FOG Photos - Problem with weird patterns on JPEGS ( in-camera converted )

Paperman

Has anyone here had any issues with weird patterns in the sky on FOG photos in "in-camera" converted JPEGS ? Looks like moire but it is not. More like lines in topographical maps, concentric circles/ellipses ...100% sure exposure below highlight clip limit - checked backscreen LCD for histogram/flashing highlights after each shot. Don't want to go into much detail as I know most of you work only RAWS here.

No problems in RAWS and no issues on JPEGS I converted using Capture NX on PC. So both conversions by Nikon software - one in camera, the other not . Not talking about a single shot ; over 100 images with heavy fog - all of them with the weird digital degradation on in-camera JPEGSs. No such problem in shots without fog; JPEGS straight from camera are perfectly usable ( as has been the case for the past 6-7 yrs ).

Golf007sd

Can you post some images for us to look at? Did you have any filters on the lenses used?

Paperman

The problem is not what I initially wrote. I can still see the patterns in RAWS converted to JPEG in PC ... Somewhat less but I can still see them.

Both JPEGS straight from camera. No filters :

Paperman

Continuing here as I am not able to write/add above for some reason - maybe due to large images.

Interestingly, the JPEG files from camera are rather small ( around ) 2.5MB for RAW files of around 18.5MB . Normally, I get 6-8 MB images out of JPEG Fine. I know there is less detail in foggy shots but looking at the size of the RAWfiles, I should not be getting these. The JPEG when converted by Capture NX is 40-50% larger at 3.5 MB but still small. Maybe that is why I see less degradation in that case.

I know this looks like simply blowing highlights but believe me the histogram is below clipping limit. First time I ever had a problem like this when histogram/highlight warnings showed me I am safe .

I guess the JPEG for some reason is too much compressed to carry the details of the sky ( which there isn't much of anyway ) .

ExpensiveHobby

Part of the reason the JPEG files are smaller than you are used to is because the majority of the photo is has light/no colors. It is my understanding that a pure black image will produce the greatest file size from a given sensor in comparison to a pure white image (smallest file size).

Paperman

That is true but why the 18.5 MB RAW then - the usual size for RAW files ?

mark_4

I can only see it very faintly on my screen, but I guess that it is fine gradations in the levels which cause posterization on the screen that you are using.

Pistnbroke

Try a portrait orientation as an experiment and see which way they run....

Msmoto

Try underexposing a few and see if the same thing occurs...

Paperman

I knew underexposing would solve the problem so I did the next day. It was foggy again and I bracketed to see 1/2 -2/3 stops under solved the problem.

The main issue here is why a perfectly exposed photo ( according to the camera's histogram about 1/3 stops below blowing highlights ) would come out to be overexposed enough to show digital degradation in the final image. Heavy fog/vapour in the air must have had an effect....That is something new for me after all these ( digital years ) ; something to watch from now on.

@Pistnbroke

I have many vertical shots as I was shooting mostly for panoramas . Same patterns at top where ever is lightest ( covering 1/3-1/2 of the sky ). So it has nothing to do with certain parts of the sensor. It is an exposure issue .

I see it is not a common problem. So if any of you hit a foggy day sometime, please let me know if you have similar issues when you expose just as you usually do. In the meantime, I will see if editing will eliminate the patterns.

heartyfisher

What are your jpeg settings (fine?, size?). also your active d-lighting settings? BTW, your exif has been striped from the images so I cant see much info to help diagnose...

PB_PM

The main issue here is why a perfectly exposed photo ( according to the camera's histogram about 1/3 stops below blowing highlights ) would come out to be overexposed enough to show digital degradation in the final image. Heavy fog/vapour in the air must have had an effect....That is something new for me after all these ( digital years ) ; something to watch from now on.

Was the histogram of a RAW file or in camera jpeg? If it's RAW I've learned not to trust the in camera histogram too much, because it makes that based off the embedded jpeg in the RAW file. That means that the jpeg might be fine, since it threw away the data, while the actual RAW file contains far more information, including blown highlights.

Msmoto

On the histogram, is there a rise in the graph on the right edge of the histogram? This may be one which actually moves off the right edge of the histogram. if present, this indicates the highlights have been clipped and that is what is being seen in the sky where the strange pattern exists.

