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DPChallenge Forums >> Photography Discussion >> Is RAW really that helpful?
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 11/09/2004 10:38:02 PM · #1
I've been noticing that many people shoot there challenge shots using the raw format. Is it really that necessary to use?
 11/09/2004 10:51:21 PM · #2
It all depends on your personal requirements. Shooting raw and saving this file is the equivalent of a negative. Certain things and adjustments can be made to the raw file while preserving the quality of the pixels. The raw is considered the digital negative.
 11/09/2004 11:07:29 PM · #3
If you want the best quality photos and prints and you want the most flexibility in processing your shots then RAW is the way to go. There is an excellent book REal World World Camera RAW with Adobe Photoshop explains everything and how to use ACR. Highly recommended.
 11/09/2004 11:10:18 PM · #4
Originally posted by doctornick:
If you want the best quality photos and prints and you want the most flexibility in processing your shots then RAW is the way to go. There is an excellent book REal World World Camera RAW with Adobe Photoshop explains everything and how to use ACR. Highly recommended.


Yup, that book IS good. Besides, as quick as the 20D is with RAW, there's no reason not to take advantage of the format. Course, that's just my opinion and you know what they say about those! LOL But seriously, it's about what fits your needs.
 11/09/2004 11:15:10 PM · #5
Shooting Raw lets you esealy change the exposure and white balance without loosing the quality of the image, anything else can be done in jpg with almost the same results, check this: //www.kenrockwell.com/tech/raw.htm

11/09/2004 11:15:39 PM · #6
I played with image quality and such, but what really really sold me on Canon's raw, was that white balance is separate from the image. Once the .jpg is saved, it's all over for white balance if you forgot. It's hard to see the effects till you're at a decent screen.

WHen I'm just shooting snapshots or stuff on the fly, I'll shoot JPG. But if I'm working on something "important" I switch over to RAW for that slight safety net that isn't there in JPG.

Just my .02
 11/09/2004 11:25:51 PM · #7
Geocide, I shoot uncompressed TIFF on almost everything.
I think any uncompressed format will give you a cleaner image over compressing. I have found RAW to be quite a bit better quality than JPEG. The only time I switch over to RAW would be when the lighting is questionable and I don't know where to set the white balance. RAW files are more forgiving when correcting lighting discrepancies than what is available with other file formats.

My recommendation would be to always shoot in the highest quality mode your camera offers.
11/09/2004 11:25:53 PM · #8
Raw is a pain in the butt. I can't open them up in PSP, so I have to open in another program, save it and open it again. grrr... to much waist of time.
 11/09/2004 11:32:45 PM · #9
The way I do is to open the images in the viewer. Select the one's I want. make whatever changes I need and then convert and save it as a tiff. I then open the tiff in PS. No problem.
 11/09/2004 11:39:20 PM · #10
It's not a waste of time at all. PhotoShope Elements 3.0 has a RAW converter, if I'm not mistaken.

Originally posted by Sonifo:
Raw is a pain in the butt. I can't open them up in PSP, so I have to open in another program, save it and open it again. grrr... to much waist of time.

11/09/2004 11:43:15 PM · #11
PSP 9 has one as well.
 11/10/2004 07:18:09 AM · #12
one point to consider with RAW vs JPG is that the algorythms use to manipulate the info from the camera will get better & easier to use in the next few years, so if you use RAW you'll be able to take advantage of that when the time comes. With JPG you're pretty much stuck with what you got now.
 11/10/2004 08:02:00 AM · #13
Ifranview is a free program that has a great plugin that will let you open (very Quickly) RAW images right off your flash card.

Irfanview will also open Raw images without the plugin but it opens them at a reduced size.. much better with the free plugin

//www.irfanview.com/
 11/10/2004 08:09:03 AM · #14
Shooting RAW allows you to use 16 bits when editing, giving you many, many more levels of color and shade and tone. On the other hand, there are some things you can't do in 16 bit. I usually don't shoot in RAW, but I've been thinking more seriously about it lately.
 11/10/2004 08:15:28 AM · #15
If you are shooting a photo specifically for DPC it seems like it would be better to shoot a smaller photo so you wouldn't have to downsize to a sliver of the original?

Tim
 11/10/2004 09:10:41 AM · #16
Originally posted by Niten:
If you are shooting a photo specifically for DPC it seems like it would be better to shoot a smaller photo so you wouldn't have to downsize to a sliver of the original?

In almost all cases, downsampling the image from the "sensor resolution" to something smaller in software (rather than in the camera) achieves better results because of the more advanced/process intensive algorithms that can be employed.

As an interesting sidebar... "maximum detail" is achieved at a 25% reduction in size for almost all cameras since the vast majority use a Bayer pattern filter. Although a sensor may have 6 megapixels, each pixel (more properly called a "photo site") is only sensitive to "light intensity" and not color. So a Bayer filter is placed in front of the sensor, and now each photo site is responsible for detecting the intensity of either red, green or blue light, resulting in "raw data" from the sensor that looks like this:



This data is then "demosaiced" into the full-color image that is presented to the user:



When you have access to the raw sensor data and reduce an image to 50% size, you can achieve 100% detail in the green channel (remember there are 2 green "pixels" in the Bayer pattern, primarily because the human eye is more sensitive to shades of green than red or blue, and green covers the most important and widest part of the visible light spectrum). When you reduce the size to 25% of the sensor resolution, you can achieve 100% detail in all 3 channels.

