More terrible sky noise with A700

[bakubo]

Some of you may remember my thread from some months back about the terrible red channel noise of the A700 (unfortunately all of Sonolta's useful responses are now gone from the thread):

http://www.photoclubalpha.com/forum/vie ... =32&t=2783

This afternoon I am working on some of my photos that I have been taking here in Japan. Here is a photo of a part of the Seto Inland Sea (瀬戸内海) and it shows the problem very well. Shot in cRAW and used ACR 5.4 to convert. This is an ISO 160 photo (no polarizer):

DSC00116.jpg

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And this is the photo converted to B&W:

DSC00116_bw.jpg

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Even at this much reduced size you can clearly see the problem.

[bakubo]

Here is a 100% color crop:

DSC00116_color_crop.jpg

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And a 100% B&W crop:

DSC00116_bw_crop.jpg

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[bakubo]

Does anyone have a solution for this problem? I never experienced it with my earlier Canon DSLRs. Everytime I use the A700 for landscape type shots that have blue sky I realize it has real problems. Back on our long road trip several months ago this problem cropped up all the time.

[aster]

That indeed is frustrating Bakubo.

It certainly doesn't make sense at ISO 160 and while the light conditions are good enough for a spotless blue sky.

I hope there's a work-around.

Yildiz

[bakubo]

I forgot to mention that this was shot in cRAW and I used ACR 5.4 to convert. I went back and added that info to my OP.

[bakubo]

That indeed is frustrating Bakubo.

Yildiz, it certainly is! This happens with just about any photo that has blue sky in it using the A700. It is, in my opinion, a fatal flaw in an otherwise excellent camera. How could Sony ever think that as common as blue skies are it is okay for them to be like this?

It certainly doesn't make sense at ISO 160 and while the light conditions are good enough for a spotless blue sky.

Yes, one would think.

I hope there's a work-around.

I hope so, but judging from my earlier thread I have my doubts.

[agorabasta]

Henry,

Judging from colour of the skies, you really can improve the outcome by changing the relative saturation and hue of the basic colours.
For the a700 in Lr3 I used the following 'calibration' -



The piece of sky here is at 100% res; ISO160.

[agorabasta]

BTW, your particular example shows bit-slicing intro'ed by processing rather than any true noise.

[Birma]

Hi Henry. Does this happen for all blue skies, or is this a similar problem to the one DK pointed out the in A550 thread (see http://www.photoclubalpha.com/forum/vie ... =32&t=3331) when it is only sometimes ?

[Winston]

Have you tried ACR 5.5? Are you sharpening the color noise?

[Dusty]

And have you compared RAW to cRAW?

Dusty

[stevecim]

Hi Henry

I've noticed the same sort of problem with the A350, in the same sort of shots, when the sky goes from darker to lighter across a frame, you get these distinct "borders" between the different shades.

which is different to the sky shot WestCoast posted there is not has large change is sky color across the frame.

One thing, on a few shots that I have printed , at 10"x12", the problem seems to go away in the final print.

So I just assumed it was a limitation of my screen

[bakubo]

BTW, your particular example shows bit-slicing intro'ed by processing rather than any true noise.

Here is a screenshot of ACR with the image so you can see the settings:

ACR_screenshot.jpg

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[bakubo]

Judging from colour of the skies, you really can improve the outcome by changing the relative saturation and hue of the basic colours.
For the a700 in Lr3 I used the following 'calibration' -



The piece of sky here is at 100% res; ISO160.

agorabasta, thanks for that. I tried it and it certainly made the blue sky a much better color, but it didn't change the problem I am having because I still get the weird effect (not really noise as you said). Since my intention when I took the photo was to convert to B&W I was a bit less concerned about the fact that the exact hue of the blue sky was not correct when I did the conversion. I had this same problem a lot in my landscape shots in the western U.S. a few months ago when I was using the A700.

By the way, do you think that it is ACR or the A700 that has so much trouble getting the hue of blue skies correct? Your hue/saturation adjustment improved things a lot, but I am wondering why it is so off-kilter to begin with? Anyway, this is a side issue to my main problem at the moment.

Thanks for you help!

[bakubo]

Have you tried ACR 5.5? Are you sharpening the color noise?

I believe that ACR 5.4 is the latest that works with PSE 6, which is what I am using. I also have PS CS2, but it only allows the use of a much older version of ACR and it doesn't support the A700.