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Circular Light Areas in Photo

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Anonymous
July 1, 2005 5:14:55 PM

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

I have a Canon A95. Occassionally (and I'm trying to narrow down when)
I take a photo and I get small circular areas which are lighter than the
rest of the area. They remind me of what would happen when painting
watercolors and an area blooms (but it is a perfect circle).

It seems to happen when the flash fires but the subject is too far away
or there are small areas of other sources of light. It also appears to
be worse at 400 ISO.

I'm trying to figure out what is happening in order to avoid the
situation. If I had to make a guess, I'm thinking the shutter speed is
fast (because the flash is firing), but the flash is not bouncing off a
close object so the camera is picking up the light from the flash. Or
if there is a window maybe it is picking up some outfoor light peaking in.

Has anyone else seen this? Does what I suggest sound plausible?

Looking for some advice on the cause.

Thanks,

Steve
Anonymous
July 1, 2005 5:14:56 PM

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

Steven Feinstein wrote:
> I have a Canon A95. Occassionally (and I'm trying to narrow down
> when) I take a photo and I get small circular areas which are
> lighter than
> the rest of the area. They remind me of what would happen when
> painting watercolors and an area blooms (but it is a perfect
> circle).
>
> It seems to happen when the flash fires but the subject is too far
> away or there are small areas of other sources of light. It also
> appears to be worse at 400 ISO.
>
> I'm trying to figure out what is happening in order to avoid the
> situation. If I had to make a guess, I'm thinking the shutter speed
> is fast (because the flash is firing), but the flash is not bouncing
> off a close object so the camera is picking up the light from the
> flash. Or if there is a window maybe it is picking up some outfoor
> light
> peaking in.
> Has anyone else seen this? Does what I suggest sound plausible?
>
> Looking for some advice on the cause.
>
It's a mote in the middle distance.

--
Frank ess
Anonymous
July 1, 2005 5:14:56 PM

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

Steven Feinstein wrote:
> I have a Canon A95. Occassionally (and I'm trying to narrow down when)
> I take a photo and I get small circular areas which are lighter than the
> rest of the area. They remind me of what would happen when painting
> watercolors and an area blooms (but it is a perfect circle).
>
> It seems to happen when the flash fires but the subject is too far away
> or there are small areas of other sources of light. It also appears to
> be worse at 400 ISO.
>
> I'm trying to figure out what is happening in order to avoid the
> situation. If I had to make a guess, I'm thinking the shutter speed is
> fast (because the flash is firing), but the flash is not bouncing off a
> close object so the camera is picking up the light from the flash. Or
> if there is a window maybe it is picking up some outfoor light peaking in.
>
> Has anyone else seen this? Does what I suggest sound plausible?
>
> Looking for some advice on the cause.
>
> Thanks,
>
> Steve

It would help if we could see one of these photos.
You might try aiming the camera straight up on a clear night and taking
a flash photo.

Scott
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Anonymous
July 1, 2005 5:14:56 PM

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

Steven Feinstein wrote:
> Scott W wrote:
> > Steven Feinstein wrote:
> >
> >>I have a Canon A95. Occassionally (and I'm trying to narrow down when)
> >>I take a photo and I get small circular areas which are lighter than the
> >>rest of the area. They remind me of what would happen when painting
> >>watercolors and an area blooms (but it is a perfect circle).
> >>
> >>It seems to happen when the flash fires but the subject is too far away
> >>or there are small areas of other sources of light. It also appears to
> >>be worse at 400 ISO.
> >>
> >>I'm trying to figure out what is happening in order to avoid the
> >>situation. If I had to make a guess, I'm thinking the shutter speed is
> >>fast (because the flash is firing), but the flash is not bouncing off a
> >>close object so the camera is picking up the light from the flash. Or
> >>if there is a window maybe it is picking up some outfoor light peaking in.
> >>
> >>Has anyone else seen this? Does what I suggest sound plausible?
> >>
> >>Looking for some advice on the cause.
> >>
> >>Thanks,
> >>
> >>Steve
> >
> >
> > It would help if we could see one of these photos.
> > You might try aiming the camera straight up on a clear night and taking
> > a flash photo.
> >
> > Scott
> >
> I uploaded three images as examples. Dust does seem to make sense, it's
> just that we took pictures at the same locations in a previous year
> using a point and shoot film camera and did not have this problem. Does
> it sound more like chance or is digital more sensitive to the dust?
>
> Light areas are:
> lapel of man
> knee of boy
> above white banner
> http://members.cox.net/sfein/images/img_1300.jpg
>
> Light areas are:
> at bottom
> on right near door
> http://members.cox.net/sfein/images/img_1258.jpg
>
> Light areas are all over the place:
> http://members.cox.net/sfein/images/img_1254.jpg
>
> I appreciate all the help from everyone.

It does look like dust, but I am surprised at how much you are getting.
We have a very small digital camera that we use from time to time, I
looked at several hundred flash photos from it and did not see dust in
any of them. I have found two photos that show just a bit of dust in
the air from my F828, but these were both taken in a wood shop where
the saw had been used just a bit before, and even then I only saw a
couple of spots.

To see two in the same shot indoors to me seems very odd, others may
have other experiences then what I have had.

