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Canon 10D, studio strobes and rainbow colors

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Anonymous
April 8, 2005 11:38:52 AM

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

I borrowed a Canon 10D to do a charity shoot that I have done in the
past with film. My chief reason was to avoid scanning about 20 or 30
negatives.

While experimenting at home with the camera attached to my Norman P2000
pack, I found some very strange color artifacts that showed up
occasionally and unpredictably. The top of an image would be magenta,
the center would have close to good color, and the bottom would go
green. The next frame would be fine.

I have an example here:
http://www-schneider.viscom.ohiou.edu/into_italy/images...
or
http://tinyurl.com/572hg

It's not the usual white balance issue that gives me a thousand hits
during a search of this forum for similar issues.

Any ideas?

BTW, I do have a Wein Safe-Synch between the 100 volt Norman trigger
and the 10D. (No fried transistors yet.)

Also, the daylight white balance setting gives the best results with
these strobes and their UV-filtered tubes and aging umbrellas.

Bill Schneider
Anonymous
April 8, 2005 4:05:31 PM

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

Dirty Harry wrote:
>>transmit the color temp to the camera when its firing at less then
full
>>power because the temp changes. Is it possible your strobes arn't
fully
>>recharged?


Thanks for your reply.

I ran some experiments where I shot frames as fast as the camera would
cycle, and also a slow series of frames to see if it mattered. It
didn't
make any difference.

The AC-powered strobes are being used at the lowest power setting I had
on
the pack (400 w-s out of a possible 2000 w-s) which gives an ISO 100
exposure of f/11. A full power 2000 w-s shot recycles in about 1-2
seconds,
and the 400 w-s portion that I used requires only a fraction of a
second to
recharge.

I'm beginning to believe that it's a camera issue with this particular
loaner 10D. I will probably resort to color neg film for this shoot
using my
own equipment, but I'm not looking forward to the film scanning task
that
lies ahead.

Bill Schneider
Anonymous
April 8, 2005 8:01:57 PM

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

william.schneider@ohio.edu wrote:
>
> Dirty Harry wrote:
> >>transmit the color temp to the camera when its firing at less then
> full
> >>power because the temp changes. Is it possible your strobes arn't
> fully
> >>recharged?
>
> Thanks for your reply.
>
> I ran some experiments where I shot frames as fast as the camera would
> cycle, and also a slow series of frames to see if it mattered. It
> didn't
> make any difference.
>
> The AC-powered strobes are being used at the lowest power setting I had
> on
> the pack (400 w-s out of a possible 2000 w-s) which gives an ISO 100
> exposure of f/11. A full power 2000 w-s shot recycles in about 1-2
> seconds,
> and the 400 w-s portion that I used requires only a fraction of a
> second to
> recharge.
>
> I'm beginning to believe that it's a camera issue with this particular
> loaner 10D. I will probably resort to color neg film for this shoot
> using my
> own equipment, but I'm not looking forward to the film scanning task
> that
> lies ahead.

can you get this problem without the strobes?

how old is the norman? I would call norman,
and ask about color. they may recognize the problem.

I wonder if the color balance during the flash duration
can vary with old tubes or old capacitors.

also, is the camera set to auto, or to daylight?
I assume daylight from your post.

does this also happen to raw files?

>
> Bill Schneider
Related resources
Anonymous
April 8, 2005 10:01:19 PM

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

<william.schneider@ohio.edu> wrote in message
news:1112971132.913612.33440@z14g2000cwz.googlegroups.com...
> I borrowed a Canon 10D to do a charity shoot that I have done in the
> past with film. My chief reason was to avoid scanning about 20 or 30
> negatives.
>
> While experimenting at home with the camera attached to my Norman P2000
> pack, I found some very strange color artifacts that showed up
> occasionally and unpredictably. The top of an image would be magenta,
> the center would have close to good color, and the bottom would go
> green. The next frame would be fine.
>
> I have an example here:
> http://www-schneider.viscom.ohiou.edu/into_italy/images...
> or
> http://tinyurl.com/572hg
>
> It's not the usual white balance issue that gives me a thousand hits
> during a search of this forum for similar issues.
>
> Any ideas?
>
> BTW, I do have a Wein Safe-Synch between the 100 volt Norman trigger
> and the 10D. (No fried transistors yet.)
>
> Also, the daylight white balance setting gives the best results with
> these strobes and their UV-filtered tubes and aging umbrellas.
>
> Bill Schneider

I don't know much about strobes but I heard that the canon 580ex flash will
transmit the color temp to the camera when its firing at less then full
power because the temp changes. Is it possible your strobes arn't fully
recharged?
April 9, 2005 4:23:52 AM

