Red Highlights

[Daniel Browning]

Great conversions, Chuck. I like the colors on the Picasa (a dcraw-derivative) one too.

I didn't see the 2.3EV worth of headroom on this raw.

I'm not surprised. Few photographers have ever even seen a raw histogram; only what that has been processed (and mangled) by their converter (or camera). That's why I used Rawnalyze: it lets one see the *true* histogram, before white balance, black clip, gamma, tone curve, etc.


(That's reason why I shoot UniWB, which allows me to see the true histogram in-camera and get +2 or +2.6 more exposure, which means a ton less noise without clipping, among other benefits.)

I used three raw converters andnone neededan EV adjustment.

The optimal exposure is totally disconnected from the amount of EV adjustment needed to achieve a pleasing brightness. Generally, the optimal exposure is "as much as possible without clipping highlights" (ETTR). For this image, the exposure could have been increased 2.3 stops without clipping. Then in post production, one reduces exposure by -2.3 EV to get the brightness back to the desired level. (But since raw converters never show the raw histogram, no one ever realizes that they have so much headroom.)

[Colin]

Ah, so are you saying that, in terms of dynamic range and detail, it's generally better to overexpose and then dial back in the raw conversion?


One question on the raw conversion....


For web display, i'd assume that we'd be looking at sRGB or what have you. If that's the case, shouldn't all of these images look similar? Or were we supposed to download them and then view them not in the web browser, or do some web browsers support embedded color space information?

[Chuck Lee]

Daniel,


Thanks for the pat. I did learn something today. I was glad I waited until I got home to look at some things before I posted. I was amazed to see those images on my new HP monitor. Obviously, we're all not seeing the same thing when it comes to high gamut renderings like these red flowers. On my HP2275w there is no visible clipping that I can see in the OP's image.


So Picasa uses a dcraw derivative for thier engine. That's interesting. I've heard that name many times. Can't say I've used it, but It's got quite a reputation along with RawTherapee (I think that's it).


Any way, I'm a SilkyPix diehard. It just flat out works for me 99% of the time. It's nice to see the differences with ACR and something as simple as Picasa from time to time. Helps keep my SP output honest and serves as a good scale for hard to render photos like this one.


Colin, Each RAW converter will render the RAW data slightly different from one another. I'll let Daniel do the in-depth. The originals are for anyone who wants to check the gradients up close and personal. If you really want to see something wild, develop this CR2 with ACR 4.4 or higher along with the Canon camera profiles. Standard, Faithful, Neutral, Landscape, etc. The outputs are miles apart when pushing a red gamut this hard. sRGB is as good as all the other color spaces when developing for the web.


That's why I'm curious as to which output renders the most true. I'd like to think that SilkyPix does. At least for me, 90% of the time it's really faithful at rendering accurate color output.

[Colin]

Daniel,


Colin, Each RAW converter will render the RAW data slightly different from one another. I'll let Daniel do the in-depth. The originals are for anyone who wants to check the gradients up close and personal. If you really want to see something wild, develop this CR2 with ACR 4.4 or higher along with the Canon camera profiles. Standard, Faithful, Neutral, Landscape, etc. The outputs are miles apart when pushing a red gamut this hard. sRGB is as good as all the other color spaces when developing for the web.


That's why I'm curious as to which output renders the most true. I'd like to think that SilkyPix does. At least for me, 90% of the time it's really faithful at rendering accurate color output.
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My only experience in rendering raw data is with DPP and Adobe Lightroom.


According to the Canon descriptions, Faithful is the only rendering option that is accurate. Neutral is compressed in color space to minimize clipping and expects generous post-processing. Everything else is a stock enhancement preset. I played with lightroom for awhile, but while I subjectively liked a few renderings better in their effect, I couldn't get images that looked much like the 'Faithful' initial settings on DPP.


Something, though, bothers me. While I'm all for tweaking images for the best representation of what we want to present, if different software takes the same data and, by default, presents a drastically different image in the same color space, then, technically speaking, I would think that means that they can't all be right, i.e., most, if not all of them, are wrong.


I think I'll put these more advanced raw rending methods on my long term wish list, along with Photoshop and more sophisticated noise reduction software. Need more time for this.... [:P]

[Daniel Browning]

Ah, so are you saying that, in terms of dynamic range and detail, it's generally better to overexpose and then dial back in the raw conversion?

Yes. When most folks do "ETTR", they don't realize that they are only doing ETTR for the JPEG on their camera, which is easily two stops off from the raw data (as in this case).

For web display, i'd assume that we'd be looking at sRGB or what have you.

Correct.

If that's the case, shouldn't all of these images look similar?

As Chuck said, the differences are due to different converters and different settings. Colors that can't be displayed in sRGB (such as the true saturated red of this flower captured by the raw file) can still be *mapped* to a similar color in sRGB. (Just as you can't take a picture of the sun and print it on paper that is bright enough to blind people: you have to "map" the brightness of the sun to a lower brightness on the paper because the paper just isn't capable of reproducing the natural world.)

