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Author Topic: Edit Tiff vs. Raw - what do I lose?  (Read 26081 times)

meyerweb

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Edit Tiff vs. Raw - what do I lose?
« on: September 18, 2011, 09:53:04 pm »

OK, I know that, in general, I should do as much editing as  possible against the raw file (using LR3) and convert to another format only if exporting for some other use.  BUT...

Many plug-ins, including the NIK plug-ins that I really like, output a new file as Tiff or PSD. So yes, I do as much editing in LR3 before using the plug-in.

But I noticed recently that Nik suggests a workflow for Dfine that calls for doing NR before doing any other edits. Now then, Dfine might not be all that much better than the NR in Lightroom, but let's assume this is an example of a more general case.

So if I run Dfine first, I then I have to apply all my edits to a Tiff or PSD file.  What do I lose compared to doing them on a raw file?

I'm assuming that if I edit an image in a plug-in, LR applies all the edits prior to passing the data to the plug-in.

Thanks.
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Kenneth Sky

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #1 on: September 19, 2011, 08:43:13 am »

I'm glad you asked this question. It's been the elephant in the room. I'm waiting as well for the answer from one of our experts.
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KeithR

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #2 on: September 19, 2011, 10:20:00 am »

Simple. Use the MUCH improved noise reduction in LR3!
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digitaldog

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #3 on: September 19, 2011, 10:31:48 am »

Basically none of these third party plug-ins do anything specifically useful in LR. They render out the raw and apply them as if you exported the data and used their siblings in Photoshop.

So its about workflow. When do you want to draw the line in the sand and stop instruction based (parametric), totally non destructive editing workflow? I can’t answer that for you. I can say I see nothing at all useful in these products because they may force me to render data before I want to. I might use them if I’m 100% sure I’m done processing the raw data and ready to render. I understand that as the raw processors improve (we just saw a major quality leap in PV 2010 over PV2003), I may want to re-render the data which means any editing thereafter has to be redone.  Once you render data, the raw processing capabilities are over, you can’t get that toothpaste back into the tube. Its fast (instruction based), high bit, wide gamut, applied in an optimal order, allows iterations (Virtual Copies) with virtually no overhead etc. For those reasons, I use as much of the raw tools as possible.
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PeterAit

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #4 on: September 19, 2011, 11:00:38 am »

As I understand things, it's a mistake to think that you are ever actually editing the RAW file. A raw file does not contain an image, it contains camera sensor data that can be processed (rendered) to create an image. So, when you view a raw file in LR, what's really happening is that LR is using it's default rendering settings to process the raw data to create the image you see on screen. When you "edit" a raw file in LR, the raw file is not changed, but the processing instructions are changed (and thus the on-screen image changes).

Bottom line, then, is that when you do NR in LR, you are not working on the raw file but on the current, on-screen rendering of it. So, once you understand this, I think you can see that your question does not really make sense. LR's NR is really good, you - or at least I - rarely need anything more.
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meyerweb

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #5 on: September 19, 2011, 12:08:40 pm »

Thanks to all.  Yes, I understand the LR3's NR is very good.  That's why I said let's look at it as a more general case regarding plug-ins.  I understand what's been said above, and I understand the workflow advantages of parametric editing,  but still have the basic question:

In terms of flexibility, capability, range of adjustment, quality of results, etc., when changing things like color temp, exposure, curves, color balance, lens corrections, etc. are the results going to be the same (or at least comparable) when working on a tiff file as when working with raw?  Or does working on a tiff file impose limits on what can be done to an image in LR or the quality of the output? Is the benefit to working with raw files in LR primarily workflow, or is there a benefit in terms of image quality, too?

If I apply a plug-in, from Nik or anyone else, create a tiff with the output of that plug-in, and then proceed to do more edits in LR3, will that impact what I can do with the image (not the workflow).

I'm not trying to justify not using raw files; I'm just trying to understand how LR3 works with non-raw files compared to raw.

Thanks again.
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bjanes

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #6 on: September 19, 2011, 12:20:46 pm »

As I understand things, it's a mistake to think that you are ever actually editing the RAW file. A raw file does not contain an image, it contains camera sensor data that can be processed (rendered) to create an image.

A raw file contains an image just as does a TIFF. The raw image contains data in a mosiac format, whereas the TIFF uses a separate channel for each of the RGB components. Shown below is a straight dump of a raw image as shown by Rawnalize--it looks to me like an image. However, it needs to be demosiaced by a raw converter just as the three separate channels of a TIFF need to be combined in Photoshop.

Regards,

Bill



If you look at a lower magnification, the image outlines can be better seen:

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Peter Stacey

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #7 on: September 19, 2011, 12:29:30 pm »

The workflow aspects aside, if you generate a tiff with a plug-in, you can continue to work on that further in Lightroom using the same tools that you would have used if you were still working with the converted RAW.

In terms of quality when working on the tiff, it's difficult to give a definite answer because it's not possible to know what you might do to an image before generating the tiff; and not being familiar with the NIK plug-ins, I don't know if they generate 8 or 16 bit tiffs. If they are producing 16 bit depth tiff's, then in general, you should probably be ok, but you never know, there might be something you want to do to the image and it breaks.