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

<william.schneider@ohio.edu> wrote in message
news:1112971132.913612.33440@z14g2000cwz.googlegroups.com...
>I borrowed a Canon 10D to do a charity shoot that I have done in the
> past with film. My chief reason was to avoid scanning about 20 or 30
> negatives.
>
> While experimenting at home with the camera attached to my Norman P2000
> pack, I found some very strange color artifacts that showed up
> occasionally and unpredictably. The top of an image would be magenta,
> the center would have close to good color, and the bottom would go
> green. The next frame would be fine.
>
> I have an example here:
> http://www-schneider.viscom.ohiou.edu/into_italy/images...
> or
> http://tinyurl.com/572hg
>
> It's not the usual white balance issue that gives me a thousand hits
> during a search of this forum for similar issues.
>
> Any ideas?
>
> BTW, I do have a Wein Safe-Synch between the 100 volt Norman trigger
> and the 10D. (No fried transistors yet.)
>
> Also, the daylight white balance setting gives the best results with
> these strobes and their UV-filtered tubes and aging umbrellas.
>
> Bill Schneider
>

Hi there.

If there are apparent bands of colour at the top of the image and at the
bottom, it sounds as if there could be a shutter fault?

Perhaps the curtains are not running at constant speed, or the sync is out.

Your strobe burning time will be much shorter when using a low power
setting, and that might just be showing up the shutter fault.

Have you tried using a shutter speed well below the Max Sync Speed, say 1-
25th?

Or if the 10D has it, try using second curtain sync.

Roy G
Anonymous
April 9, 2005 4:23:53 AM

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

Roy wrote:
>
> Perhaps the curtains are not running at constant speed, or the sync is out.
>
> Your strobe burning time will be much shorter when using a low power
> setting, and that might just be showing up the shutter fault.
>
> Have you tried using a shutter speed well below the Max Sync Speed, say 1-
> 25th?

interesting test.

i just can't figure out how the shutter speed,
for a leaf shutter can be a problem,
or (as long as it is a focal plane),
can do anything wrong but image the shutter onto the sensor.


>
> Or if the 10D has it, try using second curtain sync.
>
> Roy G
Anonymous
April 9, 2005 6:51:40 AM

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

>>can you get this problem without the strobes?

I didn't see it in some daylight shots earlier in the day. However I didn't
shoot much available light, just enough to get a feel for the camera - about
20 frames.

>>how old is the norman? I would call norman,
>>and ask about color. they may recognize the problem.

My Norman system is a little over 20 years old. I haven't seen the problem
with other cameras - but they were film cameras. Recent film pictures made
with it have been fine. This was my initial trial using the studio strobes
with a digital camera.

>>I wonder if the color balance during the flash duration
>>can vary with old tubes or old capacitors.

Don't know the answer to that. I reverted to film for the shoot - 5 rolls.
If there's a problem with the lights, it should show on film as well. The
film is at the lab now, and I'll report any problems.

>>also, is the camera set to auto, or to daylight?
>>I assume daylight from your post.

I set it to daylight. I didn't know how the in-camera processing would
affect the pictures, so I set it manually to remove one variable.

>>does this also happen to raw files?

Didn't try that because I had just 3-256MB cards and I was concerned with
having enough storage. It sounds like a good experiment though. I'll
probably try that before I give the camera back to it's owner. I did like
the quickness of autofocus and the subdued noise of the Canon 10D compared
to my Nikon N90s.

At any rate, I've got a job ahead of me this weekend scanning a bunch of
negatives. Sigh.

Bill Schneider
Anonymous
April 9, 2005 6:51:41 AM

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

William Schneider wrote:
>

> My Norman system is a little over 20 years old. I haven't seen the problem
> with other cameras - but they were film cameras. Recent film pictures made
> with it have been fine. This was my initial trial using the studio strobes
> with a digital camera.

I use an S2 Pro with both Ascor and WhiteLighning strobes,
and the results so far look perfect,
(if I take the time to light perfectly).

> >>does this also happen to raw files?
>
> Didn't try that because I had just 3-256MB cards and I was concerned with
> having enough storage. It sounds like a good experiment though. I'll
> probably try that before I give the camera back to it's owner. I did like
> the quickness of autofocus and the subdued noise of the Canon 10D compared
> to my Nikon N90s.
>
> At any rate, I've got a job ahead of me this weekend scanning a bunch of
> negatives. Sigh.

does the 10D synch at high speeds, higher than 1/125?
the cameras that synch at very high speeds like 1/1000
may do something very different with the gating of the sensor.

you have an interesting problem,
and I am hooked. I am interested in what you find out.


>
> Bill Schneider
April 9, 2005 4:52:44 PM

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

So sorry.

