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300D Rebel 550EX flash exposure, inconsistent. Diagnose?

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Anonymous
December 15, 2004 4:00:09 AM

Archived from groups: rec.photo.digital (More info?)

I'm trying to chase down some irregularity in flash photography that
I'm experiencing with my Digital Rebel with the 550EX flash unit.
It's got me scratching my head mightily, but I'm starting to suspect
that the flash unit might be intermittently defective?

Now, the first time I noticed some inconsistency in flash exposure was
at a friend's wedding I was shooting (candids, nothing essential)
where the flash photography wasn't consistent. That time was with the
550EX on the camera's hot shoe, and shooting mostly direct flash.
Since it was my first outing with the equipment I didn't think much of
the inconsistent results.

I recently took the camera on a trip and took a baotload of available
light stuff that all looked fabulous. Shot a lot with the kit lens
and the on-camera little flash and those were always well exposed
too. So, mentally I'm ruling out the camera's exposure metering and
the pop-up flash.

Now, tonight I had a chance to run a couple hundred shots at a
children's christmas party for our community. Indoor setting, low
white ceiling, shooting P mode, at ISO 400 with the kit lens and the
100-300 f/4.5-5.6 IS lens. My 550EX was atop a stroboframe this time
using the Canon off shoe cord I've carried over form my Elan outfit.
Sometimes bouncing off ceiling, sometimes direct.

Regardless of what lens I used, some shots look wonderfully exposed
(like I'm used to with my Elan andd 540EZ flash), while others are
quite underexposed and flat--as though the flash didn't fire at all or
didn't fire enough. Sometimes these are consecutive shots, but it's
not flash recycling time issues.

For instance, here's an example of 2 nearly identically composed
shots. Both are 1/60, f/5.6, same lens, same ISO. The first one
blows chunks, but the other's fine. The unexposed one was shot first:

Flat, and horrible. 235mm zoom.
http://toddh.net/photo/rebel/IMG_6340.JPG

Looks the way god intended. 220mm zoom.
http://toddh.net/photo/rebel/IMG_6341.JPG

I've tried to compare the EXIF data with Irfanview and there's no
discernible difference in the EXIF data there.

I'm starting to suspect that perhaps the flash as the only possible
point of inconsistency.

Questions:
What info does the 300D record in EXIF about the flash's
firing in TTL mode?
Doesn't seem that EXIF in irfanview is giving me anything
useful. One place says the flash fired, another place says it
didn't...on the same photo.

Is there better software for viewing photos with histogram and
EXIF data to compare frames side by side?

Anyone else notice this, or should this flash be sent for some
service?

Or am I simply overlooking bounce errors brought on by teh
stroboframe and need to start eyeing the flash exposure
confirmation light a light better?

Quite puzzled....

--
Todd H.
http://www.toddh.net/
Anonymous
December 15, 2004 7:30:45 AM

Archived from groups: rec.photo.digital (More info?)

This same problem has been posted on a YahooGroups for the 300D, using
the EX flashes. The problem seems to be the flash uses the focusing
point chosen to base its exposure on. So if you are focusing on a dark
area, the flash will give more exposure. Also on a light area, it
will give more.

Although I know this, I forgot about it just this past weekend when my
wife wanted a photo with her sister. Both were dressed in dark
clothing, so the resulting exposure came out overexposed. I was able
to lighten the image using Paint Shop Pro, and it was acceptable.

I bounced my 420EX off the ceiling, and used the central focus point,
the one I use most of the time. If I had chosen the top focus point,
the flash would have metered off the women's faces, probably doing a
better job.

Bob Boudreau
Canada
Anonymous
December 15, 2004 8:15:08 AM

Archived from groups: rec.photo.digital (More info?)

"Todd H." <t@toddh.net> wrote in message news:m0fz28jbba.fsf@ripco.com...
>
> I'm trying to chase down some irregularity in flash photography that
> I'm experiencing with my Digital Rebel with the 550EX flash unit.
> It's got me scratching my head mightily, but I'm starting to suspect
> that the flash unit might be intermittently defective?
>


Todd,

Don't know if this is the problem but have you installed the firmware hack?
I have and it wasn't until afterwards that I noticed the problem. This
could just be a coincidence, however, because I didn't use the flash much
before installing the hack.

