To RAW or not to RAW

sinnerjohn

MobiLifer
Messages
13,049
Reaction score
44,564
Real Name
John
Device
Pixel
JPEG from my Pixel: https://drive.google.com/file/d/1nmwJq0QNqLjVb5Pd6hsMAbD5JKO-29qt/view?usp=sharing
TIFF developed with Affinity Photo, optimized with DXO PhotoLab 4 - all you can get: https://drive.google.com/file/d/1MLxYjJDlkBt0B5nNR9lbshAu_YljhZXC/view?usp=sharing

that is in numbers 4MB (8bit/channel, sRGB) vs 70MB (16bit/channel, sRGB). For a real comparison you need to keep the changes as good as possible aligned with the camera image but that's quite hard - I didn't do that. Open the file and have a look at details and exposure...

NOTE: the TIFF file would be the way for print. Of course I did all my processing with my MacBook. ;)
Much better examples Tom, even though not strictly Mobile, but I guess that's your whole point. :thumbs:
 

TomHH

MobiPassionista
MobiSupporter
Messages
942
Reaction score
3,754
Real Name
Tom
Device
Pixel
sinnerjohn John, exactly! Things may look different with an iPad and Affinity Photo mobile, also having a larger screen. But I would always use my MacBook/desktop going for print ...
 

Uuglypher

MobiStar
Messages
124
Reaction score
323
Real Name
Dave
Device
iPhone 11 Pro Max
Left JPEG - right TIFF:
View attachment 166213
at same size
Hi, Tom,
In spite of mag to the pixelated level, examination of the rocky rubble pile beyond the foreground pillings is clearly revealing of the advantage of 12 bit-depth raw>tiff over 8 bit-depth JPEG. Notice the effect of the vastly greater tonal spectrum ( with attendant increase in discernible detail) in the tiff rendition. The basic premise holds true! If you want more image information- go for image files of greater bit- depth! But as I pointed out earlier, the advantage of 12 or 14 bit-depth files is difficult to impossible to demonstrate with small prints or online displays.
Best regards,
Dave
 

Uuglypher

MobiStar
Messages
124
Reaction score
323
Real Name
Dave
Device
iPhone 11 Pro Max
Chris Feichtner (nocamerabag on Instagram) has laid out his LRM raw workflow here:




A couple of notes: He says you have to have the LRM subscription to develop raw files in LRM, but that's not entirely true. In the iPhone version, at least, you can develop iPhone raw files from LRM itself or any other iPhone raw app without needing a subscription. I'd guess it's the same with the Android version. You do need a subscription to develop raw files from other cameras (Canon, Nikon, etc.).

Also, in his workflow, he does use the perspective correction tool in LRM, which does require a subscription. I do that stuff in Snapseed.

There may be one or two other things, but in the main, you can do what he does with the free version.
Good, useful links!
Feichtner’s demo of his Lightroom Mobile workflows are lucid and concise!
Dave
 

Uuglypher

MobiStar
Messages
124
Reaction score
323
Real Name
Dave
Device
iPhone 11 Pro Max
ETTR = Expose to the right. It refers to the shape of the histogram when setting the exposure for a photo. The idea is that to capture the most information/detail in a digital photo, you need to push the exposure as far into the whites (the right end) as you can without clipping, even though that means that the preview you see on your screen while setting the exposure may look overexposed. You get the properly exposed look when you edit.

EBTR = Expose beyond the right. The idea/argument here is that the preview image and histogram you see on screen when setting up your shot are using the JPEG image, which is a processed image. If you are shooting raw, the argument goes, you actually have more headroom in the whites than the onscreen preview and histogram show you, so to make best use of that extra latitude, you need to push the exposure further to the right. The JPEG-based histogram will show that you are clipping, but -- if you judge it correctly -- the raw image will not be clipped.

I did some simple tests of my own and found that my iPhone XS seems to have 0.5 to 0.75 of an fstop available beyond what the histogram shows.
Good basic summary of ETTR and EBTR.
It is important to test each camera for its individual “overhead” ; variation, even among cameras of the same brand and model can vary from 1/3 stop to two and 2/3 stops or more. Also, it is wise to test overhead at each of your favorite, most frequently used ISOs. As ISO is increased, the dynamic range decreases. This is theoretically a linear relationship - But most of our cameras haven’t read the technical literature and you will find it to be distinctly non-linear.
Best regards,
Dave
 

Uuglypher

MobiStar
Messages
124
Reaction score
323
Real Name
Dave
Device
iPhone 11 Pro Max
I’m not actually sure I would process my images on my computer. I have a desktop not a laptop and the quality of the screen is bad compared to my iPad. Images that look great on my iPad look mediocre on my computer screen. I also prefer the apps on my iPad. I do have Affinity Photo but have never sat down to learn the tuning tools on it.