One revolutionary sensor, the Foveon X3, does not use a Bayer pattern at all, but rather 3 separate layers, each of which is sensitive to either red, green or blue at full-resolution . It therefore achieves 100% detail in all 3 channels at the stated resolution of the sensor. The sample above captured by a Foveon sensor (like the Sigma SD9 or SD10), would look like this:

11/10/2004 09:54:40 AM · #17
I also use RAW for anything that might be printed in black and white. 16 bit is much better than 8 bit because there are more levels of gray.
 11/10/2004 09:58:45 AM · #18
I always shoot RAW. If there's one good reason to do that, it's exposure compensation. Though I am not exactly sure how this works, it seems it can save you from having to bracket exposures if you want to increase your camera's dynamic range. And combining exposure compensated images is DPC legal, whereas combining bracketed images is not. (Not all camera RAW format converters support adjusted exposure. My Canon G2 RAW converters did not have this option, but the dRebel converters do.)

Another good reason is that you can set the color balance after the fact. I find auto color balance often "misses" indoors, and if I manually set the color balance to tungsten, I can be pretty sure I'll forget to switch it back when I take my next outdoor shots. Raw eliminates this entirely.

Another good reason is that you have an original free of JPEG artifacts, pre-sharpening, etc.

11/10/2004 09:59:32 AM · #19
Originally posted by Nusbaum:
I also use RAW for anything that might be printed in black and white. 16 bit is much better than 8 bit because there are more levels of gray.


thanks for the tip for this week's challenge. :)
 11/10/2004 10:04:47 AM · #20
Originally posted by annasense:
Originally posted by Nusbaum:
I also use RAW for anything that might be printed in black and white. 16 bit is much better than 8 bit because there are more levels of gray.


thanks for the tip for this week's challenge. :)


I was about to say that 16bit wouldn't help when you are reducing to 8 bit jpegs, but 16bit gives you a lot more to work with when doing levels adjustments and playing with curves. It's important to not drop to 8bit until you do your final "save for web".
 11/10/2004 10:20:33 AM · #21
I'm a jpeg shooter. When I grow up, I wanna shoot RAW.
 11/10/2004 10:25:31 AM · #22
Originally posted by Nusbaum:
I also use RAW for anything that might be printed in black and white. 16 bit is much better than 8 bit because there are more levels of gray.


Curious how you get to your many levels of grey version.

If you use the channel mixer, on an 16 bit image, you end up with around 256 levels (2^8) anyway.

It certainly initially seems like a good idea to work in 16 bit, but for B&W I haven't found a way that gives any actual advantage in terms of grey levels. Would love to find one though, so please let me know!

There are certainly a load of advantages to working in 16 bit (particularly if you are using very wide gamut colour spaces) but I haven't seen a good B&W workflow that improves.

Message edited by author 2004-11-10 10:26:39.
 11/10/2004 12:30:56 PM · #23
Originally posted by Gordon:
Originally posted by Nusbaum:
I also use RAW for anything that might be printed in black and white. 16 bit is much better than 8 bit because there are more levels of gray.


Curious how you get to your many levels of grey version.

If you use the channel mixer, on an 16 bit image, you end up with around 256 levels (2^8) anyway.

It certainly initially seems like a good idea to work in 16 bit, but for B&W I haven't found a way that gives any actual advantage in terms of grey levels. Would love to find one though, so please let me know!

There are certainly a load of advantages to working in 16 bit (particularly if you are using very wide gamut colour spaces) but I haven't seen a good B&W workflow that improves.

Damn, now you are going to make me think...
8 bits per channel gives us 256 level of gray, as you stated.
16 bits per channel should give us 65536 levels of gray, right?
The fact that the channel mixer still represents as a scale of 0-255 is something that I hadn't given much thought. I assumed, and maybe in correctly, that the math for tools such as level and channel mixer worked at the 16 bit level even though the user interface still represented an 8 bit perspective. I don't have photoshop here, so I'm going to have to play with this later tonight.
 11/10/2004 01:35:21 PM · #24
Originally posted by Gordon:
It certainly initially seems like a good idea to work in 16 bit, but for B&W I haven't found a way that gives any actual advantage in terms of grey levels. Would love to find one though, so please let me know!


Fred Miranda's B&W Workflow Pro plugin for Photoshop claims that it can work in 16 bit mode with 16 bit files in Photoshop CS.
It works just like a Channel Mixer with some presets and extra's like color filter simulations, dynamic range increase and chroma noise reduction. I use it with Photoshop 6 (only 8 bit mode), so I cannot tell you anything about what it does to files in CS.

No trial versions. Perhaps you can try the forums there to ask how it handles 16 bit in CS.
 11/10/2004 03:45:37 PM · #25
There's no real reason why the channel mixer shouldn't give a 65k level greyscale image, but it appears to give a 256 level result, in either 16 or 8 bit mode.

I'll take a look at the fred miranda tools - thanks!
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