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#1
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Curious RAW quirk?
Hi all!
I took in-house photos at a party, setting the WB to flash and using an external Canon flash on my Eos 5D MarkII. What puzzles me is when I work on the Raw photo in Photoshop CS3 and the white balance shows as "as shot", if I change it to "Flash" (which was the WB setting on my camera) , I get a cooler temp. Why please this difference? Thanks, Marcel |
#2
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Curious RAW quirk?
celcius wrote:
Hi all! I took in-house photos at a party, setting the WB to flash and using an external Canon flash on my Eos 5D MarkII. What puzzles me is when I work on the Raw photo in Photoshop CS3 and the white balance shows as "as shot", if I change it to "Flash" (which was the WB setting on my camera) , I get a cooler temp. Why please this difference? The RAW processor has a different idea of what "Flash" means than does the camera! How much a difference? I generally find that if I leave the WB on auto, it does a superb job on 85% of my shots. The "auto" function in the processor, though, sometimes comes up better than the camera's; sometimes not as good. -- john mcwilliams |
#3
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Curious RAW quirk?
celcius wrote:
Hi all! I took in-house photos at a party, setting the WB to flash and using an external Canon flash on my Eos 5D MarkII. What puzzles me is when I work on the Raw photo in Photoshop CS3 and the white balance shows as "as shot", if I change it to "Flash" (which was the WB setting on my camera) , I get a cooler temp. Why please this difference? A quick look at the EXIF for my camera (Sony a900)for flash shots hasa bizarre light source temperature (below). Additionally, there is a "Light Source" value set to "Daylight" (if in that mode) or "Unknown" if I set the light source temperature directly (say to 5500K). Then the "White Balance" field is set to "Color Temperature/Color Filter". And bizzarely, the "Color Temperature" field is set to 21400 (!) with no "K" unit noted. (DL exiftool to really delve into what is delivered from the camera). In the end, I believe ACR analyzes the image to come up with a temperature (assuming I suppose that it's on average mid-grey) for the "As shot" value. A bit mysterious, overall. |
#4
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Curious RAW quirk?
On Mon, 12 Oct 2009 11:22:29 -0400, "celcius" wrote:
: Hi all! : : I took in-house photos at a party, setting the WB to flash and using an : external Canon flash on my Eos 5D MarkII. : What puzzles me is when I work on the Raw photo in Photoshop CS3 and the : white balance shows as "as shot", if I change it to "Flash" (which was the : WB setting on my camera), I get a cooler temp. Why please this difference? Don't take this as gospel, but I believe it's the case that setting the WB has no effect on an EOS Canon in RAW mode. No WB correction is applied; it's left entirely up to the post-porcessor. What Photoshop is showing you as "as shot" (Canon's own software calls it "shot settings") is merely the camera's recommendation of what WB to use in post-processing. It may or may not be what you set it to be on the camera. JPEG is a different matter. If you tell the camera to use a specific WB correction, that's what the camera uses in its conversion of the image to JPEG. BTW, my impression is that Canon sets the "flash" WB assuming that the flash output is colder than even its own flashguns produce in practical use. So if you bounce the light off of anything but a pure white reflector, the "flash" WB will produce a result that is too red. Bob |
#5
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Curious RAW quirk?
"Robert Coe" wrote in message news On Mon, 12 Oct 2009 11:22:29 -0400, "celcius" wrote: Don't take this as gospel, but I believe it's the case that setting the WB has no effect on an EOS Canon in RAW mode. No WB correction is applied; it's left entirely up to the post-porcessor. What Photoshop is showing you as "as shot" (Canon's own software calls it "shot settings") is merely the camera's recommendation of what WB to use in post-processing. It may or may not be what you set it to be on the camera. JPEG is a different matter. If you tell the camera to use a specific WB correction, that's what the camera uses in its conversion of the image to JPEG. Both of the above are correct. Good response. |
#6
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Curious RAW quirk?
