Exposure question mixing flash and ambient

[Greg Jones]

We were talking on another thread and I thought I would jump over here instead.
These are straight out of camera and I don't know if this is a normal exposure I should expect or if I can do something to get the color better.
These were done with CWB ( Gray card) and even though neither image is good , it gets my point across.

First one is shot ( ISO 800) with the ambient 1 1/3 stop under exposed and the balance picked up with the flash on ETTL. Look at the color cast I am getting from the light over head.

Second one is shot (ISO 100) with ambient way low off scale and exposure light flashing. The balanced picked up with ETTL . Looking at the color in this one it is more true to color.

Question - Why am I not getting a good color balance from the ambient ? And why is flash a better more true color ?
The histro gram is show a better exposure on the first then on the second so the exposure is better but the color is not. All other settings were let the same.

245230

Manual Exposure
Tv( Shutter Speed )
1/30
Av( Aperture Value )
2.8
Metering Mode
Center-Weighted Average Metering
ISO Speed
800
Lens
28.0 - 75.0 mm
Focal Length
40.0 mm
Image Size
3504x2336
Image Quality
Fine
Flash
On
Flash Type
External E-TTL
Flash Exposure Compensation
0
Red-eye Reduction
On
Shutter curtain sync
1st-curtain sync
White Balance Mode
Custom

245231

Manual Exposure
Tv( Shutter Speed )
1/30
Av( Aperture Value )
2.8
Metering Mode
Center-Weighted Average Metering
ISO Speed
100
Lens
28.0 - 75.0 mm
Focal Length
42.0 mm
Image Size
3504x2336
Image Quality
Fine
Flash
On
Flash Type
External E-TTL
Flash Exposure Compensation
0
Red-eye Reduction
On
Shutter curtain sync
1st-curtain sync
White Balance Mode
Custom

[Bob_A]

Because AWB doesn't really work that well in situations where you are a long way off daylight conditions (~5200K). When most of the light is from flash (~5600K), AWB works well ... for tungsten or florescent lighting it's horrible.

By balancing with ambient flash is only providing a bit of fill and the tungsten lighting will be prominent ... and you'll have a yellow color cast.

[BrianAZ]

Greg,

When you have two dissimilar light sources, you are going to get a color cast. The only way to avoid that is to put a gel on your flash to have it match the color temp of the ambient.

[Dermit]

Hey Greg, good experiment. For a shot like this what you did in the second shot is prefereable as the background is well within the range of the flash so you get a decent look by using flash as the main light contributor. If, however, you were shooting at a wedding reception and the background was much more distant a shot with the settings you had on that second shot would look more like it was done in a cave as the background would never see any light from the flash and the ambient would not contribute. This would be the typical look we get from most amatuer flash photography. So for a shot like that you would want to do more like you did in shot one which would make it look more natural. You would still get color temperture imbalance and the only way to fix it would be to gel your flash with a filter matching the color temp of the ambient light.

[Greg Jones]

Well sounds like you guys explained it well. This area of the kitchen has been a trouble spot for taking images. I keep trying to do like I thought was right by balancing it but I keep resorting back to the flash. I guess I thought Custom White balance was just that, white balanced in the lighting you are shooting. I didn't realize that tungsten and florescent would not balance well even with custom.
Dermit you mentioned the gels on the other thread and that is something I need to get and try out. I thought gels were for changing colors on backdrops and not for balancing. If I would have just thought about it, it is changing the color but changing to the correct color needed.
So when doing weddings and shooting in the church, do you always use gels ? How are you sure of the type of lighting that the church has? In todays world it could be many different types.
Hmmm, armature shooting in a cave. Guess I am guilty :oops:but I am trying to improve it.:D I have done 11 weddings and some of the shots at the alder looked just like that, in a cave. Then there were some churches that has a lighter background and came out great.
Everyone kept telling me that it was the fall of the flash but never really explained how to correct it.
What I need to do is to go to a chuch and while no one is there , take my wife and get in some practice shots.Second thought, I better find someone else because she has just about had it with me, that is why the bear is sitting at the table and not her.

