Does anyone happen to know the baseline exposure offset that Camera Raw uses for a Canon 1DSIII?
Thanks
Jonathan
Full Version: Baseline exposure offset for CR?
+0.35 EV.
I don't have any ISO 50 raw file, but I am pretty sure that ISO 50 is ISO 100 overexposed by one stop. If so, then ACR will apply -1 EV compoared to the ISO 100, i.e. the adjustment is -0.65 EV.
I don't have any ISO 50 raw file, but I am pretty sure that ISO 50 is ISO 100 overexposed by one stop. If so, then ACR will apply -1 EV compoared to the ISO 100, i.e. the adjustment is -0.65 EV.
You can easily determine this for yourself by taking a test shot, converting it to DNG, and then loading it in Rawnalyze or RawnalyzeTL.
QUOTE (JeffKohn @ Oct 20 2009, 01:31 PM) 
You can easily determine this for yourself by taking a test shot, converting it to DNG, and then loading it in Rawnalyze or RawnalyzeTL.
Jeff, I looked at their site and it seems to be a windows only program. I'm on mac.
QUOTE (Panopeeper @ Oct 20 2009, 01:13 PM)
+0.35 EV.
I don't have any ISO 50 raw file, but I am pretty sure that ISO 50 is ISO 100 overexposed by one stop. If so, then ACR will apply -1 EV compoared to the ISO 100, i.e. the adjustment is -0.65 EV.
I don't have any ISO 50 raw file, but I am pretty sure that ISO 50 is ISO 100 overexposed by one stop. If so, then ACR will apply -1 EV compoared to the ISO 100, i.e. the adjustment is -0.65 EV.
Pano, Could you please explain a little further for me. I didn't think that the exposure offset was ISO dependent. What correction should I apply to the exposure slider in CR to offset the program's offset for a IDS III, and does it have to vary with ISO?
Thanks again
Jonathan
QUOTE (jljonathan @ Oct 20 2009, 02:09 PM)
Pano, Could you please explain a little further for me. I didn't think that the exposure offset was ISO dependent. What correction should I apply to the exposure slider in CR to offset the program's offset for a IDS III, and does it have to vary with ISO?
Thanks again
Jonathan
Thanks again
Jonathan
You do not absolutely have to have Rawnalize. Any standard EXIF reader can extract the BaselineOfset from the DNG file.
QUOTE (jljonathan @ Oct 20 2009, 12:09 PM)
Pano, Could you please explain a little further for me. I didn't think that the exposure offset was ISO dependent. What correction should I apply to the exposure slider in CR to offset the program's offset for a IDS III, and does it have to vary with ISO?
It is not only ISO dependent. It is a general compensation for whatever. For example if HTP is ON, then +1 EV is applied (it adds to the adjustment, i.e. for the 1Ds3 it will be +1.35 EV); however, you have no reason to use HTP, that's for JPEG.
The adjustment (without HTP) is +0.35 EV for all ISOs. However, there is no ISO 50 in the 1Ds3 (nor in any other modern Canon DSLR). ISO 50 is simply an overexposed ISO 100. DPP too compensates for that by a negative "brightness" adjustment, and ACR substracts 1 EV from the otherwise determined adjustment.
For example most MFDBs don't have ISO steps higher than 100. Anything higher means simply automatically adjusting the intensity in post-processing; that too occurs through BaselineExposure.
Note, that this name, BaselineExposure, is not an ACR issue. ACR is doing that automatically; however, if you convert the native raw file in DNG format, the DNG converter records this information as metadata for the later raw processing, so that the DNG image can be processed based solemnly on the DNG metadata, i.e. without having to know the specialties of the camera, like HTP.
QUOTE (bjanes @ Oct 20 2009, 03:41 PM)
You do not absolutely have to have Rawnalize. Any standard EXIF reader can extract the BaselineOfset from the DNG file.
You would think so, but I have spent over an hour trying to find a suitable Mac reader and have come up with nada. They show exif info, but no offset.
Any idea what I could use with Mac?
Jonathan
QUOTE (Panopeeper @ Oct 20 2009, 04:56 PM)
It is not only ISO dependent. It is a general compensation for whatever. For example if HTP is ON, then +1 EV is applied (it adds to the adjustment, i.e. for the 1Ds3 it will be +1.35 EV); however, you have no reason to use HTP, that's for JPEG.
The adjustment (without HTP) is +0.35 EV for all ISOs. However, there is no ISO 50 in the 1Ds3 (nor in any other modern Canon DSLR). ISO 50 is simply an overexposed ISO 100. DPP too compensates for that by a negative "brightness" adjustment, and ACR substracts 1 EV from the otherwise determined adjustment.
For example most MFDBs don't have ISO steps higher than 100. Anything higher means simply automatically adjusting the intensity in post-processing; that too occurs through BaselineExposure.
Note, that this name, BaselineExposure, is not an ACR issue. ACR is doing that automatically; however, if you convert the native raw file in DNG format, the DNG converter records this information as metadata for the later raw processing, so that the DNG image can be processed based solemnly on the DNG metadata, i.e. without having to know the specialties of the camera, like HTP.
The adjustment (without HTP) is +0.35 EV for all ISOs. However, there is no ISO 50 in the 1Ds3 (nor in any other modern Canon DSLR). ISO 50 is simply an overexposed ISO 100. DPP too compensates for that by a negative "brightness" adjustment, and ACR substracts 1 EV from the otherwise determined adjustment.
For example most MFDBs don't have ISO steps higher than 100. Anything higher means simply automatically adjusting the intensity in post-processing; that too occurs through BaselineExposure.
Note, that this name, BaselineExposure, is not an ACR issue. ACR is doing that automatically; however, if you convert the native raw file in DNG format, the DNG converter records this information as metadata for the later raw processing, so that the DNG image can be processed based solemnly on the DNG metadata, i.e. without having to know the specialties of the camera, like HTP.
Pano, No HTP here! Since I am having some difficulty finding a reader for Mac, as suggested above, do I understand correctly that I should "add" +.35 to the exposure slider to get a true default?
Thanks
Jonathan
QUOTE (jljonathan @ Oct 20 2009, 05:48 PM)
do I understand correctly that I should "add" +.35 to the exposure slider to get a true default?
Just the opposite. ACR does ADD 0.35 EV; if you want to neutralize that, you should SUBSTRACT it.
However, keep in eyes, that the Brightness adjustment is very close to Exposure; the difference is, that Brightness does not increase the intensity of the highlights. Brightness +50 is the same as Exposure +1, except for the highlights. Thus if you have some brightness adjustment as default, then you don't see the "original" anyway.
QUOTE (Panopeeper @ Oct 20 2009, 09:13 PM)
Just the opposite. ACR does ADD 0.35 EV; if you want to neutralize that, you should SUBSTRACT it.
However, keep in eyes, that the Brightness adjustment is very close to Exposure; the difference is, that Brightness does not increase the intensity of the highlights. Brightness +50 is the same as Exposure +1, except for the highlights. Thus if you have some brightness adjustment as default, then you don't see the "original" anyway.
However, keep in eyes, that the Brightness adjustment is very close to Exposure; the difference is, that Brightness does not increase the intensity of the highlights. Brightness +50 is the same as Exposure +1, except for the highlights. Thus if you have some brightness adjustment as default, then you don't see the "original" anyway.
Right, I have to subtract .35. The brightness won't be a problem, I normally open files with all sliders zeroed and curves linear.
Thanks so much
Jonathan
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