Paperman

@heartyfisher,
JPEG settings at Fine e & Large, D-Lighting off, all picure settings at standard. Uploaded to photobucket as it was full size - not sure why the EXIF is gone. It shiuld be 1/80 f8 (ish) ISO 200.

@PB_PM,
The camera reads from a JPEG conversion and that histogram on back screen is/was fine. That's what I trusted all this time with DSLRs. Plus the highlights did not blink. If not rely on that info, what can I rely on ? :-?

@msmoto,

Nope, the histogram does not touch the right side at all.

By the way, are the patterns visible to you ? It's a bit hard to see when it is this size - I don't see it when I view this post on a tablet.

heartyfisher

nope cant see "it" .. maybe its your monitor/software ...

Ironheart

I can't see it either. Try a different computer? Are you sure you have a true 8bit monitor? (nooo, not that discussion again)

Paperman

Maybe 7.5 :-) ... I would have accepted it is a monitor issue but I keep seeing the same patterns when I view them in my tablet ( the original size JPEGS ). I see Photobucket does not provide full size view.

Anyway guys, the saga continues but I don't want to bore you to death with it so I will not ask any more questions - will just summarize my observation. We're having the same streak of foggy weather here and I did have time today to go out and shoot almost the exact scene today - this time purely for testing purposes with plenty of bracketing.

With ISO 200 & 1/100 being the constant, LCD backscreen histogram showed best exposure to be f7.1 - histogram not touching the right, not a single pixel of highlight flashing.

Came home, transferred the JPEGs . ISO & shutter being same
- f7.1 had the patterns
- f8 had the patterns
- f9 no visible degradation

So my DSLR histogram/highlight warning seems to be 2/3 f-stops out when it comes to fog ( I encounter no such issues under any other conditions; not blowing highlights has been the key to exposing correctly in my amateur landscape photography ).

I am at the point of giving up trying to pinpoint the reason to the problem and I will just accept it as it is. I haven't had time to work on the images yet so I don't know if it is livable or not.

heartyfisher

would be interested to see the original F7.1 files ...

Ironheart

Yes, can you post them on Dropbox including the RAW?

Paperman

Good , so you are not bored to death ! ..

Here you go - 3 images mentioned above, both JPEG & RAW. Don't forget these are just bracketed test shots for the patterns in the sky - nothing artistic here :-)

https://www.dropbox.com/sh/m2g696q5w3tsn27/AABySXuBc3kzD9Yeg4f0AB4fa?dl=0

Call me crazy but I even see it on the f9 photo . If you are not seeing anything in any of the images, my screen must have gone haywire !

spraynpray

Can't see it on the dropbox files on my screen, they look fine. As you said you are 1/3 stop blow clipping, I'd say you have maximum data in the highlight bits so whatever your problem, it isn't the camera. As has been hinted at above, don't forget the histogram is of the embedded tiny jpeg so is very limited.

One of the firmware tweaks coming for the D750 is a new raw histogram - nothing much has been said here about that feature - personally I think it is one of the most important improvements they could make.

heartyfisher

yup same here looks fine ..

Msmoto

@Paperman

It could of course be that there us a part of the histogram which is outside the right edge....and this would be blown highlights. I have noticed this in some of my shots, easily occurs in the clouds as the backlighting can change so quickly.

I notice the area on the second shot above, looks like about 1/3 of a moon in the center top. And, identical to what I have experienced in some of mine.

Suggestion: In post processing, run a brush across this area and drop the contrast to see if possibly the high lights come back in. Also, look at a RAW image, and do the contrast reduction as well. I think this is nothing but blown highlights, in spite of what is seen on the histogram.

Parke1953

They look great on my screen. I don't see any moon.

Paperman

Thank you all. If noone is seeing those concentric circles/lines/patterns, it has to be my screen. Will see what I can do about that....What mislead me was seeing the same lines on my Samsung tablet, too. I saw no reason to check the images on a 3rd device.

spraynpray

I have a Samsung phone and tablet and I find the screens are crap. I commonly see the effect you are talking about on them. I don't understand why they can't catch up with Apple in that regard.