For the other aspects, it's not as flexible or capable and you won't have as much latitude for adjustments as with the original RAW data.


« Last Edit: September 19, 2011, 12:44:51 pm by Peter Stacey »
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digitaldog

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #8 on: September 19, 2011, 12:32:51 pm »

In terms of flexibility, capability, range of adjustment, quality of results, etc., when changing things like color temp, exposure, curves, color balance, lens corrections, etc. are the results going to be the same (or at least comparable) when working on a tiff file as when working with raw? 

In a word, no.
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Jeremy Roussak

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #9 on: September 19, 2011, 12:53:45 pm »

So its about workflow. When do you want to draw the line in the sand and stop instruction based (parametric), totally non destructive editing workflow? I can’t answer that for you. I can say I see nothing at all useful in these products because they may force me to render data before I want to. I might use them if I’m 100% sure I’m done processing the raw data and ready to render. I understand that as the raw processors improve (we just saw a major quality leap in PV 2010 over PV2003), I may want to re-render the data which means any editing thereafter has to be redone.  Once you render data, the raw processing capabilities are over, you can’t get that toothpaste back into the tube. Its fast (instruction based), high bit, wide gamut, applied in an optimal order, allows iterations (Virtual Copies) with virtually no overhead etc. For those reasons, I use as much of the raw tools as possible.
Andrew, thank you! I have a gut feeling of unhappiness whenever I render a shot, for whatever reason, and find myself fiddling with it back in LR. I'm pleased to hear that it might not be entirely fanciful.

Jeremy
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dmerger

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #10 on: September 19, 2011, 12:58:47 pm »

Is the benefit to working with raw files in LR primarily workflow, or is there a benefit in terms of image quality, too?

Maybe a few tests will help answer the question.   Make a copy of a RAW file.  Develop both copies in LR with all adjustments zeroed out.  Render one copy as a Tiff (ProPhoto 16 bit).  Then, make identical adjustments to the RAW file and the Tiff in LR.  Such a test should give some indication whether the end results of LR adjustments are different for RAWs versus Tiffs.
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Dean Erger

Peter Stacey

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #11 on: September 19, 2011, 01:02:43 pm »

Maybe a few tests will help answer the question.   Make a copy of a RAW file.  Develop both copies in LR with all adjustments zeroed out.  Render one copy as a Tiff (ProPhoto 16 bit).  Then, make identical adjustments to the RAW file and the Tiff in LR.  Such a test should give some indication whether the end results of LR adjustments are different for RAWs versus Tiffs.

It's not really a test that works that well, because you can't extrapolate the results beyond the test images you use. The results only tell you about the images you test, nothing more. Further edits might be OK in one image with one set of adjustments, but not be OK on another image or with another set of adjustments.

And that's not to say you should never render a tiff or psd out of Lightroom. If you have to, you have to. LR is not a complete replacement for Photoshop and there are many legitimate reasons why you might want to edit at the pixel level. It's just, if you can achieve something as easily in LR working with the RAW data, then that is the most flexible and least destructive approach to your workflow.
« Last Edit: September 19, 2011, 01:17:19 pm by Peter Stacey »
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dmerger

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #12 on: September 19, 2011, 01:22:23 pm »

It's not really a test that works that well, because you can't extrapolate the results beyond the test images you use. The results only tell you about the images you test, nothing more. Further edits might be OK in one image with one set of adjustments, but not be OK on another image or with another set of adjustments.

Peter, what you say is true, obviously.  However, as an analogy, it's not possible to prove a scientific theory, yet people do experiments all the time.  For example, no one has proved the theory of gravity.  No one has disproved it, either, but no one can be certain that another experiment might some day disprove the theory.

My point being that a few test images could prove that LR handles RAWs differently than Tiffs. Or the tests may show no difference, in which case I'd say you still learn something.  If you do more tests and still see no difference, you learn more, but of course such tests can never prove that there will never ever be any difference.   ;)
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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #13 on: September 19, 2011, 01:29:22 pm »

This thread makes me wonder whether I've been doing what I thought I was doing in my workflow.

I use DxO Optics Pro as a preprocessor to perform its automagical measured optical corrections for my various sensor-lens combinations, and have it configured to emit a DNG file, which I then open in Lightroom.  Presumably, Lightroom invokes the Adobe Camera Raw module to render it.  (If I open the DNG produced by DxO in Photoshop, the initial display is ACR.)

My assumption was that I wasn't losing any of the raw file's luminance data along the way.  Obviously, some of the information must be shifted around a bit as part of the DxO optical munging, but I haven't been thinking of that as a loss so much as compensation for the optical deficiencies of the camera.

I realize that without knowing the internals of the DxO product, it probably is impossible to determine whether any useful data are being dropped on the floor.  But assuming DxO actually is doing only what I have configured it to do -- i.e., just the optical corrections and no other image processing -- is there any reason to suspect that I am providing Lightroom with any less information than it would have if it was parsing the camera manufacturer's raw file directly?