Scott
Anonymous
July 1, 2005 5:26:57 PM

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

Steven Feinstein wrote:
> I have a Canon A95. Occassionally (and I'm trying to narrow down when)
> I take a photo and I get small circular areas which are lighter than the
> rest of the area. They remind me of what would happen when painting
> watercolors and an area blooms (but it is a perfect circle).
>
> It seems to happen when the flash fires but the subject is too far away
> or there are small areas of other sources of light. It also appears to
> be worse at 400 ISO.
>
> I'm trying to figure out what is happening in order to avoid the
> situation. If I had to make a guess, I'm thinking the shutter speed is
> fast (because the flash is firing), but the flash is not bouncing off a
> close object so the camera is picking up the light from the flash. Or
> if there is a window maybe it is picking up some outfoor light peaking in.
>
> Has anyone else seen this? Does what I suggest sound plausible?
>
> Looking for some advice on the cause.
>
> Thanks,
>
> Steve
Yes. Usually when using flash, in a place where there is dust in the
air. The dust particles will reflect the flash causing this problem.


--
Ron Hunter rphunter@charter.net
Anonymous
July 1, 2005 5:31:28 PM

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

Frank ess wrote:
> Steven Feinstein wrote:
>
>> I have a Canon A95. Occassionally (and I'm trying to narrow down
>> when) I take a photo and I get small circular areas which are lighter
>> than
>> the rest of the area. They remind me of what would happen when
>> painting watercolors and an area blooms (but it is a perfect circle).
>>
>> It seems to happen when the flash fires but the subject is too far
>> away or there are small areas of other sources of light. It also
>> appears to be worse at 400 ISO.
>>
>> I'm trying to figure out what is happening in order to avoid the
>> situation. If I had to make a guess, I'm thinking the shutter speed
>> is fast (because the flash is firing), but the flash is not bouncing
>> off a close object so the camera is picking up the light from the
>> flash. Or if there is a window maybe it is picking up some outfoor light
>> peaking in.
>> Has anyone else seen this? Does what I suggest sound plausible?
>>
>> Looking for some advice on the cause.
>>
> It's a mote in the middle distance.
>
Are you saying that the flash is reflecting off of dust? This may be
possible since the last batch were pictures of a person riding a horse
in an indoor arena (on dirt), but the light areas seem pretty big for
dust. As an example, one of the areas I'm looking at is about 1/6th the
height of the picture. Would a reflection off of dust look that large?

Also, if it is a mote, am I limited to not using the flash in dusty areas?

Thanks for your response.
Anonymous
July 1, 2005 5:31:29 PM

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

On Fri, 01 Jul 2005 13:31:28 -0400, Steven Feinstein
<stevefeinstein@netscape.net> wrote:

>Frank ess wrote:
>> Steven Feinstein wrote:
>>
>>> I have a Canon A95. Occassionally (and I'm trying to narrow down
>>> when) I take a photo and I get small circular areas which are lighter
>>> than
>>> the rest of the area. They remind me of what would happen when
>>> painting watercolors and an area blooms (but it is a perfect circle).
>>>
>>> It seems to happen when the flash fires but the subject is too far
>>> away or there are small areas of other sources of light. It also
>>> appears to be worse at 400 ISO.
>>>
>>> I'm trying to figure out what is happening in order to avoid the
>>> situation. If I had to make a guess, I'm thinking the shutter speed
>>> is fast (because the flash is firing), but the flash is not bouncing
>>> off a close object so the camera is picking up the light from the
>>> flash. Or if there is a window maybe it is picking up some outfoor light
>>> peaking in.
>>> Has anyone else seen this? Does what I suggest sound plausible?
>>>
>>> Looking for some advice on the cause.
>>>
>> It's a mote in the middle distance.
>>
>Are you saying that the flash is reflecting off of dust? This may be
>possible since the last batch were pictures of a person riding a horse
>in an indoor arena (on dirt), but the light areas seem pretty big for
>dust. As an example, one of the areas I'm looking at is about 1/6th the
>height of the picture. Would a reflection off of dust look that large?
>
>Also, if it is a mote, am I limited to not using the flash in dusty areas?
>
>Thanks for your response.

One-sixth of the picture is an awfully large dust mote!
It would be great if you could post a link to a copy of a pic that
shows this, then we would have a much better idea of what you mean.

--
Bill Funk
replace "g" with "a"
Anonymous
July 1, 2005 7:22:23 PM

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

Scott W wrote:
> Steven Feinstein wrote:
>
>>I have a Canon A95. Occassionally (and I'm trying to narrow down when)
>>I take a photo and I get small circular areas which are lighter than the
>>rest of the area. They remind me of what would happen when painting
>>watercolors and an area blooms (but it is a perfect circle).
>>
>>It seems to happen when the flash fires but the subject is too far away
>>or there are small areas of other sources of light. It also appears to
>>be worse at 400 ISO.
>>
>>I'm trying to figure out what is happening in order to avoid the
>>situation. If I had to make a guess, I'm thinking the shutter speed is
>>fast (because the flash is firing), but the flash is not bouncing off a
>>close object so the camera is picking up the light from the flash. Or
>>if there is a window maybe it is picking up some outfoor light peaking in.
>>
>>Has anyone else seen this? Does what I suggest sound plausible?
>>
>>Looking for some advice on the cause.
>>
>>Thanks,
>>
>>Steve
>
>
> It would help if we could see one of these photos.
> You might try aiming the camera straight up on a clear night and taking
> a flash photo.
>
> Scott
>
I uploaded three images as examples. Dust does seem to make sense, it's
just that we took pictures at the same locations in a previous year
using a point and shoot film camera and did not have this problem. Does
it sound more like chance or is digital more sensitive to the dust?

