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RAW vs. JPEG

One question we're often asked is what's the image quality advantage of RAW vs. JPEG. For digital SLR's the difference can be fairly major, especially when using some more advanced third party conversion tools. Our experience of prosumer level RAW conversion has always been mixed, yes it offers the perfect digital negative but often the RAW conversion software doesn't allow enough parameter change to affect much change.

Olympus doesn't really provide much in the way of RAW conversion flexibility. You can essentially convert from RAW to TIFF or JPEG and that's about it, it's about time Olympus allowed its owners to fully exploit the advantages of RAW (digital exposure compensation, White balance modification, post processing options, dynamic range) otherwise it's pretty pointless having a RAW format on the camera.

Test scene

As you can see from the crops below RAW images converted using Camedia Master Pro do appear to be sharper than JPEG's straight from the camera but they also have more visible demosaic artifacts. RAW crops taken from TIFF, click to download a high quality JPEG output from Camedia Master Pro.

JPEG RAW

Resolution chart

No improvement in resolution from shooting RAW, indeed the RAW converted image appears to have stronger and more visible moiré than the straight-from-the-camera JPEG. RAW crops taken from TIFF, click to download a high quality JPEG output from Camedia Master Pro.

JPEG RAW


Overall Image Quality / Specific Issues

The C-5050 Zoom was bound to attract quite a bit of critical analysis as it is one of the first digital cameras to utilize a five megapixel CCD in the smaller 1/1.8" (7.2 x 5.3 mm) size. This reduction in size from the previous 2/3" (8.8 x 6.6 mm) CCD means smaller photodetectors and an even higher requirement on the lens systems.

On the positive side the C-5050 Zoom has very good resolution, indeed we couldn't distinguish its resolution chart from that of the current five megapixel class leader, the Sony DSC-F717. That's impressive on its own, a sign that the Olympus lens system has the required resolution. Metering was on the whole good as was color balance. For my tastes images were a little too contrasty, although this can easily be compensated by adjusting the contrast setting downwards. Sharpening artifacts (halos) were sometimes evident although no worse than we see on other digital cameras.

One problem which showed up fairly quickly during our test period was purple fringing (or chromatic aberrations), I've covered this in some detail at the top of this page so won't linger but I really didn't expect fringing to be as strong and consistent (even at small apertures) as this. The other issue could be noise levels which are definitely higher than other comparible cameras, whether this would be an issue to you really depends on your use for the images. For my tastes at least I would say that noise at the lower ISO sensitivies is higher than I would like to see on a modern high-end digital camera.

Red Overexposure Color Shift

This is a problem I haven't seen recently. It only occurred in the two shots below, I took the first, noticed the problem and took the second shot at a different angle. The red portion of the bridge in direct sunlight has been pushed into overexposure (red channel is 255) and the levels of the other channels causes the color to shift to orange. You can see the true color of the bridge to the right of the image.

Jagged diagonals / Demosaic artifacts

One thing which you will see in C-5050 Zoom images, especially if you zoom in, are jagged diagonals and demosaic artifacts. The jagged diagonals are very similar to those seen previously on the Canon G2, diagonal lines which are made up of groups of pixels in a 45 degree line. Another and probably related problem are visible Demosaic artifacts which appear as a dotted pattern around or along a line of detail.


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