I was not aware that the 10D had a leaf shutter, I thought it was an D SLR.

Just forget my suggestion.

Roy G

"Crownfield" <Crownfield@cox.net> wrote in message
news:4257476B.6075@cox.net...
> Roy wrote:
>>
>> Perhaps the curtains are not running at constant speed, or the sync is
>> out.
>>
>> Your strobe burning time will be much shorter when using a low power
>> setting, and that might just be showing up the shutter fault.
>>
>> Have you tried using a shutter speed well below the Max Sync Speed, say
>> 1-
>> 25th?
>
> interesting test.
>
> i just can't figure out how the shutter speed,
> for a leaf shutter can be a problem,
> or (as long as it is a focal plane),
> can do anything wrong but image the shutter onto the sensor.
>
>
>>
>> Or if the 10D has it, try using second curtain sync.
>>
>> Roy G
Anonymous
April 9, 2005 4:52:45 PM

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

Roy wrote:
>
> So sorry.
>
> I was not aware that the 10D had a leaf shutter, I thought it was an D SLR.

you were right, it does not.
I was just being inclusive,
in that mechanical shutters should not produce a color shift.

>
> Just forget my suggestion.
>
> Roy G
>
> "Crownfield" <Crownfield@cox.net> wrote in message
> news:4257476B.6075@cox.net...
> > Roy wrote:
> >>
> >> Perhaps the curtains are not running at constant speed, or the sync is
> >> out.
> >>
> >> Your strobe burning time will be much shorter when using a low power
> >> setting, and that might just be showing up the shutter fault.
> >>
> >> Have you tried using a shutter speed well below the Max Sync Speed, say
> >> 1-
> >> 25th?
> >
> > interesting test.
> >
> > i just can't figure out how the shutter speed,
> > for a leaf shutter can be a problem,
> > or (as long as it is a focal plane),
> > can do anything wrong but image the shutter onto the sensor.
> >
> >
> >>
> >> Or if the 10D has it, try using second curtain sync.
> >>
> >> Roy G
Anonymous
April 9, 2005 5:51:55 PM

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

In message <1112985502.823168.155390@z14g2000cwz.googlegroups.com>,
william.schneider@ohio.edu wrote:

>I'm beginning to believe that it's a camera issue with this particular
>loaner 10D.

If it were the camera, I might suspect a mis-aligned microlens, but it
doesn't happen all the time.

In the sample you show, the magenta-ish top is also the most well-lit
part of the image. Perhaps there is ambient light in the room,
relatively green to the strobes, that shows up more when the aperture is
open more, and the flash contribution is weaker?

--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
Anonymous
April 9, 2005 7:15:04 PM

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

>>Perhaps there is ambient light in the room,
relatively green to the strobes, that shows up more when the aperture is
open more, and the flash contribution is weaker?

I considered that, and extinguished all ambient light except for the
tungsten modeling lamp of the strobe. It didn't make any difference.

Also at f/11 ambient light wouldn't amount to much because of its relative
weakness compared to the strobe. I used 1/60 and 1/100 as shutter speeds
during the experiment. But like your suggestion, I thought I'd try anyway.

It remains a mystery with this particular camera, and I'm just going to
chalk it up to "one of those things". I used film for the shoot, but now
I've got 5 rolls to edit and scan. The Canon 10D goes back to its owner
Monday.

I'm going to ask another photographer at work to borrow his 20D at some
point to see if it works OK with studio strobes.

Thanks everyone for your leads and suggestions about this problem.

Bill Schneider
Anonymous
April 9, 2005 7:15:05 PM

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

William Schneider wrote:
>
> >>Perhaps there is ambient light in the room,
> relatively green to the strobes, that shows up more when the aperture is
> open more, and the flash contribution is weaker?
>
> I considered that, and extinguished all ambient light except for the
> tungsten modeling lamp of the strobe. It didn't make any difference.
>
> Also at f/11 ambient light wouldn't amount to much because of its relative
> weakness compared to the strobe. I used 1/60 and 1/100 as shutter speeds
> during the experiment. But like your suggestion, I thought I'd try anyway.
>
> It remains a mystery with this particular camera, and I'm just going to
> chalk it up to "one of those things". I used film for the shoot, but now
> I've got 5 rolls to edit and scan. The Canon 10D goes back to its owner
> Monday.
>
> I'm going to ask another photographer at work to borrow his 20D at some
> point to see if it works OK with studio strobes.
>
> Thanks everyone for your leads and suggestions about this problem.

your analytical approach is good.
in newsgroups you see complete failures of reasoning, but that is not
your problem.
let us know what you find out.

do you get the off color with any other flash?
I assume that the flash was in manual mode?
that eliminates any interaction errors.


>
> Bill Schneider
!