Light areas are:
lapel of man
knee of boy
above white banner
http://members.cox.net/sfein/images/img_1300.jpg

Light areas are:
at bottom
on right near door
http://members.cox.net/sfein/images/img_1258.jpg

Light areas are all over the place:
http://members.cox.net/sfein/images/img_1254.jpg

I appreciate all the help from everyone.
Anonymous
July 1, 2005 8:35:18 PM

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

Steven Feinstein wrote:
> Scott W wrote:
>
>> Steven Feinstein wrote:
>>
>>> I have a Canon A95. Occassionally (and I'm trying to narrow down when)
>>> I take a photo and I get small circular areas which are lighter than the
>>> rest of the area. They remind me of what would happen when painting
>>> watercolors and an area blooms (but it is a perfect circle).
>>>
>>> It seems to happen when the flash fires but the subject is too far away
>>> or there are small areas of other sources of light. It also appears to
>>> be worse at 400 ISO.
>>>
>>> I'm trying to figure out what is happening in order to avoid the
>>> situation. If I had to make a guess, I'm thinking the shutter speed is
>>> fast (because the flash is firing), but the flash is not bouncing off a
>>> close object so the camera is picking up the light from the flash. Or
>>> if there is a window maybe it is picking up some outfoor light
>>> peaking in.
>>>
>>> Has anyone else seen this? Does what I suggest sound plausible?
>>>
>>> Looking for some advice on the cause.
>>>
>>> Thanks,
>>>
>>> Steve
>>
>>
>>
>> It would help if we could see one of these photos.
>> You might try aiming the camera straight up on a clear night and taking
>> a flash photo.
>>
>> Scott
>>
> I uploaded three images as examples. Dust does seem to make sense, it's
> just that we took pictures at the same locations in a previous year
> using a point and shoot film camera and did not have this problem. Does
> it sound more like chance or is digital more sensitive to the dust?
>
> Light areas are:
> lapel of man
> knee of boy
> above white banner
> http://members.cox.net/sfein/images/img_1300.jpg
>
> Light areas are:
> at bottom
> on right near door
> http://members.cox.net/sfein/images/img_1258.jpg
>
> Light areas are all over the place:
> http://members.cox.net/sfein/images/img_1254.jpg
>
> I appreciate all the help from everyone.
Hi,

I noticed the same type of light circles, only with flash from a great
distance where the pictures were grossly underexposed, and were
presumably shot at ISO 400 (automatic) in my Canon S-500. I assumed that
it was a kind of digital "noise", and can't imagine why ISO 400 shows up
dust more than ISO 100.

Morton
Anonymous
July 1, 2005 9:06:17 PM

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

Bill Funk wrote:
> On Fri, 01 Jul 2005 13:31:28 -0400, Steven Feinstein
> <stevefeinstein@netscape.net> wrote:
>
>
>>Frank ess wrote:
>>
>>>Steven Feinstein wrote:
>>>
>>>
>>>>I have a Canon A95. Occassionally (and I'm trying to narrow down
>>>>when) I take a photo and I get small circular areas which are lighter
>>>>than
>>>>the rest of the area. They remind me of what would happen when
>>>>painting watercolors and an area blooms (but it is a perfect circle).
>>>>
>>>>It seems to happen when the flash fires but the subject is too far
>>>>away or there are small areas of other sources of light. It also
>>>>appears to be worse at 400 ISO.
>>>>
>>>>I'm trying to figure out what is happening in order to avoid the
>>>>situation. If I had to make a guess, I'm thinking the shutter speed
>>>>is fast (because the flash is firing), but the flash is not bouncing
>>>>off a close object so the camera is picking up the light from the
>>>>flash. Or if there is a window maybe it is picking up some outfoor light
>>>>peaking in.
>>>>Has anyone else seen this? Does what I suggest sound plausible?
>>>>
>>>>Looking for some advice on the cause.
>>>>
>>>
>>>It's a mote in the middle distance.
>>>
>>
>>Are you saying that the flash is reflecting off of dust? This may be
>>possible since the last batch were pictures of a person riding a horse
>>in an indoor arena (on dirt), but the light areas seem pretty big for
>>dust. As an example, one of the areas I'm looking at is about 1/6th the
>>height of the picture. Would a reflection off of dust look that large?
>>
>>Also, if it is a mote, am I limited to not using the flash in dusty areas?
>>
>>Thanks for your response.
>
>
> One-sixth of the picture is an awfully large dust mote!
> It would be great if you could post a link to a copy of a pic that
> shows this, then we would have a much better idea of what you mean.
>
Well it's 1/6th the height, not 1/6th the entire image. But still
pretty large.
Anonymous
July 1, 2005 9:11:30 PM

