Since Lightroom is so good, what do you use Photoshop for?

Started 6 months ago | Discussions thread
MiraShootsNikon
Contributing MemberPosts: 624
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Re: Actually . . . .
In reply to ttbek, 5 months ago

ttbek wrote:

MarkJH wrote:

ttbek wrote:

MiraShootsNikon wrote:

Ron AKA wrote:

MiraShootsNikon wrote:

Ron AKA wrote:

Dave Stott wrote:

This is a strange dialogue. Lightroom doesn't alter pixels 'cos a RAW file doesn't have any pixels. ACR likewise doesn't create a pixel based file till you exit it.

A RAW file has to have pixel data. That is basically what it has captured from the pixels in your sensor. Just look at the metadata for a RAW file, and it will tell you the height and width in pixels, and total pixels. What it doesn't have is a physical dimension such as inches. So there is no resolution in pixels per inch, just dimensions in pixels.

RAW processing is the business of assembling groups of red-green-blue pixel data from your camera's sensor into single pixels of a given color.

I think we said the same thing. My only point was that the RAW file contains pixel data. All the rest is very interesting, but not relevant to the point that the camera sensor captures pixel data, and the RAW file is a digital recording of it.

No. We are not saying the same thing.

You seem to think Bayer RAW "pixel data" and interpolated raster "pixel data" are basically the same idea or concept. They aren't. You're talking about entirely different kinds of pixels employed for entirely different purposes, manipulated in entirely different ways.

It's not "irrelevant" that Bayer RAW data, if you could "see" it, would look nothing like an interpolated raster image. It's not "irrelevant" that the tools one might use to manipulate such different kinds of data work differently, produce different results, for different reasons.

You're caught up on the word "pixel," here, and choosing not to see the forest for the trees. Your argument is essentially this: "Any language that uses the roman alphabet is really just the same language. It's all just letters."

Actually... you seem to be under a misconception MiraShootsNikon. While it is true that the RAW processors interpolate the RAW data, this is done as the very first step. So essentially, step one is to take any language using the Roman alphabet and translate it, after that it's all the same language and worked with the same way. In other words, they do end up being manipulated in exactly the same way with differences being only in that first interpolation step, which I have not seen any RAW developer expose any user adjustable options for. Dave Stott is a bit off the mark, RAW editors do not create an image file until exported, but they do keep a rasterized intermediate file in RAM which is what all the manipulations occur on that is based on as you say "interpolated raster pixel data." So yes, lightroom does alter pixel data, just not of the source (and neither does any other program as long as you don't overwrite your original file). If you don't believe me you can go look at the source code of some of the open source RAW converters (and yes, I am quite sure the closed source ones are not doing things drastically differently).

But I think, ttbek, that you aren't giving Mira enough credit. For two reasons:

(a) Her original post, above, did observe that both Lightroom and ACR generate a raster preview that reflects changes made as users employ them; and

(b) your post *assumes* that proprietary converters don't perform operations any differently than the open source code you've seen--but if that were true, then proprietary conversions wouldn't look so much better than most of the open source conversions I have seen!

If you're going to say that I would like to see actual examples. Also, when I say it's not drastically different, I mean the methodology, not the fine tuning. I'm curious just which programs you are referring to and if you're dealing with the Bayer interpolation step, or what happens after.

Samples wouldn't have much to say about the fact that you're using knowledge of free code you have seen to describe the workings of proprietary code you haven't.

Also, it's pretty easy to see how distinctly different RAW converters approach their job: we have examples in every single DPReview camera overview, in which they show us the differences (at 1:1) between results from the reviewed camera's OEM converter and Adobe.

Frankly, I don't believe it that Lightroom or ACR work as you say--that they make a raster conversion and then simply push the pixels of that conversion according to your edits. And here's my evidence: if what you say were true, then Lightroom's heal / clone operations could look identical to those from Photoshop. But Adobe has gone on record many times saying that Lightroom's clone-heal operations are limited to what they can currently process from RAW interpolation. They aren't in other words, simply pushing pixels on a raster intermediate. Sure, that's what's happening with the preview you see in the program itself, but when you export, your changes are actually baked straight from a novel RAW interpolation.

I was going to write a second post addressing things like this. There are portions of RAW converters that rely on extracting more of dynamic range, etc.. which isn't your standard jpeg format. For reasons like this a RAW converter needs to preserve it's order of operations (operations are actually applied in one order, not matter which order you chose to apply them in), which in turn means that there are limitations on things like cloning. So, yes, I wrote that first post hastily. Things like changing exposure will grab info from the RAW differently (but does not change how they do the Bayer interpolation). Other things, like sharpening, will be basically identical in both programs. If that last part you said were true, then what you see and what is exported would have greater differences than they do.

What's interesting, to me, is that you acknowledge that there is a difference between the working Lightroom / ACR preview and the raster export. Your explanation of how these tools work makes most sense only if there is no difference, because you are essentially arguing that the working preview is the final conversion.

Now, I do understand that the "RAW intermediate held in RAM" you describe would supposedly differ from the ACR / Lightroom preview in the sense that the preview is a JPEG with a compression / render quality you can control, while the "RAW Intermediate" you describe would presumably not be a compressed JPEG. But I don't want to make your argument for you--maybe you'd say that it is.

However, your suggestion that there are limitations on how Lightroom / ACR might push this "RAW Intermediate's" pixels with cloning / healing because of the "order of operations" sounds pretty vague, to me. Like you're reaching, ya know? Because if there's a bit mapped image in RAM full of full-color pixels ready to be manipulated, then we really should have every Photoshop clone / heal / patch option and all of those tools' quality available in Lightroom. Unless Adobe is justly lying / bull$hitting us for some bizarro reason.

I really think MarkJH sunk your battleship with that one, dude.

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