Thanks guys now I don't have to beat myself up over this any more.

[Shooting]

I\'ve been doing weddings for years. I never used or never plan on using gels. I keep it simple. I do a custom white balance and any more corrections I do in the raw editor (I shoot jpeg) in Photoshop CS3..if there is still too much tungsten I just use the blue picture filter in CS3 and that fixes it. I keep it simple, enjoy my shooting and fix in post processing.

[airfrogusmc]

Greg, I kinda like a little warmth in the background as long as it doesn't inpact the skintone to much. Here's a shot from a corporate job I shot last weekend. I usaully meter the ambient and let that go down 1 stop or so from what I set my camera and strobe for. The ambiet was meter at 1/60 at 2 I shot at 1/60 at 2.8. raw 5500K.
5D 35 1.4L 1600 ISO manual spot

http://i4.photobucket.com/albums/y118/airfrogusmc/IMG_8214.jpg

if your not crazy about the warm light in the background you can filter the strobe so its putting out 3200K (whats that an 85 filter?) and set your camera for 3200K any adjusting from there on out is easy if you're shooting raw. Or do a quick mask in photoshot (CS2) mask out the couple so the background is selected and go to Image/Adjustments/Photofilter/pull down to cooling 80 and adjust in the % until you get what you like. here...
http://i4.photobucket.com/albums/y118/airfrogusmc/IMG_82142.jpg

Myself I don't mind the warmth in the B/G.

[Greg Jones]

I\'ve been doing weddings for years. I never used or never plan on using gels. I keep it simple. I do a custom white balance and any more corrections I do in the raw editor (I shoot jpeg) in Photoshop CS3..if there is still too much tungsten I just use the blue picture filter in CS3 and that fixes it. I keep it simple, enjoy my shooting and fix in post processing.

Yea, I agree ,keep it as simple as possible.Just not enough time to set up the way you would like. No I don't have that kind of experience but enough to know simple and fast.
I like to try and get the the proper settings and the best image I can the first time. One big reason is that I am in a learning process and working at getting the best first shot is teaching me how do set up properly.
I have been shooting for 5 years and even though I have a good understanding of how the camera and setting work it is not second nature to me yet. It is getting better but when you work a full time job you have to learn slowly.
I have CS2 and not CS3 yet.
Thanks for your input.

[Greg Jones]

Greg, I kinda like a little warmth in the background as long as it doesn't inpact the skintone to much. Here's a shot from a corporate job I shot last weekend. I usaully meter the ambient and let that go down 1 stop or so from what I set my camera and strobe for. The ambiet was meter at 1/60 at 2 I shot at 1/60 at 2.8. raw 5500K.
5D 35 1.4L 1600 ISO manual spot

http://i4.photobucket.com/albums/y118/airfrogusmc/IMG_8214.jpg

if your not crazy about the warm light in the background you can filter the strobe so its putting out 3200K (whats that an 85 filter?) and set your camera for 3200K any adjusting from there on out is easy if you're shooting raw. Or do a quick mask in photoshot (CS2) mask out the couple so the background is selected and go to Image/Adjustments/Photofilter/pull down to cooling 80 and adjust in the % until you get what you like. here...
http://i4.photobucket.com/albums/y118/airfrogusmc/IMG_82142.jpg

Myself I don't mind the warmth in the B/G.


Cool Allen, I like it, nice shot ! The first one is fine with me . I don't mind it when the b/g is warm as long as the subjects are correct.
There comes the times when you want to get a shot of the whole dance hall at the reception, then I don't like the warmth.
You mention 85 filter and cool 80 . Can you tell me what 80 & 85 is ? Seems we are a ways of from the color temp to be that.

