Last week I was visiting Sean at his rental in Playa del Carmen and was awed by his view overlooking the water. We went up to the terrace and I used Photosynth on my iPhone to capture this panoramic photo of his gorgeous view:

Later when I got home and looked at the photo I saw how much noise there was. It was getting into the evening so the iPhone’s tiny sensor picked up a lot of ugly noise in the photo, which can be viewed especially in the sky.
After posting the photo to my Facebook I was pretty unhappy with how it turned out since there was so much ugly noise in the sky. I rememebered that one of the products Topaz makes (we use Topaz Adjust for some of our photos) was Topaz Denoise.
I downloaded the program and fired it up to test it out on this photo. With it I was able to clean up a lot of the noise and save a lot of the photo:

I already have Photoshop installed so it was easy. Note: to use Topaz DeNoise you need to have one of these installed on your system:

You need to adjust preset settings depending on your situation. For this particular photo I used the JPEG – strongest preset because there was so much noise in the sky.

There is a tradeoff between how strong you make the effect and the resulting blurriness it creates.
So to preserve detail you need to use less of the effect. To get rid of heavy amounts of noise, you will lose detail and the rest of the photo will have to be more blurry.
For this particular photo, when I used the “jpeg – strongest” setting in Topaz DeNoise the clouds looked good but I lost a lot of detail and sharpness of the buildings.

So what I did was use two settings: I selected the buildings/non-sky using the Quick Selection Tool (W)

I fired up Topaz Denoise, and used “jpeg – moderate” to get rid of the noise in the bottom part of the photo without losing too much detail. I then selected the inverse (sky), fired up Topaz Denoise, and used “jpeg – strongest” to get rid of the heavy noise in the sky, where blurring wasn’t much of a problem.

Here is the resulting photo, using strongest denoise for the sky and moderate denoise for the bottom half and the buildings:

This was a more complicated way of doing this, obviously. Often times you can just use 1 setting and get your photo de-noised in a just a few clicks.
Overall I’m happy with how Topaz Denoise performs. While you can use the blur tool in Photoshop to create a similar effect in parts of a noisy photo, Denoise makes this possible without losing a lot of detail in between (and the process is way faster). While the program can’t perform miracles (by sending magical fairies back in time to increase sensor size in your iPhone or camera), it does give you an ability that you probably can’t get with any other tool – to remove noise in tricky situations like the one above.
There’s a 30 day free trial of Topaz Denoise – so try it out yourself. You can even download the photo I used if you want to play with it or use it to follow along the tutorial.
+Max Spiker has been playing with Photoshop since 2000 and HDR photography since 2005 when he discovered it on Digg. He's been a fan of the technique ever since.
hi Max!
I have been using another technique to get rid of the noise in the sky but not ruining the forground. In Photo shop, I make a Duplicate layer of my photo, use the denoise filter of my choice at 100%, then after it is applied, I go up to the opacity slider and adjust it till I like the look of the effect on the photos sky. Then, if I need to make the foreground look less blury, I can “Erase” this de-noise layer on an where in the shot I dont want de-noised. after that i can just make a new layer and hit de-noise again and adjust it back to where the fore ground looks good, then erase out the sky, reveling the image below which is the de-noised sky layer only… it works well when you have too much details to try and separtae with a quick select tool. I often use the pen tool to make selections so i can be as precise as i want to be.