We were jogged into action the other day as a result of an article published on a blog we follow.
The question raised was ‘What file type gives the best quality?’
So, off we went to find out!
For this review we used a Nikon D300 with Nikkor 18-70 lens, set at ISO 200, on aperture priority.
To start with the basics, most people use jpeg as their standard file type, a lot of advanced users pick RAW ( All camera manufacturers have their own version of this file type). These files contain full image information but without any sharpenening or other in camera enhancements.
In the case of Nikon, jpeg has 2 options: jpeg ‘size priority’, which makes all files the same size and jpeg ‘optimise priority’, which does not constrict the file size.
Jpeg files by nature are compressed files, effectively some of the data is discarded, in its simplest form, if 2 blocks of data next to each other are identical one is deleted to make the files smaller.
Second is RAW (NEF as Nikon call it) has 3 options: uncompressed, lossless compression and compressed. They are as described: ‘uncompressed’ the whole file nothing taken away, ‘Lossless compression’ compressed but no loss of data, and ‘Compressed’ some data loss.
But, all is not as straightforward as it would first appear, as our test images will prove.
Whole frame with cropped are marked
jpeg size priority
jpeg optimal priority
Raw uncompressed
Raw lossless
Raw compressed
Conclusions
Bearing in mind the size of area we have cropped down to.
The jpeg files exhibit a degree of softness, size priority showing the largest amount.
The RAW files display a larger amount of detail, the greatest amount being in the uncompressed file, followed by the lossless file (strange since it is described as being lossless!) and last of all the compressed file.
If you are considering using your images for display purposes we would strongly suggest using uncompressed Raw files and making adjustments with whatever imaging software you use, then saving the final image as a jpeg.
For general use ie smallish images and personal use jpeg file will prove more than adequate.