I hope you guys don't mind me asking these questions. I have read on all of this but it is so hard to comprehend what your not a seasoned photographer.
You get to the point that you should know these basics but the fear of looking stupid holds you back from asking questions. I know there arn not stupid questions but .....
I am getting some great input from all of you, clearing up some of my fears of the digital photoraphy world.:D

[airfrogusmc]

Greg some info on filters.
http://en.wikipedia.org/wiki/Filter_(photography)

http://en.wikipedia.org/wiki/Wratten_number

Color temp.
http://en.wikipedia.org/wiki/Color_temperature

[Wilt]

So when doing weddings and shooting in the church, do you always use gels ? How are you sure of the type of lighting that the church has? In todays world it could be many different types. ...

What I need to do is to go to a chuch and while no one is there , take my wife and get in some practice shots.Second thought, I better find someone else because she has just about had it with me, that is why the bear is sitting at the table and not her

If you bring a Rosco PlusGreen and a Rosco CTO set you will be covered for the many situations (different strengths -- but usually 1-2 strengths of any of them, not the full range)

You can balance flash to match fluorescent ambient, you can balance flash to match Tungsten.



Just tell your wife that you don't to bother her with all of the modelling chores, and you will just go out and hire an 18-21 year old gal in need of some side money, and watch her reaction! ;)

[Wilt]

You mention 85 filter and cool 80 . Can you tell me what 80 & 85 is ? Seems we are a ways of from the color temp to be that.


80A is from the film days, where you take daylight-balanced film and shoot in tungsten ambient, so you put the 80A over the lens to balance to the film.

Conversely, the 85B is used with tungsten-balanced film to correct the bluish cast of daylight.

[Greg Jones]

Greg some info on filters.
http://en.wikipedia.org/wiki/Filter_(photography)

http://en.wikipedia.org/wiki/Wratten_number

Color temp.
http://en.wikipedia.org/wiki/Color_temperature


Thanks Allen, got some reading to do.

[Greg Jones]

If you bring a Rosco PlusGreen and a Rosco CTO set you will be covered for the many situations (different strengths -- but usually 1-2 strengths of any of them, not the full range)

You can balance flash to match fluorescent ambient, you can balance flash to match Tungsten.



Just tell your wife that you don't to bother her with all of the modelling chores, and you will just go out and hire an 18-21 year old gal in need of some side money, and watch her reaction! ;)


Wilt, if your balancing say tungsten with a gel , what does that do to the on camera strobe temp ? Will it change it to maybe the wrong temp when mixing ?

The only part that my wife would be upset over is the paying the money part, she knows I am harmless other wise. ;)

[Wilt]

Wilt, if your balancing say tungsten with a gel , what does that do to the on camera strobe temp ? Will it change it to maybe the wrong temp when mixing ?



Restate your question, as I am not sure what you are asking.

The filters I mentioned (PlusGreen, CTO) are put on electronic flash so that its output matches ambient lighting.

You can also balance Fluorescent to daylight like, with MinusGreen gel. And you can balance Tungsten to daylight with Blue filter.

[Greg Jones]

Restate your question, as I am not sure what you are asking.

The filters I mentioned (PlusGreen, CTO) are put on electronic flash so that its output matches ambient lighting.

You can also balance Fluorescent to daylight like, with MinusGreen gel. And you can balance Tungsten to daylight with Blue filter.

Hmmm, re asked the question but I must have hit the wrong button.

Sorry, I know what I mean :confused: let me try again, lol.

I am in Tungstin ambient lighting and I have a 580ex strobe flash attachment.
I am going to mix both the tungstin light and light from the 580 flash attached.
I put on a gel filter to balance the temp of the ambient tungstin lighting but at the same time it is on my flash so will it cause the flash to have a different output of temp.
I have a feeling I have this all wrong in my thinking. You said that it will change the flash to match the tungstin ambient light. I thought what I was tring to do was to change the ambient tungstin to match the flash.

Now when I change the flash to match the tungstin ,won't I still have the orange from the color temp of tungstin ?

I am going to B&H and look at them so I have a better idea of what is going on. I will be back.

