Saturday, 10 December 2011

Exercise: RAW

In this exercise we are exploring the power of using the RAW format when taking images.

As a comparison we are to take images of three scenes, daylight, high contrast and artificial lighting. For each scene we are to shoot in both RAW and JPEG. The camera should be set up as optimal as possible so that the JPEG image is shown in its best light, this would include exposure and white balance.

Using a RAW converter we are then asked to process the image as best as possible and note the differences between the RAW conversion and the standard JPEG.

The first image was taken a week after Remberance Sunday at a local small memorial. The sun was starting to set and I chose a white balance of sunny with and exposure of 1/80 sec at f/5.0 ISO 100. This was a fairly good exposure but there was a small amount of highlight clipping on the cross. Adjusting the recovery slider h compensated for this in RAW.

The Temp and tint was also adjusted slightly so that the quite overpowering colour of the poppies was brought to a realistic shade, something that the JPEG has failed to do. Finally a small amount of additional contrast  was added. This has also warmed up the image reflecting the warmth in the sun at the time of shooting.

Looking at the small images there is not a great deal between them indicating that the camera settings were not to far out and the image was reasonably exposed.

The first image is the original JPEG followed by the RAW conversion.

The second set of images were the high contrasting images, take of a dark car's grill. This was an interesting conversion. The original image had a lot of under exposure leading to shadow clipping. When this was removed the image became 'grey and flat' but the grill could be seen clearly. further adjustments for the contrast and adding a high contrasting tone reset the image to something like the original but without any highlight or shadow warnings.

Finally the white balcance was adjusted to give a cooler looking image which I think adds more impact.This did leave the edge of the number plate with a blue tinge so I used a selective mask in Lightroom and reduced the saturation

The final set of images were taken indoors using a tungsten lamp. The camera's white balance was set for tungsten and the histogram checked for correct exposure.

The camera did well to compensate for the colour cast as seen in the first JPEG image. It was felt that the colour was a little too warm and this was adjusted using the temperate and tint sliders in the RAW version to reduce the colours to a more realistic level. A small curve was then added to boost the contrast a little.

Overall there is very little difference in the two images, perhaps just the minor adjustments and added constant has made the RAW conversion slightly better.

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