The Fallacy of the "JPEG+Raw" option (Page 3): Thank you for the information. It is interesting how some of us (me included) blindly accept a certain combination of settings and never...

dave sproul Loc: Tucson AZ

Thank you for the information.

It is interesting how some of us (me included) blindly accept a certain combination of settings and never question why?

JohnFrim Loc: Somewhere in the Great White North.

Perhaps I have missed some details, but if shooting only RAW, how do you set the ideal exposure for either ETTR or EBTR? Do you simply push the histogram to the right? Is the histogram being displayed still only relevant to a JPEG or is it now restricted to only the RAW file? Can blinkies be used as a quick setting guide?

Uuglypher Loc: South Dakota (East River)

JohnFrim wrote:

Perhaps I have missed some details, but if shooting only RAW, how do you set the ideal exposure for either ETTR or EBTR? Do you simply push the histogram to the right? Is the histogram being displayed still only relevant to a JPEG or is it now restricted to only the RAW file? Can blinkies be used as a quick setting guide?

Hi, John,
ETTR is simply the JPEG exposure that is just short of clipping highlight detail in a JPEG file. Whether you use the blinkies or the histogram as your most accurate index of ETTR depends on your camera. In my Sony A77 the histogram is dead-on accurate...far more so than using the blinkies. In my Sony A99 it's exactly the reverse.

Happily, both of my Sonys have an ERADR of one and 2/3 stops (which help reduce confusion regarding which camera is in-hand when adding ERADR!)

And yes, the histogram display is still relevant ONLY to a JPEG file. The histogram frame reflects ONLY the DR for a JPEG file. It simply serves to help you decide when you've reached the ETTR exposure, at which point you add the pre-determined exposure stops of ERADR (extra raw-accessible dynamic range).

There are other alternatives:
It should be noted that some folks us a gray card incident light reading to extrapolate to the ETTR exposure... and thence to EBTR. Some who are most comfortable with the Zone System of Exposure use a spot reading of the brightest detailed highlights (Zone viii) to render them in Zone V, and then extrapolate to EBTR. Different strokes....

I hope this helps.

Dave

JohnFrim Loc: Somewhere in the Great White North.

Yes, it helps, and thank you for the clarification.

Uuglypher Loc: South Dakota (East River)

magnetoman wrote:

Crikey! I certainly feel informed Dave! A very int... (show quote)

Hi, Dave,
Glad to hear the info is proving helpful and is not unduly overwhelming. I can easily understand how it could be!

Dave

Uuglypher Loc: South Dakota (East River)

dave sproul wrote:

Thank you for the information.

It is interesting how some of us (me included) blindly accept a certain combination of settings and never question why?

Hi, Dave

Join the club, we all, under some circumstances, simply accept some "stuff" simply because it's most convenient at the moment to do so. I recall an aphorism from my youth in the Lancaster County Pennsylvania Dutch country: "Ve gets too soon oldt, und too late schmardt!

Best,
Dave

steve_stoneblossom Loc: Rhode Island, USA

Just curious. Have you compared histograms of identical images shot raw only and raw + JPEG?

repleo Loc: Boston

Uuglypher wrote:

Hi, repleo. br Thanks for your questions; they let... (show quote)

Thanks Dave. You weren't unclear, but this information is new to me and I wanted to make sure I understood it correctly. Great to know.

Uuglypher Loc: South Dakota (East River)

steve_stoneblossom wrote:

Just curious. Have you compared histograms of identical images shot raw only and raw + JPEG?

Hi, Steve,
Not for the almost twelve years that I've been shooting either Raw captures by ETTR or EBTR or occasional JPEGs ( out of necessity)

I recall that back when I was trying JPEG+raw the histograms were roughly comparable in the computer after download. You can see the pre-normalization and post-normalization histograms of ETTR and EBTR images earlier in this thread.

Do you have some of interest to the discussion?

Dave

kymarto Loc: Portland OR and Milan Italy

Loss of 50 to 75% or more of tonal or color spectra? That sounds like a gross exaggeration. Please tell us how you arrived at that figure.

Uuglypher Loc: South Dakota (East River)

[uquote=kymarto]Loss of 50 to 75% or more of tonal or color spectra? That sounds like a gross exaggeration. Please tell us how you arrived at that figure.[/quote]

Hi, Toby,
Thanks for joining in.

