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Why the jaggies in this shot?

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MisterPootieCat

MisterPootieCat

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I have a set of roughly 60 shots taken over a period of maybe 45 minutes and all of them exhibit jaggies along the top edge of the buildings where lights are placed at regular intervals. The first link is the original shot, just converted to JPEG via DPP and uploaded. The second shot is a crop showing the area with the jaggies.

Shot information: 40D & EF 50mm F1.4 and no filter,

Av mode, F8, 3 seconds, ISO 125, RAW, AWB, Picture Style: Standard (3/1/0/0), using self-timer and MLU, long exposure NR was on, One-Shot AF.

Is this normal? Is there something about the lighting on the building that would cause this? All of the shots taken show the same peculiar jaggies on the tops of the buildings. I haven't seen any other shots from this camera body that show this weird edge detail. I've also tried viewing the shots in ZoomBrowser, DPP, Elements 6.0, Microsoft's Fax & Picture Viewer, IE 6.0 & 7.0. The results are always the same.

Here's the original shot (big file warning!):

http://farm3.static.flickr.com/2215/2283340182_cffa08eaf1_o.jpg

and here's a crop of just the area in question:

 
Forgot to mention this shows up when viewing the RAW file, also converted to TIFF and same-same.
 
I do not believe you are experiencing a malfunction in your gear. it's most likely a "blooming" effect associated with such a high contrast line. That edge light is so intense on a long exposure in comparison to the rest of the scene - it not only clips and blows out , there is a "blooming" effect where those pixels bleed over.

Try shooting it again and this time bracket the a couple - 3 stops over and under the optimal exposure and blend the exposures in HDR.

With a little masking and history brush you can minimize the effect and bring out even more detail normally not seen when you are exposing for a certain part of the frame - such as the sky.

Do you mind if I photoshop this and post it back up here? This shot has so much potential it's scary.

I mean , suitable for framing.

Darryl
 
I like the shot, still not sure what you mean by "blooming" though. Feel free to run it through PhotoShop, I don't know how to use it and it would be kind of cool to see what you come up with! And thanks for the nice words too!
 
It's an anti-alias issue. As high contrast lines get closer and closer to being horizontal, there are less pixels to step between as the lines go across the screen. Computers and cameras try and adjust for this by adding anti-aliasing to smooth out the "jaggies" that become evident. The lights on these buildings are so close to being horizontal that they only have 3-4 vertical pixels to jump between from one end to the other. If you can, try to take the shot into photoshop, draw a mask around the lights and apply a fairly heavy horizontal only blur (directional blur). This should smooth them out a little.

Good luck.

Marco
 
I included a cropped image showing the jaggies.
 
One of these days I'll need to learn how to use PP tools. I have Elements 6.0 but don't use it.

Could you briefly share what you did? I love how the colors are much richer in the shot you posted.
 
mjbiii said:
It's an anti-alias issue. As high contrast lines get closer and
closer to being horizontal, there are less pixels to step between as
the lines go across the screen.
Click to expand...
This goes beyond that, though. There almost seems to be a pixelation effect where 1x2 pixel tiles are there, and it is due to the extra red fringing. The red fringing may be infrared light out of focus, and infrared usually shows up as a reddish magenta to purple color with daylight white balance.

The fact that the image is grossly over-sharpened doesn't help at all.

--
John

 
MisterPootieCat said:
One of these days I'll need to learn how to use PP tools. I have
Elements 6.0 but don't use it.

Could you briefly share what you did? I love how the colors are much
richer in the shot you posted.
Click to expand...
The color saturation of an image is always easy to manipulate; the only problem is that if you have a lot of chromatic noise in the image, it will get more chromatic as you boost the saturation. The other person probably dod some NR and used a proper downsizing algorithm, so it doesn't look noisey, at least at a small size.

Speaking of noise, ISO 125 is generally an ISO to normally avoid on the 30D and 40D cameras. It is just ISO 100 under-exposed, under the hood, and has much more noise in the shadows than ISO 160.

--
John

 
If you shot raw you can turn off sharpening completely and apply some selective sharpening in photoshop. There are 2 places where sharpening is applied in DPP. On the Raw tab and the RGB tab. If that doesn't help, you'll need to reshoot it and try to expose for the highlights. a 4 stop bracket may or may not be enough. You can also do some manual exposures to make sure you get the correct exposure.

It's unlikely but it is possible to hit the AA filter limits if contrast is really high. I've never done it but you can try pushing the lens over its limits by stopping down to f/22. Diffraction kicks in making the shot softer, and may also slightly soften the neon line light. A side effect is that the lensflares increase in intensity.

--
Imqqmi

http://www.pbase.com/imqqmi
 
John Sheehy said:
mjbiii said:
It's an anti-alias issue. As high contrast lines get closer and
closer to being horizontal, there are less pixels to step between as
the lines go across the screen.
Click to expand...
This goes beyond that, though. There almost seems to be a pixelation
effect where 1x2 pixel tiles are there, and it is due to the extra
red fringing. The red fringing may be infrared light out of focus,
and infrared usually shows up as a reddish magenta to purple color
with daylight white balance.

The fact that the image is grossly over-sharpened doesn't help at all.

--
John

Click to expand...
I was using the Standard Picture Style with 3,1,0,0 parameters. When you say oversharpened are you referring to my original shot or the one that was modified by Darryl?

I'll play around with the sharpening (it was shot in RAW) and see if that helps.
 
John Sheehy said:
MisterPootieCat said:
One of these days I'll need to learn how to use PP tools. I have
Elements 6.0 but don't use it.

Could you briefly share what you did? I love how the colors are much
richer in the shot you posted.
Click to expand...
The color saturation of an image is always easy to manipulate; the
only problem is that if you have a lot of chromatic noise in the
image, it will get more chromatic as you boost the saturation. The
other person probably dod some NR and used a proper downsizing
algorithm, so it doesn't look noisey, at least at a small size.

Speaking of noise, ISO 125 is generally an ISO to normally avoid on
the 30D and 40D cameras. It is just ISO 100 under-exposed, under the
hood, and has much more noise in the shadows than ISO 160.

--
John

Click to expand...
I don't use the 1/3 or 2/3 stop ISO settings anymore. When I saw your earlier post about how the camera makes the exposure adjustments and increased noise it just doesn't make sense to use them. So now my camera is set to only display full stop ISO's and to be honest I don't really feel like I'm missing anything. I also don't use Long Exposure NR, again because of all the noise it adds.
 
You said you shot this in raw. Did the raw processor apply sharpening? If so, how much? Using raw, BTW, is an excellent choice. It will provide great opportunities for improving your shot.
 
Kiddpeat said:
You said you shot this in raw. Did the raw processor apply
sharpening? If so, how much? Using raw, BTW, is an excellent choice.
It will provide great opportunities for improving your shot.
Click to expand...
Well, the sharpening parameters in the camera were set to 3 with 0 to 7 as the range available. I understand these parameters don't actually get applied to the RAW shot. When I open the shot in DPP it will use the camera's settings to display the image. For the shot posted DPP read the camera settings and applied them when creating the JPEG image. Contrast was +1 if that matters.

FWIW: I've tried turning the sharpening off (0) and still see the jaggies although they are somewhat blurred. Also tried all of the different WB settings, contrast, saturation, and color tone. If I turn EC down to -2 stops the jaggies are almost gone but can still be seen. Of course the image is way too dark at that point to be worth looking at.
 
An excellent question, however DPP tells me the shot was taken in RAW and 3888x2592 resolution. And I've never tried SRAW yet.
 
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