eccles
23rd of July 2007 (Mon), 10:38
This has been discussed in several threads in the compact and G series forums, but raw is usually considered more relevant to dSLR users, especially since of the later Canon models, only their dSLR range now supports raw as delivered.
But recent hacks for many Powershot cameras (discussed here: http://photography-on-the.net/forum/showthread.php?t=305198 ) that allow raw images have raised the question, is it worth it?
I have a Canon S3 with 500D close up, 1.5x Canon teleconverter and Raynox DCR-250 close up. The main use I have for it is to photograph butterflies, dragonflies and damselflies. I spend many hours walking round nature reserves hunting for these insects and the compact size and weight, not to mention price, of this kit are reasons why I use it in preference to a dSLR. The flip screen is also a very useful feature for taking shots of insects on the ground or high up.
My favourite means of photographing medium sized insects is with the 500D close up lens. With the camera at maximum zoom I can fill the viewfinder with a 1-1/4" damselfly with adequate depth of field from around 12" away. Focussing distance is between 12-20". Larger butterflies and dragonflies can be snapped by zooming out until the subject is the right size, or by removing the close up lens altogether.
Occasionally when an insect is particularly skittish and difficult to approach I have tried sticking the 1.5x teleconvertor in front of the 500D closeup lens, and it actually works, enabling a 2" subject to fill the screen from about 3 feet away.
One nuisance with the S3 is that it can exhibit chromatic aberration at the edges of a shot. It looks like the Digit 2 processing corrects this most of the time but occasionally red/green colour fringing can be seen that can just be discerned on an A4 print. Adding the 500D increases this slightly, although most of the time the processing steps in and corrects it. Stacking the teleconverter as well though is too much, and edges are almost always red/green away from the centre of the frame.
Using the teleconverter on the camera on its own also shows some signs of the problem.
The workaround for the above problems was to shoot with enough space around the subject such that it could be cropped away. This obviously limited the resolution of the final image, although with a little care I could still get an acceptable 8x10" print.
Then I read about and installed the HDK raw hack. You take a picture and a raw image gets saved with the camera produced jpg. There is a raw to DNG format conversion program that enables you to work with Photoshop.
Now, I can use the lens correction feature of Photoshop to get rid of all the red/green fringing, meaning I can fill the frame with the subject because I don't have to crop it. I use the stacked lenses more because I know I can get away with it. I can balance sharpness and noise reduction much more cleanly than with a jpg. I can rescue shadow detail and (some) blown highlights, and the occasional jpg artifacts have gone. With care I can produce images that look more like that from a dSLR than from a compact, bearing in mind of course the superior sensor and IQ from a real dSLR.
What this extra work will not do is add loads more actual detail. A perfectly shot landscape will look just about as good with the camera produced jpg image as one produced from the raw image put through Photoshop, even when pixel peeking at 100%. And sometimes for some reason, I just can't get the post processed raw image to look as good as the camera jpg even though the jpg actually came from the raw image in the first place.
By way of an example of what raw processing can do, take a look at the butterfly below. This was taken with the 500D closeup attached to the S3. Image quality was set to the highest possible setting. Taking the shot produced a normal high quality jpg plus a raw image. The raw image was converted with the Raw to DNG conversion tool and loaded into Photoshop where lens correction, sharpening and noise reduction, and saturation adjustments were applied. Because my printer drivers don't seem to like Photoshop and I haven't figured out why, the image was saved as a high quality JPG for printing. This JPG was resized with a little additional sharpening for display here.
http://members.lycos.co.uk/majorbludnock/gatekeeper2800x600.jpg
Now look at the two following images which are 100% crops of the same shot, the first being the jpg produced by the camera, the second taken from the raw image that was eventually resized and reproduced above. The second image shows little extra detail as such, but it is by far the cleaner of the two with no noticeable red/green fringing.
http://members.lycos.co.uk/majorbludnock/IMG6978jpgcrop.jpg
http://members.lycos.co.uk/majorbludnock/cropraw.jpg
These are not fixed or fiddled results. They are actual images produced from a photo shot by myself with the Canon S3 + 500D closeup lens in a real world situation. The hack is the HDK version.
These differences would probably not be too noticeable on a 6x4 print but they certainly are on an A4 print, and in my opinion the extra effort involved in processing raw images for larger prints is well worth it.
Admittedly there are tools such as PTLens that can work with JPG images to do similar tricks, but because working with jpgs does not allow the complete separation of red/green/blue elements that are preserved in the raw image the result is not as good. Neither can it rescue minor exposure problems such as poor shadow detail because the information that could have been used to do this has been thrown away by the camera when producing the jpg.
