Canon 10D and RAW - truths vs. misconceptions

[raivo_vanags]

Just got my Canon 10D and am packing bags for the trip. I have read

the manual once and have done some reading on RAW file format before

but there�s one (well may be several) thing I�m not sure I understand

correctly. Please look at my thought-flow and tell me where I�m

wrong:<p>

 

1)RAW files are not compressed files (unlike JPEGs) and thus they are

without any loss of data/exposure/whatever u\you call it.<p>

2)If you shoot RAW file you can almost perform it like point&shoot

camera action (excluding ISO settings, apertures, etc.) � you

<b>may</b> not worry about light balancing, under/overexposing, etc.

as you can change it all on your editing software.<p>

3)If you choose to adjust light balance, exposure level, etc. it will

be recorded on RAW and if done correctly with camera there will be

little you need to do with PC.<p>

4)It�s better to convert RAW to 16bit TIF than 8bit because of higher

quality.<p>

5)If all you need from the image is 10x15cm (is it 4x6�?) print from

the picture then Large JPEG format is more than enough.<p>

6)When you shoot in RAW format then you have to choose an embedded

JPEG format for the shot as well. You should choose the smallest one

because:<p>

a)It takes less space on your CF card;<p>

b)You can convert a RAW file to Large JPEG file and this image would

be exactly the same as if you shot it on Large JPEG setting at first

place (it�s your problem you used 2x the space needed for the shot).

(or should shoot RAW+Large JPEG to have a) some quick prints and

files to show to friends and b)to have those files for editing

purposes and fine prints)<p>

 

P.S. On a side note/question � does digital photography changes the

need for filters (like 81s, polarizers, neutral density, etc.) or

not? Why?<p>

P.S.S. Is it true digital is not usable after 1sec long exposures or

I have misread it somewhere (I haven't had time to test it myself).

If yes then why?<p>

 

 

Best,

[geddert]

<ol>

<li>true

<li>false (in part). Its true that you don't need to worry about white balance, but you certainly DO NEED to worry about over/underexposing because different raw info will be stored accordingly.

<li>don't know - i'm still waiting on my 10d to figure that one out

<li>true, but if an only if you have the hard drive space and the ability to back it up... there are always trade offs.

<li>true, but why not save it in the highest quality raw, just in case it happens to be fantastic shot.

<li>don't know, expect for "b" it can be the same, but it won't be exactly the same, especially if you convert it to jpeg using one of the aftermarket converters like capture pro which are higher quality converters than canons software.

</ol>

P.S. digital photography does not change the need for filters, though it can reduce it. If you want to make things a bit more warm (yellow), and don't have a 81 along you can always add that digitally, likewise you can blend pictures for natural densite stuff (see <a href="http://www.luminous-landscape.com/tutorials/digital-blending.shtml">http://www.luminous-landscape.com/tutorials/digital-blending.shtml</a>), the one thing you will use the same as in the past is a polarizer because that "effect" can't be added after the fact. Comeing to think of it, the only filter you really need with digital is a polarizer...

<p>

P.S.S. No this is false... they do start to show problems with minute long exposures...

[vesa_perala]

Here's my take:

 

1. True although in practice it is compressed (lossless though).

 

2. To me it seems that there is not much reserve if you overexpose

some parts. You may make them darker by using exposure compensation in post-processing but at least in my initial tests I didn't get much more detail back.

 

3. Yes, if the settings (WB, exposure, etc.) were correctly set then you can just use the "as shot" settings when you convert the images to JPEG or TIF.

 

4. That's what I have heard although unless you do heavy post-processing it may be difficult or impossible to notice the difference.

 

5. I'm sure even less would be enough.

 

6a. That is true but extracting the JPEG from the RAW is faster than converting it from RAW, so it depends.

 

6b. I'm not sure if it is 100% the same but close enough I quess. The size difference between RAW+smallest and RAW+largest is not 2x in CF memory consumption. RAW+smallest is in the 7MB range and RAW-largest in 9MB range I think.

 

Vesa

 

PS. I think some filters are still necessary and some are not.

 

PPS. I think the limit with the best cameras is in minutes range not 1 second anyway.

[isaac sibson]

1) False. They are Losslessly compressed, like a .zip file is, so they take less room on the card. Also note that the LZW compression algorithm used has variable compression levels depending on the data to be compressed, thus the files will not all be the same size (as they would if they were not compressed)

 

2) To a point. Blown-out highlights or loss of shadow detail can still happen, so exposure is still quite critical.

 

4) Depends on your intended output really. The vast majority of computer graphics cards use 8-bit ramdacs, thus on-screen there is no possible benefit of using 16 bit per channel (48 bit) Tiffs over 24 bit ones. Some of the latest generation of graphics cards (those from Ati, Matrox and 3dlabs) use 10 bit RAMDACs. However, you're unlikely to see the difference. A very good photoprinter may, however, be able to make something of the difference.

