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nech770 Feb 5, 2010 2:57 PM

RAW why is this desireable?
 
ok a really basic newbee question... why is RAW something people want? Is it because you then don't let the camera compress it or process it so you can decide how it looks?
I just want to understand.
thanks in advance.

TCav Feb 5, 2010 4:11 PM

Quote:

Originally Posted by nech770 (Post 1048582)
ok a really basic newbee question... why is RAW something people want? Is it because you then don't let the camera compress it or process it so you can decide how it looks?

That's exactly it.

shoturtle Feb 5, 2010 4:25 PM

Your thought is exactly it, it is good if you are into post production, and enjoy the after shooting aspect of photography. You can do way more with RAW in post production then with jpeg.

For lazy folks like myself. I tend to shoot only jpeg as I let the camera do the processing and compression. Also if you travel allot, Raw eats up allot of memory, so it can be limiting on the number of shots you can take with RAW vs jpeg on a long trip.

Hards80 Feb 5, 2010 5:33 PM

also it gives you about a stop to stop n a half latitude to get back clipped highlights and dark shadows.

VTphotog Feb 5, 2010 8:14 PM

Most RAW converters not only allow you more exposure latitude, but also are able to correct white balance, and preserve more fine picture detail than the camera algorithms. The down side, as mentioned, is larger file sizes and more time taken in post processing.

brian

nech770 Feb 6, 2010 8:31 PM

Quote:

Originally Posted by Hards80 (Post 1048636)
also it gives you about a stop to stop n a half latitude to get back clipped highlights and dark shadows.

sorry what does this mean in English? what is stop to stop n a half and clipped highlights
Just trying to learn..

VTphotog Feb 7, 2010 12:33 AM

Clipped highlights simply means overexposure, but in some cases, if it is not too overexposed, the RAW file will have enough greater capacity, due to using 12 or 14 bits vs the 8 bits per color channel in jpeg, to allow you to adjust setting in the raw converter to recover the highlight detail that would be lost if the camera created the jpeg. Stops, are measures of light, same thing basically as EV.

brian

peripatetic Feb 7, 2010 2:20 AM

Read this article for a primer.

http://www.luminous-landscape.com/tu...aw-files.shtml

There is another advantage. When I first started out on DSLR 6 years ago I became convinced that shooting RAW was a good idea. I'm very glad I did, as the RAW converters of today are much better than they were back then. I can now revisit shots I took 6 years ago and get a better image from them than I did back in 2004.

BillDrew Feb 8, 2010 8:28 AM

I like to shoot RAW when there isn't enough time to make sure I am getting the exposure and/or white balance right. Fast changing special occasions with the grand kids in uneven/mixed lighting is a good example. As several folks have said, RAW allows more chances to fix errors.

TCav Feb 8, 2010 8:38 AM

Yes, if you only have one chance to get it right, shoot RAW. If things weren't ideal when you took the shot, you can take advantage of more wiggle room when post processing a RAW image than a JPEG image.

nech770 Feb 8, 2010 8:39 AM

ok so it is better for post processing.. but what if I have NO CLUE what I am doing so I can't fix the pics am I better off not using RAW? Do you need to use camera specific s/w for pp? Like I use Linux... so if my camera comes with windows or mac s/w am i SOL?

TCav Feb 8, 2010 8:48 AM

There are options for Linux users (Hopefully, JimC will chime in here.) but they are limited. You do have some latitude when working with JPEG files, so you can correct for minor problems with exposure or white balance, but not as much as when working with RAW. If you anticipate having to do a lot of post processing, the tools and options for doing it with RAW files tend to be very different from those for JPEG files, so your experience JPEGs may not transfer when you start working with RAW. If shooting RAW doesn't get in the way of other things you want to do, and you can find suitable tools for working with RAW files, you might want to stick with RAW for a while just to see how it goes.

shoturtle Feb 8, 2010 8:55 AM

If you shot in jpeg, you let the camrera do the processing and compression, but you can also do small amount of process on jpeg files if you do not want to get to into post processing.