So there you have it. You decide for yourself.
Regards,
Eccles.
But recent hacks for many Powershot cameras (discussed here: http://photography-on-the.net/forum/showthread.php?t=305198 ) that allow raw images have raised the question, is it worth it?
I have a Canon S3 with 500D close up, 1.5x Canon teleconverter and Raynox DCR-250 close up. The main use I have for it is to photograph butterflies, dragonflies and damselflies. I spend many hours walking round nature reserves hunting for these insects and the compact size and weight, not to mention price, of this kit are reasons why I use it in preference to a dSLR. The flip screen is also a very useful feature for taking shots of insects on the ground or high up.
My favourite means of photographing medium sized insects is with the 500D close up lens. With the camera at maximum zoom I can fill the viewfinder with a 1-1/4" damselfly with adequate depth of field from around 12" away. Focussing distance is between 12-20". Larger butterflies and dragonflies can be snapped by zooming out until the subject is the right size, or by removing the close up lens altogether.
Occasionally when an insect is particularly skittish and difficult to approach I have tried sticking the 1.5x teleconvertor in front of the 500D closeup lens, and it actually works, enabling a 2" subject to fill the screen from about 3 feet away.
One nuisance with the S3 is that it can exhibit chromatic aberration at the edges of a shot. It looks like the Digit 2 processing corrects this most of the time but occasionally red/green colour fringing can be seen that can just be discerned on an A4 print. Adding the 500D increases this slightly, although most of the time the processing steps in and corrects it. Stacking the teleconverter as well though is too much, and edges are almost always red/green away from the centre of the frame.
Using the teleconverter on the camera on its own also shows some signs of the problem.
The workaround for the above problems was to shoot with enough space around the subject such that it could be cropped away. This obviously limited the resolution of the final image, although with a little care I could still get an acceptable 8x10" print.
Then I read about and installed the HDK raw hack. You take a picture and a raw image gets saved with the camera produced jpg. There is a raw to DNG format conversion program that enables you to work with Photoshop.
Now, I can use the lens correction feature of Photoshop to get rid of all the red/green fringing, meaning I can fill the frame with the subject because I don't have to crop it. I use the stacked lenses more because I know I can get away with it. I can balance sharpness and noise reduction much more cleanly than with a jpg. I can rescue shadow detail and (some) blown highlights, and the occasional jpg artifacts have gone. With care I can produce images that look more like that from a dSLR than from a compact, bearing in mind of course the superior sensor and IQ from a real dSLR.
What this extra work will not do is add loads more actual detail. A perfectly shot landscape will look just about as good with the camera produced jpg image as one produced from the raw image put through Photoshop, even when pixel peeking at 100%. And sometimes for some reason, I just can't get the post processed raw image to look as good as the camera jpg even though the jpg actually came from the raw image in the first place.
By way of an example of what raw processing can do, take a look at the butterfly below. This was taken with the 500D closeup attached to the S3. Image quality was set to the highest possible setting. Taking the shot produced a normal high quality jpg plus a raw image. The raw image was converted with the Raw to DNG conversion tool and loaded into Photoshop where lens correction, sharpening and noise reduction, and saturation adjustments were applied. Because my printer drivers don't seem to like Photoshop and I haven't figured out why, the image was saved as a high quality JPG for printing. This JPG was resized with a little additional sharpening for display here.
http://members.lycos.co.uk/majorbludnock/gatekeeper2800x600.jpg
Now look at the two following images which are 100% crops of the same shot, the first being the jpg produced by the camera, the second taken from the raw image that was eventually resized and reproduced above. The second image shows little extra detail as such, but it is by far the cleaner of the two with no noticeable red/green fringing.
http://members.lycos.co.uk/majorbludnock/IMG6978jpgcrop.jpg
http://members.lycos.co.uk/majorbludnock/cropraw.jpg
These are not fixed or fiddled results. They are actual images produced from a photo shot by myself with the Canon S3 + 500D closeup lens in a real world situation. The hack is the HDK version.
These differences would probably not be too noticeable on a 6x4 print but they certainly are on an A4 print, and in my opinion the extra effort involved in processing raw images for larger prints is well worth it.
Admittedly there are tools such as PTLens that can work with JPG images to do similar tricks, but because working with jpgs does not allow the complete separation of red/green/blue elements that are preserved in the raw image the result is not as good. Neither can it rescue minor exposure problems such as poor shadow detail because the information that could have been used to do this has been thrown away by the camera when producing the jpg.
So there you have it. You decide for yourself.
Regards,
Eccles.