Given that the brightest available stop of exposure contains half (50% , if not more...) of its bit-depth's contribution of tonal and chromatic spectrum (depending on how much of the lower reaches of the DR was used...) -and that most cameras (about 70% of those tested) have AT LEAST one full stop of ERADR (if not more)... then for each stop of available exposure sacrificed , there is loss of 50% or more of its bit-depth's contribution. If two full stops of ERADR are sacrificed, the the loss is 75%. If two and 2/3 stops of ERADR are sacrificed, the loss is beyond 75%. And if the choice was also to expose to the left, well, you do the math.

Thus, if I were to fully expose my raw captures according to the JPEG histogram, Each image would have testified to sacrifice: one and 2/3 stops worth of tonal and chromatic spectra (somewhere between 50% and 75%) provided by their 14 bit-depth. To my mind, I'd rather not waste that much of the potential contribution of the sensor of a camera, 1/2 to 2/3 of the price of which supposedly went to the cost of the sensor.

This is all based on the twice-as-much /half-as-much relationship between full stops upon which we base so much of our exposure theory and practice.

The 2004 white paper by Bruce Fraser ""RAW Capture, Linear Gamma, and Exposure" is quite illuminating.
http://www.adobe.com/digitalimag/pdfs/linear_gamma.pdf

Dave

neilds37 Loc: Port Angeles, WA

Linda From Maine wrote:

Though I have been following some of the ETTR discussions, this is the first I have read on why not to choose jpg and raw for the same shot. Really interesting to know, Dave, and will definitely affect future photo ops. Thank you!

(my reason for shooting jpg+raw to date was purely a convenience thing - viewing the jpgs in Picasa prior to choosing which raw file to edit in PS Elements via ACR and the other software I have.)

The Faststone Image Viewer views and can edit RAW files, and has a vastly superior editor than Picasa, (IMO). When in the viewer with a full-screen image move the cursor to the very top, and a strip of the folder's thumbnails appears. Move the cursor to the extreme right, and the EXIF appears, move cursor to extreme right and editing options appear, move cursor to extreme bottom and a selection of various utilities appears.

Free download. Give it a try.

neilds37 Loc: Port Angeles, WA

Appreciate your taking the time to put this together, Dave. I just now moved my camera from jpg+Raw to RAW only.
Cheers,

DirtFarmer Loc: Escaped from the NYC area, back to MA

neilds37 wrote:

The Faststone Image Viewer views and can edit RAW files...

I had always thought that Faststone just worked on the embedded jpg in the raw file. However, I looked at the faststone.org site and they have a raw library to enable them to use the actual raw data. At least that's how I interpreted their site. I don't use Faststone, so I can't say how well they do at raw editing, but it appears to be there.

I have been using IrfanView for a long time (before Faststone came out) so I have no real incentive to use Faststone. IrfanView has convenient navigation tools that I use a lot and I haven't found similar things in Faststone (space bar/backspace key for shifting to the next/previous image in a folder). The navigation tools may be there -- perhaps I just haven't spent enough time with Faststone to find them? I use Lightroom/Photoshop for the raw editing.

IrfanView and Faststone started out (as far as I can tell) as image viewers, and the editing capability was added later. I think LR/PS has much more capability in the editing department. However, LR/PS take a long time to load, while IrfanView/Faststone load very fast which makes them very useful for just viewing photos.

Uuglypher Loc: South Dakota (East River)

neilds37 wrote:

Appreciate your taking the time to put this together, Dave. I just now moved my camera from jpg+Raw to RAW only.
Cheers,

Thanks for your support, Neil.
I' ve broach the topic within a number of threads over the past few years, but I've become more and more irritated at various comment I read about the relative merits of 8-bit depth, vs. 12-bit depth vs. 14-bit depth vs. 16-bit depth formats regarding the relative numbers of tones of gray and hues provided by each format...with no mention that those figures are true only when the entire available dynamic range is utilized in the exposure.

We all should know from experience with the JPEG-adjusted in-camera histogram frame (the width of which represents the entire dynamic range allotted to JPEG) that the brightest stop (the right half of the histogram frame) provides 50% of the available tonal and color spectra. The next brightest stop ( half of the remaining half of the frame) provides 25% ...and so on...until we get over to the far left where the darkest stop may provide only 4 or 8 almost black gray tones.

Well, the same applies, with the same proportions but vastly different tonal and color numbers to the maximum DR available for the different bit-depths of raw image data captures... which the camera manufacturers cannot accurately state...because of "process variance" in production of silicon-based semiconductors (including our cameras' sensors). Each camera thus must be individually tested for how many more stops of exposure or parts thereof are available for raw exposure.

So...all this put together suggested that a thread was overdue dealing with specifically how use of the JPEG + RAW option is a very misleading "convenience" as regards the image data quality captured.

Best regards,
Dave