Question about Camera Raw vs Picasso exposure difference.

[Bruce A]

I hope someone might have an answer. I have been on a two week vacation and took several photos. While away I uploaded the raw files to my notebook and viewed them on Picassa and all seemed fine. When I arrived home I copied them to my PC and viewed them via the mini bridge in PS CS5. I was somewhat astonished to notice they all seemed over exposed by about 1 stop viewed via the mini-bridge and Camera Raw. I then viewed them in Picassa on my PC and the image quality was much the same as viewed via Picassa on my notebook. I recalibrated the PC monitor, but the difference is still there. Does anyone know why viewing the photos via the mini-bridge or Camera Raw would look one stop overexposed compared to Picassa?

I wonder now how my images might look look to others (with calibrated monitors) on both here and my Flickr site.

[OsmosisStudios]

Picasa is wrong. Theyre only showing you a preview: Camera RAW is showing you the working file you have to play with. The RAW files you get from the camera are ALWAYS going to need some developing work in your RAW editor.

[i speak in math]

picasa also auto-corrects raw exposure so you don't know what the original exposure looks like until you open it in camera raw or another "real" raw editor.

[SwissJon]

Originally Posted by OsmosisStudios

Picasa is wrong. Theyre only showing you a preview: Camera RAW is showing you the working file you have to play with. The RAW files you get from the camera are ALWAYS going to need some developing work in your RAW editor.

I'm curious. When Lightroom/PS open RAW files for editing, are they doing so using ACR, or converting the file? I'm wondering what the advantage is, if LR & PS use ACR as a plug in, in opening the file in ACR?

[Bruce A]

Thanks for your responses, now I understand and feel more confident about my previous processing. I also used Nikon's Capture NX2 and the images were the same as Camera Raw. So Picasa's raw file viewer is somewhat a fraud. It is what it is I suppose.

[ravncat]

Originally Posted by SwissJon

I'm curious. When Lightroom/PS open RAW files for editing, are they doing so using ACR, or converting the file? I'm wondering what the advantage is, if LR & PS use ACR as a plug in, in opening the file in ACR?

LR and PS are opening and converting the file via ACR - however the conversion that is displayed via ACR is displayed with only the baseline adjustments embedded within the camera for raw (not JPG). The advantage of lightroom is clearly the cost and the data management structure. The advantage of the ACR plugin in photoshop - is that it's just a part of photoshop and photoshop is much more capable at editing than lightroom

The baseline adjustments* can be found within the metadata and are often only a small exposure adjustment (for example, It's +.5 stops for most nikon cameras at most iso's.) ACR also generally applies a tone curve - if you want to get closer to the original raw data you've got to switch to the linear tone curve.

Finally, The actual raw data as is is impossible to display as a photograph, because it hasn't been "put together" so to speak - since the sensor doesn't read colors. it has to be compiled through interpolation via the bayer filter. So some conversion routines are being automatically done - I'm not sure where that conversion is taking place, but I suspect it is the raw converter (such as ACR) We only get previews of the raw files because of the jpg embedded in the raw data. I think some other more robust conversion tools can let you look at the raw data and even determine how to put the data together (rawtherapee maybe)

*interestingly, if you have ever noticed that two digital cameras seem to be giving you different exposures (or more accurately different brightness of the same mid tone that was metered for and not the entire exposure overall)in raw even when taken at the same aperture shutterspeed and iso, it's partially because of those basline exposure adjustments - you can undo them by subtracting or adding the opposite in lightroom. (Of course different cameras will give different exposures due to different dynamic range and color filters over the sensors and the way's the ISO standard can be interpreted )

wow - that was alot more than i thought to write!