Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Nikon dSLR

Reply
 
Thread Tools Search this Thread
Old Dec 31, 2009, 5:31 PM   #1
Senior Member
 
gregg's Avatar
 
Join Date: Feb 2003
Location: Tampa, FL
Posts: 264
Default better shooting raw and converting to JPG?

I recently shot a couple...D70s (tamron 70-300, sunpak flash).....I don't have any raw software but found a free program (photoscape) to batch convert raw to JPG. Is there any advantage to doing this as opposed to shooting JPG directly from the camera? It seems to me that since the RAW seems to be smoother and free of anything that would degrade the photo in the compression process in the camera that it makes more sense to shoot raw and batch convert....aside from the obvious fact of now having raw photos I can later Post Process.

Gregg

PS.... are there any RAW NEF PP programs free for windows XP?


_____________________________________
D40, D70s
tamron 70-300mm (psuedo macro switch at 180-300)
sigma 18-200mm OS
nikon 18-70mm

Last edited by gregg; Jan 1, 2010 at 3:02 AM.
gregg is offline   Reply With Quote
Sponsored Links
Old Dec 31, 2009, 5:57 PM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Actually, there are a number of free raw converters available for Windows XP.

Most are using some or all of Dave Coffin's dcraw.c code (adding more features, a nice GUI interface, etc.). I've looked at photoscape in the past, and I suspect it's probably using it, too (although from what I can tell, it's doing some of the adjustments you make *after* the demosaic process).

Here are a couple of free raw converters:

Raw Therapee

UFRaw

You probably already know most of this stuff (rest of this post). I'm copying it from an older post on the subject:

Yes, there can be many advantages to using some of them (and you will find differences in the quality of their output, available adjustments, default tone curves, and much more). You tend to have a lot more leeway when shooting raw, as the image hasn't yet been processed.

The vast majority of digital camera use a Bayer type Color Filter Array. A digital camera's built in image processing performs the demosaic process so that you end up with a usable image format with red, green and blue values represented at each pixel location (even though each photosite is only responsive to one color, thanks to the color filter arrays being used over modern sensors).

This is a relatively complex subject, with a variety of demosaic algorithms used (and some are better than others, depending on the camera's sensor, filter design, subject type and more).

The raw file produced by a given camera model is somewhat unique (with different byte offsets for information included in the metadata and much more), and a complicated process is needed to convert the image into a viewable format (and different raw converters will have different approaches to giving you the best image possible, with some of them using better algorithms compared to others for this conversion). So, you have to use a raw converter that supports your camera's unique files to convert them into a format that is understood by image viewers and editors.

A camera's image processing when shooting jpeg is making decisions that may not always be what you want. Manufacturers have to decide on what kind of tone/contrast curves to use to make an image that looks good to most viewers, and sometimes they use processing that can be a bit too contrasty (causing loss of detail in shadows and highlights), in order to give cameras owners a more "punchy" image straight from the camera.

Ditto for things like sharpening, which is mostly increasing the contrast at color/brightness transitions in an image using edge detection techniques (which can destroy detail if overdone). The same thing is true for how the camera compensates for the temperature of the lighting you're shooting in (your White Balance settings handle that). You can easily modify things like White Balance later if you shoot in raw (basically, white balance is nothing more than a set of RGB multipliers that are applied during the conversion process).

The camera's jpeg processing is also limited by the speed of the cpu/hardware for image processing built into the camera, as to the sophistication of the algorithms used, since they are trying to process images in a split second between shots. As a result, you can often do better if you shoot in raw, using a high powered PC to process the data from the camera's sensor, without the limitations of needing to process it in a split second that the camera's image processing has to deal with.

The individual photosites in a sensor are only sensitive to one color each, and with most Bayer Pattern sensor designs, you have twice as many pixels that are sensitive to green. The raw conversion algorithms take the values from the red, green, and blue photosites and combine them via sophisticated interpolation techniques so that all 3 colors are stored at each pixel in order to give you a usable/viewable image.

The raw file has not combined the output of photosites in any way. That's what the raw conversion process does (or in camera processing if you shoot in jpeg). There are a number of different algorithms used, and some are better than others. You can see some of the common ones discussed here (requires Adobe Acrobat Reader):

http://www.ece.gatech.edu/research/l.../bahadir05.pdf

Here is another document discussing raw conversion techniques:

http://www.dalibor.cz/files/Ting%20C...erpolation.pdf

When you convert to TIFF or JPEG using a raw converter, you've gone through this demosaic process of combining the values from the red, green and blue sensitive photosites so that red, green and blue are stored at each pixel location. Ditto for shooting in jpeg (the camera is performing the raw conversion if you shoot jpeg).

Most raw converters are doing some additional processing, too (sharpening, contrast, etc.). Ditto for in camera processing (which is doing the raw conversion for you).

Personally, I'd save the raw files, no matter your preference in raw converter, as technology is continuing to improve and you may want to reprocess cherished images later using better tools.

For example, beginning with dcraw.c version 7.60, David Coffin started using AHD (Adaptive Homogeniety Directed) for the interpolation algorithms. This was in part due to Paul J. Lee, who collaborated with Hirakawa Keigo (the original co-author of AHD algorithm as part of his Ph.D thesis).

Once Paul fully understood the algorithm, he modified dcraw.c to use it and gave a prototype to Dave. After some comparison studies, Dave was convinced that AHD was superior to VNG and other demosaic algorithms. Dave converted and optimized the prototype created by Paul J. Lee, integrating it into dcraw.c versions 7.60 and later (and he's continuing to refine it). Note that most products using Dave's code allow you to select between multiple demosaic algorithms (since Dave' code still supports older algorithms like VNG).

