Jpeg or RAW ( & Why) June 2013

Started Jun 8, 2013 | Photos thread
GeorgianBay1939
GeorgianBay1939 Veteran Member • Posts: 4,044
Re: Straightforward answer to your question

walkaround wrote:

gardenersassistant wrote:

walkaround wrote:

... there is no such thing as a "Raw version of the image".

Hmm... I think we'll have to agree to differ about that. Presumably you didn't mean that literally.

What can you "differ" about? A Raw file is a sensor dump, not an image file. "Open" (convert) it in 4 different photo applications, and all 4 will render a different jpeg to show you on the screen. This is basic stuff.

When I go here (and other places) to try to get a definition and description of RAW files.

http://en.wikipedia.org/wiki/Raw_image_format

I find that the file contents contains information in addition to sensor data (dump) which is required to demosaic the sensor data to produce some sort of imagery, TIFF, JPEG or whatever. There are lots of very technical discussions in this forum and other relating to just what those proprietary RAW formats contain. Way beyond my pay grade.

... there is no such thing as a "Raw version of the image".

Would it be more correct to say RAW format of the image?

Am I nit-picking or is there something substantive in the difference in terminology?

Fair enough. We have different opinions. No problem there.

It does leave me curious though as to where this line of thinking might lead. Suppose I capture a scene with my SX240, which can only capture a relatively low dynamic range. And suppose that capture has highlights which are blown in the JPEG file but recoverable from the RAW file of that exposure. Because a greater dynamic range has been compressed into the fixed range expressible in JPEG format the “recovered” image will look grey and flat compared to the un-recovered out of the camera version. Let us suppose it is now sufficiently grey and flat looking for you to regard it as having an "HDR look".

Suppose that the same scene is now captured with another camera, and the JPEG file delivered by that camera does not have blown highlights (and for the sake of argument let's suppose the two JPEG files extend the same amount into the shadows). Will the second JPEG image not look just as grey and flat as the “recovered” version from the SX240, even though it has not been "recovered"? So presumably you would in that case regard the out of the camera JPEG version as having an "HDR look"?

This makes me wonder where you would draw the line as to how much dynamic range can be expressed in JPEG format before an image takes on an "HDR look". Would I be right in thinking that where a camera can capture a large dynamic range (a full frame camera for example), its JPEG images should in your opinion have their highlights blown in PP and or their shadows pushed to black so that the image covers a small enough remaining dynamic range that it can be expressed in JPEG format without taking on an "HDR look"?

I really have no idea what you're saying here. Actual camera dynamic range is not the same as Lightroom-tweaked dynamic range. Have you used Lightroom much? The "Highlight" slider affects more than just the highlights. Watch the histogram as you move it.

This is what I mean about Raw Religion. You think you can shoot 10 stops from the camera and then add 2 stops in the shadows and 2 stops in the highlights, and now you have a 14 stop DR with no penalty? Sorry my friend.

I shoot RAW and I don't think that I "can shoot 10 stops from the camera and then add 2 stops in the shadows and 2 stops in the highlights, and now you have a 14 stop DR with no penalty"

I haven't the skills, yet, to calibrate just how many stops I am getting while loading the sensor.  I don't understand, yet, the vagaries of tone mapping when I have to convert a 12 or 14 bit file to an 8 bit JPEG image.  And I do not yet, have a clear understanding of the difference between Tonal Range and Dynamic Range, (in spite of reading lots of "opinions expressed as fact" on the internet.) Lots to learn.  I do know that there is no free lunch.

I do know that by shooting RAW,  ETTR and moderately pushing the darks that I can get an image like this one routinely.

Friends enjoying a "polarized" rainbow after dinner last night.  http://www.dpreview.com/forums/post/51638766

I could NEVER do that when I was shooting JPEGS, no matter how I played with exposure, ISO, and a whole slew of in-camera processing settings.  Even  by blowing the cumulus cloud above the rainbow, I wouldn't be able to recover so much of the detail in the faces ...  without putting a lot of blotchy noise into bottom left hand corner.

Perhaps you could clarify what you mean by "RAW Religion"  as I am unfamiliar with the term (or concept.)   Thank you.

Tom

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