Any use in 8bit JPG to 16bit TIFF conversion?

If you shot a JPG instead of RAW (damn it!), and you want to process the photo

in PS (contrast, levels, color balance and saturation, sharpen...), would it be

better to convert it to 16bit TIFF before all the manipulations? Thanks.

Sorry, but you won't gain a thing with that conversion.....

.

 

Just load it on screen and convert to 16-bit, then save as TIF or PSD - try layers and PSD for fum!

 

You'll never get back what's already been lost in the original JPG camera output, so be forgiving of yourself, and don't expect too much!

 

Show us some samples - before and after.

 

And shoot RAW from now on! ;-)

 

Click!

 

Love and hugs,

 

Peter Blaise peterblaise@yahoo.com Minolta RAW Photographer http://www.peterblaisephotography.com/

You've already lost information in saving as a JPG. Converting to 16-bit TIFF won't bring any of that information back. However, it can prevent you from losing even MORE information if you plan on editing and resaving the images in the future.

 

steve

When you do lightening or darkening of an area with a feathered edge this is certainly going

to be a good idea, because in 16 bit the gradients calculated will be smoother. Actually all

gradient manipulations will benefit from converting an 8 bit file into a 16 bit version prior to

manipulation. I alwas turn 8 bit files into 16 bit before I make any changes to it. The

difference in end results is quite easy to spot.

Steve and Erik. Thanks for your answers. They are exactly what I was hoping for.

If you shot as large/fine jpeg it is likely, that given good exposure technique, you have as

good an image as you would have converting from RAW. Converting the 8 bits to 16

before processing in an image editor will give smoother results than working with just 8.

Converting to TIFF is a good idea to prevent damage on subsequent saves.

 

The camera's processor translates the 12 bit data from the sensor to 8 bit jpeg in a non

linear fashion. There is little loss and you are saved the time and trouble to risk screwing

up the RAW process. That is what I take away from repeated readings of Ken Rockwell's

site and trying it both ways myself.

 

If one can get exposure correct with slide film, one can do the same with digital. RAW, it

seems, is for those who can't or who like to endlessly mess around with things instead of

making more images. There is nothing wrong with messing around. Just don't despair over

having shot jpegs; unless, of course, your exposures are for crap. :)

 

Cheers

 

Jim

Cognitive dissonance is a psychological phenomenon first identified by Leon Festinger. It occurs when there is a discrepancy between what a person believes, knows and values, and persuasive information that calls these into question.

 

"Converting the 8 bits to 16 before processing in an image editor will give smoother results than working with just 8. Converting to TIFF is a good idea to prevent damage on subsequent saves."

 

"RAW, it seems, is for those who can't or who like to endlessly mess around with things instead of making more images."

 

 

--

 

Don E

I disagree with everything James just said. You do not convert to a 16 bit workspace as it is too much of a stretch for 256 tomes to be spread out to 65,536.

 

If one feels people shoot raw as a safety net for exposure over jpg, they really haven't had the print experience and perhaps shouldn't be flying the jpg flag. You've bought a really nice camera and it took a great deal of effort to get the manufactures to start allowing us to shoot in raw. The benefits of 16 bit vs 8 bit capture are touched on here, and also why you shouldn't go to 16 bit from 8.

 

http://www.peimag.com/pdf/pei03/pei0506_03/caponigropei0506_03.pdf

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Thanks, folks, for adding to my "Photo Fallacies" list!

 

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"... repeated readings of Ken Rockwell's site ..."

 

... WILL make you go blind!

 

As he says himself, he's a photographer, not a writer, but he writes anyway!

 

To quote my own earlier response to Ken Rockwell from:

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00HMcl

 

[begin quote]:

 

"How to read Ken Rockwell 101"

 

Ken Rockwell is a photographer, a photographer who also writes on the web for his own entertainment. I find three disparate elements in his writing, although I find he mixes them all together indiscriminately, and therein lies the rub, I find that people seldom sift the wheat from the chaff when referring to Ken Rockwell's writing. Here are the three elements to his writing that I find:

 

1 - experience

 

Ken Rockwell is a photographer, and when he writes about his own experience, I find it useful at least as a reference to compare to my own experience, and sometimes he gives voice to something I've yet to put into words. Good.

 

2 - speculation

 

Ken Rockwell keeps right on writing even though he has no experience of the topic he is writing about, like his post on [a camera he's never used]. He admits he's never seen one or used one, and since he already has his own DSLR gear, he's not even interested in the [camera], but ... he keeps on writing nonetheless as if he were writing about the camera or his experience of it! But, since he has no experience of it, this part of his writing becomes messy and not so referential. Bad.

 

3 - provocative

 

Ken Rockwell likes to provoke and does not hesitate to poke anyone in the eye. I've not spent much time looking at his pictures, so I can't say as much for his photography! Rather than explore things uninteresting to him, he dismisses them summarily, often with an insulting moniker. Again, nothing referential here. Bad.

