RAW

12bit vs 14bit RAW and compressed vs uncompressed… Does it matter?

You know that to get the most of your DSLR you should be shooting in RAW, right? But these days Nikon cameras gives you even more options: 12-bit or 14-bit, and compressed or uncompressed RAW (NEF) files. Which should you choose?

Short question: Does it matter? Will you see any difference between compressed (lossy) and uncompressed (lossless) RAW? And between 12 and 14 bits?

Short answer: No it does not matter. Choose 12-bit compressed (because they take up less space) and forget about this topic. Or choose 14-bit uncompressed because theoretically you’re getting the “most” from your camera – you just have to live with the file sizes.

 Approximate RAW file
size on a Nikon D7000
12 bit 14 bit
compressed 12.6 MB 15.7 MB
uncompressed 14.9 MB 18.8 MB

Not happy with the short answer? Then read on…

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Microsoft camera raw codec pack interferes with Lightroom?

Does Microsoft's Camera Codec break lightroom?

On Wednesday 26 July 2011 Microsoft added “raw” image support to Windows 7 in the form of the Microsoft Camera Codec Pack. This 8MB download will enable Windows users to decode vendor-specific “raw” files (a.k.a. digital negatives) directly from Windows Explorer, or from any application using Windows Imaging Codecs (WIC).

I wrote in a previous post why it is a good idea to “shoot in raw”. Problem is just that the raw files are large and clunky, and require special software to decode. For this reason some photographers (including Ken Rockwell) decide to shoot JPG, despite all the disadvantages of their approach. So this is great news because Microsoft just made it easier to live with raw files. Good job, Microsoft!

But… I downloaded and installed this codec, and immediately noticed something curious. It seems like the Microsoft Codec Pack interferes with the decoding of my Nikon’s D7000’s raw files in Adobe Lightroom 3.4.1. In Lightroom’s Library module the images are displayed as preview images but then remain at low resolution, even when zooming in. Only after switching to Lightroom’s Develop module are the files properly decoded at full resolution. I have only observed this for my specific camera (Nikon D7000) using my version of Lightroom (3.4.1 64-bit) running on my home PC (Windows7 64-bit SP1). But, tellingly, Lightroom resumed working normally as soon as I uninstalled the codec pack.

Not sure if this is a coincidence on my specific machine or a real wide-spread bug. Please comment on this post if you can confirm or debunk this issue.

The Olympus PEN E-PL1 vs Nikon D3000 paradox

Petavoxel recently bemoaned the fact that the majority of sensors in recent micro four thirds EVIL cameras (or MILCs, if you prefer) perform poorly compared to contemporary APS-C sized sensors in digital SLRs. The only exception was the Panasonic GH1, which put up quite a respectable showing compared to its μ4/3 stablemates.

Yesterday dpreview posted their review of the E-PL1, and they were very happy with its high ISO performance. I quote:

Overall, the E-PL1’s images are the most natural and convincing here – avoiding the D3000’s overly contrasty, noisier images …  Most impressive is the E-PL1’s ability to produce results comparable with the EOS 500D and Pentax K-x, despite its smaller sensor.

But what does DXO Labs have to say? They disagree, showing that the big three leave the E-PL1 gasping for photons with a lowly 487  points in the low-light ISO stakes.

Hence, the paradox.

How do these two $500-ish cameras weigh up against each other?

How can this be? Is either DXO Labs or dpreview writing nonsense? The keen observer will notice that there are two significant differences in the way these two respected websites measure image quality:

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So, what's so great about "raw" files?

Have you ever heard an enthusiastic photographer saying something like “I shoot everything in raw”? But what is a “raw” file? Sounds like raw meat, doesn’t it? Why do people use these?

Few people think about it twice, but pretty much every photo on the internet is stored as a JPEG file. This also happens to be the kind of file you get out of most digital cameras. In fact, most consumer-grade cameras can give nothing else but JPEG output. This is no coincidence: JPEG’s been around since 1992, and it turns out that it’s a really great file format for photographs. JPEG allows you to store a lot of image information in a reasonably small file, and is quick to decode and write. Unfortunately JPEG is a lossy standard, which means you always lose some image information when creating a JPEG.

Contrary to common belief, this “lossy” property is not the main reason to avoid using JPEG. The JPEG algorithm is actually really clever in the way it loses its information, meaning the human eye often can’t see the difference between a lossy JPEG and its lossless equivalent. Look at the seagull below to see what I mean.

A JPEG file compressed at 95% quality. (click for detail)
File size = 78 KB
Scarcely any degradation artefacts, despite the fact that a losslessly compressed PNG would have required more than 300 KB.
Compressed JPEG at an extremely low 30% quality. (click for detail)
File size = 9 KB.
Compression artefacts are visible (sky, detail in lantern glass), but the image remains perfectly recognizable due to the clever way JPEG works. And this is an extreme example.

No, the reasons why you should be interested in raw files are more subtle…

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