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Speedlight gel question
When shooting indoor events under an artificial light source the light temperature is not going to be same as the speed light. The speed light is going to be 5600K and the indoor light source will be different.
If you shoot with out gelling the speed light (auto white balance) you will end up with a different white balance between your subject (illuminated by the speed light, and the ambient light.) In the case of incandescent lighting this will result with good white balance for your subject but everything in the background illuminated with the incandescent light source will have an orange / warm tint.
With incandescent lighting you can get pretty close with ether setting your white balance at 3200K or using a custom White balance with a 1/2 CTO gel.
I have no problem with setting a custom white balance for the ambient light source, but after that I am guessing and test shooting to get the gel right, or close to right.
I am looking for a more scientific precise method to match the gel (speed light temp) with the ambient light. I do not have a light meter or color meter.
Yes I am trying to see if there is a more scientific method to this rather than fudging, guesstimating, winging, and hoping all without spending a nickle.
Sam
If you shoot with out gelling the speed light (auto white balance) you will end up with a different white balance between your subject (illuminated by the speed light, and the ambient light.) In the case of incandescent lighting this will result with good white balance for your subject but everything in the background illuminated with the incandescent light source will have an orange / warm tint.
With incandescent lighting you can get pretty close with ether setting your white balance at 3200K or using a custom White balance with a 1/2 CTO gel.
I have no problem with setting a custom white balance for the ambient light source, but after that I am guessing and test shooting to get the gel right, or close to right.
I am looking for a more scientific precise method to match the gel (speed light temp) with the ambient light. I do not have a light meter or color meter.
Yes I am trying to see if there is a more scientific method to this rather than fudging, guesstimating, winging, and hoping all without spending a nickle.
Sam
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14-24 24-70 70-200mm (vr2)
85 and 50 1.4
45 PC and sb910 x2
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Quarik is right , there are commercial color temperature meters, Sekonic, among others, but those are used more by movie studios, I think.
Moderator of the Technique Forum and Finishing School on Dgrin
IE: first do A, then B and your done. Kinda like a magic wand.
Trying to make it very fast and accurate as opposed to trial and error.
Sam
But I doubt in the real world if it is ever quite that simple, don't you, Sam?
Moderator of the Technique Forum and Finishing School on Dgrin
Makes sense!
How about this?
1. Shoot straight, no flash.
2. use that photo as a preset WB. and notice the kelvin.
3. Choose the gel to match that K.
Possible?
This the direction I was thinking, but, and it's a big but............the camera Canon 5D II doesn't provide that temp information.
If I put it in CS5 or Lightroom I get the info. So it seems it's back to fiddling and fudging.
Jim posted: If you have a full gel pack and a color temp meter, measure ambient, select the needed gel, and voila!
But I doubt in the real world if it is ever quite that simple, don't you, Sam?
Of all the things on my want list a color meter isn't there.
If life were too simple it would be boring..............yet once in awhile simple wouldn't hurt.
Sam
Which leads us back to Chimping. I tried it just now on my 5DMk2 and of course you're right. I took a photo, used that as WB, then did my best guess in three photos of what that K was. Not bad, but ? is, what arena are you shooting in?
You could potentially find and set the WB and have it cycle over and over with garbage for results, especially in fluorescent or even Mercury lights, right. So you may never actually have all of your photos White balanced is my worst-guess scenario!
It does mean that you need a computer with you for the color measurement but the results can be much more accurate than any meter I know of, and it's using your camera's metering to do the measurement so it's partially calibrated to your system by default. (If you could use an external meter you would have to interpret those results into your system using a separate calibration, which you avoid by using your camera for the color sampling.)
Adobe products do round the results so if you want to be even more precise you can use RAWTherapee, which gives you the original numbers.
Remember that you will get both a WB color temperature differential plus a color tint offset. As long as they are close numerically (after filtration), you should not notice the difference too much in a resulting monitor image and/or print.
Moderator of the Cameras and Accessories forums
I was really hoping I hadn't thought this through and there was any easy answer. :cry
For most events I try to limit the amount of gear I cart into the venue. Less to keep track of and less to end up in sticky fingers.
I don't think one needs to be absolutely accurate gelling the flash. With incandescent lighting a custom white balance or 3200K with a 1/2 CTO will normally get you close. For most event images this will be good most people will not see big difference. I was just trying to get it to the next level but like most quality issues to get 10% improvement ya need to expend an additional 75% effort.