In any event I've seen exactly the same problem with my rebel/300d and the
550EX. So far I've used mine on the camera show only. I've paid attention
to the flash and it defiantly fires but it seems like it's firing late.
I've corrected the problem by turning the flash and he camera off and then
back on and it seems to work fine. I assumed it was a sync problem between
the camera and flash but being a newbie at this I haven't figured out how to
correct it properly.

At least you know you're not the only one. ;-)

--

Rob
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Anonymous
December 15, 2004 11:01:12 AM

Archived from groups: rec.photo.digital (More info?)

"Todd H." <t@toddh.net> wrote in message news:m0fz28jbba.fsf@ripco.com...
>
> I'm trying to chase down some irregularity in flash photography that
> I'm experiencing with my Digital Rebel with the 550EX flash unit.
> It's got me scratching my head mightily, but I'm starting to suspect
> that the flash unit might be intermittently defective?

<snip>

>
> Questions:
> What info does the 300D record in EXIF about the flash's
> firing in TTL mode?
> Doesn't seem that EXIF in irfanview is giving me anything
> useful. One place says the flash fired, another place says it
> didn't...on the same photo.
>
> Is there better software for viewing photos with histogram and
> EXIF data to compare frames side by side?
>
> Anyone else notice this, or should this flash be sent for some
> service?
>
> Or am I simply overlooking bounce errors brought on by teh
> stroboframe and need to start eyeing the flash exposure
> confirmation light a light better?
>

Just found this link. http://www.usefilm.com/photo_forum/17/5177/

I'm not sure if its the exact problem we're having but it does have a lot of
useful information regarding the Rebel and the 550EX.

--

Rob
Anonymous
December 15, 2004 12:20:09 PM

Archived from groups: rec.photo.digital (More info?)

"Robert R Kircher, Jr." <rrkircher@hotmail.com> writes:

> "Todd H." <t@toddh.net> wrote in message news:m0fz28jbba.fsf@ripco.com...
> >
> > I'm trying to chase down some irregularity in flash photography that
> > I'm experiencing with my Digital Rebel with the 550EX flash unit.
> > It's got me scratching my head mightily, but I'm starting to suspect
> > that the flash unit might be intermittently defective?
> >
>
>
> Todd,
>
> Don't know if this is the problem but have you installed the firmware hack?
> I have and it wasn't until afterwards that I noticed the problem. This
> could just be a coincidence, however, because I didn't use the flash much
> before installing the hack.

I haven't. I'm using Canon firmware. I meant to mention that. Doh!

> At least you know you're not the only one. ;-)

Thanks for the data point!

--
Todd H.
http://www.toddh.net/
Anonymous
December 15, 2004 12:28:14 PM

Archived from groups: rec.photo.digital (More info?)

"railfan" <arailfan@post.com> writes:
> This same problem has been posted on a YahooGroups for the 300D, using
> the EX flashes. The problem seems to be the flash uses the focusing
> point chosen to base its exposure on. So if you are focusing on a dark
> area, the flash will give more exposure. Also on a light area, it
> will give more.
>
> Although I know this, I forgot about it just this past weekend when my
> wife wanted a photo with her sister. Both were dressed in dark
> clothing, so the resulting exposure came out overexposed. I was able
> to lighten the image using Paint Shop Pro, and it was acceptable.
>
> I bounced my 420EX off the ceiling, and used the central focus point,
> the one I use most of the time. If I had chosen the top focus point,
> the flash would have metered off the women's faces, probably doing a
> better job.

Hi Bob,

I'm not sure if I understand completely. For what it's worth, I use
the central focus point all the time (force of habit fro mthe Elan
days) and use prefocus on nearly every shot. Is this to say that the
evaluative flash metering weight the focusing point zone's exposure as
the highest priority? Or does it maniacally partial meter that area?

If so, I can see where that could in general give some issues, but in
the instance of the two images I posted, I'm not sure how that could
fully explain it either?

http://toddh.net/photo/rebel/IMG_6340.JPG
http://toddh.net/photo/rebel/IMG_6341.JPG

Or, what a minizzle.... maybe it does explain it.