Chris

Peter Stacey

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #14 on: September 19, 2011, 01:40:23 pm »

Peter, what you say is true, obviously.  However, as an analogy, it's not possible to prove a scientific theory, yet people do experiments all the time.  For example, no one has proved the theory of gravity.  No one has disproved it, either, but no one can be certain that another experiment might some day disprove the theory.

My point being that a few test images could prove that LR handles RAWs differently than Tiffs. Or the tests may show no difference, in which case I'd say you still learn something.  If you do more tests and still see no difference, you learn more, but of course such tests can never prove that there will never ever be any difference.   ;)


Totally agree with the basic principle. To take the scientific argument further, in testing a hypothesis, you don't try to prove your own theory correct, but generally try to show that it fails, or that the null hypothesis (opposite view) is correct. By eliminating the alternatives, you draw a stronger argument to show that your original hypothesis has general application as a theory.

The only difference I would have is that I wouldn't view a few images as being a sufficiently large sample size, particularly given the variables involved. If you want to draw some general conclusions, you would have to test lots of images.

But that's taking the thread totally off topic.

I will still premise my view with the fact that it's quite possible to work with tiffs and psds without breaking them. Even before smart objects came to Photoshop, we used to work on tiffs and psds without breaking them. But, it's less flexible and the files may have less latitude for adjustment, so if you can do something equally well in LR with it's tools, there's not much need to produce a tiff. If you can't do it as well in LR with its tools, then you might not have a choice but to use a plug-in.
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digitaldog

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #15 on: September 19, 2011, 01:48:22 pm »

I use DxO Optics Pro as a preprocessor to perform its automagical measured optical corrections for my various sensor-lens combinations, and have it configured to emit a DNG file, which I then open in Lightroom.  Presumably, Lightroom invokes the Adobe Camera Raw module to render it.  (If I open the DNG produced by DxO in Photoshop, the initial display is ACR.)

My assumption was that I wasn't losing any of the raw file's luminance data along the way.

That DNG is rendered (demosaiced) data. So no, you are not sending the actual raw data from DxO to LR in the same way as simply using the original data (or converted DNG) in LR. Keep in mind that a DNG can contain rendered data. No different from a TIFF.
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fdisilvestro

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #16 on: September 19, 2011, 01:55:55 pm »

is there any reason to suspect that I am providing Lightroom with any less information than it would have if it was parsing the camera manufacturer's raw file directly?

Chris

DNG files produced b DxO Optics Pro are not really Raw files as the ones that come out of the camera. First, they have been interpolated and demosaiced, since that's the only way for DxO to apply the optical corrections.

These DNGs still are not completely rendered files, that's why they open in ACR. Compared to Tiff's, they are not color space encoded nor gamma corrected.

You could assign a camera profile and perform white balance and color space encoding as in a RAW file in LR/ACR.

An important note is the way blown out highlights are treated when using this workflow: the resulting DNG don't have those highlight at saturation (equivalent to 255 in 8 bits) meaning that if you perform white balance in LR/ACR and then apply highlight recovery, your highlights may result non neutral. In this case you should perform white balance in DxO before producing the DNG.

More on this thread

Slobodan Blagojevic

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #17 on: September 19, 2011, 02:01:10 pm »

... it's not possible to prove a scientific theory, yet people do experiments all the time.  For example, no one has proved the theory of gravity.  No one has disproved it, either, but no one can be certain that another experiment might some day disprove the theory....

So, from a practical standpoint, you are saying that some day some guy might jump from a tall building and... not fall to the ground?

hjulenissen

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #18 on: September 19, 2011, 02:36:59 pm »

Basically none of these third party plug-ins do anything specifically useful in LR. They render out the raw and apply them as if you exported the data and used their siblings in Photoshop.

So its about workflow. When do you want to draw the line in the sand and stop instruction based (parametric), totally non destructive editing workflow? I can’t answer that for you. I can say I see nothing at all useful in these products because they may force me to render data before I want to. I might use them if I’m 100% sure I’m done processing the raw data and ready to render. I understand that as the raw processors improve (we just saw a major quality leap in PV 2010 over PV2003), I may want to re-render the data which means any editing thereafter has to be redone.  Once you render data, the raw processing capabilities are over, you can’t get that toothpaste back into the tube. Its fast (instruction based), high bit, wide gamut, applied in an optimal order, allows iterations (Virtual Copies) with virtually no overhead etc. For those reasons, I use as much of the raw tools as possible.
I want a plugin api in lightroom that allows 3rd party plugins to "hookin" to the pipeline at any given point, and do its thing on the fly.

This might mean that re-rendering in Lightroom is slowed down for certain plugins, and that one LR database cannot be exported to another LR installation without having the same plugins installed, but I can live with that...

-h
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digitaldog

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Re: Edit Tiff vs. Raw - what do I lose?
« Reply #19 on: September 19, 2011, 02:38:06 pm »

I want a plugin api in lightroom that allows 3rd party plugins to "hookin" to the pipeline at any given point, and do its thing on the fly.

So do I (and an anti gravity machine). I don’t expect I’ll get my wish anytime soon.
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