What's happening here? - Tilted Forum Project Discussion Community

ngdawg · 01-27-2008, 09:33 AM

This appears to be something new and I'm not sure if it's the memory card, the camera, settings, etc.(although I was shooting in Auto for this set).
Hopefully the problem will show up here-the sawtoothed pixellation on the edges in the photo. This was taken yesterday-colors are accurate, shot in RAW format. Nothing else is pixellated, just any edge where two colors meet. The more contrast between the colors, ie; red to white, the more pronounced the "sawtoothage".
Can't be ISO because there's no abnormal graining and I can't get the stats because the photo can only be saved or uploaded as something other than RAW. Below are both a cutout showing the effect and the original unretouched.

Note that while there is some blurring, there is no distortion in this other than the edges.
This is the shot:

As a whole, it's relatively crisp, shot on a partly sunny afternoon, about 4pm. EV was at -1 to cut glare. Lens used was a Sigma 28-200mm. Wish I could get the stats, but they're not showing anywhere.
Card used is a SanDisk 1.0g.

JumpinJesus · 01-27-2008, 09:47 AM

That's odd. This is the only image this has happened to so far?

My guess would be the sensor. But if this is the only image it's happened to, then I'm at a loss.

Is the top image a 100% zoom%?

ngdawg · 01-27-2008, 10:28 AM

Top image is about a 200%. It happened to the whole set at this diner (about 10 shots), but not at the preceeding shoot the same day, which was shot in Very Fine Jpeg.
While I was in the shower, a thought occured that perhaps my card reader has corrupted the card. ?? There were two prongs, one on either end, that had to be pushed back up in line with the rest before this card was inserted last week after a shoot of an abandoned house. Checking those photos, there is no sawtoothing going on. Seems to be only the RAWs of yesterday.
I also used the camera today to review what was going on and the effect remains, so now it's embedded-I have to use the blur tool really carefully to get rid of it.

Edit:I rechecked the jpgs shot yesterday at about 120% and there is some sawtoothing, just not as pronounced as in the RAWs. Then again, their quality overall isn't as crisp.

skibum · 01-27-2008, 12:05 PM

what RAW converter you using? SOme do odd things others don't. Could be a camera issue as well. I doubt its the card...

allaboutmusic · 01-27-2008, 12:25 PM

It almost looks like dithering at the edges. I wonder if it could be connected to the sensor pattern - IIRC, most have red, green and blue alternating and use an algorithm to extrapolate the data between them. I assume no sharpening or anything was applied.

It can't be a memory card corruption, the fact that it's only edges indicates it's probably some kind of logic error somewhere in the chain.

ngdawg · 01-27-2008, 12:47 PM

RAW converter? I use Irfanview to view the images and save them through that.
Allaboutmusic: Could you be more specific? What 'sensor pattern'? The exchange of info between lens to camera to card? Nothing was applied post-shot. The second image is exactly what came from the camera and the crop from that.

allaboutmusic · 01-27-2008, 01:05 PM

The Bayer pattern is the most common sensor arrangement, this article has a little information on it:

http://www.dpreview.com/news/0706/07...akhighsens.asp

I found this webpage on Irfanview and RAW files by the way, you might want to have a look:

http://en.irfanview-forum.de/viewtopic.php?=&p=4415

forseti-6 · 01-27-2008, 01:59 PM

It's possible it's just chromatic aberration caused by limitations of the sensor. This is basically caused by the sensor being confused at what it's seeing and thus it'll portray it as something that's not really there. The lens might have something to do with it as well.

JumpinJesus · 01-27-2008, 03:08 PM

upon closer inspection of the zoom image, it does appear that rather than a sawtooth pattern, it looks as if there are alternating pixels of various shades and tones of red, blue, and green.