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

Morton Linder wrote:
> Steven Feinstein wrote:
>
>> Scott W wrote:
>>
>>> Steven Feinstein wrote:
>>>
>>>> I have a Canon A95. Occassionally (and I'm trying to narrow down when)
>>>> I take a photo and I get small circular areas which are lighter than
>>>> the
>>>> rest of the area. They remind me of what would happen when painting
>>>> watercolors and an area blooms (but it is a perfect circle).
>>>>
>>>> It seems to happen when the flash fires but the subject is too far away
>>>> or there are small areas of other sources of light. It also appears to
>>>> be worse at 400 ISO.
>>>>
>>>> I'm trying to figure out what is happening in order to avoid the
>>>> situation. If I had to make a guess, I'm thinking the shutter speed is
>>>> fast (because the flash is firing), but the flash is not bouncing off a
>>>> close object so the camera is picking up the light from the flash. Or
>>>> if there is a window maybe it is picking up some outfoor light
>>>> peaking in.
>>>>
>>>> Has anyone else seen this? Does what I suggest sound plausible?
>>>>
>>>> Looking for some advice on the cause.
>>>>
>>>> Thanks,
>>>>
>>>> Steve
>>>
>>>
>>>
>>>
>>> It would help if we could see one of these photos.
>>> You might try aiming the camera straight up on a clear night and taking
>>> a flash photo.
>>>
>>> Scott
>>>
>> I uploaded three images as examples. Dust does seem to make sense,
>> it's just that we took pictures at the same locations in a previous
>> year using a point and shoot film camera and did not have this
>> problem. Does it sound more like chance or is digital more sensitive
>> to the dust?
>>
>> Light areas are:
>> lapel of man
>> knee of boy
>> above white banner
>> http://members.cox.net/sfein/images/img_1300.jpg
>>
>> Light areas are:
>> at bottom
>> on right near door
>> http://members.cox.net/sfein/images/img_1258.jpg
>>
>> Light areas are all over the place:
>> http://members.cox.net/sfein/images/img_1254.jpg
>>
>> I appreciate all the help from everyone.
>
> Hi,
>
> I noticed the same type of light circles, only with flash from a great
> distance where the pictures were grossly underexposed, and were
> presumably shot at ISO 400 (automatic) in my Canon S-500. I assumed that
> it was a kind of digital "noise", and can't imagine why ISO 400 shows up
> dust more than ISO 100.
>
> Morton
The worse ones were shot in action mode which shows as automatic in the
EXIF, but it's most likely shot at 400. The picture of the 4 people was
shot at 50 so I'm surprised that one had the issue (maybe dust shows up
more on black - which was the color of the suits).

Steve
July 1, 2005 9:31:18 PM

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

In article <U5fxe.22219$FP2.20527@lakeread03>, stevefeinstein@netscape.net
says...
> >
> Are you saying that the flash is reflecting off of dust? This may be
> possible since the last batch were pictures of a person riding a horse
> in an indoor arena (on dirt), but the light areas seem pretty big for
> dust. As an example, one of the areas I'm looking at is about 1/6th the
> height of the picture. Would a reflection off of dust look that large?
>
> Also, if it is a mote, am I limited to not using the flash in dusty areas?
>
> Thanks for your response.
>

Its a"built in" limitation of using the in camera flash which is VERY close
to the lens.

It happens for the same reason that you are more likely to get "RED EYE" in a
picture with the in camera flash.

In a dusty atmosphere a very small dust mote can appear as a HUGE bright,
globelike bright spot.


--
Larry Lynch
Mystic, Ct.
Anonymous
July 1, 2005 9:52:21 PM

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

Steven Feinstein wrote:
> Frank ess wrote:
>> Steven Feinstein wrote:
>>
>>> I have a Canon A95. Occassionally (and I'm trying to narrow down
>>> when) I take a photo and I get small circular areas which are
>>> lighter than
>>> the rest of the area. They remind me of what would happen when
>>> painting watercolors and an area blooms (but it is a perfect
>>> circle). It seems to happen when the flash fires but the subject is
>>> too far
>>> away or there are small areas of other sources of light. It also
>>> appears to be worse at 400 ISO.
>>>
>>> I'm trying to figure out what is happening in order to avoid the
>>> situation. If I had to make a guess, I'm thinking the shutter speed
>>> is fast (because the flash is firing), but the flash is not bouncing
>>> off a close object so the camera is picking up the light from the
>>> flash. Or if there is a window maybe it is picking up some outfoor
>>> light peaking in.
>>> Has anyone else seen this? Does what I suggest sound plausible?
>>>
>>> Looking for some advice on the cause.
>>>
>> It's a mote in the middle distance.
>>
> Are you saying that the flash is reflecting off of dust? This may be
> possible since the last batch were pictures of a person riding a horse
> in an indoor arena (on dirt), but the light areas seem pretty big for
> dust. As an example, one of the areas I'm looking at is about 1/6th
> the height of the picture. Would a reflection off of dust look that
> large?
> Also, if it is a mote, am I limited to not using the flash in dusty
> areas?
> Thanks for your response.

It's worse in compact digital cameras because (1) the depth of field is
much greater so that things which would be completely out of focus on
large cameras can be in focus on compact ones (because of the much smaller
sensor and shorter focal length lens) and (2) the axial separation between
flash and lens is less.

Either post-process the image, reduce the dust, or take several pictures
and hope that one is OK.