Flying Fossil Feb 8, 2010 10:51 AM

I have shot both raw and jpeg + raw/jpeg with my A-700 and all the lens.
I rarely see enough difference to merit the extra space that raw consumes and in some cases, the jpeg even looks better than the raw version.
I have reverted to shooting jpeg only and haven't missed any shots due to exposure or color. I have missed focus a few times in sports but hey, I have no clue what I am doing. :eek:

JimC Feb 8, 2010 10:52 AM

Quote:

Originally Posted by nech770 (Post 1049703)
ok so it is better for post processing.. but what if I have NO CLUE what I am doing so I can't fix the pics am I better off not using RAW? Do you need to use camera specific s/w for pp? Like I use Linux... so if my camera comes with windows or mac s/w am i SOL?

Nope (you're not SOL). I rarely use a camera manufacturer's software for anything.

For starters, look at digiKam 1.0.0 in a free option for converting raw files, managing your images, performing a number of image enhancements and much more.


Digital Imaging products for Linux are coming along quite nicely now. For example, I use digiKam for a lot of tasks (managing images, cropping, usm, refocus algorithms, resizing, curves, etc.). It's an easy to use photo management solution with lots of good editing plugins available (make sure to install the latest kipi plugins, too). If you're not familiar with it, see page for more info. If you look under the About menu choice, you'll see links to an overview, feature lists and more.

http://www.digikam.org

Make sure to install showfoto, too . It's got most of the same functionality that's built into digiKam, except that it doesn't have the album related features. I keep both installed in the Linux distros I use.

Krita is also coming along nicely, and it's well integrated into the KDE Office Suite.

http://krita.org/

Another product worth looking at is Lightzone (commercial, but now available for Windows, Mac and Linux operating systems):

http://www.lightcrafts.com/lightzone/

Eric Hyman also offers Bibble for multiple operating systems (Windows, Mac, Linux). Bibble 5 Pro was just released, and it's really slick software.

http://bibblelabs.com/products/bibble5/

Google's Picasa is also available for Linux:

http://picasa.google.com/linux/

Make sure to see Raw Therapee (also available for Windows and Linux). It's free.

http://www.rawtherapee.com/

For imaging editing, make sure to look at Cinepaint, too (it supports 16 bit editing and more, where the Gimp is limited to 8 bits at this time, although work is well underway to support higher bit depth editing in the GIMP).

http://www.cinepaint.org/

You can also run a lot of Windows applications under Wine. I've been pretty surprised at how many applications run fine that way. I even have multiple versions of IE installed in Wine, so I can check to see if a given browser version has problems with a site, without running Windows to find out.

You can also run a copy of Windows in a Virtual Machine under Linux if you absolutely need something that won't run in Linux or Wine. I'd look at the free Sun Virtualbox for that purpose. It's coming along nicely:

http://www.virtualbox.org/

nech770 Feb 8, 2010 7:03 PM

Jim,
Thanks for ALL the useful info.. I use digikam, and gimp... I will look at the other progs... good to know that a lot of stuff works under WINE... I gave up a long time ago on wine... when it didn't work so well.. maybe time to relook into it...
Thanks again

peripatetic Feb 9, 2010 3:37 AM

Bibble looks pretty good to me.

If it had been this good 18 months ago I might not have joined the Lightroom fold.

JimC Feb 9, 2010 10:07 AM

Yes. I've been very impressed with Bibble 5 Pro. I especially like that it's cross platform, too (Linux, Mac, Linux), since I run both Windows and Linux on my PCs.

billy Feb 9, 2010 1:53 PM

2 Attachment(s)
Here's a good example of why RAW is so important. While shooting a wedding, my flash unit started outputting at about 1/2 power. I didn't notice as I wasn't chimping (looking at the LCD to see the quick review of the shot I just took), and I saw the flash firing.
Attachment 148526
Here was the final JPEG. Luckily I was shooting in RAW+JPEG, so I was able to salvage the shot, and produce this.
Attachment 148527
Not perfect, but much better than the above shot.

