my point is really about what is simply impossible to do once you've left raw.Impossible : restoring crushed blacks or blown whites (this actually includes moderate-to-heavy white balance changes, as it changes tonal values of individual color channels)
...Do yourself a favor and try LR4!
I'm using the raw converter that came with my pentax k20d. I don't do any adjustments in there because it isn't very good. I do all my adjustments in Picture Window Pro once the raw file has been converted to tiff.
I recently read about highlight recovery. This makes it clear that there is information in the raw file that can only be recovered by the raw conversion process and that is then lost or not available once the file has been converted to tiff.
Apart from this highlight information, is there anything else that can only be done on the raw file and which would be lost/unavailable once you've moved to tiff? What can good raw converters do that a good photo editor simply cannot? I was happy with my toolset but now at least I realise I'm missing some of the highlight information that is in my raw files but not in the converted tiffs.
Thanks
Anthony
When you make the RAW conversion you basically only take a slice of the data contained in the RAW file, and thus loose part of the color and luminance adjustment possibilities available there. Thus all further adjustments in PS are restricted to that information content and can be only subtractive. For this reason all basic adjustments should be done in RAW, before conversion. Lightroom 4.2 is an amazing tool for this, I really have stopped using Photoshop almost totally, only if I need local blurring etc. Better results with LR 4.2, faster.
I'll say it again, RAWs are tiffs ... Otherwise working in tif is safe.
People have mistaken what is lost taking a 12 or 14 bit tif to 8 bit jpg as the "baking" process that also affects tifs. As Erik said, when you do raw conversion you add a 2.2 gamma log factor so that can lose data if you push it past 255. Otherwise working in tif is safe.
Even if one's digital camera could capture a vast dynamic range, the precision at which light measurements are translated into digital values may limit usable dynamic range. The workhorse which translates these continuous measurements into discrete numerical values is called the analog to digital (A/D) converter. The accuracy of an A/D converter can be described in terms of bits of precision, similar to bit depth in digital images, although care should be taken that these concepts are not used interchangeably. The A/D converter is what creates values for the digital camera's RAW file format.
Erik - you say data is lost if you set black and white points at raw conversion time. What if you don't? What if you simply demosaic without adjusting black and white points and move straight into an RGB TIFF image editor (e.g. Photoshop) ? Is any data lost in that case? Is there anything I can no longer do (i.e. impossible as opposed to just less convenient) ?Most conversions from raw to "developed" would include at least:
Hi Tony, you're correct that I don't own Lightroom but my point is really about what is simply impossible to do once you've left raw. For example, I can't believe there is anything you can do with regard to printing from the raw file that couldn't just as well be done from a tiff file, and choice of printing application would then come down to personal preference. Whereas with highlight recovery, that can only be done to the raw file.
Thanks
Anthony
no it does not... in a typical raw converter "speak" recovery is not about "data is there" ( in a region with clipped raw channel(s) ), recovery is about postprocessing to paint (note that it is not a part of the raw conversion exactly) that part (where you have clipping) of an image using the data from unclipped raw channels and/or the data from surrounding areas in that image to make that area (where you have clipping) suitable/acceptable to your intended visual objective
Petrus - lots of people say as you say, but why? It sounds like the similar advice given about scanning in the "olden days" - do all your adjustments in the scanner software. I think this was mostly because photoshop in those days was mostly limited to 8-bits, but the myth hung around for much longer even when photo editors had better support for 16 bit files.
Fine-art - Vladimirovich is, I'm sure, correct in what he says, but it doesn't change the argument. I believe that the raw processor can recover/paint highlights to "unclip" them by using information that only exists in the raw file (by examing the raw luminance information in adjacent pixels). Once the raw data has been converted, the photo editor will not be able to do this "painting". Hence, highlight "recovery" as performed by Camera Raw, can only be done during the raw conversion phase and cannot be done afterwards (I think).
Anthony
The point of a raw file is to retain as much information possible about the signal coming from the camera sensor. The point of a developed file is usually to "look good". What is the point in trying to make a bastard that is neither?
tlooknbill - I don't understand your last sentence in your last post at all.
If you really want to be particular about data loss you need a program that uses scientific image formats. This will avoid losing rounding errors in image manipulations making operations truly reversible.
