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OP
nac

nac

Aspiring Novelist
Tried CHDK...

File size of a full resolution RAW image is about 18MB. It takes roughly 4 min to write the images (RAW+JPEG) in my memory card (Class 4). RAW images have heavy lens distortion and too much noise. Noisier than camera processed JPEG. Yeah, its noisier because its a RAW. I have a doubt here...
DSLR have a sophistication to use some quality lenses. Even those do produce distortion?

I read, I can do a lot with RAW. I hoped so until I saw RAW images taken with my cam. But now I don't know what all I could do with it.

Superfine images show no difference than Fine Jpeg other than larger file size. It may gives little more control over editing, I don't know.

Battery Indicator: Nice feature. Fully recharged (One month ago), shows 77% battery life up on first use after recharge.

Battery seems to be getting drained sooner with CHDK. But members of CHDK forum gives a different reason. Does RAW file writing takes extra power to do the job? I mean power consumption of taking RAW images is higher than JPEG (like 1 JPEG = 3 RAW) or may be CHDK need some power to run this firmware, I don't know.

Exposure bracketing: I don't know how this works for the cameras which have this feature in their original firmware. With CHDK it's quite easy to do.

That's all I tried and my first impression is below average.

Edited from jpeg... Do you guys think, CHDK RAW can be edited better?

lowres.jpg
 

marvelousprashant

Cyborg Agent
@nac You will need a converter to convert the chdk raw files into normal raw files. The popular software for handling those raw files are Lightroom and DxO Optics Pro. I prefer former.

Maybe you can upload a raw file along with full reso jpeg somewhere. I will see if RAW output is of any use.
 
OP
nac

nac

Aspiring Novelist
^ Yeah, I sure do that... I will be going to take some photographs today. I will upload them...

In CHDK forum, they were suggesting few software for processing RAW files.
Rawtherapee
Irfanview

I couldn't use Rawtherapee as it needs minimum of 2GB RAM and Irfanview, I don't know how good it is...

About noise. Generally, compact cameras are not producing tack sharp pictures. With that quality this RAW adds too much noise. When I tried to reduce noise and do other enhancement image is not as good as camera processed jpeg. May be I don't know how to do it perfectly.
 

marvelousprashant

Cyborg Agent
I think Lightroom is the best when it comes to handling noise. Since you have mentioned 2GB RAM I would like to add that Lightroom is pretty resource heavy too
 
OP
nac

nac

Aspiring Novelist
Okie... Better I start posting queries related to this. How to get a quality RAW image?
 

marvelousprashant

Cyborg Agent
Okie... Better I start posting queries related to this. How to get a quality RAW image?

CRW_5661.jpg


In your RAW I found an interesting thing. Noise control is much better than JPEG output from my SX240. I have applied Luminance smoothing of +80 in this image. On a jpeg image this would look like water color. Comparing details in your RAW vs edited RAW... more than 90% details are preserved after noise reduction
 
OP
nac

nac

Aspiring Novelist
Wow!!! Thanks for you time and effort guys...

lm2k, Yeah sure I will shoot some photos in different lights. But the sad thing is even the VGA size has noticeable noise.

Prashant, Nice work.
But we shouldn't apply same level of noise reduction for both the RAW and jpeg. As jpeg are already processed in camera. Noises are much less than when we compare the images right out of the camera. And very little amount of noise reduction would suffice with jpeg.

I will check about retaining those details after editing.
 

marvelousprashant

Cyborg Agent
post link to original jpeg. The image you posted is highly resized

I dont think your RAW is "noisy" Fine grains only visible in 100% crop (no edit)
Capture.PNG
 
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OP
nac

nac

Aspiring Novelist
I haven't edited any... And imageshack reduced the image size. I will post the link to full size jpeg.

There should be some way to get the code for full resolution. But I have searched, but with no success. I am uploading it again...

Note: It is a full resolution image (2MB) takes time to load in low bandwidth connection.

img5661r.jpg
 
OP
nac

nac

Aspiring Novelist
By the by, what's the value you guys used to correct the lens distortion. I guess it should be the same value across all the images.
 

marvelousprashant

Cyborg Agent
Used +50 distortion and +115 scale (to remove the round images without reducing size of image) With this adjustment distortion seems to be gone but image is slightly wider both horizontally and vertically (visible as grey strip in jpeg below)

Color retention in shadow : RAW vs JPEG ( +5 exposure )

rj.JPG


Details in overexposed areas (-5 exposure of sun)

rj2.JPG


Looks useless but there is no denial that RAW retained more details in overexposed areas too. I bet it will be very helpful in images that have overexposed areas due to flash.

There is not much difference in noise performance in this image. Bringing RAW noise levels to JPEG image does not lead to loss of detail and both images seem to have the same amount of detail overall.
 
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OP
nac

nac

Aspiring Novelist
Wow!!!
Greener is RAW and purple is jpeg, right? Too much purple in jpeg.

I see little distortion with +50 and 115 and the good thing is, it retains the original resolution.

After some search one of the CHDK member used +69 and cropped. It lost the size when cropped. I don't know whether it's the perfect setting, just he uses this setting.

Just check this settings and comment which one is better or if you get any other settings better than these two. I tried and couldn't come to conclusion that the distortion is gone completely.

So, as far as detail is concern both are retaining the same details.
 

lm2k

Journeyman
In your RAW I found an interesting thing. Noise control is much better than JPEG output from my SX240. I have applied Luminance smoothing of +80 in this image. On a jpeg image this would look like water color. Comparing details in your RAW vs edited RAW... more than 90% details are preserved after noise reduction

very neat edit ,btw how exactly u reduced the noise near the horizon?
 

marvelousprashant

Cyborg Agent
@Im2k I use Lightroom Luminance smoothing for noise reduction. I also applied a graduated filter of +2.25 exposure in line with horizon which overexposed the noise at horizon and exposed the houses and trees

@nac
Green is RAW

I did not know the difference between scaling and crop until today. Scaling magnifies the image to original resolution which is good thing for RAW.
For perfect settings click a picture of graph paper
 
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