http://www.flickr.com/photos/gibranparvez/3872301344/sizes/l/ - full size The Pacific coast, looking north from a cliff near Muir Beach Overlook, north of San Francisco, near Point Reyes. Anti-aircraft gun emplacements were built nearby during WWII to defend the west coast against a potential Japanese attack. ------------------ I took this photograph in July of 2008. I played with some of the exposure, and I found that the quality of some areas of the photo severely deteriorated when I did so. It's very apparent in the clouds in the top-left area of the photo; any way of removing such artifacting? It was a result of me playing with the "offset" and "exposure" levels in CS3.
I really like the composition here What camera are you using? If possible, shoot in RAW for landscapes, as it allows you to play around with levels and lighting without impacting image quality too much. With JPEG, you're limited to just 256 tones per channel (16 million colours) while most dSLR cameras produce RAW files with 4,096 tones per channel (68 billion colours). This gives you many, many, many more colours to play with and it massively reduces artifacting if you need to make adjustments. It's also worth bearing in mind that darker areas of the scene are most susceptible to artifacting because colour information isn't stored linearly. Most of the tones are stored at the brighter end of the image, so if you underexpose a RAW image, you're losing a massive amount of the colour information that the sensor can collect. Typically, the camera will record data across six stops (+3 EV to -3 EV) with (I think) 2,048 colour tones in the brightest part, then 1,024, 512, 256, etc, so it's important with RAW at least to use the full range of the histogram. I tend to overexpose (it's generally known as 'exposing to the right') to capture the detail in the dark areas, but it's important not to lose it in the brighter areas too. Taking that into account, if you under-expose by 1 stop, you're losing half of the potential colour tones! I don't bother really looking at the image review in too much detail, apart from checking for loss of detail in highlights and making sure the composition is as good as possible. Instead, I tend to study the histogram more than anything else, as that gives you a better idea of good/bad exposure. Hope this helps!
Ahh thank you so much, Tim! I'm using a Canon Powershot SD1000 point'n'shoot. I captured the whole wide angle by taking several photos and having CS3's photomerge function put them together. Photomerge is usually either a hit or a miss. This one was a hit- the photos are stitched together seamlessly.
That's a pretty good result from a point and shoot - I wouldn't have known that it was a photomerge either, had you not said! What you could try and do to keep the sky in check (and reduce the noise you're seeing) is to take two photos using the camera's manual mode, presuming it has one. Take one that correctly exposes the foreground and another that captures the mood of the sky - you can then switch the sky into the well-exposed foreground and maintain good exposure across all of the image. You will probably need to use a tripod to capture the foreground in similar lighting conditions to what you've got in that photo, as you'll need to use a reasonably long shutter speed.
Hope you don't mind, but I ran it through Noise Ninja, using the noise brush to filter the sea and USM amount dropped to 17. Sponge tool set to desaturate 50% cleaned up the residual colour artefacts in the clouds. I'd thoroughly recommend investing in NN or one of the alternatives (such as Neat Image) if you're finding a lot of your jpegs are coming out noisy.
I used to own a Fujifilm S7000. A good camera for the time but it interpolated 6.3mp to 12mp with predictably noisy results, even when shooting RAW. Fortunately, my current Pentax is light years ahead but the obsession with noise still persists. Something else to look at if you're shooting with a creative compact or DSLR, would be Guillermo Luijk's Zero Noise. Admittedly, I've never got round to trying this myself. http://www.guillermoluijk.com/article/nonoise/index_en.htm http://www.guillermoluijk.com/software/index.htm