BTW, I also use GIMP, however the UFRaw plug-in still isn't supporting the EOS 7D (although they have it listed on their site). So, I installed the included Digital Photo Professional Canon software on my WinXP VM, and used that to convert the RAW. DPP works very well, and I was pleased with the outcome.

billy Feb 9, 2010 2:03 PM

Quote:

Originally Posted by JimC (Post 1049755)
You can also run a copy of Windows in a Virtual Machine under Linux if you absolutely need something that won't run in Linux or Wine. I'd look at the free Sun Virtualbox for that purpose. It's coming along nicely:

http://www.virtualbox.org/

I use this setup on a daily basis. Runs flawlessly, and I'm even using an older version of Vbox.

rfortson Feb 12, 2010 2:48 PM

Quote:

Originally Posted by peripatetic (Post 1049183)
There is another advantage. When I first started out on DSLR 6 years ago I became convinced that shooting RAW was a good idea. I'm very glad I did, as the RAW converters of today are much better than they were back then. I can now revisit shots I took 6 years ago and get a better image from them than I did back in 2004.

That is definitely true, and not often touted as a benefit to shoot raw. While jpeg processors built into cameras continually improve, when you shoot jpeg, that's as good a shot as you'll ever get from that file. When you shoot raw, you can take advantage of the improvement in raw processors (and computers) for as long as that file is still readable.

Ordo Feb 12, 2010 5:45 PM

Raw vs jpeg seems to me as another market compromise we should asume. For good or for bad.

JimC Feb 12, 2010 6:23 PM

One of the problems I'm seeing with some camera models (including models from Sony, Pentax, Nikon and others) is that there appears to be some level of Noise Reduction at the raw level. For example, some of the newer Sony models have this characteristic, and evidence *very* strongly suggests the same thing is happening with some Nikon models (like the D90, as well as some of the Pentax dSLR models. Ditto for some Olympus models.

So, because manufacturers are trying a bit *too hard* to look good on popular tests showing performance at the raw level, it limits a user's ability to extract the most out of a camera's raw images later (because the sensor data is being manipulated at the raw level).

Unfortunately, a lot of the current tests of a camera's ability based on raw files are usually taken as "gospel" on how one sensor compares to another, even though the [supposedly expert] testers may not have [yet] realized the manipulation of raw data going on by some of the camera manufacturers (as it tends to be a bit subtle and hard to detect unless you know what to look for using more sophisticated tools for raw file analysis).

IOW, I'd take any tests of Signal to Noise ratios and more with a "grain of salt", as those tests can be fooled by raw file manipulation. Instead, let your eyes be the best judge of how images from different cameras compare to each other.

peripatetic Feb 13, 2010 6:42 AM

Quote:

IOW, I'd take any tests of Signal to Noise ratios and more with a "grain of salt", as those tests can be fooled by raw file manipulation. Instead, let your eyes be the best judge of how images from different cameras compare to each other.
Of course in one respect that's all that matters - it's your cash, so buy what looks good to you.

But you radically overestimate the ability of any person's eye to make meaningful and reliable distinctions in such matters. DXOMark may be imperfect and/or controversial, but it's repeatable and the methodology is published for anyone to replicate. In other words, it's science and based on hard data, I'll take that over anecdotes any day.

JimC Feb 13, 2010 7:03 AM

I don't ignore their tests. But, I would sure supplement them using my own eyes as a guide.

For example, if you look at Sensor numbers, Signal to Noise Ratio comparisons and more between the Nikon D300 and D90, you'd assume that the D90 has much better image quality.

But, if you look at the photos, you may come to a totally different conclusion. For example, if you look at the D90 review at dpreview.com, they have some comparisons between these cameras at both the raw and jpeg level. They indicated that no amount of reshooting could get the D90 to match the D300's output (and they made similar comments about them for both raw and jpeg images).

It's also very difficult to judge the quality of things like noise patterns by looking at their graphs. Originally, they had .pdf files online for cameras tested that allowed you to see the patches they were measuring to get a better idea of how cameras compared. But, AFAIK, they don't let you see that anymore. Instead, you're stuck looking at numbers and graphs to try and tell how image quality compares (which IMO, by themselves, can be very misleading).

peripatetic Feb 13, 2010 7:15 AM

Quote:

For example, if you look at Sensor numbers, Signal to Noise Ratio comparisons and more between the Nikon D300 and D90, you'd assume that the D90 has much better image quality.
Then you really need to read the charts and the site info on interpretation again, because that is absolutely not what they suggest IMO; it suggests that the sensor performance is almost identical.


