit
background, you meter the background and set the exposure in manual
mode. Then set the exposure to underexpose by 2 f-stops. Then tell
the flash to overexose by 2 f-stops. That will balance the person and
the background. But it should be in manual mode to work right.

Good luck with it.

Thanks for the information. I will try this.

Jamie

Perhaps things work as you describe under some other camera system, but
that system would be sufficiently badly-designed as to be considered
broken. In the EOS system, when you dial in FEC, the camera does *NOT*
alter the shutter or aperture, those values stay the same, and the flash
emits a greater or lesser amount of light according to the FEC value.

I would have to say that this is what appears to happen for me when I change
the FEC.

j

Not only is the scenario you mentioned wrong, it would also be completely
useless. If FEC didn't result in an underexposure or overexposure from
the flash, then it would do no good whatsoever, and all of the people who
set negative FEC to keep fill flash subtle, or positive FEC to overcome
backlit situations would suddenly be in a lot of trouble.

Just because it seems so odd to me that someone would spout as much
incorrect information as you have, I decided to do a sanity check, so I
just threw my flash on my XT, and gave it a try. Yes, I'm right. Dialing
in FEC does, indeed, alter the exposure from the flash. Go try it.
Afterwards, read http://photonotes.org/articles/eos-flash/index3.html ,
particularly the section titled "flash exposure compensation".

steve