[Wilt]

Hmmm, re asked the question but I must have hit the wrong button.

Sorry, I know what I mean :confused: let me try again, lol.

I am in Tungstin ambient lighting and I have a 580ex strobe flash attachment.
I am going to mix both the tungstin light and light from the 580 flash attached.
I put on a gel filter to balance the temp of the ambient tungstin lighting but at the same time it is on my flash so will it cause the flash to have a different output of temp.
I have a feeling I have this all wrong in my thinking. You said that it will change the flash to match the tungstin ambient light. I thought what I was tring to do was to change the ambient tungstin to match the flash.

Now when I change the flash to match the tungstin ,won't I still have the orange from the color temp of tungstin ?

I am going to B&H and look at them so I have a better idea of what is going on. I will be back.


Two approaches, one usually much more feasible than the other!

1. change the flash to match ambient color temp, then balance camera to the tungsten/correct in PP

2. change the ambient color temp to daylight, then shoot with flash and no PP color balancing work needed.

The problem with #2 is how on earth you put on filter on every ambient light!

So you do #1, putting a CTO gel on the flash to balance its output to tungsten, then set color balance in camera (to 3400K or 3200K or custom balance, if shooting JPG) or change photo to the correct balance during RAW PP.

[Greg Jones]

Two approaches, one usually much more feasible than the other!

1. change the flash to match ambient color temp, then balance camera to the tungsten/correct in PP

2. change the ambient color temp to daylight, then shoot with flash and no PP color balancing work needed.

The problem with #2 is how on earth you put on filter on every ambient light!

So you do #1, putting a CTO gel on the flash to balance its output to tungsten, then set color balance in camera (to 3400K or 3200K or custom balance, if shooting JPG) or change photo to the correct balance during RAW PP.

Ok, think I have it ,wasn't sure until I read your post. I did find this Strobist site and it help but I was still confused a bit. http://strobist.blogspot.com/2006/03/lighting-101-using-gels-to-correct.html

Now let me expalin my thought and see if I am understanding.

The flash out put with the gel is throwing out a color temp the same as the ambient say tungstin. With the this same color temp being casted to match the tungstin the camera will adjust to the temp of 3200k that you set it at.
Man I hope I got this right !

I see on the Strobist site that he cuts it inot strips and uses velcro to attach. I am going to look and see if I can find small amounts to try. I am seeing large sheets on it on B&H but I didn't look too hard yet.

Thanks again

[airfrogusmc]

Don't forget that dimmer ambient tungsten's could be 2400K so if you have a filter on your flash thats making your strobe 3200 you're still going to have that warm light in the background. And with real bright ambient tungsten lights they could be 3400 maybe 3800 K and that will give you very cool light in the background. Thats why I just make sure the skin tone looks good and don't worry about the warm tones in the background. In fact I think its looks rather nice. Ads a warmth to the overall feel of the image. Nice if your shooting wedding in my opinion. Thats the thing about event photography there are going to be things that its probably not practical to try and control. Find something thats going to work for you that you can do consistently. It could take years to get to the point where your half way pleased.

[Wilt]

Ok, think I have it ,wasn't sure until I read your post. I did find this Strobist site and it help but I was still confused a bit. http://strobist.blogspot.com/2006/03/lighting-101-using-gels-to-correct.html

Now let me expalin my thought and see if I am understanding.

The flash out put with the gel is throwing out a color temp the same as the ambient say tungstin. With the this same color temp being casted to match the tungstin the camera will adjust to the temp of 3200k that you set it at.
Man I hope I got this right !

I see on the Strobist site that he cuts it inot strips and uses velcro to attach. I am going to look and see if I can find small amounts to try. I am seeing large sheets on it on B&H but I didn't look too hard yet.

Thanks again

Yup.

And you can obtain sample swatch books of Rosco gels.

[Greg Jones]

Oh yea I forgot you said that. I think you said B&H. I will look back in the post.

Thanks, Greg