Would a flash gel help?

[John E]

I recently took some pictures of a banquet in a dimly lit (incandescent light) hotel ballroom. In order that the background wouldn't be totally dark, I used ISO1600 on most of the shots where I knew the background would be part of the picture, such as shooting a picture of people seated at a table in the middle of the ballroom. I tried keeping the shutter at about 1/60 sec.

I noticed that the color of the flash and the color of the background are very different. Even after correcting the white balance for the foreground, the background is still very yellow.

My question is: Would a flash gel help to keep the background and foreground colors similar or is there a better way to shoot this situation?

[LeuceDeuce]

I can't believe you didn't blow highlights, and you still have so many plugged shadows with those settings. Dimly lit is an understatement :)

I've never used a gel so I'm not sure where to direct you in their useage, but I can help with the pp after the fact. I did a very quick edit by duplicating the layer, color correcting for the areas outside the flash zone, and blending the layers with a mask. I did a rough here, but you would reduce the opacity of the mask brush as you got closer to the flash zone. Otherwise you'll get whites turning a bit blue at the transition points like I have here.

[kirkt]

The short answer to your question is "Yes". If you choose the gel to match the ambient light, then you can use the camera white balance setting that matches your overall light. The flash is very high color temp (white/blue), the ambient light low temp. If you lower the color temp of the flash, then you will even the lighting in your image and make the WB correction more uniform. Even if you shoot RAW, the fact that there are 2 different color temps in the same image make for a problem in post.

LD's post processing assumes some things about the color of objects in the background and also a distinctly separated foreground (flash light) and background (ambient light), which is probably okay most of the time. But if you had a bunch of shots to correct like this, that processing may be time consuming.

Kirk

[John E]

Thanks for the advice, guys. I'll try using an ambient colored gel next time. For me, taking pictures in a dimly lit hotel ball room has been difficult. Not only is using a flash difficult because you cannot bounce, trying to match the flash and ambient light is also difficult.

[LeuceDeuce]

Thanks for the advice, guys. I'll try using an ambient colored gel next time. For me, taking pictures in a dimly lit hotel ball room has been difficult. Not only is using a flash difficult because you cannot bounce, trying to match the flash and ambient light is also difficult.

Why can't you bounce?

[John E]

Why can't you bounce?

I can't use bounce because the ceilings are too high and the walls are too far away. At least that is what I thought. Am I wrong? Is bounce effective in a large ballroom

[cdifoto]

Get a CTO and set your camera to tungsten and you should be good to go.

You can still bounce in a ballroom:

http://photography-on-the.net/forum/showthread.php?t=466874

[yogestee]

Get a CTO and set your camera to tungsten and you should be good to go.

You can still bounce in a ballroom:

http://photography-on-the.net/forum/showthread.php?t=466874

Whats a CTO??

[cdifoto]

CTO stands for Color Temperature Orange.

[yogestee]

CTO stands for Color Temperature Orange.

Is that a made up acronym??

[cdifoto]

Yep. Someone made it up at some point in time, but it wasn't me.

[kirkt]

Here you go, JohnE:

http://strobist.blogspot.com/2008/05/lighting-102-62-gelling-for-tungsten.html

[LeuceDeuce]

I can't use bounce because the ceilings are too high and the walls are too far away. At least that is what I thought. Am I wrong? Is bounce effective in a large ballroom

Here's a great thread by Curtis N about that:

http://photography-on-the.net/forum/showthread.php?p=4893926#post4893926

I used bounced flash at a recent ballroom competition (hotel ballroom) and the results were great.

[macobee]

I can't use bounce because the ceilings are too high and the walls are too far away. At least that is what I thought. Am I wrong? Is bounce effective in a large ballroom

set your flash to full power and bounce away, it can be done with very high ceilings even!

[PETERSYMES]

Make sure the ceiling is a fairly nutural colour though or things may get even more complicated.

[John E]

Thanks guys. Curis' thread is amazing. I wonder if I could have set my shutter to 1/250, ISO 1600 and obliterated the ugly yellow background tungsten light, as Curtis did. Then I wouldn't even have a need for a CTO gel. I'm going to try that next time.

[kirkt]

Also remember that at full power, your recycle times go up and you will drain the batteries on your flash faster, so carry spares. I suppose it comes down to what kind of shots you want - do you want to light the entire room or focus the lighting on your subject and de-emphasize the rest of the room? With bounce, you have little control over the ratio of light falling on the subject versus the background and little control over the direction of the light if you are bouncing from the ceiling.

The original issue in the thread was the problem with color balance from competing light sources. In Curtis N's thread, he had virtually no competing light sources in the setting where he shot the two stage producers, so his flash, colored by the ceiling upon which he bounced his flash, dictated the relatively uniform color. His exercise was to demonstrate that a 580EXII could be used to bounce off of a high ceiling, not that it would eliminate the issue of multiple color temperature light sources. The flash only had to illuminate the relatively unlit scene, so pushing the ISO gave him the "correct" exposure for his scene. In a setting like the banquet room above, remember that when you shoot full power and increase your ISO, you are going to increase the ambient contribution as well (the pesky tungsten lamps that caused the problem in the first place). So your flash somehow needs to be able to overpower all of the lights in the scene (including the background) if you are going to get a uniform white balance from bouncing our flash only. In this case, you probably want to go to the venue ahead of time and experiment with the bounce to see if you can balance the ambient and flash contributions in manual mode with a combination of shutter speed and ISO. If you can, try to get your subjects to move closer together and crop in tighter on the faces so that most of the extraneous background (like tungsten lamps on walls) is eliminated. Usually, if you need the background in the shot for context of the location or event, then it will (hopefully) be more interesting and you can light it with bounce so that it, and the subject, gets equal emphasis. Remember that, when photographing people, you want a reasonably good representation of skin, so take some reference shots with a white balance card if you are going to bounce. The more locations and surfaces that you use for bounce, the more reference shots you will need if you want to reproduce skin tines properly. Otherwise people may end up looking too blue.

If you can't, then make life easier and get more control over your lighting by using the various CTO or other appropriate gels. This way your white balance reference will not change unless there is an extremely powerful local ambient light source that is different than the gel you choose. Also, get your flash off of the camera hotshoe to give your lighting a little more directionality, and maybe an 80/20 bounce or mini-softbox. You will have much more control of your light and the extra gear is compact and relatively inexpensive. If you use all of these techniques, your shots will also have more variety.

Good luck,

Kirk

PS -Read this case study to help understand balancing ambient fill and flash:
http://strobist.blogspot.com/2008/04/on-assignment-controlling-daylight-pt-1.html

[John E]

Thanks for the excellent explanation Kirk. I've order some 1/2 CTO gels and will try to experiment with them. During this shoot, I took many pictures of a VIP shaking hands with different individuals near a wall. For those shots I did use an umbrella off to my left and used another 580 ex II with a ratio of 4:1. Those pictures came out wonderful. It was only the pictures that the flash had to compete with the tungsten background that the light color temperature is drastic. You would think that someone would invent a gel that fits on a camera better than having to tape it on or use velcro (or have a flash that changes color temperature). Wouldn't that be wonderful?

[kirkt]

A flash that changes color temp?! You and your Nobel Prize - go get it! I think the key to all of this is to experiment after finding enough info to get you most of the way there. Sounds like you have plenty of gear and knowhow. Have fun!

Kirk