Thanks for the pat. I did learn something today. I was glad I waited until I got home to look at some things before I posted. I was amazed to see those images on my new HP monitor. Obviously, we're all not seeing the same thing when it comes to high gamut renderings like these red flowers.

Yes, cheaper monitors and laptops (like my Macbook Pro) do an especially poor job. I'm using a NEC 2490WUXi, which has very good reproduction of sRGB.

On my HP2275w there is no visible clipping that I can see in the OP's image.

Pull it into photoshop and isolate the red channel to see the clipping. There are many areas with no detail (253+). The blue and green channels are fine, which is why we can still see some detail in those areas.

Of course, most monitors will show even more of it as blown (including blue and green channels) even though it isn't.

sRGB is as good as all the other color spaces when developing for the web.

I would add that most computers/browsers aren't color aware and so cannot deal with anything other than sRGB. But it would be possible to upload a 16-bit tiff that has a color space with a very wide gamut (e.g. BetaRGB) so that nothing was clipped in the image *file*. But to view it, the display has to convert it to sRGB anyway, and so it will get clipped. So unless it will be printed, it's better to do a quality conversion to sRGB (and avoid clipped colors) during raw conversion.

Daniel,

http://photography-on-the.net/forum/...d.php?t=485349

Is there any validity to this one. Like that poster, I'm lazy too.

Yes. Those instructions will often get your Uni-WB within 1/3 stop, which is close enough for most folks. The best method takes a little more work, but you only have to do it once in the life of the camera:

http://www.dpreview.com/forums/read....ssage=31582853

One of these days I'm going to try to build a Custom Picture Profile that does a reverse sRGB curve like so:

http://www.dpreview.com/forums/read....ssage=31842306

That would allow the histogram to be linear instead of gamma, which is much easier to see and use.

If your taking about the green cast white balance for accurate raw histograms,

Yes, that's precisely it.

I tried, but just couldn't get use to it.

The way I do it is to switch back and forth, because color is obviously an important part of composition.

The biggest thing that I keep messing up on is forgetting to shoot a white/gray card at the beginning of session.

Just make sure all your subjects wear something white. ("I hereby award you this commemorative white ribbon in honor of UniWB Awareness Day.")

We would all have a better idea of what color those red flowers really are!!

Indeed. One of those mysteries that keeps our interest. ("Were those skies really that purple? Or was it just Velvia film? We'll never know.")

Something, though, bothers me. While I'm all for tweaking images for the best representation of what we want to present, if different software takes the same data and, by default, presents a drastically different image in the same color space, then, technically speaking, I would think that means that they can't all be right, i.e., most, if not all of them, are wrong.

That's certainly a valid way to look at it. Technically, they're all wrong. All that matters is the one that gets in wrong in the most pleasing way.

[Chuck Lee]

Colin,


I personally like SilkyPix. I started using it when I shot Pentax.I'm use to it and can get alot out of my photos. Most of the time I can pull around 1 to 2 ev out of blown highlight land. I don't shoot for that, but can use it if it's there. I find most photographers that shoot in raw find a particular program they like andworks for them.Raw rendering color accuracy is a subjective game that requires a bit of practice with ones chosen program. Once a confidence level is reached, it is very hard to switch to something else. Look at Bryan's photos. His color is as consistent across all images as any photographer I've ever seen. It is more than obvious that he knows "his" workflow. Whether, raw or in-camera, if you know what the output is going to look like based on the control variables you can get repeatable results and feel confident with what you are doing. Heck, just try shooting the same scene in JPEGusing the in camera scene modifiers; Standard, Faithful, Landscape, etc. and you will see all the variationthat the built-in raw processor can offer. Which one of those is right?


So, Take your time.......it's alot to digest.


Later...

[Chuck Lee]

(That's reason why I shoot UniWB, which allows me to see the true histogram in-camera and get +2 or +2.6 more exposure, which means a ton less noise without clipping, among other benefits.)

Daniel,


http://photography-on-the.net/forum/showthread.php?t=485349


Is there any validity to this one. Like that poster, I'm lazy too.


If your taking about the green cast white balance for accurate raw histograms, I tried, but just couldn't get use to it. Most of the time, under normal conditions I shoot 40D at +.3ev and the 5D no-comp. I use center weighted alot but find that evaluative works best most of the time on my 5D. I try to set custom WB based on conditions and shoot with "K" selected WB. I find that 5000K is a great place to park!! I try to shoot "to the right" in high ISO and that works pretty good.


The biggest thing that I keep messing up on is forgetting to shoot a white/gray card at the beginning of session. Man, I could save myself hours of post time if I'd just remember that one silly little thing. If I could get in the habit I'd spend 70.00 on a Gretag color chart and use that as well!


And this is good advise to the OP to practice doing when shooting flowers, etc. I suspect 4600 Kelvin is just a bit cool for that scene. A white/gray card could have really helped there. We would all have a better idea of what color those red flowers really are!!