Hi there community,
I have recently started using Nikon Capture NX-D to "pre-convert" the RAW files of my Nikon D750. The Nikon software just does a great job with the colors and camera settings, etc. In a second step, however, I import the images into Lightroom, which is obviously the richer tool for fine tuning.
I have tried two paths to do this:
1. Export the RAW file as a JPEG from NX-D
2. Export the RAW file as a 16 bit TIFF from NX-D
When I import the JPEG and TIFF into Lightroom and then export both as JPEGs, I notice that the JPED-based JPEG file is significantly larger (from 1/3 larger up to twice the size) than the TIFF-based JPEG file. However, the quality seems to be almost identical. At 100 % the difference is imperceptable. At 200, 300, 400, 500 % some difference becomes visible but is basically negligable (and at that level of maginification the slightly less detailed TIFF-based JPEG doesn't necessarily look worse to me).
Does anybody have an explanation for such a big difference in file size with hardly any difference in image quality? Am I missing something? If anything, I would have expected the difference in file size to be the other way around, with the lossless TIFF file as a base producing the larger JPEG file with more detail.
If there is truly no (noticable) difference in quality, I would of course prefer the smaller files to save disk space. Even for large scale printing I guess the difference would be imperceptible.
I am attching two sample images (TIFF-based JPEG and JPEG-based JPEG) and screenshots of their 100 % and 500 % magnification.
Thanks a lot for your help!
I just exported from LrC a 19.73MB Jpeg (from a 45MP sensor) with a long edge of 1188 px and a size limit of 200KB, and successfully produced a file of 189KB. Unless your image is so incredibly detailed that it cannot be compressed that small, it would seem that it should be possible to do what you want. Have you double/triple checked the export settings?
I have revisited this image (See below). When exporting, if I pull the 'Image quality' slider down to 0% it exports at a file size of 208.3 kb; which explains why it will not export if I set the max size to 200 kb.
I also tried exporting using the 'JPEG optimizer' plugin. With recompression, the file size goes up to 563 kb! Without recompression, if I remove just the EXIF thumbnail the file size comes down to 194.7 kb. Removing ALL the metadata brings it down to 188.9 kb. An interesting learning exercise.
JPEG compression works by analying the image for repetitive elements using Fourier transform math. It doesn't matter what the source of your image is, what matters is the complexity of the image. An image of a wall with no detail and just solid color will be very compressable. An image like what you show here with basically a lot of chaos and very little repetition will be very hard to compress down.