(Jan 28, 2015, 10:44)EdMak Wrote: How do I work out how much is lost. 99% of the pics I have posted here, are via jpeg, never changed to Tiff. Thanks Ed.
JPEGs are just fine, Ed, no need to change.
(Jan 28, 2015, 07:49)canonsnap Wrote: Then you have to change it to TIFF to be able to work on it in any image programme as jpeg is a lossy format.
A JPEG file does not need to be changed to TIFF. JPEG is the most widely used and universally compatible image format. It can be opened, viewed and edited directly in any imaging software. JPEG format is called "lossy" because data compression loses some of its data when the file is saved
. (A file in any
image format might lose data while it is being worked on
, depending on the editing procedures being applied.)
(Jan 28, 2015, 07:49)canonsnap Wrote: The problem with shooting in jpeg is that the camera processes the image and approximately 1/3 of the digital information is lost and is irretrievable......there is still not enough of the image file left to significantly improve the shot.
It is correct to state that some data is lost when an image is saved
as a JPEG file, due to the data compression processes involved, but the point is whether that lost data matters. In my opinion, usually it does not.
In many shots, using a modern DSLR set up to give the desired photo style, and assuming that the exposure and white balance were set close to the correct values when shooting (which should be a primary aim for anyone aspiring to be a competent photographer), and when the camera has recorded its maximum-size, highest-quality JPEGs, the lost data is usually irrelevant when working on the image to create the final result.
In many cases, the JPEG will be visually reasonable
straight from the camera, but it can usually be enhanced in computer software. The processing required, to turn it into a high quality
image, will still have more than enough data to work on. Regarding photo quality, it would probably be very difficult to distinguish the final resulting photo from one produced using the raw data from the same captured shot.
The recommended resolution for a wall mounted photo is around 300 pixels per inch. Hence, as an example, the maximum print size from an uncropped image shot by a 16 MP DSLR would be about A3 or about 16 by 11 inches, and it should be viewed from about 2 feet away. Unless the viewer has peregrine falcon vision, or uses a powerful pixel-peeping magnifier, I doubt that he/she would be able to discern whether that print was produced by processing a camera JPEG file or a raw data file.