"Robert Coe" wrote in message
news On Mon, 12 Oct 2009 11:22:29 -0400, "celcius" wrote: : Hi all! : : I took in-house photos at a party, setting the WB to flash and using an : external Canon flash on my Eos 5D MarkII. : What puzzles me is when I work on the Raw photo in Photoshop CS3 and the : white balance shows as "as shot", if I change it to "Flash" (which was the : WB setting on my camera), I get a cooler temp. Why please this difference? Don't take this as gospel, but I believe it's the case that setting the WB has no effect on an EOS Canon in RAW mode. No WB correction is applied; it's left entirely up to the post-porcessor. What Photoshop is showing you as "as shot" (Canon's own software calls it "shot settings") is merely the camera's recommendation of what WB to use in post-processing. It may or may not be what you set it to be on the camera. JPEG is a different matter. If you tell the camera to use a specific WB correction, that's what the camera uses in its conversion of the image to JPEG. BTW, my impression is that Canon sets the "flash" WB assuming that the flash output is colder than even its own flashguns produce in practical use. So if you bounce the light off of anything but a pure white reflector, the "flash" WB will produce a result that is too red. Bob Hi Bob! I think you've got a point in saying that setting the WB on the camera has very little incidence in Raw mode. John says that leaving it on "auto" is fine. I thought, reading the posts here in the past, that it was always better to set the proper WB even when shooting in Raw mode. Now, I'm back to square 1 ;-) Mind you, the beauty here is the fact that being in Raw, everything.. or almost is possible. Marcel |
#7
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Curious RAW quirk?
"celcius" wrote:
I think you've got a point in saying that setting the WB on the camera has very little incidence in Raw mode. John says that leaving it on "auto" is fine. WB has no effect on the camera raw data. It is a correction applied only when that data is converted to a JPEG. The camera always generates a JPEG for viewing, which is also used to generate an histogram. But if you don't "shoot JPEG", it is not saved as a file. I thought, reading the posts here in the past, that it was always better to set the proper WB even when shooting in Raw mode. Now, I'm back to square 1 ;-) Setting WB depends on what you want. It can be, for example, set to provide no correction in order to get an accurate histogram. It can be set to "auto", just to provide Exif data for what the camera calculates as the correct adjustment. It can be set manually to whatever you think is "correct" to perhaps get more a more accurate looking preview image. All of those are reasonable settings, and none of them provide exactly the same results. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#8
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Curious RAW quirk?
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#9
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Curious RAW quirk?
me wrote:
On Mon, 12 Oct 2009 14:56:34 -0800, (Floyd L. Davidson) wrote: "celcius" wrote: I think you've got a point in saying that setting the WB on the camera has very little incidence in Raw mode. John says that leaving it on "auto" is fine. WB has no effect on the camera raw data. It is a correction applied only when that data is converted to a JPEG. The camera always generates a JPEG for viewing, which is also used to generate an histogram. But if you don't "shoot JPEG", it is not saved as a file. To be precise a copy of the JPEG used for in camera review and the histogram(s) is saved within the RAW file it self. But it is *not* saved as a JPEG file, it has to be extracted. Just how precise that is also depends on the camera. For example, with a Nikon camera it is the same image data but an extracted file differs significantly. The distinction might not be significant, but the embedded image does not contain the Exif data (the extraction process may add some from the NEF file though), and that includes lacking the 160x120 embedded thumbnail in the camera generated JPEG file. One odd result of the above is that if the thumbnail is extracted from the NEF file, written to a JPEG file and then put on a CF card, the camera will not be able to display it from that file. It can display either the NEF or the camera generated JPEG file though. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#10
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Curious RAW quirk?
"celcius" wrote in message
... Hi all! I took in-house photos at a party, setting the WB to flash and using an external Canon flash on my Eos 5D MarkII. What puzzles me is when I work on the Raw photo in Photoshop CS3 and the white balance shows as "as shot", if I change it to "Flash" (which was the WB setting on my camera) , I get a cooler temp. Why please this difference? Thanks, Marcel Thank you all! Since I shoot exclusively in Raw, I've learned something very useful today. I used to shoot only in JEPG, but this group and others have convinced me to use Raw. This has served me well since I was able to save photos that might have been completely wasted otherwise. I find Raw especially useful when I shoot with flash and it seems the risk of getting a so so photo is greater. Cheers, Marcel |
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