David
Anonymous
July 1, 2005 10:25:28 PM

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

Steven Feinstein wrote:
> Scott W wrote:
>
>> Steven Feinstein wrote:
>>
>>> I have a Canon A95. Occassionally (and I'm trying to narrow down when)
>>> I take a photo and I get small circular areas which are lighter than the
>>> rest of the area. They remind me of what would happen when painting
>>> watercolors and an area blooms (but it is a perfect circle).
>>>
>>> It seems to happen when the flash fires but the subject is too far away
>>> or there are small areas of other sources of light. It also appears to
>>> be worse at 400 ISO.
>>>
>>> I'm trying to figure out what is happening in order to avoid the
>>> situation. If I had to make a guess, I'm thinking the shutter speed is
>>> fast (because the flash is firing), but the flash is not bouncing off a
>>> close object so the camera is picking up the light from the flash. Or
>>> if there is a window maybe it is picking up some outfoor light
>>> peaking in.
>>>
>>> Has anyone else seen this? Does what I suggest sound plausible?
>>>
>>> Looking for some advice on the cause.
>>>
>>> Thanks,
>>>
>>> Steve
>>
>>
>>
>> It would help if we could see one of these photos.
>> You might try aiming the camera straight up on a clear night and taking
>> a flash photo.
>>
>> Scott
>>
> I uploaded three images as examples. Dust does seem to make sense, it's
> just that we took pictures at the same locations in a previous year
> using a point and shoot film camera and did not have this problem. Does
> it sound more like chance or is digital more sensitive to the dust?
>
> Light areas are:
> lapel of man
> knee of boy
> above white banner
> http://members.cox.net/sfein/images/img_1300.jpg
>
> Light areas are:
> at bottom
> on right near door
> http://members.cox.net/sfein/images/img_1258.jpg
>
> Light areas are all over the place:
> http://members.cox.net/sfein/images/img_1254.jpg
>
> I appreciate all the help from everyone.

With the exception of the first picture, the flash should have been
turned off. Flash is useless beyond about 20 feet, and will only cause
the problem you are seeing, and will force the camera into a mode that
will probably result in a picture that is worse than it would be without
flash. In the first case, the problem is easily solved by just about
any photo editor. In the others, it is pretty much a lost cause.
Don't use the flash if the subject is beyond 20 feet, and don't use it
in dusty environments.


--
Ron Hunter rphunter@charter.net
Anonymous
July 1, 2005 10:28:50 PM

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

Morton Linder wrote:
> Steven Feinstein wrote:
>
>> Scott W wrote:
>>
>>> Steven Feinstein wrote:
>>>
>>>> I have a Canon A95. Occassionally (and I'm trying to narrow down when)
>>>> I take a photo and I get small circular areas which are lighter than
>>>> the
>>>> rest of the area. They remind me of what would happen when painting
>>>> watercolors and an area blooms (but it is a perfect circle).
>>>>
>>>> It seems to happen when the flash fires but the subject is too far away
>>>> or there are small areas of other sources of light. It also appears to
>>>> be worse at 400 ISO.
>>>>
>>>> I'm trying to figure out what is happening in order to avoid the
>>>> situation. If I had to make a guess, I'm thinking the shutter speed is
>>>> fast (because the flash is firing), but the flash is not bouncing off a
>>>> close object so the camera is picking up the light from the flash. Or
>>>> if there is a window maybe it is picking up some outfoor light
>>>> peaking in.
>>>>
>>>> Has anyone else seen this? Does what I suggest sound plausible?
>>>>
>>>> Looking for some advice on the cause.
>>>>
>>>> Thanks,
>>>>
>>>> Steve
>>>
>>>
>>>
>>>
>>> It would help if we could see one of these photos.
>>> You might try aiming the camera straight up on a clear night and taking
>>> a flash photo.
>>>
>>> Scott
>>>
>> I uploaded three images as examples. Dust does seem to make sense,
>> it's just that we took pictures at the same locations in a previous
>> year using a point and shoot film camera and did not have this
>> problem. Does it sound more like chance or is digital more sensitive
>> to the dust?
>>
>> Light areas are:
>> lapel of man
>> knee of boy
>> above white banner
>> http://members.cox.net/sfein/images/img_1300.jpg
>>
>> Light areas are:
>> at bottom
>> on right near door
>> http://members.cox.net/sfein/images/img_1258.jpg
>>
>> Light areas are all over the place:
>> http://members.cox.net/sfein/images/img_1254.jpg
>>
>> I appreciate all the help from everyone.
>
> Hi,
>
> I noticed the same type of light circles, only with flash from a great
> distance where the pictures were grossly underexposed, and were
> presumably shot at ISO 400 (automatic) in my Canon S-500. I assumed that
> it was a kind of digital "noise", and can't imagine why ISO 400 shows up
> dust more than ISO 100.
>
> Morton

I believe you have the cause and effect reversed. The use of flash, at
long ranges will cause the camera to use ISO400, so you see the problem.
If there is enough light for ISO100, it is likely the flash didn't fire.


--
Ron Hunter rphunter@charter.net
Anonymous
July 1, 2005 10:55:13 PM

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

In article <nSexe.22218$FP2.16918@lakeread03>,
Steven Feinstein <stevefeinstein@netscape.net> wrote:

> I have a Canon A95. Occassionally (and I'm trying to narrow down when)
> I take a photo and I get small circular areas which are lighter than the
> rest of the area. They remind me of what would happen when painting
> watercolors and an area blooms (but it is a perfect circle).
>
> It seems to happen when the flash fires but the subject is too far away
> or there are small areas of other sources of light. It also appears to
> be worse at 400 ISO.
>
> I'm trying to figure out what is happening in order to avoid the
> situation. If I had to make a guess, I'm thinking the shutter speed is
> fast (because the flash is firing), but the flash is not bouncing off a
> close object so the camera is picking up the light from the flash. Or
> if there is a window maybe it is picking up some outfoor light peaking in.
>
> Has anyone else seen this? Does what I suggest sound plausible?
>
> Looking for some advice on the cause.
>
> Thanks,
>
> Steve

It's fabric lint in the air reflecting your flash.
Anonymous
July 1, 2005 11:26:20 PM

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

Steven Feinstein wrote:
[]
> I uploaded three images as examples. Dust does seem to make sense,
> it's just that we took pictures at the same locations in a previous
> year using a point and shoot film camera and did not have this
> problem. Does it sound more like chance or is digital more sensitive
> to the dust?