 

PS) The need for warm-up filters is removed. Polarisers could be useful (if they're something you use, I don't), and with the limitations on dynamic range of digital cameras, NDs and particularly graduated NDs could be seen as more important than with 35mm.

 

PPS) That depends on the camera in question. Many little P&S cameras won't allow such exposures because the tiny sensors used produce a great deal of noise and many hot pixels in such an exposure. Canon's DSLRs are among the very best digital cameras on the market with regard to long exposure capability and quality, and the D60 in particular was superb with exposures even of several minutes.

[hans_eckelman]

I've done 10" x 15" professional prints using the JPG format of the camera with beautiful results. I've seen 20" x 30" pictures printed from the JPGs that started to show some artifacting, but hardly noticable unless you were looking close for them.

[david_kieltyka1]

1) The 10D's RAW files are compressed (I know the Nikon D100 at least can save uncompressed RAW) but it's a loss-less form of compression. JPEG is a loss-y form of compression...it throws away image data.

 

2) Not really. Getting the exposure correct is important regardless of which file format your camera uses to save your photos. Digital has very little overexposure latitude. Blow out the highlights and they're gone for good. Establishing correct color balance is also important in some situations. When doing product photography for instance. Otherwise you can just use AWB (auto white balance) and then adjust to taste in post-processing.

 

3) The RAW file will contain your camera's white balance, saturation, contrast and some other settings. You can convert the file with these settings applied if you want. At the conversion stage you can compensate a bit (but not much) for overexposure and a great deal for underexposure. Grossly underexpsosed photos will be noisy and will lack shadow detail. Best to get the exposure right in the first place.

 

4) Yes. A 16-bit file allows you to do levels & curves adjustments with much less data loss than the same operations performed on 8-bit files. For viewing & printing purposes you can convert to 8-bit format. I use an unsharp masking Photoshop action that does this for me. (Sharpening is the *last* thing I do to a photo before printing or saving for monitor display.)

 

5) JPEG doesn't throw away much spatial resolution but it does have an impact on tonal gradation. To my eyes JPEG prints often look harsher at large sizes than prints made from properly converted RAW files. Note: preserving tonal gradation is the main reason why doing image processing in 16-bit format is a good idea.

 

6) I've set up my friend's 10D (mine is still on order) to save the smallest possible embedded JPEG. A larger JPEG doesn't increase the RAW file size too much but on a smaller CF card every bit saved (literally) helps.

 

I rarely use filters in color photography, just a polarizer once in a while to reduce glare. Digital color balance control pretty much does away with warming & cooling filters. Neutral density filters will still come in handy if landscape photography, or just shooting in high contrast situations, is your thing. Or you can take highlight & shadow exposures and composite the two in post-processing. (You can do this with film too.)

 

For black & white photography using a deep red filter in certain situations is still important. You can digitally simulate the basic look of a red filter but you can't simulate its ability to see through atmospheric haze. A #25 red is my most-used filter whether on digital or film cameras.

 

Long exposures...most D-SLRs handle them quite well. My little Canon G2 consumer digicam can do 15-second exposures with very little noise (at ISO 50). Now for *really* long exposures (many minutes, hours) you'll need a film camera.

 

-Dave-

[jim_larson1]

My contribution:

 

2)The great curse of digital photography is that YOU personally do all of the post shooting lab work. Instead of using chemicals, you now use a computer.

 

Shooting RAW enables greater control over the "lab work" when you get to the PC. If you shoot JPEG, the "camera settings" do all the lab work for in the camera. That is nice if you do no post-processing on your PC. If you do post-processing on a JPEG, you have to deal with the "camera settings" (good or bad). With post processing on a RAW image, you do not have to deal with the camera settings.

 

In short, if you shoot RAW you only have to worry about the lens/exposure issues. Exposure is very critical as digital reportedly has less dynamic range than high quality film (harder to properly expose details in dark areas of frame without overexposing the brightest areas). Things like "white balance" and "sharpening" can be changed/adjusted later.

 

3) Someone **PLEASE** correct me if I am wrong: It is my understanding that the camera settings for sharpness, contrast, white balance etc only really apply to JPEG's and not the RAW files? For RAW files, ALL adjustments are done on the PC. In other words, for RAW setting max sharpness in the camera is the SAME as setting max sharpness in the software, and the effects are NOT additive. The intent is that most people will use *superior* software to anything that Canon will supply, so most people won't use it.

 

5) Large JPEGs are fine for printing. Small JPEGS (embedded or not) are more than adequate for screen viewing and email. If you PRINT photos, then you are more likely to want to photoshop the image first (crop, enlarge, color balance, sharpen). If you are photoshopping an image, then you are always best off starting from the uncompressed and unmanipulated RAW file, and using the tools in Photoshop (or photoelements) for the adjustments.