01-27-2008, 09:33 AM	#1 (permalink)
ngdawg peekaboo Location: on the back, bitch	What's happening here? This appears to be something new and I'm not sure if it's the memory card, the camera, settings, etc.(although I was shooting in Auto for this set). Hopefully the problem will show up here-the sawtoothed pixellation on the edges in the photo. This was taken yesterday-colors are accurate, shot in RAW format. Nothing else is pixellated, just any edge where two colors meet. The more contrast between the colors, ie; red to white, the more pronounced the "sawtoothage". Can't be ISO because there's no abnormal graining and I can't get the stats because the photo can only be saved or uploaded as something other than RAW. Below are both a cutout showing the effect and the original unretouched. Note that while there is some blurring, there is no distortion in this other than the edges. This is the shot: As a whole, it's relatively crisp, shot on a partly sunny afternoon, about 4pm. EV was at -1 to cut glare. Lens used was a Sigma 28-200mm. Wish I could get the stats, but they're not showing anywhere. Card used is a SanDisk 1.0g.

01-27-2008, 09:47 AM	#2 (permalink)
JumpinJesus Junkie Location: Chicago	That's odd. This is the only image this has happened to so far? My guess would be the sensor. But if this is the only image it's happened to, then I'm at a loss. Is the top image a 100% zoom%? __________________ "I can normally tell how intelligent a man is by how stupid he thinks I am" - Cormac McCarthy, All The Pretty Horses

01-27-2008, 10:28 AM	#3 (permalink)
ngdawg peekaboo Location: on the back, bitch	Top image is about a 200%. It happened to the whole set at this diner (about 10 shots), but not at the preceeding shoot the same day, which was shot in Very Fine Jpeg. While I was in the shower, a thought occured that perhaps my card reader has corrupted the card. ?? There were two prongs, one on either end, that had to be pushed back up in line with the rest before this card was inserted last week after a shoot of an abandoned house. Checking those photos, there is no sawtoothing going on. Seems to be only the RAWs of yesterday. I also used the camera today to review what was going on and the effect remains, so now it's embedded-I have to use the blur tool really carefully to get rid of it. Edit:I rechecked the jpgs shot yesterday at about 120% and there is some sawtoothing, just not as pronounced as in the RAWs. Then again, their quality overall isn't as crisp. Last edited by ngdawg; 01-27-2008 at 10:38 AM..

01-27-2008, 12:25 PM	#5 (permalink)
allaboutmusic Aurally Fixated	It almost looks like dithering at the edges. I wonder if it could be connected to the sensor pattern - IIRC, most have red, green and blue alternating and use an algorithm to extrapolate the data between them. I assume no sharpening or anything was applied. It can't be a memory card corruption, the fact that it's only edges indicates it's probably some kind of logic error somewhere in the chain. Last edited by allaboutmusic; 01-27-2008 at 12:28 PM..

01-27-2008, 01:05 PM	#7 (permalink)
allaboutmusic Aurally Fixated	The Bayer pattern is the most common sensor arrangement, this article has a little information on it: http://www.dpreview.com/news/0706/07...akhighsens.asp I found this webpage on Irfanview and RAW files by the way, you might want to have a look: http://en.irfanview-forum.de/viewtopic.php?=&p=4415 Last edited by allaboutmusic; 01-27-2008 at 01:07 PM..

01-27-2008, 12:05 PM	#4 (permalink)
skibum Crazy Location: Colorado	what RAW converter you using? SOme do odd things others don't. Could be a camera issue as well. I doubt its the card...

01-27-2008, 12:47 PM	#6 (permalink)
ngdawg peekaboo Location: on the back, bitch	RAW converter? I use Irfanview to view the images and save them through that. Allaboutmusic: Could you be more specific? What 'sensor pattern'? The exchange of info between lens to camera to card? Nothing was applied post-shot. The second image is exactly what came from the camera and the crop from that.

01-27-2008, 01:59 PM	#8 (permalink)
forseti-6 Existentialist Location: New York City	It's possible it's just chromatic aberration caused by limitations of the sensor. This is basically caused by the sensor being confused at what it's seeing and thus it'll portray it as something that's not really there. The lens might have something to do with it as well. __________________ "Don't cry because it's over. Smile because it happened." - Dr. Seuss

01-27-2008, 03:08 PM	#9 (permalink)
JumpinJesus Junkie Location: Chicago	upon closer inspection of the zoom image, it does appear that rather than a sawtooth pattern, it looks as if there are alternating pixels of various shades and tones of red, blue, and green. __________________ "I can normally tell how intelligent a man is by how stupid he thinks I am" - Cormac McCarthy, All The Pretty Horses