Glitch with Canon 300D?
 

I've been taking a few 'bulb' pictures recently, and on one batch noticed a
slight lightened colour cast down the right hand side 10% of the picture,
similar to how you might with film where a bit of light has leaked in. I
originally put it down to some light entering the lens from a source I
hadn't seen in the dark, but took some more today and got the same thing.
Any ideas what this could be? I've not noticed any leakage of light on
settings other than bulb before. Is my camera/lens bollixed? Any suggestions
gratefully received.

Glitch with Canon 300D?
 

Woollyzone wrote:
|| I've been taking a few 'bulb' pictures recently, and on one
|| batch noticed a slight lightened colour cast down the right
|| hand side 10% of the picture, similar to how you might with
|| film where a bit of light has leaked in. I originally put it
|| down to some light entering the lens from a source I hadn't
|| seen in the dark, but took some more today and got the same
|| thing. Any ideas what this could be? I've not noticed any
|| leakage of light on settings other than bulb before. Is my
|| camera/lens bollixed? Any suggestions gratefully received.

Did you cover the viewfinder/eye peice? That is often the
source of stray light.

--
"Weak and fearful people deny, and hide from, the horrors of the
world, believing that the pretense of a benign world will make
it so. This self-deception ultimately creates more horror." --
Machiavelli

Glitch with Canon 300D?
 

"BJ in Texas" wrote in message
. net...
Woollyzone wrote:
|| I've been taking a few 'bulb' pictures recently, and on one
|| batch noticed a slight lightened colour cast down the right
|| hand side 10% of the picture, similar to how you might with
|| film where a bit of light has leaked in. I originally put it
|| down to some light entering the lens from a source I hadn't
|| seen in the dark, but took some more today and got the same
|| thing. Any ideas what this could be? I've not noticed any
|| leakage of light on settings other than bulb before. Is my
|| camera/lens bollixed? Any suggestions gratefully received.

Did you cover the viewfinder/eye peice? That is often the
source of stray light.

No I didn't, but I didn't think there was any light coming in from behind.
Its possible there was however, so I'll try again and take your advice and
see if it makes any difference. Thanks for incredibly quick response!

Glitch with Canon 300D?
 

Woollyzone wrote:

I've been taking a few 'bulb' pictures recently, and on one batch noticed a
slight lightened colour cast down the right hand side 10% of the picture,
similar to how you might with film where a bit of light has leaked in.

www.google.com: amplifier glow

Glitch with Canon 300D?
 

In message ,
"Woollyzone" wrote:

No I didn't, but I didn't think there was any light coming in from behind.
Its possible there was however, so I'll try again and take your advice and
see if it makes any difference. Thanks for incredibly quick response!

Quite a bit of light can come in through the viewfinder. Outside in
bright daylight, I have seen f-stop and shutter speed figures on the top
LCD of my cameras that showed a considerable amount of light, only to
realize that the lens cap was on. For example, in Av mode at f/8, the
shutter speed might read 1/4. Cover up the viewfinder with my finger,
and it goes to 30s.
--


John P Sheehy

Glitch with Canon 300D?
 

In message . com,
" wrote:

www.google.com: amplifier glow

On my Canon 10D, I see that in the lower right edge on some long images.
--


John P Sheehy

Glitch with Canon 300D?
 

wrote:

www.google.com: amplifier glow

On my Canon 10D, I see that in the lower right edge on some long images.

The AG on my 10D shows up on long exposures as a patch of bright that
extends from the right edge to about ~15% across the image towards the
left. It dribbles away, not an abrupt transition. The OP's
description is consistent with this, but of course it is possible "real
light" is worming it's way in somehow. A weird lens flare?

Simple experiment: wrap the camera in some towels, put it into a dark
closet (preferably at night), and take a picture of the blackness.

Glitch with Canon 300D?
 

wrote in message
oups.com...
wrote:

www.google.com: amplifier glow

On my Canon 10D, I see that in the lower right edge on some long images.

The AG on my 10D shows up on long exposures as a patch of bright that
extends from the right edge to about ~15% across the image towards the
left. It dribbles away, not an abrupt transition. The OP's
description is consistent with this, but of course it is possible "real
light" is worming it's way in somehow. A weird lens flare?

Simple experiment: wrap the camera in some towels, put it into a dark
closet (preferably at night), and take a picture of the blackness.


Although I haven't yet tried testing it to see if it was light leakage from
through the viewfinder, I'm pretty confident that its AG, as it matches your
description of it. Its easily cropped out, but to ensure it all goes, it
means losing about 20% of the width of the picture.

Glitch with Canon 300D?
 

Woollyzone wrote:

Although I haven't yet tried testing it to see if it was light leakage from
through the viewfinder, I'm pretty confident that its AG, as it matches your
description of it. Its easily cropped out, but to ensure it all goes, it
means losing about 20% of the width of the picture.

No need to crop: just subtract a dark frame from the image. Read
around:

www.google.com: dark frame

This will also remove hot pixels from the image, and even some residual
"fixed pattern noise". This dark-frame subtraction has to be done with
the raw camera data. The higher-end PhotoSlop code can probably do it,
but you can download various astronomical image processing tools for
free.

Alternatively: my 1DMk2 doesn't suffer from the problem to anywhere as
near a degree as the 10D. If the 20D/350D is the same: buy a new
camera. It's Christmas. And it's what Canon wants you to do anyways
;-)

Glitch with Canon 300D?
 

In message ,
"Woollyzone" wrote:

Although I haven't yet tried testing it to see if it was light leakage from
through the viewfinder, I'm pretty confident that its AG, as it matches your
description of it. Its easily cropped out, but to ensure it all goes, it
means losing about 20% of the width of the picture.

If you take an image immediately afterward with the same ISO and
exposure time, with the lens cap on and the viewfinder cover, you have
the necessary data to subtract it. I don't know how well software can
take advantage of it; for best results, the subtraction should be done
to the RAW data, and I don't know if there are any programs that will do
that and still do a quality RAW conversion. The 20D has this as a
feature; it subtracts the black frame from the image before writing the
RAW file (if you enable the feature, and it only works with 1 second or
longer).
--


John P Sheehy