7 replies to this topic

[kderby]

Hi

I recently found horizontal stripes (see attached screen shot)  (that look like noise) in 3 images (shot at same time in same lighting, etc.)  The images before and the images after (where the composition varied only slightly), do not have the horizontal noise.  Shot on a D750, ISO 1250, f/4 @ 1/160.  SB800 did fire.  Both the camera and lens are very new.  

 

I wonder if the problem is a card issue (SanDisk Ultra 30MB/s 16GB) or a camera issue?  

 

 

I have not been able to recreate the problem.

thanks for any insights!

kDerby

[Merco_61]

That looks like a fragmented file. This can happen either in-camera while writing to the card, while ingesting when reading from the card or writing to disk. It can be something screwy when Lightroom created the preview as well. Is the artifact still there if you open the nef with ACR in PS?

 

Is your card formatted in-camera or has it been formatted elsewhere?

 

The Ultras are on the slow side for a D750, they are usable, but the Extreme or even Extreme Pro work better as they let the camera work at full speed instead of having to wait for the buffer to clear.

[Brian]

What mode are you shooting in: uncompressed NEF or lossless compressed NEF, lossy NEF?

[Ron]

I agree with Peter about the Sandisk Ultras. They do write and read sluggishly, even on older cameras like my D610. And, I've had a couple that went south on me. Fortunately, I had already dumped the pictures to my hard disk.

 

I've also seen some references to this sort of thing cropping up when you use Lightroom to import photos directly to the computer... rather than taking the intermediate step of copying them to the HD using the computer's file system and then importing into Lightroom. If that's the case, the picture on your card might be OK (assuming you haven't already reformatted the card).

 

However, at this point, I'm guessing that the card is bad.

 

--Ron

[kderby]

Thank you for your responses!  

@Brian, lossless compressed NEF

@Nikonian, I actually pulled that card from my d7100 at the end of my shoot, did not reformat (leaving 100 d7100 images on that card), shot 40 more photos (only 3 of which were affected).

Just tested opening the NEF in camera raw and still see the horizontal lines.

Thanks for noting the slowness of the Ultra's, agreed!  and usually i do shoot on an Extreme Pro or Extreme card, just was the tail end of the shoot and grabbed the old card from the old camera.  I am now retiring that card but still want to know if it was the culprit.  

 

Attaching the actual photo & a screen capture of the Camera Raw screen...  It's hard to see the lines in the thumbnail that is posted, so i'm attaching a zoomed in screen capture. . . the lines fun the full length of the image. 

 

Thanks again, this is so helpful

 

 

 

Thanks Ron, the card is reformatted so image is gone . . . but there is no big loss as the photo affected is not a master, nor a critical image.  I'm going to retire the card.  And I'm going to start coping to hard drive before importing to LR.  I used to do that, great idea!

[Merco_61]

A card that was formatted in another camera can do strange things to files as you write to the card. 

[Brian]

This is the sort of problem that a lossless-compressed image can show with a couple of "bit errors" in the file. Not sure of Nikon's algorithm, but the standard Adobe lossless/compressed algorithm uses "differences" of pixels (uses subtracted values) running down a row, then uses variable-length coding to store them. A few errors- and "wham"- the row will not decompress properly, and it looks like what you show.

 

I always format the card in the camera that it will be used in. If the problem comes up again, try using uncompressed NEF. If the problem carries over, it might be worth getting the camera checked. 

[kderby]

this is really good to know, very helpful, thank you Peter

I won't toss the Ultras, just keep them as backup.

 

I always wondered if I should reformat a blank card when switching between cameras, now i know. . thank you thank you

Thank you Brian!