Are you saying that perhaps the first picture underexposed because the
center focus point lands in Santa's white beard and the metering is
trying to make that white beard a middle gray? The 2nd (properly
exposed) picture happens to have skintones on the central focus point.

And, is there a way for me to make this think flash meter like the
Elan which did a great friggin job. I can't believe they'd take a
step backwards in flash accuracy in 10 years, but it seems as though
they may have done just that?

Best Regards,
--
Todd H.
http://www.toddh.net/
Anonymous
December 15, 2004 4:29:17 PM

Archived from groups: rec.photo.digital (More info?)

In the first picture the camera is taking it's metering reading from a lot
of white subject matter. It doesn't realize that this is supposed to be
white and sets the exposure to render it 18% gray.
The second picture has much less white in the metering area and therefore
exposed the subject better.

My suggestion to you is to select a portion of the subject that had good mid
tones (not a lot of bright or dark areas) and use the FE (Flash exposure)
lock button (with your right thumb). This will fire the preflash and your
exposure will be calculated based on good mid tone reflectivity.
Then, while this reading is still locked into the camera, recompose and
refocus on the subject how you wish. (Keep your feet and the subject in the
same place) Trip the shutter and your exposure should be correct.

D.B.

"Todd H." <t@toddh.net> wrote in message news:m0fz28jbba.fsf@ripco.com...
>
> I'm trying to chase down some irregularity in flash photography that
> I'm experiencing with my Digital Rebel with the 550EX flash unit.
> It's got me scratching my head mightily, but I'm starting to suspect
> that the flash unit might be intermittently defective?
>
> Now, the first time I noticed some inconsistency in flash exposure was
> at a friend's wedding I was shooting (candids, nothing essential)
> where the flash photography wasn't consistent. That time was with the
> 550EX on the camera's hot shoe, and shooting mostly direct flash.
> Since it was my first outing with the equipment I didn't think much of
> the inconsistent results.
>
> I recently took the camera on a trip and took a baotload of available
> light stuff that all looked fabulous. Shot a lot with the kit lens
> and the on-camera little flash and those were always well exposed
> too. So, mentally I'm ruling out the camera's exposure metering and
> the pop-up flash.
>
> Now, tonight I had a chance to run a couple hundred shots at a
> children's christmas party for our community. Indoor setting, low
> white ceiling, shooting P mode, at ISO 400 with the kit lens and the
> 100-300 f/4.5-5.6 IS lens. My 550EX was atop a stroboframe this time
> using the Canon off shoe cord I've carried over form my Elan outfit.
> Sometimes bouncing off ceiling, sometimes direct.
>
> Regardless of what lens I used, some shots look wonderfully exposed
> (like I'm used to with my Elan andd 540EZ flash), while others are
> quite underexposed and flat--as though the flash didn't fire at all or
> didn't fire enough. Sometimes these are consecutive shots, but it's
> not flash recycling time issues.
>
> For instance, here's an example of 2 nearly identically composed
> shots. Both are 1/60, f/5.6, same lens, same ISO. The first one
> blows chunks, but the other's fine. The unexposed one was shot first:
>
> Flat, and horrible. 235mm zoom.
> http://toddh.net/photo/rebel/IMG_6340.JPG
>
> Looks the way god intended. 220mm zoom.
> http://toddh.net/photo/rebel/IMG_6341.JPG
>
> I've tried to compare the EXIF data with Irfanview and there's no
> discernible difference in the EXIF data there.
>
> I'm starting to suspect that perhaps the flash as the only possible
> point of inconsistency.
>
> Questions:
> What info does the 300D record in EXIF about the flash's
> firing in TTL mode?
> Doesn't seem that EXIF in irfanview is giving me anything
> useful. One place says the flash fired, another place says it
> didn't...on the same photo.
>
> Is there better software for viewing photos with histogram and
> EXIF data to compare frames side by side?
>
> Anyone else notice this, or should this flash be sent for some
> service?
>
> Or am I simply overlooking bounce errors brought on by teh
> stroboframe and need to start eyeing the flash exposure
> confirmation light a light better?
>
> Quite puzzled....
>
> --
> Todd H.
> http://www.toddh.net/
!