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Old Mar 15, 2007, 9:06 PM   #1
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Hi
I've just bought panasonic Tz1 and I've got problem with pictures taken indoors (lights on) with flash. On every picture with flash walls are pink. Without flash everything is ok. I tried all WB settings and have similar results. In daylight or in less lighted room (for example 1 bulb instead of 3) I've got no problem with flash, walls are white.

flash off

flash on





1 bulb on (white wall)


3 bulbs on (pink)


I don't know if my tz1 is broken or is it natural for this camera. I've taken the same pictures with my brother's fz7 (much bigger flash) and walls were white on most of it. When Fz7 had problems the walls were light orange not red/pink. I would be greatfull if sb could look at this.
Thanks
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Old Mar 16, 2007, 9:45 AM   #2
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What kind of bulbs do you have? Incandescent or florescent replacements? What wattage?

The fundamental problem is that your light sources have different color temperatures. The incandescents, if that's what they are have a color temperature between 2700 & 3000 Kelvin whereas the flash has a color temperature of about 6000 Kelvin (daylight). I'm sure if the camera is firing the flash it issetting white balance to6000K and with just one bulb lit the flash predominates so that works out OK. With three bulbs lit the incandescent is a much more significant part of the light hence the shift in color.

You might try setting the white balance to tungsten as a starting point.
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Old Mar 16, 2007, 9:50 AM   #3
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Mixed light sources can be tough for a camera.

The flash is closer to daylight. But, the ambient lighting you have is a much different color temperature.

So, if you set it for Incandescent, the flash is going to mix a totally different color of light in with it (and vice-versa).

Chances are, the Auto WB with flash is assuming that the flash is providing most of the light. So, when you have a lot of incadescent or other light sources mixed in with it, it can throw the colors off.

I don't see a way to tweak the WB using a Kelvin Temperature with your camera (unless I missed it). But, it appears that your model does support a custom white balance that allows it to measure the light from a Photographic Gray or White card. Unfortunately, that's not going to take your flash into consideration.

What you may want to try is using the Custom White Balance with a target that is partially illimunated by your indoor light sources and a bit of sunshine coming in through a window (which is going to be close to your flash temperature) to get a better balance. If you don't have another target, sometimes a white coffee filter can work well.


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Old Mar 16, 2007, 9:58 AM   #4
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I missed a feature. From the specs, it looks like your Panasonic has a White Balance "fine tune" feature. So, you may want to experiment with it to get better results.

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Old Mar 16, 2007, 1:46 PM   #5
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BTW, I noticed the EXIF in a photo I looked at in indicated the camera was shooting at 1/30 second, f/2.8, ISO 100

Your Panasonic appears to lean towards slower shutter speeds with flash (at least at wider zoom settings). That can let in more ambient light. Some models use a faster shutter speed by default.

Personally, I prefer a slower shutter speed by default. It's a matter of preference and the lighting you'll be shooting in.

If your model doesn't have a way to control shutter speed directly (a faster shutter speed would let in less ambient light so that the flash was contributing more to the exposure, without impacting flash range at lower ISO speeds), you may be able to try a few other techniques.

If it can't control shutter speed (no manual exposure mode), sometimes zooming in can help (the camera's lens loses light as more zoom is used and it would probably use a longer flash burst to try and help make up for it as long as you were within the flash range (and it will be shorter as you zoom in more with a compact camera like your Panasonic, since the lens is much brighter on it's wide end.

Setting the ISO speed to a lower value can also help reduce ambient light exposure (so that the flash is contributing more). But, you will lose a bit of maximum flash range if you use either technique (each time you double the ISO speed, the flash range increases by 1.4x).

Then, with the flash contributing more to the exposure, you'd probably be fine using Auto White Balance (using flash or daylight presets as alternates).

Or, do the opposite... Instead of trying to get your flash to provide most of the light and setting your white balance for it, try to keep the aperture wide open (f/2.8 on the wide end of your zoom) with the slower 1/30 second shutter speed. Then, increase your ISO speed to make it more sensitive to light and set the white balance to your artificial light source.

The camera's autoexposure should then try to use a shorter flash burst (since the ambient light will be contributing more at a higher ISO speed at 1/30 second with the aperture wide open at f/2.8 ). Then just set the White Balance to ambient instead as a starting point (since it should then be providing the majority of the light) and you'll need less fine tuning.

Just be careful of motion blur from subject movement or blur from camera shake if the ambient light is contributing more at shutter speeds that slow.

Using a higher ISO speed will mean a higher noise level. But, personally, I'd prefer a tad more noise in order to pick up more ambient light. I prefer this technique more often than not when using a flash (higher iso speeds, slower shutter speeds, letting the flash contribute less to the exposure).

