Blue Skies, Noise and Achieving a Balance

[soenda]

I have been wrestling for some time with trying to control noise that shows up in my shots that include bright blue sky. Granted, I'm working with a compact camera and its sensor limitations: Panasonic FZ7. I've pretty much ruled out processing errors---the noise is there in the original image. RAW is not an option for the Panny. But the solutions suggested to me all come at a fairly high cost in sharpness or contrast. I guess it's a balancing act. Here's a recent shot where I tried using a different interpolation routine for resizing for posting. I would be interested in what people think about the noise vs detail balance.

[sean_mcr]

I have a couple of things for you that will be of great use to you. I'll let you have them in the next couple of days when i have a little more time











Sean

[andrys]

Soenda, there are jaggies in this resizing. Did you use simple bicubic?

As for noise, I now often exclude the sky or big blocks of dark areas
when sharpening back on a resize-down for web viewing. The resizing
alone will eliminate most of the sky or grey block noise. The sharpening
on the rest of it will be focused more on that than on noise that results then.

To get realllly good control on noise, I've found Noiseware Professional
(or Standard) has the greatest easy-to-use control over every gradation
of it. I chose professional because it keeps the exif data but also it's
just really flexible. But CS or CS2/3 alone can do a lot with noise.

You can also use other kinds of masks and sharpen only what you want
or blur what you want and then history-brush back the less sharp or
more sharp underlying layer image as wanted.

[soenda]

Soenda, there are jaggies in this resizing. Did you use simple bicubic?

No, this was something called "Pixel Resize." Paintshop Pro 9 is my processor, and I generally resize with their own interpolation resampler "Smart Size." Out of curiosity I did downsizing versions with Smart Size, bicubic, and bilinear. This seemed to cause the least degree of aliasing of the four options. One I did not try was the weighted average option, so that might be worth a shot, too.

As for noise, I now often exclude the sky or big blocks of dark areas when sharpening back on a resize-down for web viewing. The resizing alone will eliminate most of the sky or grey block noise. The sharpening on the rest of it will be focused more on that than on noise that results then.

I generally save sharpening for the very last step, but have never tried selecting out the sky at that point. Certainly worth a shot. Thanks for the suggestion.

Here is another shot taken on the same evening, although of a different side of the building. I applied additional noise reduction to the sky and applied final sharpening only to the building in the shot. I think that it does seem somewhat better this way.

[andrys]

I generally save sharpening for the very last step, but have never tried selecting out the sky at that point. Certainly worth a shot. Thanks for the suggestion.

Here is another shot taken on the same evening, although of a different side of the building. I applied additional noise reduction to the sky and applied final sharpening only to the building in the shot. I think that it does seem somewhat better this way.

It's definitely better, though resizing down will reduce noise on its own
for the sky purposes. The softness of the sky makes it seem less
static for some reason, almost as if it's moving. And the building
stands out more as a result. Interesting lines.

Nice lighting in this one too!

[dang]

If you're only needing an NR program for web shots, you can get Neat Image that processes up to 1024 pixel size free here: http://www.neatimage.com And Helicon might have a trial you can find, which is suppose to be much better, and faster than older versions of NR. They have some nice programs for portraiture too.

[jchambers]

I always select the sky with the magic wand in photoshop (using shift and select to get all of the sky) and then run noiseware pro filter on it. This is my 2nd to last final step. I then inverse the selection, which basically selects everything else but the sky and run an unsharp mask.

Seems to work a treat. No noise in the sky (which is certainly not wanted) and no loss of detail on everything else.

[simplephotography]

Or you expose to the right, generate several images from your RAW file (eg four images, each time one stop down), combine them with Photomatix, and voila, a perfect image with no noise!

[sean_mcr]

Or you expose to the right, generate several images from your RAW file (eg four images, each time one stop down), combine them with Photomatix, and voila, a perfect image with no noise!

Good advice about shooting to the right. But Sue doesn't shoot raw she's using a point and shoot which is the real reason for her noise woes

[andrys]

Or you expose to the right, generate several images from your RAW file (eg four images, each time one stop down), combine them with Photomatix, and voila, a perfect image with no noise!

Generally done with a tripod to get exact matches for best results.
Soenda is doing a lot of street shooting, and mainly on the move, so
that approach will be used more sparingly, I imagine.

The pt and shoots that are always with you have their delights, like
getting a photo at all rather than not getting one. One time a deer
stopped at my car window and I thought, "If only I had a camera"
forgetting I had one in my purse.

[sean_mcr]

There wasn't a need for hdr as the dynamic range is fine in the shot. Exposing to the right is good practice but most effective when shooting raw


It's a good camera the FZ, one of the best of its type. But it does not handle noise very well. I'm still not sure why sue shot at ISO 200, the lens has IS it's a static subject, the camera could have easily had a lower ISO. DP review stated the the Z7's noise was even worse then the camera it replaced, the Z5. I don't mind noise there's a time and a place for it, but it wasn't right for this image and i'd let the IS do its work and reduce the ISO if you find yourself in that situation

Jaggies

It's quite a complex subject to resolve at low res, all those converging lines, light edges on dark backgrounds. Jaggies are always an issue when there's not enough res to resolve the detail, it makes it a real task to sharpen. Some sensors and lenses can resolve detail better then others.


But you got the shot sue and it's not such an issue at full res. The noise is easily dealt with. I can't recall the last time i left my house with out my camera i don't care if you shoot with a P&S or 1D a camera is no good back at home