RAW files from a Canon A540

I have been playing around with CHDK for some years. It is a program that runs from your camera’s memory card. On top of its operating system. It can enhance the functionality on many Canon cameras.

I’ve mostly used it to add a live histogram, show which parts of the image that are under and over exposed, display real battery usage (My Canon A540 doesn’t show how much battery that’s left) and to create time lapse videos. Today I decided to take a picture in RAW (CHDK adds RAW support as well) and compare the result with the normal JPG file.

This is the first time I try anything in RAW so I’m a total beginner. To generate a JPG I loaded the CRW file in Picasa and used the Export function. Then I opened both JPGs in Gimp, cropped and exported them again. This isn’t optimal but I hope it’s good enough.

From what I can see the noise on the RAW file looks more natural than the JPG generated in the camera. The JPG is lighter and that might be the cause of the smear in it?

Then I tried to get a better result. First by using UFRaw, then RawTherapee. As you see it didn’t help. I would like to try darktable but I don’t have Linux on this computer so that’s for another day.

I also played a bit with converting the RAW to B/W and it looks good. Might be the bigger grains that tricks me though. I’ll play around with it more later.

If anyone is familiar with this and would like to provide me another generated JPG I can send you the RAW file. Just put a comment below.

A 100% crop from the normal JPG file (click it)

A 100% crop from the RAW file converted in Picasa (click it)

A 100% crop from the RAW file converted in UFRaw (click it)

A 100% crop from the RAW file converted in RawTherapee (click it)

See the Exif data from the JPG file (extracted with ExifTool).

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Ola

Mångsysslande doer & klätterentusiast. Jag driver varumärket Sten & bloggen Klätterbilder. Jag konsultar inom IT & Marknadsföring samt undervisar inom webb på Folkuniversitetet. Jag älskar att fota. /// Doer & climbing enthusiast. I run the climbing brand Sten & the blog Klätterbilder. Consulting with IT & marketing & teaching at Folkuniversitetet. I love to take pictures.

2 reaktioner på ”RAW files from a Canon A540”

  1. Kamerorna har oftast lite förinställningar som den lägger på i samband med konverteringen från den interna raw-filen till att den generat jpegen. Så det är bombis därför jpegen är ljusare bland annat.

  2. Jo precis och man kan ju tänka sig att den algoritmen borde vara optimerad för kameran. Kanske? Jag gjorde det mest för att jag var nyfiken. Och för att träna lite på att jämföra.

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