Quote:

It's also very difficult to judge the quality of things like noise patterns by looking at their graphs. Originally, they had .pdf files online for cameras tested that allowed you to see the patches they were measuring to get a better idea of how cameras compared. But, AFAIK, they don't let you see that anymore. Instead, you're stuck looking at numbers and graphs to try and tell how image quality compares (which IMO, by themselves, can be very misleading).
The image is integrated in the page now. Hover your mouse over the slider bars at the right of the graph and it shows the underlying image used to make the measurements.

I believe it is always sensible to normalise for the Print view because this gives the best comparison unless you are going to be printing at substantially higher resolutions than one of the two cameras allows.

http://dxomark.com/index.php/eng/Image-Quality-Database/Compare-cameras/%28appareil1%29/294|0/%28appareil2%29/295|0/%28onglet%29/0/%28brand%29/Nikon/%28brand2%29/Nikon

Comparing the D90 to the D300 shows about a half stop advantage to the D90 overall, but the differences are very small and chiefly in DR and color and tone sensitivity in low-light conditions.

Quote:

But, if you look at the photos, you may come to a totally different conclusion.
Actually being able to judge margins than fine by eye? Good luck. You may be able to convince yourself that you can tell them apart, but I'd be willing to bet under controlled double-blind conditions you wouldn't have a snowball in the Sahara's chance. :-)

aka - the cameras sensors are essentially equivalent for general purpose photography. Though of course the D300 is a much better camera in other respects.

JimC Feb 13, 2010 7:28 AM

Interesting. But, I don't think those are the actual images used for the measurements (rather they appear to be designed to give you an idea of what to expect at a given point on the graph).

The .pdf files they used to allow you to download with test results, included the actual gray and color patches being used for their measurements.

JimC Feb 13, 2010 7:41 AM

Quote:

Originally Posted by peripatetic (Post 1051644)
Actually being able to judge margins than fine by eye? Good luck. You may be able to convince yourself that you can tell them apart, but I'd be willing to bet under controlled double-blind conditions you wouldn't have a snowball in the Sahara's chance. :-)

Some experienced reviewers may disagree with you (for example, Phil Askey and crew). ;-)

It's pretty easy for me to see that D300 images look better when viewing some of the comparisons taken in controlled conditions.

Things like S/N ratio tests can be very misleading in the amount of detail being retained. You'll even see articles at the Dx0Mark site discussing how NR at the raw level impacts their test results (which is why they're using extrapolated data for some cameras models now, where they've been able to detect manipulation of data at the raw level).

However, some pretty smart people have presented very strong evidence of NR at the raw level for cameras that they have not yet detected doing it, using pretty sophisticated raw analysis tools to reach their conclusions. They're looking for more obvious smoothing of data and there are more subtle techniques that make manipulation of data at the raw level much harder to detect without using a different analysis approach. You can end up with softer images and still have a great S/N ratio on most tests.

JimC Feb 13, 2010 7:57 AM

Now, some tests are more sophisticated. For example, if you look at Imatest results, you can see a bit more about a camera's noise pattern (versus just S/N ratios). You'll see a lot of discussion in Dave Etchells' reviews when looking at Imatest results. For example, here are the results for the D90:

http://www.imaging-resource.com/PROD...D90IMATEST.HTM

JimC Feb 13, 2010 8:18 AM

P.S.

Here's a discussion of D90 raw file analysis showing evidence of high ISO NR that you may find interesting:

http://forums.dpreview.com/forums/re...ssage=32401883

Nikon also appears to be performing long exposure NR at the raw level with some models, even with long exposure NR turned off. Here's an article discussing it:

http://www.astrosurf.com/buil/nikon_test/test.htm

They also appear to do other types of preprocessing of raw data. For example, Dave Coffin (the author of dcraw.c ) noticed that Nikon was modifying raw data years ago with some of their cameras (applying multipliers to raw data). See question #12 from this interview with Dave in 2005:

http://www.dpreview.com/news/0504/05...ninterview.asp

In fact, I had a long conversion with Dave the night before that interview (we were mostly discussing Nikon's encryption of RGB multipliers for White Balance at the time, and he had offered to do an interview with Steve's at the time, too). We've also had a number of discussions since then (mostly about dcraw.c, it's licensing, etc.).

peripatetic Feb 13, 2010 10:58 AM

Everyone does some NR as they read the data off the sensor. It seems Nikon and now Sony do it more aggressively than Canon.

