High ISO Magenta Noise Again

P

petr

Senior Member
Hello, photographers again, Nikon D750 users especially!


About half year ago, I wrote about my D750 showing magenta noise along the bottom of the frame with strongest intensity in the left bottom corner (camera in the horizontal position) when shooting at ISO setting from 5000 up (see http://nikonites.com/d750/36462-high-iso-magenta-noise.html#axzz4N4CTo445). I also attached a sample high ISO exposure with the described noise taken outside in the night for you to see what I ment. During discussion I thought it was caused with ADL mode ON while shooting RAW. Looks like I was wrong, the problem persists so I am limited to enjoy photography with this otherwise awesome camera under ISO 5000 only which makes me quite sad and disappointed:-(


Today, I am going to show you four test images (ISO 12800 and 6400) right from the camera (no manual image data alternation applied, all supportive image quality modes OFF) taken with the lens and viewfinder window cups on. Two of them are in-camera and other two Capture NX-D converted JPGs with NR OFF from flat 14-bit lossless compressed RAWs and resized for upload. The higher ISO, the more vivid magenta noise is visible even without any further shadow (or anything else) processing, i.e. right on the camera screen (with brightness set to zero, i.e. medium level). However, it might help you to see the problem better if you post-process attached images for yourself or even test your D750 the same way I just did. And then please let me know your results. Thanks a lot.


Anyone with a suggestion or explanation now? Any feedback very appreciated, professional especially:)


ISO 6400 in-camera.jpg

ISO 12800 Capture NX-D.jpg

ISO 12800 in-camera.jpg

ISO 6400 Capture NX-D.jpg
 
cwgrizz

cwgrizz

Senior Member
Challenge Team
I see it and on the 12800 ISO it seems to go higher up on the photos, about 2/3 of the way. At 6400 it is seems to not go up more than about 1/3 of the way. I can't tell you why it is doing it, but I do see it when I really look closely.

I might add that to see it I had to click on each photo to see a little larger version.
 
Horoscope Fish

Horoscope Fish

Senior Member
I can't see the magenta noise on these shots at all unless I work them up in Photoshop.

Here's the 12800ISO shot with a massive Levels adjustment applied to the Midtones. That's what I have to do before I can clearly see the magenta noise being discussed. With this adjustment the magenta is more prominent on my monitor than what I'm seeing in this post but this should give you an idea:
.....
ISO 12800 in-camera.jpg
.....
12,800 ISO; Midtones slider at 2.50​
 
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P

petr

Senior Member
I had a similar discussion here:

https://www.dpreview.com/forums/post/58501991

Thanks a lot for your contributions. Seems like D750 users should take this kind of sensor behavior for granted and hope for future advancement in the digital imagery technology. By then, we probably must avoid using very high ISO numbers for paid photography unless we love heavy post-process with every picture taken when pushing sensors to their extremes. I admit that my existing experience with hand-held low light shots of action does not fully correspond to my expectations from this class of DSLR about which I had made extensive research before I decided to get one. No D750 review available on the internet to date ever mentioned this specific issue so I never expected to experience one. Well, I will stick with the strategy of shooting only under ISO 5000 for paying clients.


I appreciate every input in this discussion I started and would consider it closed from now on.
 
B

Blacktop

Senior Member
I don't see a problem at all. Normally I don't take shots with the lens cap on but I tried it with my D750 at the same setting as yours.

The first shot is with the Adobe Standard profile, the other is the Flat profile.

_DSC2330.jpg


_DSC2331.jpg


Please post a properly exposed shot at 12800 ISO.

Here is one SOOC from RAW to jpeg with the Camera Flat profile at 12,800 ISO

_DSC2328.jpg
 
B

Blacktop

Senior Member
Well, I will stick with the strategy of shooting only under ISO 5000 for paying clients.
Click to expand...
@petr. I don't know what kind of images you shoot for paying clients, but if you're needing to shoot them at those high ISOs it might be a good idea to look into using a flash setup instead.
 
P

petr

Senior Member
I understand your point. Nevertheless, on the dance floor there isn't any room for a flash setup and many people being photographed from close do not wish or do not like bright flashes shot right into their faces. Bounced flash is not an option eighter as the walls are too high or far or painted with other colors than white or there are no walls around when people are dancing outside under open night sky. So as you can see the situations I usualy have to capture in professional quality naturaly expected by the paying client are very challenging for the camera's electronics. Mostly such images get underexposed because ISO 12800 at 1/250s (longer times were never good enough to capture dancing people in good sharpness in those very low light conditions) is usually not enough for the sensor to collect sufficient amount of light, so extensive post-processing is the way how to make the pictures looking acceptable for my client. All the above is clear. I just do not like when I see uneven magenta cast along the edge of the frame in the processed images, it just drives me nuts. I often must get rid of it by cropping. The noise grain does not bother me that much. Do you people thing that there would be any sense to thing that D5 would help me better to achieve what I need to without dealing with heavy post-process or cropping? Does the price difference between D750 a D5 reflect the difference in RAW image quality captured in those very low light action conditions?
BTW, I can't post any image showing the magenta mess now as I have only finished jpgs after all that post-processing and cropping done.
 
Marcel

Marcel

Happily retired
Staff member
Super Mod
One thing you must accept is that photography is just light catching. When there isn't enough light, the results suffer. You can raise iso as high as you want, no quality light = low quality pictures.

Long time ago, I was the photographer for a local disco and people just got used to the flash. In those days, I was using film and the highest iso available for color prints was 800. So you've got to work with what you have.

Now this being said, I'm certain that a D5 would get you better results.
 
P

petr

Senior Member
Please check this unprocessed (just resized) night image from my D750. Don't bother about the hand-shake blurr if you notice any, just concentrate on the noise along the bottom edge especially and also on some weird lines along the top edge. What do you think? BTW, I don't think this highlight-weighted picture is underexposed (clouds look ok to me), it was dark like that.

DSC_3879.jpg
 

Attachments

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M

mikew_RIP

Senior Member
:confused:

Please dont take offense treat this like a chat while where having a drink:D to me you seam to be going to extreme with your uploads too show a fault,if its the case the best thing to do is to send it off to Nikon,this last sample is under exposed and far too small a file to see anything worth while in.
One question and ime sorry if i have missed it,do you see the same results with all lenses,i ask because in this m4/3 world i have moved into there is a banding problem with the Panasonic 20mm f1.7 and the 16mp sensor,its only that combination and it doesnt matter if the sensor is in a Olympus or a Panasonic,just to make it worse not every one gets it.
 
P

petr

Senior Member
Please check this unprocessed (just resized) night image from my D750. Don't bother about the hand-shake blurr if you notice any, just concentrate on the noise along the bottom edge especially and also on some weird lines along the top edge. What do you think? BTW, I don't think this highlight-weighted picture is underexposed (clouds look ok to me), it was dark like that.

View attachment 231585
 
M

mikew_RIP

Senior Member
Again the file size is too small,its 76.8kb the exposure adjusted file looks like this,its breaking up too much to be of any use to check for anything.

DSC_3879e.jpg
 
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