 

As I say, the problem with referring anyone to read Ken Rockwell is the lack of clarity as to when he's writing about his own experience, speculating, or merely provoking for effect.

 

[... end quote.]

 

 

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"... RAW, it seems, is for those who can't or who like to endlessly mess around with things instead of making more images ..."

 

RAW is the most resources you can capture with your camera.

 

Period.

 

Why capture less?

 

Did ANYONE desire to capture less than possible with film CAPTURE - use only APS ISO 800 film?!?

 

I don't get the drive *down* to lowest possible DISTRIBUTION standards for digital CAPTURE?!?

 

Perhaps an analogy best served is JPG = ISO 800 6x4" print, RAW = ISO 100 19x13" print? Still a horribly inaccurate and incomplete analogy, but close. Okay, I've printed JPG to 19x13" and I must say the PRINTER did a fantastic job. If Ken Rockwell shot Polaroids, I'd think he'd like JPG.

 

"... RAW ... is for ... endlessly mess around with things ..."?!?

 

RAW IS QUICK: With RAW, I can do an immediate straight conversion to output using my favorite converter -- http://www.irfanview.com/ for Windows is FREE, but many, many RAW converters abound -- and do nothing but accept in-camera defaults, just like JPG but KEEPING a high-bit, un-lossy original.

 

RAW IS FLEXIBLE: Unlike JPG, and more like en-developed film, I can go back in moments, or years, and re-develop my RAW for any reason. Those of us used to revisiting our negatives over time should LOVE RAW since it not only allows us to revisit our negatives, but also allows us to RE-DEVELOP them, as it were, in a different solution. As Ansel Adams loved about sheet film, each RAW "negative" can be developed in it's own way, over and over, differently as out software and our skill set grows.

 

RAW is freedom, JPG is death.

 

=====

 

"... Cognitive dissonance -- when there is a discrepancy between what a person believes, knows and values, and persuasive information that calls these into question ..."

 

I presume you mean "trust your own experience" and ignore Ken Rockwell?

 

=====

 

"... Converting the 8 bits to 16 before processing in an image editor will give smoother results [when making subsequent tweaks] than working with just 8. Converting to TIFF [upon first save] is a good idea to prevent [additional] damage on subsequent saves [as would happen with JPG] ..."

 

My experience exactly. Apparently also the experience of many others. I'd love to see examples of images that ANYONE has that contradict that experience!

 

=====

 

"... do not convert to a 16 bit workspace as it is too much of a stretch for 256 tones to be spread out to 65,536 ..."

 

Huh?

 

Look at the histogram immediately after converting from 8-bit into 16-bit per channel, and then look at the histogram after any tweak and then try to sell THAT fallacy to yourself!

 

ANY adjustment, especially curves or exposure compensation results in w-a-y less posterization in 16-bits per channel than the same adjustments in 8-bit. For scientific purposes, try the exact same tweaks in 8-bit and 16-bit versions of the same file and not only look at the histograms of each, but layer the results on top of each other and look at Photoshop's DIFFERENCE mode, and of course, print out as large as you can with each and inspect to see what matters to you. Okay, some printers (4-ink, 2,400dpi or less especially) may not show much difference. Much, but even there, difference show for me. Moving along to a 6- or 8-ink 5,400dpi printer and wow, how smooth is the 16-bit and how posterish is the 8-bit ... my experience anyway!

 

=====

 

Momo, once in 16-bit, do a sub-pixel gaussian blur -- 0.1 or 0.2 or 0.3 or so on to 0.9 pixels -- to smooooth out the histogram, although any curves or exposure adjustment once in 16-bit per channel will also smoooth out the histogram. Anyone: try the same thing in 8-bit and see if THAT makes you as happy as the 16-bit experience!

 

Click!

 

Love and hugs,

 

Peter Blaise peterblaise@yahoo.com Digital Photographer since w-a-y back when TIFF WASN'T owned by Adobe! http://www.peterblaisephotography.com/

 

Raw is the negative and jpeg is the print. Sure it is easier and more convenient to order 4x6 prints from a shop and then toss the negatives to the bin. No need to waste time messing around in the darkroom either.

"... Cognitive dissonance -- when there is a discrepancy between what a person believes, knows and values, and persuasive information that calls these into question ..."

 

"I presume you mean "trust your own experience" and ignore Ken Rockwell?"

 

Peter

 

KR's a good example of CogDis based on your righteous rants 8-)

I haven't read him.

 

I refer to (among other things) jpeg shooters throwing away image capture data (16bit raw), then recommending padding out the jpeg with empty bits (a 16bit tif) in order to get "smoother" results in PS.

 

It is kinda screwy thinking -- which is another way to say "cognitive dissonance".

 

 

Regards,

 

Don E<div></div>