Per-pixel sharpness differs between cameras and is affected by NR and AA filters. Always has been.

I'll absolutely be willing to put down a modest amount of money against ANYONE being able to tell me which camera (from the same sensor size) made which A4 print. I'd happily put down $50 in a double-blind test of Phil Askey's ability to tell the difference between a D90 and D300 print. Caveat - it has to be a real-world subject not a test chart.

JimC Feb 13, 2010 11:02 AM

It probably would be hard to tell the difference with an A4 print. But, camera buyers tend to be "pixel peepers" and want to see the camera that performs the best looking at 100% crops. ;-)

That's where reviews come in showing the differences, using controlled conditions photos, etc.

Sure, in real world use, that may not make any difference. I've seen images that look pretty bad looking at 100% crops that print just fine. But, camera buyers tend to want the "best" for a given dollar amount (assuming they can tell that from looking at 100% crops, right or wrong), and I doubt you'll change that behavior anytime soon.

peripatetic Feb 13, 2010 11:07 AM

Quote:

But, camera buyers tend to be "pixel peepers" and want to see the camera that performs the best looking at 100% crops. ;-)
The phase "get a life" springs immediately to mind for some reason. :-)

Reading many of the review sites and manufacturers' claims, and contrasting those against the DXO tests, I am thoroughly convinced that we are seeing very modest improvements and those will become even more modest over time as we approach the limits that physics is imposing. Pretty much the only thing that counts in the efficiency of the sensor is how large it is. Just like the film days.

The Emperor is naked and the review crowds (Steve excepted of course) are fashion critics talking about his latest outfits. :P

JimC Feb 13, 2010 12:19 PM

Quote:

Originally Posted by peripatetic (Post 1051697)
Pretty much the only thing that counts in the efficiency of the sensor is how large it is. Just like the film days.

I think we're probably at or past that point. I've been quite surprised looking at images from 6MP dSLR models at higher ISO speeds and comparing detail to newer 12MP dSLR models at the same ISO speeds, looking at photos taken in the same conditions. There's really not a lot of difference in them at a typical print or viewing size. Some of that is probably more aggressive NR, and some of that is probably because higher resolution sensors are placing more demands on the lens quality needed for best results. So, unless you're using the best premium quality lenses, you may not see much difference moving to a higher resolution model.

Of course, in better lighting with the aperture stopped down for better DOF, diffraction limitations are probably entering the equation, too. Yet, the megapixel war continues.

Chato Feb 13, 2010 12:35 PM

Quote:

Originally Posted by JimC (Post 1051695)
It probably would be hard to tell the difference with an A4 print. But, camera buyers tend to be "pixel peepers" and want to see the camera that performs the best looking at 100% crops. ;-)

That's where reviews come in showing the differences, using controlled conditions photos, etc.

Sure, in real world use, that may not make any difference. I've seen images that look pretty bad looking at 100% crops that print just fine. But, camera buyers tend to want the "best" for a given dollar amount (assuming they can tell that from looking at 100% crops, right or wrong), and I doubt you'll change that behavior anytime soon.

I read these articles you posted and must say they are not very convincing. For one thing Nikons software processing is different between camera models and can account for this increased noise far better than thinking that the RAW file has been tweaked. Just updating the firmware often changes the question of noise.

But even if Nikon DOES use NR in the RAW files, if you have to blow the image up by 400 percent in order to see it, the question becomes academic.

Dave

JimC Feb 13, 2010 2:16 PM

Quote:

Originally Posted by Chato (Post 1051712)
...For one thing Nikons software processing is different between camera models and can account for this increased noise far better than thinking that the RAW file has been tweaked...

