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 raw +jpeg



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June 03, 2015, 09:12:43 PM
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Offline lensoreat

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raw +jpeg
« on: June 03, 2015, 09:12:43 PM »
well,  i need to go to work,  but why are my images when i shoot raw + jpeg,  so different ,   i might understand that somewhat,  but what i don't understand is when i click on the pef file to edit it  ( here the darker images and more detail ) and it comes up either in pdcu, or fs viewer,   the image appears even more overexposed than the jpeg,  not at all like the darker more detailed pef file i clicked on ?  
shouldn't it show up as the darker more detailed image as it appears to me on the computer ?   shot with k200d,  m50/1.7

June 04, 2015, 02:50:17 AM
Reply #1

Offline Pacerr

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Re: raw +jpeg NOT!
« Reply #1 on: June 04, 2015, 02:50:17 AM »
OK, let's do this again.

You've NEVER, EVER seen a RAW image, never will. A RAW file is a data file full'a little 1's and 0's.

What you've seen when you THOUGHT you were seeing a RAW "image" is a RAW file converted by some (probably undefined) JPG processing protocol into a JPG image. (Or sometimes it's a TIFF conversion, but that's fairly rare today.)  Your question should be why's one JPG conversion apparently different than any other JPG conversion.

It's a good bet that at least one of those images is converted according to the JPG selections you've made as preferred default settings in your camera. What that other image looks like depends entirely upon which set of JPG defaults the viewing program has as default conversions from RAW into a viewable image on the screen.  (PDCU, for instance, uses the camera default settings stored in the RAW side bar file.)

Don't ever say "RAW image", say RAW data file, and you've taken your first step toward understanding how to get the most from any RAW file. Think of a RAW data file as an exposed but as yet undeveloped film negative. It can be manipulated in many ways in the development process, but once developed (saved as a JPG) it's frozen in place forever. I can still modify it somewhat during the printing process but I can't ever go back and re-do the development choices.

The advantage of using a RAW file as the seed for a viewable image is that you can always start 'from scratch' with no pre-defined 'JPG limitations' applied to the original file. Even if you change the heck out of the first viewable image and save it, you're gonna save an image file - probably a JPG - and the original RAW file will safely return to whence it came ready to be screwed up again at a future time. You may be able to mess with the JPG file later to some extent but you'll never be able to revert to, or access, the original RAW data you 'threw away' when you save to an image file like JPG or TIFF.

You must also understand that the 'image' you see on most web sites has been 'corrupted' to force fit it into that site's idea of a reasonably compact image file that doesn't consume excessive bandwidth. You don't wanna send your buddies 25 MB snapshots.

« Last Edit: June 04, 2015, 03:08:06 AM by Pacerr »
H2  -  I'm not gettin' any smarter in my old age -- I'm just finally beginnin' to run out of really stupid things to do. Doesn't mean I'm not tryin' though.

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June 04, 2015, 05:02:16 AM
Reply #2

Offline Mike Pearson

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Re: raw +jpeg
« Reply #2 on: June 04, 2015, 05:02:16 AM »
Great explanation Hank  8)

Mike
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June 04, 2015, 10:06:52 AM
Reply #3

Offline Pacerr

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Re: raw +jpeg
« Reply #3 on: June 04, 2015, 10:06:52 AM »
Thanks, Mike.

Or try this, Dave:

I could produce architectural plans for a house (a RAW file) but you couldn't live in it (see it) until you actually interpreted the plans by building with real materials (by making a JPG image of it).

The original plans (a RAW data file) could be used over and over again since there'd be no change to the plans themselves. Each house built from those plans however would be a unique creation (a JPG image) which you could modify somewhat by your interpretive (post processing) choice of materials and modifications. But you could never revert the house (image)  to the original plan except by somehow "un-modifying" it -- and even then it wouldn't be to the plans themselves but to an actual house exactly like the plans.

The JPG image right out of the camera is the first "house" built from the RAW file plan using the camera's default interpretation of the plans intent. Subsequent JPG images are simply subsequent interpretations of the original plans. I'd be as surprised if they were anywhere near identical images as I would if all houses built from one set of plans were identical.


H2  -  I'm not gettin' any smarter in my old age -- I'm just finally beginnin' to run out of really stupid things to do. Doesn't mean I'm not tryin' though.

No trees were killed or injured in the sending of this email, but billions of electrons were really, really agitated.

June 05, 2015, 07:49:37 AM
Reply #4

Offline lensoreat

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Re: raw +jpeg
« Reply #4 on: June 05, 2015, 07:49:37 AM »
" Or try this, Dave:

I could produce architectural plans for a house (a RAW file) but you couldn't live in it (see it) until you actually interpreted the plans by building with real materials (by making a JPG image of it).

The original plans (a RAW data file) could be used over and over again since there'd be no change to the plans themselves. Each house built from those plans however would be a unique creation (a JPG image) which you could modify somewhat by your interpretive (post processing) choice of materials and modifications. But you could never revert the house (image)  to the original plan except by somehow "un-modifying" it -- and even then it wouldn't be to the plans themselves but to an actual house exactly like the plans.

The JPG image right out of the camera is the first "house" built from the RAW file plan using the camera's default interpretation of the plans intent. Subsequent JPG images are simply subsequent interpretations of the original plans. I'd be as surprised if they were anywhere near identical images as I would if all houses built from one set of plans were identical."

--------------------------
thanks for both those explanations,  this above,  and the first one,  pacerr;
    
guess mainly i was surprised a bit when i opened the raw data file ( the house plans ) and it was not the more detailed less exposed shot that showed originally on my computer screen --  
 maybe you can see what i mean by this screen shot,   typical is pef 304 - opened in pdcu ,  and on the far right in the middle behind it sort of,   the darker,  more detailed -( can see more of the detailed clouds in the sky for example-)- smaller pef behind  as viewed on the computer screen after downloading it;  

 in  pdcu ( and faststone viewer as well ) it shows up with less detail in the sky, more exposed,   different than the pef as viewed originally on the computer screen -

i didn't know why the pef file opened in pentax digital camera utility program ,  didn't have all the detail in other words,   and trying to manipulate it various ways with the program ,  admitting i'm no stretch of the imagination,  very good with these programs,  but couldn't really get the detail back to that i had originally seen.  
dave