Maybe one day I’ll sit down and really learn to process RAW but at the moment I prefer a wall
Who shoots raw image data captures?
Only those photographers / including smartphone photographers - hoping to capture the maximum image data quality ( highest possible S:N ratio and a 12 bit-depth tonal spectrum of 4096 rather than the paltry tonal spectrum of 256 tones of a piddly 8 bit-depth JPEG image file). That diddly-squat JPEG file might - in a stretch- provide an acceptable 16x20 full frame print, but a properly exposed 12 bit-depth raw capture* will easily yield a TIFF file that prints out at 36”x48” with amazing discernible detail.
But keep in mind that a properly exposed raw capture is a totally different imaging medium from a quotidian JPEG file - and requires a totally different exposure strategy.

A jpeg is exposed by the same strategy as has been used for exposing photosensitive emulsions since the latter half of the19th Century. A subject tone is exposed to produce that same tone in the finished image.

A raw image data capture is properly exposed such that every brightness value in the entire histogram - from darkest shadow detail to brightest highlight detail - has been exposed with the maximum possible number of photons with no saturation of any of the electron wells . “ Expose for the brightest possible image with no clipping of highlight detail; but come as close to clipping as possible without actually clipping!” That’s a totally different exposure strategy from that used for Jpegs and traditional emulsion photography.

The properly exposed raw image file provides an immensely greater potential creative latitude in post processing than can ever be imagined for a JPEG file.

Who shoots raw image files ? Those aware of the above stated principles of optimal raw image data exposure. That’s who (to answer your earlier question).

Dave

of lots of 8in x 8in which is what I am about to do. In that way my images and my DH’s images can both go up without either of us having to sacrifice. Not surprisingly he prefers his and I prefer mine although nice together.
Well, hi there Sinnerjohn, TomHH, and ImageArt, so, yd wanna see proof of the pudding, eh?
Well, you sure won’t get it with display online! And if that’s your level of aspiration re image data quality, I agree that you stick with 8-bit Jpegs for your image display.
But any who decry the ability of a 12 bit-depth tiff file of a raw capture image from any decent 12 bit- depth mobile phone camera to yield a detail and resolution-rich 36”X 48” print to be viewed at NDV of 7 to 9 feet or greater is simply speaking out of ignorance born of inexperience! They have never given it a serious effort!
Best I can do for you is to post three identical tiny crops from a jpeg and two raw> tiff file s that yielded a magnificent 18”X 36” print. Compare the 8 bit-depth jpeg with the ETTR raw exposure and the EBTR exposure that benefitted from the camera’s full dynamic range. Those crops came from the same site in those three image files.
Read ‘em and weep!
Don’t discount the ability of raw image files from smartphones to deliver large prints of exceptional quality.
The nay-sayers who obviously have never actually given it a serious try remind me of the aeronautical engineers who, after careful theorizing, determined that the bumblebee cannot fly!
Best regards,
Dave
View attachment 166191View attachment 166192View attachment 166191View attachment 166191View attachment 166191View attachment 166192View attachment 166191View attachment 166192
additional consideration!:
Even if you are not into large prints from your smartphone images, you may still wish to capture raw image data simply for the creative latitude that the 12 bit-depth files provide. Consider;


JPEG: 8 bit- depth, low signal:noise ratio, 256 tonal spectrum. Millions of colors.

Raw capture 12bit-depth: high S:N ratio, 4096 tonal spectrum, and billions of colors.


From the point of view of potential creative/ artistic latitude in post processing the difference is immense.


A jpeg is a pre-cooked image with relatively minimal opportunity to exert significant imaginative, creative post processing.


The 12 bit-depth raw image data file, if captured using the camera’s full raw-accessible dynamic range (by use of EBTR) is far more than the oft claimed “digital negative”. It is functionally more akin to an infinite variety of as yet I imagined and unprocessed virtual images - including, of course, the image envisioned by the photographer when the shutter was squeezed.

The caution that exposure of a raw capture use the camera’s full raw accessible DR is crucial. For example if a camera’s sensor has a full stop of “overhead” and it remains unused by exposing as for a Jpeg file, fully 50% or more of the image’s potential image data quality (S:N ratio and tonal spectrum) will have been forfeited. Hence the need to know the amount of “overhead” - and to be sure to use it’
Dave
 

Attachments

  • DAD88E52-96A5-41AB-9E0D-CB9931FCF9D3.jpeg
    DAD88E52-96A5-41AB-9E0D-CB9931FCF9D3.jpeg
    345.9 KB · Views: 40
Last edited:

myphotoyear

MobiStarter
Messages
18
Reaction score
53
Device
iPhone 11
For me, I think the main reason to use RAW on the iPhone is for the creative possibilities, rather than Apple making the decisions on what your photo looks like, you can have more control on the output, to as much extent as you want. RAW is something I dabble in rather than use it all the time, but I think anyone with aspirations of doing more with their photography should give it a try. Pixelmator Photo (iPad) is a good one to try with RAW and the auto mode will get you so far without having to spend ages on editing. Can’t wait for ProRAW to be available on more devices not just 12 Pro/Max, as that gives you the best of both worlds!
 
Top