 

6) My advice: Processing RAW images take a long time (even if you use default parameters). Extracting embedded JPEGS is quick. Shoot everything with RAW+SMALL JPEG. Use the extracted JPEGS for quickly viewing on a computer, and selecting photos for printing/further work. The "small" JPEGS are not really all that small. When you get down to doing the photoshop or printing, then use the RAW images.

 

I recommend bringing a laptop with you, and reviewing extracted pictures nightly. This a) Gives you instant feedback on what you have done right/wrong. b) Allows you to have a empty CF card each day, c) is really fun!

 

Filters: 81's etc manipulate light before it reaches the sensor. Photoshop (or RAW converter) manipulates the image after it reaches the sensor. In the past, you had little access to the photolab, so you *had* to use the filters. Now you have the photolab (for better or worse) so you have the *option* to adjust later.

 

A circular polarizer, however, REALLY affects the light that hits the sensor, so it REALLY is only something that can be done when you take the picture. Note: If you try to stitch a landscape taken with a circular polarizer, you are in for a bad surprise!!

 

Long exposure: Have not tried it, but I understood this to be a high iso problem with MULTI-MINUTE exposures.

[ky2]

<p><i>P.S. On a side note/question � does digital photography changes the need for filters (like 81s, polarizers, neutral density, etc.) or not? Why?</i><br><br>

This is a mixed bag. I don't use warmers any more. Polarizers do things that are hard to replicate digitally later (removing reflections, for example). ND filters are still very much needed. If you're used to using filters, you shouldn't alter your technique, unless the ftop-penality rate is too high.

</p>

 

<p><i>P.S.S. Is it true digital is not usable after 1sec long exposures or I have misread it somewhere (I haven't had time to test it myself). If yes then why?</i><br><br>

My S2 Pro is pretty good upto 30 seconds (even when blown up to 16x20), and I have made successful 2 minute exposures with it too. Still, for EXTRA LONG exposures (>5 minutes) I prefer film.

</p>

[raivo_vanags]

Thanks a lot to all who answered! I really appreciate it!<p>

<I>My advice: Processing RAW images take a long time (even if you use default parameters). Extracting embedded JPEGS is quick. Shoot everything with RAW+SMALL JPEG. Use the extracted JPEGS for quickly viewing on a computer, and selecting photos for printing/further work. The "small" JPEGS are not really all that small. When you get down to doing the photoshop or printing, then use the RAW images.</I><p>

I needed to hear this � that's what I wanted to ask on that particular question.<p>

<i>The size difference between RAW+smallest and RAW+largest is not 2x in CF memory consumption. RAW+smallest is in the 7MB range and RAW-largest in 9MB range I think.</i><p>

Yes, I didn't actually meant 2x � just a description:) In fact my 10D shows I can shoot 75 frames in RAW+smallest mode and 60 frames with RAW+largest setting. It's with empty 512MB CF card.<p>

<i>For black & white photography using a deep red filter in certain situations is still important. You can digitally simulate the basic look of a red filter but you can't simulate its ability to see through atmospheric haze. A #25 red is my most-used filter whether on digital or film cameras.</i><p>

Dave � can you elaborate how do you go with b&w photography in digital? You justshoot pictures with #25 and then convert them to color before starting to edit in photoshop?<p>

Best,

[photobyalan.com]

<i>"Processing RAW images takes a long time..."</i>

<p>

It takes about 18 seconds per image to convert them to TIFF on a slow Pentium 4 machine, and that's using Canon's ZoomBrowser, which isn't exactly speedy. Considering the benefits of shooting in RAW format, that doesn't seem like such a long time. <p>

 

<i>"For black & white photography using a deep red filter in certain situations is still important. You can digitally simulate the basic look of a red filter but you can't simulate its ability to see through atmospheric haze. A #25 red is my most-used filter whether on digital or film cameras."</i><p>

I have had excellent results by shooting in full color and using the channel mixer controls in photoshop. Since you can adjust the channels so that you are using mostly the red information in the photo it is almost exactly the same as putting a red filter over the lens, except you don't have to calculate exposure compensation because there is none. In reality, you <i>do</i> have a red filter in the optical path, since the red-sensing pixels have a red filter over them. You do get penetration of atmospheric haze, and with a little manipulation, you can get a reasonable approximation of infrared film. If you're using Photoshop Elements, this option isn't available. You need the full version of photoshop to do use channels.<p>

 

<a href=http://www.luminous-landscape.com/tutorials/b-w_better.shtml>Here is a brief tutorial from Luminous Landscape.</a><p>

<a href=http://computer-darkroom.com/tutorials/tutorial_2_1.htm>Here's another.</a>

[raivo_vanags]

Thanx Alan!

[david_kieltyka1]

Using the 10D with a #25 red filter on the lens...I desaturate the photos in Adobe Camera RAW and use ACR's color temperature & tint controls to get things looking the way I want. I'll post some examples once I take some worth posting. :-)

 

-Dave-