I use an astronomy program Images Plus which can do RAw conversion to 32 bit floating point fit format. This is widely used in scientific imaging.
http://fits.gsfc.nasa.gov/fits_viewer.html (http://fits.gsfc.nasa.gov/fits_viewer.html)
If you really want to be particular about data loss you need a program that uses scientific image formats. This will avoid losing rounding errors in image manipulations making operations truly reversible.Floating-point implementation does not avoid round-off errors, consequently arithmetic implemented in float32 is generally not "truly reversible".
I use an astronomy program Images Plus which can do RAw conversion to 32 bit floating point fit format. This is widely used in scientific imaging.
http://fits.gsfc.nasa.gov/fits_viewer.html (http://fits.gsfc.nasa.gov/fits_viewer.html)
If you really want to be particular about data loss you need a program that uses scientific image formats. This will avoid losing rounding errors in image manipulations making operations truly reversible.
That would make very nasty banding.
Can you show us some practical examples where using a 32bit FP implementation you were able to achieve a visibly superior results?
Its really limited by the ability of the person. All image editing functions can be done in 32 bit floating point space. You will never get combing.
No, it does not have a "secret sauce" function that makes your image wonderful. You have to do it, as in know what you are doing with luminance and color curves, etc.
Maybe people should look at http://clarkvision.com/ (http://clarkvision.com/), his site is what got me into using the program. He uses it.
Ok, Here is my first HDR attempt in this program. I had to spend a fair amount of 1/2 hr figuring out how to do it.
This was a 3 shot bracket on a bobbing ferry hand held to the window. The image is nothing special, it was just an opportune shot to pass time. You can see a black edge around 2 sides where the shots had to be aligned. I could have done translate and rotate but it was fast enough I don't think there was much rotate.
The whites were badly clipped in one shot. The whole lower tree area was black or near black in the other. You get the idea. It was done in part of the time since the prior post.
Now, we have all seen many gross HDRs put on the web for display as final images. This looks pretty realistic considering it was a fast cobble together with a lot of time spent trying to align the shots.
ImagesPlus is an excellent but specialized program. It is more suited for processing of astronomical images than for general photography and is often used for sensor analysis using raw files. However, it is less suitable for general photography. Among other considerations, it does not appear to be color managed. It converts my D800e images into an untagged color space. ACR/LR (among others) is better suited for general photography. What about printing with profiles and softproofing?
Iris (http://www.astrosurf.com/buil/us/iris/iris.htm) is another astronomical program favored by techies for analysis of raw files. It can split the CFA image into its channels (RGGB), perform mathematical operations, and perform demosaicing, WB and gamma corrections. It also does Richardson-Lucy deconvoluiton and VanClittret filtering. It also is not color managed. For general photography, I will stick to ACR/LR.
Regards,
Bill
Now show how the 32 bit floating point benefited the image which was the reason for asking you to post examples.
It converts the file as straight linear data. Gamma is under the color menu, you have to do it yourself.
You are absolutely right it is not good for going to print. It will not understand a color calibrated screen. It will not provide a soft-proof for printing. You will have to send the document to another program for that. I have always used PS for that.
Gamma is easy enough to do, but you seem to miss the point that ImagesPlus in not color managed. Do you render into ProPhotoRGB? And what camera profile do you use.
Bill
ImagesPlus is an excellent but specialized program. It is more suited for processing of astronomical images than for general photography and is often used for sensor analysis using raw files. However, it is less suitable for general photography. Among other considerations, it does not appear to be color managed. It converts my D800e images into an untagged color space. ACR/LR (among others) is better suited for general photography. What about printing with profiles and softproofing?I suggest MATLAB. Most anything that can be done to a dataset in a usual programming language (such as c++, java and whatever photoshop is implemented in) can be done in MATLAB. The trade-off is that implementation effort is lower, while execution time is higher. There are specialized "toolboxes" for e.g. image processing. It even defaults to 64-bit float precision :-)
Iris (http://www.astrosurf.com/buil/us/iris/iris.htm) is another astronomical program favored by techies for analysis of raw files. It can split the CFA image into its channels (RGGB), perform mathematical operations, and perform demosaicing, WB and gamma corrections. It also does Richardson-Lucy deconvoluiton and VanClittret filtering. It also is not color managed. For general photography, I will stick to ACR/LR.
Regards,
Bill