Yes. I already explained that to you - please re-read my post.

David
Anonymous
July 1, 2005 11:26:21 PM

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

David J Taylor wrote:
> Steven Feinstein wrote:
> []
>
>>I uploaded three images as examples. Dust does seem to make sense,
>>it's just that we took pictures at the same locations in a previous
>>year using a point and shoot film camera and did not have this
>>problem. Does it sound more like chance or is digital more sensitive
>>to the dust?
>
>
> Yes. I already explained that to you - please re-read my post.
>
> David
>
>
Sorry David, I misinterpreted your message. I thought when you were
comparing compact digital to larger cameras you meant larger digital
cameras (i.e. DSLRs or even higher-end fixed lens). I did not think you
meant vs film. So just to be sure, your description holds true for
compact film cameras as well. The depth of filed is greater for compact
digital vs compact film and most likely the flash is closer to the lens
(which is true of my cameras).

Thanks,

Steve
Anonymous
July 1, 2005 11:54:55 PM

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

On Fri, 01 Jul 2005 15:22:23 -0400, Steven Feinstein
<stevefeinstein@netscape.net> wrote:

>I uploaded three images as examples. Dust does seem to make sense, it's
>just that we took pictures at the same locations in a previous year
>using a point and shoot film camera and did not have this problem. Does
>it sound more like chance or is digital more sensitive to the dust?
>
>http://members.cox.net/sfein/images/img_1300.jpg
>http://members.cox.net/sfein/images/img_1258.jpg
>http://members.cox.net/sfein/images/img_1254.jpg

Wow, I've never seen that before.

You can rule out dust on the surface of the lens / front filter by
taking a couple of photos in quick succession with AF switched off (to
prevent any possible front-element rotation) but framed slightly
differently. However, I'm not sure how this would get illuminated by
the flash.

So, the only other plausible idea is as others have suggested - dust
floating around in the air, quite close to the front element being
illuminated by the flash - not much you can do about that...

--
Owamanga!
http://www.pbase.com/owamanga
Anonymous
July 1, 2005 11:54:56 PM

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

Owamanga wrote:
> On Fri, 01 Jul 2005 15:22:23 -0400, Steven Feinstein
> <stevefeinstein@netscape.net> wrote:
>
>
>>I uploaded three images as examples. Dust does seem to make sense, it's
>>just that we took pictures at the same locations in a previous year
>>using a point and shoot film camera and did not have this problem. Does
>>it sound more like chance or is digital more sensitive to the dust?
>>
>>http://members.cox.net/sfein/images/img_1300.jpg
>>http://members.cox.net/sfein/images/img_1258.jpg
>>http://members.cox.net/sfein/images/img_1254.jpg
>
>
> Wow, I've never seen that before.
>
> You can rule out dust on the surface of the lens / front filter by
> taking a couple of photos in quick succession with AF switched off (to
> prevent any possible front-element rotation) but framed slightly
> differently. However, I'm not sure how this would get illuminated by
> the flash.
>
> So, the only other plausible idea is as others have suggested - dust
> floating around in the air, quite close to the front element being
> illuminated by the flash - not much you can do about that...
>
> --
> Owamanga!
> http://www.pbase.com/owamanga
I do have other pictures from the same day where I don't see the circles
so I don't think it is dust on the lens (though I will clean it). The
picture of the 4 people standing was done on a different day and I was
hoping it was a one-time thing. Now I'm going to have to check for
focus and dust reflections when I review an image.
Anonymous
July 2, 2005 1:03:25 AM

