Sat 02-Jun-12 11:15 PM | edited Sat 02-Jun-12 11:19 PM by Gerard Pas
I’ve run into a bit of an issue with creating images for the web such as here at Nikonians. I shoot entirely in RAW / NEF. I’m not having the camera create JPEG copies largely because space as at a premium with the D800 even on my 64GB card.
Any image I like I’ll convert to a JPEG using ViewNX2 but mostly I use Adobe LR4.1 or PS CS6 with the new 7.1 DNG Converter. The JPEGS are then reduced to size meeting posting criteria such as here: 900px on the longest side at 150kb. Even at full resolution when a dark border touches a brighter border I’m getting some “jpeg artefacts”. I understand why this might occur from a 45MB 14 bit loosless compressed NEF file @ 7,360pc X 4,912px then downsizing to a 780 X 520px 140kb JPEG file but I’m seeing it even at the full size JPEG after conversion – when viewing the file at 3:1. The smaller files even have a combination of “rim” lighting (a halo) as can be seen in the submitted image below. Yes you have to pixel peep to see it but it’s there; look at the head where the black meets the blue.
Anybody else encountering this and if so what are you doing about it? Any ideas?
I don't see much wrong here, perhaps the size is too small to clearly see artifacts. It looks there is a bit too much sharpening. This may contribute to the issue. A good practice is to sharpen the original RAW file conservatively, just enough to overcome the AA filter. Then downsize for web posting. Then sharpen again, with a small radius.
Also, watch the JPEG quality settings. The more compression, the smaller the file size, but the more artifacts. This is true also for full size JPEGs.
>A good practice is to sharpen the original RAW file conservatively, just enough to overcome the AA filter. Then downsize for web posting.<
Why would you sharpen prior to downsizing? The action of downsizing will partially destroy the sharpening you applied. It also will return a downsampled image that shows false detail because original detail combined with sharpening effect will have been interpolated through the action of downsizing.
Sun 03-Jun-12 01:24 PM | edited Mon 04-Jun-12 01:14 PM by Gerard Pas
Thanks for the advice on sharpening guys but this is not solely an issue of sharpening and that’s why I didn’t bring it up; these artefacts are occurring before any sharpening is applied to the image at all. The sharpening only exacerbates the issue when downsizing.
Again, is anyone else seeing “jpeg artefacts” after converting their NEF files? What are you doing about it and or what suggestions might you have to stop them from appearing. This file was first converted to a DNG from the NEF using LR4, then a JPEG using CS6.
edit: I'm really hoping someone with some experience and or who uses the D800 and has seen similar might be able to assist me with this issue. Yes there was a little sharpening added to the above image but again I'm seeing it on images that are simply converted before applying any editing at all.
I have not seen anything like that with my images, but my workflow is a Nikon View / Nikon Capture workflow.
Try a post in the Digital Post Processing forum. Rick Walker has a similar workflow to the one you are using and has a D800. There was one situation from another Lightroom user who had moire created during resizing. The Lightroom resampling routine was apparently the issue and adjusting resampling settings solved the problem for the image in question.
Nice shot. I see the artefact adjacent to large edge luminence differences. Where the edge is dark there is a resulting lighter fringe. On a high resolution the edge transistion would appear smoother, spread out over more pixels.
If this is the case, there are a couple of solutions.
1/ Reduce the image size in CS by resampling the image with bicubic or bicubic sharper, then save as a JPEG.
2/ Add some clarity only after the image is exported as a smaller JPEG in Lr by importing back into Lr.
Mon 04-Jun-12 10:02 PM | edited Mon 04-Jun-12 10:03 PM by Gerard Pas
I did some tests with other NEF images, doing as you suggest for resizing down to a JPEG: it did the job very well. I am grateful to you for your input here as I was grasping at straws a little. I simply assumed "automatic resizing" would do the trick and it wasn't. Thank you ever so much.
Tue 05-Jun-12 03:50 AM | edited Wed 06-Jun-12 04:08 AM by jrp
> "a 45MB 14 bit loosless compressed NEF file @ 7,360pc X 4,912px then downsizing to a 780 X 520px 140kb JPEG file"
May I ask why you downsize and compress so heavily? The forum limits are 1200 px for the long edge and 300kB for the file size. Less downsizing and compression would most likely make the artefacts less noticeable.