The analysis was being done on the raw files (*before* the camera should be performing any image processing). That's their point (that these cameras are processing the raw data versus leaving it alone and letting you process as desired later, without it being manipulated by the camera manufacturer first). ;-)

Chato Feb 13, 2010 2:55 PM

Quote:

Originally Posted by JimC (Post 1051734)
The analysis was being done on the raw files (*before* the camera should be performing any image processing). That's their point (that these cameras are processing the raw data versus leaving it alone and letting you process as desired desired later, without it being manipulated by the camera manufacturer first). ;-)

Firmware changes, and the difference in firmware between models can have a profound effect on RAW files...

Certainly did effect noise with my D1x. Didn't change noise on my D2x

Dave

starling Feb 19, 2010 4:36 PM

Well, I've used RAW, and I think that at this point, with today's DSLRs and compact digicams, with their high resolutions and functions that help get detail in shadows while retaining highlights, RAW is more trouble than its worth.

Most people keep reading about this on reviews and forums and think it's a very important feature that they must have. The reality is that, especially on a compact digicam, you get as much just using the camera's best JPEG setting. Once you get the file on your computer, only work on a copy, and if that copy is also in JPEG format, do all of your post-editing in one go before you save the file. That way, you don't lose any quality that would be worth frigging around with those large RAW files. Alternatively, you could also make that original copy a TIFF file, or the native format of your photo editor if it has one, and then you can work on it all you want without any data loss. Then you only save the final work in JPEG.

Chato Feb 19, 2010 5:40 PM

Quote:

Originally Posted by starling (Post 1054284)
Well, I've used RAW, and I think that at this point, with today's DSLRs and compact digicams, with their high resolutions and functions that help get detail in shadows while retaining highlights, RAW is more trouble than its worth.

Most people keep reading about this on reviews and forums and think it's a very important feature that they must have. The reality is that, especially on a compact digicam, you get as much just using the camera's best JPEG setting. Once you get the file on your computer, only work on a copy, and if that copy is also in JPEG format, do all of your post-editing in one go before you save the file. That way, you don't lose any quality that would be worth frigging around with those large RAW files. Alternatively, you could also make that original copy a TIFF file, or the native format of your photo editor if it has one, and then you can work on it all you want without any data loss. Then you only save the final work in JPEG.

:confused-smiley:

peripatetic Feb 20, 2010 3:13 AM

Quote:

Originally Posted by starling (Post 1054284)
Well, I've used RAW, and I think that at this point, with today's DSLRs and compact digicams, with their high resolutions and functions that help get detail in shadows while retaining highlights, RAW is more trouble than its worth.

Most people keep reading about this on reviews and forums and think it's a very important feature that they must have. The reality is that, especially on a compact digicam, you get as much just using the camera's best JPEG setting. Once you get the file on your computer, only work on a copy, and if that copy is also in JPEG format, do all of your post-editing in one go before you save the file. That way, you don't lose any quality that would be worth frigging around with those large RAW files. Alternatively, you could also make that original copy a TIFF file, or the native format of your photo editor if it has one, and then you can work on it all you want without any data loss. Then you only save the final work in JPEG.

There are at least 4 important things you get with RAW:
1. The ability to set white balance after the shot is taken.
2. The ability to apply the noise reduction appropriate to the image.
3. The ability to recover 0.5 to 1.5 stops of highlights that would be blown in JPG.
4. The ability to apply sharpening appropriate to the image instead of a default setting which is often to much or too little.

If you don't understand those things or they are not important to you then you might as well use JPG.

However if you have to (or really want to shoot JPG) mitigating steps can be taken:
1. Modern image processing applications do some quite clever things after the fact w.r.t. white balance.
2. Turn down noise reduction to its minimum setting.
3. Use the DR extension or highlight preservation setting. Or just be careful with your exposure and ETTR.
4. Turn down sharpening to its minimum level.

So I guess it may be more trouble than it's worth if you don't want to invest in the more sophisticated image processing applications like Lightroom, Aperture, Bibble, etc. If you do use one of those then there is no real penalty to using RAW.


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