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

Ron Hunter wrote:
> Morton Linder wrote:
>
>> Steven Feinstein wrote:
>>
>>> Scott W wrote:
>>>
>>>> Steven Feinstein wrote:
>>>>
>>>>> I have a Canon A95. Occassionally (and I'm trying to narrow down
>>>>> when)
>>>>> I take a photo and I get small circular areas which are lighter
>>>>> than the
>>>>> rest of the area. They remind me of what would happen when painting
>>>>> watercolors and an area blooms (but it is a perfect circle).
>>>>>
>>>>> It seems to happen when the flash fires but the subject is too far
>>>>> away
>>>>> or there are small areas of other sources of light. It also
>>>>> appears to
>>>>> be worse at 400 ISO.
>>>>>
>>>>> I'm trying to figure out what is happening in order to avoid the
>>>>> situation. If I had to make a guess, I'm thinking the shutter
>>>>> speed is
>>>>> fast (because the flash is firing), but the flash is not bouncing
>>>>> off a
>>>>> close object so the camera is picking up the light from the flash. Or
>>>>> if there is a window maybe it is picking up some outfoor light
>>>>> peaking in.
>>>>>
>>>>> Has anyone else seen this? Does what I suggest sound plausible?
>>>>>
>>>>> Looking for some advice on the cause.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Steve
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> It would help if we could see one of these photos.
>>>> You might try aiming the camera straight up on a clear night and taking
>>>> a flash photo.
>>>>
>>>> Scott
>>>>
>>> I uploaded three images as examples. Dust does seem to make sense,
>>> it's just that we took pictures at the same locations in a previous
>>> year using a point and shoot film camera and did not have this
>>> problem. Does it sound more like chance or is digital more sensitive
>>> to the dust?
>>>
>>> Light areas are:
>>> lapel of man
>>> knee of boy
>>> above white banner
>>> http://members.cox.net/sfein/images/img_1300.jpg
>>>
>>> Light areas are:
>>> at bottom
>>> on right near door
>>> http://members.cox.net/sfein/images/img_1258.jpg
>>>
>>> Light areas are all over the place:
>>> http://members.cox.net/sfein/images/img_1254.jpg
>>>
>>> I appreciate all the help from everyone.
>>
>>
>> Hi,
>>
>> I noticed the same type of light circles, only with flash from a great
>> distance where the pictures were grossly underexposed, and were
>> presumably shot at ISO 400 (automatic) in my Canon S-500. I assumed
>> that it was a kind of digital "noise", and can't imagine why ISO 400
>> shows up dust more than ISO 100.
>>
>> Morton
>
>
> I believe you have the cause and effect reversed. The use of flash, at
> long ranges will cause the camera to use ISO400, so you see the problem.
> If there is enough light for ISO100, it is likely the flash didn't fire.
>
>
Not reversed. That is exactly what I said. I use "flash on" in low light
situations. As I said, I only see those circles at ISO 400 with long
distances and therefore underexposed pix.
Morton
Anonymous
July 2, 2005 1:12:38 AM

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

"David J Taylor"
<david-taylor@blueyonder.co.not-this-bit.nor-this-part.uk.invalid> wrote in
message news:wNgxe.60413$G8.5450@text.news.blueyonder.co.uk...
> Steven Feinstein wrote:
> []
> > I uploaded three images as examples. Dust does seem to make sense,
> > it's just that we took pictures at the same locations in a previous
> > year using a point and shoot film camera and did not have this
> > problem. Does it sound more like chance or is digital more sensitive
> > to the dust?
>
> Yes. I already explained that to you - please re-read my post.

I don't think that smaller DOF would help a lot with this - in any case the
light circles are way out of focus.

But anyway, I had the same on my A300. Some shots where ruined this way, and
mine were even worse, as you didn't need any coordinates to help somebody
locate them :-)
I think it's better to do what somebody else suggested, take many frames and
hope some are clean, as to reduce the dust from the air is, ehm, a bit
difficult :-)

Kostas
Anonymous
July 2, 2005 2:24:23 AM

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

In message <U5fxe.22219$FP2.20527@lakeread03>,
Steven Feinstein <stevefeinstein@netscape.net> wrote:

>Also, if it is a mote, am I limited to not using the flash in dusty areas?

That kind of flash, yes. It is very close to the lens, so any dust that
is close to both will be many stops brighter than the subject.

If you had a separate flash, it could be used far from the camera
(higher, besides, or behind) so that no dust will be much closer to the
flash than the subject, and be visible in the capture at the same time.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
Anonymous
July 2, 2005 2:47:23 AM

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

I get that all the time when taking pictures on a construction site.

There can be dust in the air, and you can't even see it.

But the flash fires, and it shows them all over the picture.

Maybe you could use this phenomenon to check for dusty air.

Greg Chapp


"Steven Feinstein" <stevefeinstein@netscape.net> wrote in message
news:U5fxe.22219$FP2.20527@lakeread03...
> Frank ess wrote:
>> Steven Feinstein wrote:
>>
>>> I have a Canon A95. Occassionally (and I'm trying to narrow down
>>> when) I take a photo and I get small circular areas which are lighter
>>> than
>>> the rest of the area. They remind me of what would happen when
>>> painting watercolors and an area blooms (but it is a perfect circle).
>>>
>>> It seems to happen when the flash fires but the subject is too far
>>> away or there are small areas of other sources of light. It also
>>> appears to be worse at 400 ISO.
>>>
>>> I'm trying to figure out what is happening in order to avoid the
>>> situation. If I had to make a guess, I'm thinking the shutter speed
>>> is fast (because the flash is firing), but the flash is not bouncing
>>> off a close object so the camera is picking up the light from the
>>> flash. Or if there is a window maybe it is picking up some outfoor
>>> light
>>> peaking in.
>>> Has anyone else seen this? Does what I suggest sound plausible?
>>>
>>> Looking for some advice on the cause.
>>>
>> It's a mote in the middle distance.
>>
> Are you saying that the flash is reflecting off of dust? This may be
> possible since the last batch were pictures of a person riding a horse in
> an indoor arena (on dirt), but the light areas seem pretty big for dust.
> As an example, one of the areas I'm looking at is about 1/6th the height
> of the picture. Would a reflection off of dust look that large?
>
> Also, if it is a mote, am I limited to not using the flash in dusty areas?
>
> Thanks for your response.
Anonymous
July 2, 2005 3:07:35 AM

