[Update 25 August 2011: Thanks to the people who e-mailed me and the thread at dpreview it is clear now that my camera was set to a ratio of 16:9 which is which why the RAW file was tagged to “crop”. Setting to a ratio of 3:2 results in a full image within Adobe Camera RAW. So case closed. Meanwhile…FACEPALM]
I recently bought the Sony NEX-5 camera to accompany my Nikon D700 for those occasions where size and discreteness take priority. I hadn’t used the NEX-5 much in anger but I did take it on a field-test to Venice last week. Although the NEX-5 cannot compete with the D700 in fast moving situations or in low light conditions, I was generally pleased with the result. But I noticed something peculiar.
In terms of my workflow, I use Photoshop CS4 with Camera RAW 5.7…of course Adobe have, in their infinite wisdom, decided not to support Camera Raw in older releases of Photoshop (the current version being CS5) so RAW files from newer cameras such as the NEX-5 are not supported. That’s fine; I use Adobe DNG Converter to convert the Sony RAW files (ARW) to DNG which Camera Raw 5.7 reads with aplomb. This is OK, not a problem, but then I noticed that Picasa 3.8.0 and FastPictureViewer 1.5 displayed more of the image than that shown in Camera RAW.
Upon investigation into the image size variances, it seems that Sony have tagged their NEX-5 RAW images to indicate that the useful part of the image is a subset of the complete image captured by the sensor; the RAW image does have all of the sensor image but Camera RAW is only displaying part of the image by respecting Sony’s EXIF tags. The reason Sony have “EXIF-cropped” the image is probably because of concerns on vignetting and perhaps because other lens aberrations may become visible at the edges of the images.
How big are the size differences? The RAW file contains an image of 4,608 x 3072 pixels; the “cropped” image is 4,592 x 2,576 pixels. The following two images show the differences these can make.
NEX-5 “EXIF-cropped” image:
NEX-5 full image:
There is perhaps a hint of vignetting visible at the top corners of the full image. But it certainly isn’t objectionable and there do not appear to be any other noticeable degradations in the image quality of these “additional” areas. Perhaps the vignetting and other quality issues are more apparent when using the wide-angle “pancake” lens? Unfortunately I did not have an opportunity to test the pancake lens. Regardless, I think Sony should give us the option to be able to extract as much of the image from the sensor…perhaps via a camera firmware update giving us a menu-option to allow the RAW file EXIF tags to indicate that all the of the image data is usable.
In the meantime, I’ve used Thomas Knoll’s utility “DNG Recover Edges” to re-tag the DNG file so that all of the image is available and can be seen in RAW converters such as Adobe Camera RAW 5.7. As is seen in the above two images, there are situations where recovery of the “cropped” areas is very beneficial.
“DNG Recover Edges” for Windows and the Mac can be found here:
Windows – http://www.luminous-landscape.com/recover_edges/DNG%20Recover%20Edges%20Win.zip
Macintosh – http://www.luminous-landscape.com/recover_edges/DNG%20Recover%20Edges%20Mac.dmg
Note that the Windows version runs fine on my Windows 7 Ultimate 64-bit machine. I can’t vouch for the Mac edition.
Another way to recover the “cropped” areas is to use ExifTool to change the EXIF tags but that requires a bit more knowledge on which tags to change.
[Update 25 August 2011: Thanks to the people who e-mailed me and the thread at dpreview it is clear now that my camera was set to a ratio of 16:9 which is which why the RAW file was tagged to “crop”. Setting to a ratio of 3:2 results in a full image within Adobe Camera RAW. So case closed. Meanwhile…FACEPALM]
Article by Kulvinder Singh Matharu – 2011
