I'm not really sure what forum to ask this in ... however ... I have a brand new Samsung Galaxy S8, I am experimenting taking DNG photos with this camera. I see occasional photos have a semicircular halo, which I don't like, even if it is somewhat faint, and it's always in the same spot. But some photos show no sign of this artifact. I don't see this on the JPGs from the same cell phone. Example below.
What causes this, and can I stop it from happening?
>not really sure what forum to ask this in
1 - which Adobe program are you using? (a Moderator may move this message if you name the program)
2 - a Samsung forum to find out if other users are having the same problem, or maybe your camera is simply defective
It doesn't matter what product I'm using, the halo is there whenever I use the photo in ANY Adobe or non-Adobe product (for example, the halo is there if I open the photo in Irfanview) so this is really a question about photography rather than software.
I will look for Samsung forums. Great idea. Thank you.
Since the problem is there in all programs, I would find out about a return & replace of the device... after checking a Samsung forum to find out if other people are having the problem
There's no question that Samsung has had problems in recent years -- (exploding phones, washing machines and corruption charges). Not dismissing a defect but if halo is only present in DMG images, it might be a filter or setting in your camera.
Interesting ... and thank you for the comment.
I am not aware of any filter or setting being used, but as I'm still very new with this camera, I will look carefully.
Also the Lightroom or Camera Raw forums could probably offer you some guidance on how to remove the halos.
Well, the reason I went into the Lounge instead of Lightroom is that I don't want the camera putting these halos there; I don't consider this a software issue at all. I do not want to have software remove the halos after the fact, I was hoping some camera expert who comes in here might advise on what is causing this and how to prevent it.
I did see this post earlier, but haven't had time to look into it. I do have an S8 also, so I might try and run some test. How did you shoot the photos? Via Lightroom Mobile?
No Lightroom Mobile involved, in fact my only use of LR was to display the DNG, the photos are otherwise unedited by Lightroom, and as I said I also looked at them in Irfanview, with similar findings.
To shoot DNG with a Galaxy S8, you want to go into Pro mode in the camera app, and then you automatically get both a DNG and a JPG.
I'll have to try that. Just got the phone, as my old phone died.
DNG showing this rainbow artifact: Dropbox - 20170723_172131.dng
Associated JPG (as far as I can tell, not showing this artifact) Dropbox - 20170723_172131.jpg
DNG of the black exposure, showing same circular rainbow artifact (although I had to increase the exposure in LR by +2 to be sure I see it): Dropbox - 20170727_172425.dng
Associated JPG, no apparent rainbow artifact at exposure +2: Dropbox - 20170727_172425.jpg
The difference between the jpeg and the DNGs as you sent them was that the jpegs had not pushed up the shadow detail. Whereas ACR opened with the shadow controls pushed up to +100 and clarity pushed high emphasising that banding.
This is your "Dark" image which was taken at ISO 500. All ACR controls are at 0 except the Exposure which I have pushed up to +5.0 to see the effect
On my Galaxy S7 I tried the black test (photographing the black foam in a dark room).
Using ISO 100 : I got this by pushing the exposure control in ACR up to +5.0
At ISO500 - the banding is just say visible but the image noise has helped hide it (once again exposure is pushed up to +5.0 in ACR)
At ISO 1250 - the banding was hidden by excessive noise (again this is with ACR exposure right up at +5.0 - something I just wouldn't do with a phone image at that ISO)
My view is this is just banding in the shadows ( I don't know what bit depth the DNG files from Samsung are as native but I doubt it is 14bit like a DSLR )
With all that in mind I reprocessed your café DNG keeping the near blacks near to black
It looks like you just have to accept with the tiny sensor in the phone (and probably limited bit depth even in RAW) you cant push the near blacks in the same way as you can a DSLR
So, that's a great explanation, and a relief that I don't have to send the camera back. On the other hand, while I didn't expect this highly touted cell phone camera to really come close in quality to my DSLR, I am disappointed by this artifact when I choose to use a higher ISO. One of the reasons I got this camera was because it was able to shoot RAW, but maybe I'll just stick with the JPGs for now.
I would still shoot raw - I do with my S7 - just be careful with the controls in ACR and Lightroom. For those screenshots above, I had pushed the exposure well beyond what I would do with my SLRs let alone the phone.
I would much rather start in ACR with a RAW file than with an already processed jpeg. I find the jpegs from the S7 to be over-sharpened and too contrasty and the white balance not ideal. They look good on the phone's screen but upload them - Yuk!
With the RAW files , I can usually get a decent image.
So maybe I need to experiment more, thanks!
Can you post a link to a DNG file. I don't have an S8 but I do have an S7 for comparison.
Do you see that pattern if you photograph black (i.e cover the lens with dark card), or dark gray - take a pic of a dimly lit dark card.
Hi, Dave, I will try to provide the DNG tonight, and also experiment with the black exposure. Thank you.