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

Matt wrote:
> On Fri, 01 Jul 2005 15:22:23 -0400, Steven Feinstein
> <stevefeinstein@netscape.net> wrote:
>
>
>>Scott W wrote:
>>
>>>Steven Feinstein wrote:
>>>
>>>
>>>>I have a Canon A95. Occassionally (and I'm trying to narrow down when)
>>>>I take a photo and I get small circular areas which are lighter than the
>>>>rest of the area. They remind me of what would happen when painting
>>>>watercolors and an area blooms (but it is a perfect circle).
>>>>
>>>>It seems to happen when the flash fires but the subject is too far away
>>>>or there are small areas of other sources of light. It also appears to
>>>>be worse at 400 ISO.
>>>>
>>>>I'm trying to figure out what is happening in order to avoid the
>>>>situation. If I had to make a guess, I'm thinking the shutter speed is
>>>>fast (because the flash is firing), but the flash is not bouncing off a
>>>>close object so the camera is picking up the light from the flash. Or
>>>>if there is a window maybe it is picking up some outfoor light peaking in.
>>>>
>>>>Has anyone else seen this? Does what I suggest sound plausible?
>>>>
>>>>Looking for some advice on the cause.
>>>>
>>>>Thanks,
>>>>
>>>>Steve
>>>
>>>
>>>It would help if we could see one of these photos.
>>>You might try aiming the camera straight up on a clear night and taking
>>>a flash photo.
>>>
>>>Scott
>>>
>>
>>I uploaded three images as examples. Dust does seem to make sense, it's
>>just that we took pictures at the same locations in a previous year
>>using a point and shoot film camera and did not have this problem. Does
>>it sound more like chance or is digital more sensitive to the dust?
>>
>>Light areas are:
>>lapel of man
>>knee of boy
>>above white banner
>>http://members.cox.net/sfein/images/img_1300.jpg
>>
>>Light areas are:
>>at bottom
>>on right near door
>>http://members.cox.net/sfein/images/img_1258.jpg
>>
>>Light areas are all over the place:
>>http://members.cox.net/sfein/images/img_1254.jpg
>>
>>I appreciate all the help from everyone.
>
>
> Classic ORBS
> http://homepage.ntlworld.com/h.cowell/orbs.htm
>
> I don't agree with the paranormal suggestions, since I was able to
> generate them on demand, by thumping a rather dusty chair and shooting
> it with flash.
>
> The classic digital ORB (always worse on digital) is caused by flash
> illumination/backscatter from near field dust, the point being
> defocused into a lightened circle.
>
> Of course, they show up worse on black.
> It also seems logical that they would be worse at high ISO, if the
> alternative is a wider aperture.
>
> They also seem to be common in church wedding photos - I guess it's
> the number of people that raises dust, and that you tend to be working
> at the outer end of flash range, so the flash is at maximum, and the
> relative nearfield illumination is greater
>
> There is no reason a film camera can't produce orb effects - a fixed
> focus compact would be most likely to, but they just don't seem to be
> as bad.
>
Probably because in a normal P&S camera, the sensor is quite small,
compared with the size of 35mm film, so the effects are more significant.


--
Ron Hunter rphunter@charter.net
Anonymous
July 2, 2005 5:34:49 AM

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

In message <zJlxe.4800$t07.212@fe12.lga>,
Morton Linder <mort@cloud9.net> wrote:

>As I said, I only see those circles at ISO 400 with long
>distances and therefore underexposed pix.

The further away the subject, the relatively closer the dust can be that
is lit by the flash and seen by the lens, and therefore, the brighter.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
Anonymous
July 2, 2005 10:29:58 AM

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

Steven Feinstein wrote:
[]
> Sorry David, I misinterpreted your message. I thought when you were
> comparing compact digital to larger cameras you meant larger digital
> cameras (i.e. DSLRs or even higher-end fixed lens). I did not think
> you meant vs film. So just to be sure, your description holds true
> for compact film cameras as well. The depth of filed is greater for
> compact digital vs compact film and most likely the flash is closer
> to the lens (which is true of my cameras).

Steve, I was trying to avoid emotive words like "point-and-shoot" and
"DSLR"!

There is a considerable difference in sensor size ( factor of five or
more), and therefore lens focal length, and therefore depth of field,
between point & shoot cameras and 35mm kit (meaning either film cameras or
DSLRs). This depth of field difference makes the flash-illuminated motes
more visible, as they will be less out-of-focus, and therefore present a
visible disk (which may be quite a large fraction of the image as you have
seen) rather than an "invisible" blur. Some digital cameras do have the
flash very close to the lens, which can mean that the path distance from
the flash to a more just in front of the lens may be a lot less than in
either a DSLR or a 35mm compact camera.

Your comment about underexposure, ISO 400, dark subjects, and flash at its
limiting distance are all factors which might make this effect more
visible. As you've observed, dust actually on the lens would appear at a
fixed location in the image (for a particular zoom setting), and perhaps
it's more difficult for the front lens surface to be illuminated by the
flash! Probably the best way to cure it is an off-camera flashgun.

I hope that clarifies what I meant.

Cheers,
David
Anonymous
July 2, 2005 10:33:30 AM

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

Belgos wrote:
[]
> I don't think that smaller DOF would help a lot with this - in any
> case the light circles are way out of focus.

Bear in mind that the difference between point-and-shoot and 35mm sensors
could be around 5 times in linear size, so the equialvent out-of-focus
light circle on 35mm might more than fill the frame, and simply be
perceived as a general contrast reduction or haze.

David
!