CHDK Forum
Using CHDK => General Help and Assistance on using CHDK stable releases => Hello, I'm a NEWBIE - HELP!! (Newbies assistance, User Guides and thank you notes) => Topic started by: kyrcy on 20 / February / 2011, 14:11:43
-
I followed the steps to enable raw in CHDK on a Canon A570 IS, but shots are still saved as jpg. Does anyone know what I might be doing wrong?
-
I followed the steps to enable raw in CHDK on a Canon A570 IS, but shots are still saved as jpg. Does anyone know what I might be doing wrong?
Jpegs are always saved. If you enabled raw, they are saved as an additional file.
If you are trying to transfer the images over USB, the raws may not show up, depending on your choice of raw extension and prefix.
-
If you are trying to transfer the images over USB, the raws may not show up, depending on your choice of raw extension and prefix.
The RAW files may be on your memory card but not visible if your connect your camera to your computer with a USB cable to download pictures to the PC. You cannot see the RAW's unless you plug the SD card into an actual SD card reader on your PC. And even then, you will probably find them in a different folder than the jpg's.
-
The RAW files may be on your memory card but not visible if your connect your camera to your computer with a USB cable to download pictures to the PC. You cannot see the RAW's unless you plug the SD card into an actual SD card reader on your PC. And even then, you will probably find them in a different folder than the jpg's.
This depends a lot on the camera and settings. That's why I kept my post vague ;)
-
Given enough storage space is it a good idea to always use raw to have "digital negatives" in addition to jpg files that are also saved?
-
Given enough storage space is it a good idea to always use raw to have "digital negatives" in addition to jpg files that are also saved?
I guess it would not hurt to do so but saving RAW files is quite slow - which can be annoying in some shooting situations. Also, Canon P&S cameras do quite a bit of processing and image correction before compressing an image to JPG so your "digital negatives" will need a lot of post processing work to look as good as the Canon created JPG files.
-
Also, Canon P&S cameras do quite a bit of processing and image correction before compressing an image to JPG so your "digital negatives" will need a lot of post processing work to look as good as the Canon created JPG files.
Unless you consider processing and image correction as things that make JPGs look bad.
-
Unless you consider processing and image correction as things that make JPGs look bad.
I can see that some people might like to customize how their processing and image correction are done. What I was trying to say is that unlike a dSLR, the RAW files are not really usable without some sort of processing to clean up distortions. And CHDK RAW images have significantly less dymanic range (less bits per pixel essentially) than RAW images you get with a dSLR. Go ahead and have fun maximizing the quality of your pictures - just don't expect the same results from a $79 P&S that you get from a $1500 dSLR.
-
-
You commit common fallacy by thinking that processing/manipulations improve quality.
So do you think that the RAW images produced by CHDK should be used unprocessed as that is the best "quality"? Have you ever actually looked at any of those images ? Maybe the A570 is unique but from what I have seen on my camera's RAW images and read about others here on the forum, there is significant barrel distortion in an unprocessed image. How do those look to you when printed out at highest "quality" (i.e. unprocessed) and hanging on your wall ?
EDIT : Bright and sunny day with 18" of fresh snow here so I went out and played with my camera. As long as I was not using wide angle setttings (i.e. barrell distortion) then both my JPG and DNG pictures looked really good. I think I can say the DNG's were slightly sharper and the contrast was better. Reds looked better on the DNG's but the greens were a little better on the JPG's. Of coarse this is when zooming into pictures on my 21" Samsung LCD monitor - not the greatest in the world - but at least the images were side-by-side using the Shotwell program.
-
No processing will restore what's lost, so from technical POV RAW is 'the best quality' (this should apply to geometric distortions as well). Although masked distortions and other beautifiers may have subjective 'qualities' but it's not fair to call it better quality just because one finds it more pleasing.
-
agreed
-
No processing will restore what's lost, so from technical POV RAW is 'the best quality' (this should apply to geometric distortions as well).
This absurd. If by "quality" you mean anything to do with how humans perceive the image, then your claim is complete nonsense. If by quality you just mean the best source data for transformation to something humans perceive (or for analytical purposes that don't involve rendering an image), you have a point, but it's not what most people mean when they talk about image quality.
Modern compact cameras are designed with severe distortion in the lenses *because the designers knew they could correct it in software*.
For the purpose of accurately reproducing a scene *as a human would see it*, an image with the distortion uncorrected is clearly lower quality than an image in which the distortion has been corrected. Software cannot add back data that was never recorded, but it certainly can transform that data into something that provides a more accurate representation *to a human viewer*. You cannot correct barrel distortion in your head. A computer can, and to a human, the resulting image is undeniably a more accurate representation of the original scene.
-
-
:-X
-
-
-
-
Modern compacts are designed with this kind of 'problem' to give better zoom range or more compact package, because it can be adequately addressed in software.
Next thing you know, we will be discussing whether mulitple element lenses give lower quality because they distort the image of a single element lense - which in turn distorts the perfect quality of the image from a pinhole camera.
But its probably time to stop feeding the trolls.
-
The quality of Hubble's images could have been improved by introduction of new data e.g. characteristics of distortions, from processing multiple frames etc. It wasn't equivalent of those tricks done in cameras, that only apply cosmetic changes and don't introduce new information.
@water...
If you have problem with this discussion, then find yourself another activity.
-
The quality of Hubble's images could have been improved by introduction of new data e.g. characteristics of distortions, from processing multiple frames etc. It wasn't equivalent of those tricks done in cameras, that only apply cosmetic changes and don't introduce new information.
Modern cameras (including many recent powershots) *do* know the characteristics of the lens (for example, the amount of barrel distortion at a given zoom level), and correct for it. It is directly equivalent. Some resolution is lost when applying this kind of transformation, but again, the resulting image appears to a human observer as a more accurate representation of the original scene.
RAW is the purest *data* you can get. Without processing, it is not the highest quality *image* by any reasonable standard. As the cameras get more sophisticated processing on board, this will only increase.
Do you believe that an image with white balance applied is lower quality than one without ? Hot pixel removal ? De-bayering ?
I really shouldn't continue this argument, but IMO it is important for CHDK users to understand this. There is a strong tendency to expect raws to produce better *images*, users need to be clear raw is just purer *data*. Producing good images is entirely up to the users, and with RAW substantial post processing will be required to even reach the same level of visual quality as camera jpegs.
RAW should not be treated as a final product, it just allows the user to replace the cameras processing pipeline with their own.
-
http://chdk.setepontos.com/index.php?topic=5574.msg62652#msg62652 (http://chdk.setepontos.com/index.php?topic=5574.msg62652#msg62652)
Pretty much says it all ...
-
Expanded/contracted image loses sharpness/resolution accuracy (and FOV), so you can't arbitrarily say, that in general quality is improved, when some aspects are compromised.
with RAW substantial post processing will be required to even reach the same level of visual quality as camera jpegs.
One can exceed that level just by excluding beautifiers/stylizations imposed in camera.