It all depends on what you want to accomplish.

You may not want the area surrounding or behind your subject to stand out as much (so settings where the flash would contribute more to the exposure and the ambient light less may be desired, so that the background is not well illuminated).

Or, you may want ambient light to contribute more (so that the background is better illuminated by it, with the flash contributing less to the exposure of your subject, so that the lighting is not as harsh.

Pros and Cons.

In any event, the reason it's difficult for you to get a more accurate color in that lighting (multiple bulbs providing artificial lighting + a flash) is because the 1/30 second shutter speed with f/2.8 is allowing neither one to dominate the exposure.

So, if you can use settings to allow just one to contribute more in those conditions, it will make it easier for you to use one of the white balance presets to get it closer.

Then, use the White Balance fine tune feature with a preset or a custom white balance to get it even better.

If that doesn't suffice, you can use an image editor to get it closer.


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Old Mar 16, 2007, 6:59 PM   #6
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Thanks for Your replies.
The lights on the pictures were mixed but in one room I have 4 same bulbs and it is similar but little better.
JimC I took some pictures using zoom as You said and it really helped - walls are white with zoom. Higher iso - only a bit better (brighter picture, but still that pink colour). With the rest of your advice I'm gonna experiment.
So you think that this is typical for this model and it is not faulty? I ask because it's new and I could return/exchange it but I'm very pleased with other pictures so if it is "normal" behaviour I will not.
Thanks a lot.
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Old Mar 16, 2007, 7:20 PM   #7
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migug wrote:
Quote:
JimC I took some pictures using zoom as You said and it really helped - walls are white with zoom.
Yes, the concept behind this (zoom in more, leave ISO speed set lower) is to force the camera's lens to let in less light, since you don't have direct control of the aperture via settings. The camera's lens loses light as you zoom in more, so zooming in has the same effect.

So, the Autoexposure will keep the flash on for longer (the way the flash strength is varied is by keeping the flash on for a shorter or longer period of time). That allows the flash to contribute a greater percentage to the image compared to your artificial lighting sources so that the white balance looks closer using flash (since the camera's auto WB is likely setting it for flash if you use it). Alternatively, force it to flash or daylight using this technique and see if you get better results (when zoomed in like that with the ISO speed set lower).

This technique will reduce your flash range. But, as long as you stay within the rated range, your flash will contribute more than ambient light at longer focal lengths with your type of camera.

Quote:
Higher iso - only a bit better (brighter picture, but still that pink colour). With the rest of your advice I'm gonna experiment.
If you use a higher ISO speed, you'll want to do the opposite (keep the lens set to wider zoom settings so that you are letting in more light). Then, try one of the presets that best matches your artificial lighting (for example, incandescent) and use the WB fine tuning option to try and get rid of the color cast (since ambient light will be contributing more to the exposure using this technique).

What we're trying to accomplish is finding a way to allow one light source (artificial or flash) to contribute significantly more to the exposure compared to the other. That way, we can set the White Balance to the dominate light source with an available preset option and have less "tweaking" to do with the fine tune feature (or during post processing using an editor later).

Quote:
So you think that this is typical for this model and it is not faulty? I ask because it's new and I could return/exchange it but I'm very pleased with other pictures so if it is "normal" behaviour I will not.
It's unusual for someone to have 3 or 4 lightbulbs like you apparently have in a smaller area when using a flash. So, that allows more ambient light (light sources other than the flash) to enter the exposure. That's why the problem goes away with only 1 bulb on, and is more pronounced with multiple bulbs on.

That (more ambient light from artificial sources), combined with a slower default shutter speed with flash (1/30 second) can create WB issues due to the mixed lighting. Most models will use a slightly faster shutter speed by default which would let less ambient light in. There are pros and cons to both approaches. I personally like a little slower shutter speed like your model is using.

But, it can complicate WB in some cases. It can also lead to motion blur from subject movement if ambient light is contributing too much to the exposure and your subject is not relatively still. So, if you use the technqiue of setting a higher ISO speed, not zooming in as much, and setting your White Balance to the preset that matches the lighting, you have to be more careful about subject movement (because you can get motion blur from ambient light exposure).

There are pros and cons to either approach. There is only so much flexibility you'll have in a compact model like this one without full manual exposure available. So, any choice a manufacturer makes tends to be somewhat of a compromise.

I'd play with the settings and see if it's a good fit for the conditions you'll shoot in more often.
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Old Mar 16, 2007, 7:29 PM   #8
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Thank You very much
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