Sam
Let's use tungsten light as our example.
- Camera set to AWB
- Shoot a white card
- Review that shot on your camera's LCD
- Note the orange coloration
- While that image is showing, pull out your gel(s) and hold one close to the LCD image, over the white card.
- Match the gel color as close as you can to the LCD image color.
- Put this gel on your flash
- Set your camera's WB to "Custom WB", and choose the image that you were looking at, the one you matched the gel to.
- Take a shot ~ viola!!! Your flash color balance and your ambient match
(or as close as you can get)
Simple enough?Hope that helps...
FWIW, you can buy a color temperature meter... although they are not really the most cost effective way of working, if the things you are shooting are color critical and you are being paid for it then you may want to pick up one of these.
The best situation is for you (Sam) is to practice seeing the light and noticing the general temp of it and matching that with a gel. It's not quick, it's not easy, but once you get the hang of it it is reliable, especially if you are looking to create images that are pleasing to the eye and exact color matching is not critical.
I'll just work on my guess and by-golly methodology.
Sam
Step 1, once only: Use a white reference material. Expose using only your flash, and set up custom white balance to make that perfectly white.
Step 2: Set the camera to the custom white balance acquired from step 1.
Step 3: Take a photo of the white reference material under ambient light only. This is photo A.
Step 4: Take a photo of the white reference material again under ambient light only, but shooting THROUGH the gel. This is photo B.
Compare the histograms of photo A and B on the LCD. For any color component, you should only see a vertical shift based on exposure difference. There curve should look identical, only shifted downwards in photo B when compared to photo A. By flicking back and forth between the two view finders, you should be able to quickly find the right gel. If you had the wrong one, note the color shift, delete photo B, and re-shoot with a new gel.
This is probably totally wrong and I've probably missed something important, so this is probably more of an educational bold statement than a solution that works in practice, but I can't see why this WOULDN'T work.
Basically I know what the flash temp is. It's about 5600K. I know how a particular gel will modify the flash temp. The main effort with this post was to see if there was a simple 1,2,3 method to match up the ambient and flash temps in a simple more scientific way.
The scientific way would be to use a color temp meter, but they are way too expensive for casual use.
That leaves the old method. Set a custom white balance for the ambient. Guess at the ambient color temp, gel the flash to match your guess, take a shot and see how the flash exposed subject looks color wise as compared to the ambient background. If they are close......shoot!
Sam
Ditto....
This is precisely my method and it works solidly. One detail perhaps forgotten. Lay the gels on the white card to compare to the sample image on lcd. That way they have a white background.
Also, I tend to lean a bit warm with my images. I usually match up the gel to sample image and then choose the next darker...richer gel for my flash.
Jeff
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I use gels all the time on my flash. Nikon has done a pretty good job of creating gels for the SB-900 that have micro chips on them that send the info to the camera. If am in a room that has mostly tungsten lighting, I put the tungsten gel, CTO (color to orange), on my speedlight. I set my color temperature to tungsten and shoot. Tungsten bulbs can have a lot of different temperature values depending on their age and type, so I still need to adjust a little in post. The biggest problem I have with color balance is with the compact florescent bulbs. Their color temperature can be down around 2500K which is below the scale on most cameras. I used to shoot motion picture film and we used color meters, but they are crazy expensive and you still end up using you eyes to make decisions on what gels and lights to use.
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Nikon D700 (3 bodies), Nikon 14-24 f2.8, Nikon 24 f/1.4, Nikon 24-70 f/2.8, Nikon 50 f/1.4, Nikon 85 f/1.4, Nikon 70-200 f/2.g VRII, SB-900(2), SB-800(5)
*I am a noob and am just jumping into the kiddie pool of lighting.
If you have one source of light with one color temp it's easy to adjust in RAW, but the issue with flash and ambient light is that in most cases you end up with two different color temps. It can be very difficult to impossible to correct for mixed lighting.
The idea of gelling the flash is to match whatever the ambient light color temp is. Then it's easy to adjust the final color temp in the RAW conversion if necessary.
Sam
What about using a color checker passport. Shoot the passport in ambient then shoot it with your ungelled flash and create a dual luminance profile. Another option to use it would be to use it to set a custom white balance in camera, my camera displays that temp in kelvin and gel to get close. I did the dual luminance in a gym this winter for some shots and it worked quite well. Definitely cheaper than a color temp meter. Just my $.02 worth.
http://www.ohiohikerphotography.com
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