Products using some or all of David's code to perform the raw conversion benefit from these improvements, while adding their own enhancements and features. Keep in mind that a number of other raw converters use some or all of David's source code for the demosaic part, while adding a GUI front end and more features to augment the conversion algorithms.

See the "Other Raw Photo Decoders" section here:

http://www.cybercom.net/~dcoffin/dcraw/

UFRaw is one popular free product that uses Dave Coffin's code for the demosaic algorithms.

To get a raw file (either native or .dng) into a usable (i.e., viewable or printable image), it needs to be converted to another format that has already gone through the demosaic process (for example, to a TIFF or JPEG image), combining values for red, green and blue at each pixel location. That's where a raw converter comes in (Adobe Camera Raw, UFRaw and many more).

If you really want to understand it, you may want to consider studying Dave Coffin's dcraw.c source code. Dave's a pretty sharp guy (and a really nice guy if you spend some time getting to know him). He's really dedicated to helping others get the most from their camera's raw output. You may also want to take a look at the latest libraw library (which uses a lot of Dave's dcraw.c code).

http://www.libraw.org/
JimC is offline   Reply With Quote
Old Dec 31, 2009, 7:14 PM   #3
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

Shooting RAW is a good idea if you want to fine tune color and exposure of individual photos. If you're going to batch convert anyway, shooting JPEG in the first place will save you time and storage space, and the results will probably be indistinguishable from the batch converted RAW images.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is offline   Reply With Quote
Old Dec 31, 2009, 7:34 PM   #4
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

I disagree. I've seen much better results from raw in difficult lighting, especially at higher ISO speeds from an older camera model like the OP's D70s (where the JPEG engine isn't as sophisticated as some of the newer models).

You don't have to tune the color and exposure for each individual photo either. ;-)

Heck, the last time I shot raw+jpeg, I started wondering why I even bother to shoot the jpeg it's so simple just to use the raw files instead.

If you don't want to do any post processing, you can even use something like free Google Picasa and view your images. Newer versions build previews so that once you let it run through them (which doesn't require any work on your part), there's very little difference in browsing speed compared to jpeg files on a modern computer. It's using a dcraw.c based engine for the conversion using the "as shot" white balance settings. Even though it's using a simpler VNG algorithm (versus the more sophisticated demosaic algorithms dcraw.c code is capable of supporting), I still usually find the output a bit better than the jpeg files with most camera models.

Then, as your browsing through them, just tag the ones you want to keep for easier tracking (or export them to another folder for uploading to a printer if desired, just like you may do with your jpeg images).

Shooting raw also gives you more flexibility if you do need to make changes (versus a conversion using the default exposure, as shot white balance, etc.). Using something other than Picasa is probably a better bet in that case, though.

Or, if you want an even better solution in a very fast product (commercial versus free), I'd give the new Bibble 5 Pro a try.

http://www.bibblelabs.com/products/bibble5/
JimC is offline   Reply With Quote
Old Dec 31, 2009, 8:08 PM   #5
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

Nikon even has a codec for NEF files so you can look at and print them without converting them. But it and probably all the batch processing tools use the same settings that the JPEG files would have. Why would a freeware RAW batch processor do a better job than the JPEG engine in the camera? Who knows more about a Nikon camera than Nikon?
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is offline   Reply With Quote
Old Dec 31, 2009, 8:23 PM   #6
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Nikon's conversion really isn't bad (at least using Capture NX2). The noise reduction algorithms are actually pretty decent. The last time I used it I was relatively impressed with it after comparing output with other raw converters at higher ISO speed settings. But, I ended up using the Bibble samples instead, although it was a close call.

But, I don't know about their codecs (which may use a simpler approach). I suspect that any of those routes (freeware converters using dcraw.c based code, Nikon's codecs, Nikon's dedicated software, newer commercial raw converters) is going to be better than the camera produced jpeg images from that camera model, especially if you don't get the exposure just right or need to use higher ISO speed settings.
JimC is offline   Reply With Quote
Old Dec 31, 2009, 11:42 PM   #7
Senior Member
 
bper's Avatar
 
Join Date: Jan 2006
Location: Washington State
Posts: 454
Default

Gregg - Have you checked out Nikon's free program ViewNX. It has a raw converter in it for NEF files. You can download it from the Nikon site.

I have Capture NX2 and use it a lot, but use ViewNX to look through the images first. I know many people do all there post processing with just it - Bruce
bper is offline   Reply With Quote
Old Jan 1, 2010, 1:36 AM   #8
Senior Member
 
gregg's Avatar
 
Join Date: Feb 2003
Location: Tampa, FL
Posts: 264
Default

thanks everyone...I suppose then the answer is assuming that if the batch converter software on my computer is better then what's in my d40 or d70s then it will be better

photoscape will only let you batch convert and not manipulate RAW NEF...

I also have on an (old version) of photoshop (7) that won't even open a RAW file.

I do have a couple of the discs that came with both my cameras....I thought you can only use those for a short period of time and then have to pay for it....maybe not

Now if I wave my magic wand, Nikon will come out with a D70s firmware update that will have 1600 iso looking as good as it does on the d40...I can wish

gregg

Last edited by gregg; Jan 1, 2010 at 2:59 AM.
gregg is offline   Reply With Quote
Old Jan 1, 2010, 2:07 AM   #9
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

You have to pay for CaptureNX but ViewNX is free.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is offline   Reply With Quote
Old Jan 1, 2010, 2:15 AM   #10
Senior Member
 
gregg's Avatar
 
Join Date: Feb 2003
Location: Tampa, FL
Posts: 264
Default

ahh...thanks
gregg is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 7:11 AM.