M8 Uncompressed 14-bit DNG

Neither dynamic range or signal-to-noise ratio would be affected. For M8/9 cameras at ISO 640 and below, thrse characteristics depend primarily on the exposure (light reading the sensor when the shutter is open) and the analog technical characteristics of the sensor's photo sites (quantum efficiency, full-well capacity, read noise) and the ADC read noise. Above ISO 640 the data stream read noise increases for reasons I don't understand.

The difference, if there is any, would be in the quality of changes in tone and color throughout the image.

Many companies use non-linear, lossy compression for raw data. The idea is if you only compress highlight regions, the discarded information mostly eliminates shot noise. In essence the non-linear lossy compression filters the shot noise from the brightest regions in the image. This can not improve the analog signal to noise ratio, but it can make bright, featureless areas such as the sky or water appear smoother. If you are going to discard information by implementing lossy compression, you might as well choose the least useful information. Besides, the mathematical model for shot noise is unambiguous. So one could even add the shot noise back into the image (of course no one does this).

It turns out SONY may need to improve their lossy raw compression. There are endless posts on other photography forums demonstrating and complaining about IQ degradation in SONY's raw, lossy-compression algorithms.

Everything I've read reports Leica's lossy raw compression methods do not have a significant impact on most images. I know from personal experience the same is true for Nikon. No doubt other brands also use lossy raw compression that has little or no effect on rendered IQ.
 
tom.w.bn said:
The question is: did someone really observe a noticeable difference? I invested a lot of time and found exactly 0% improvement in dynamic range or noise.
Click to expand...
That is not surprising. The (standard) decompressed M8 files behave much like 12-bit files ( like Nikon) albeit a bit stepped because of the LUT, which makes no difference in real life. One has to be exceedingly critical to find a significant difference in result between a 12-bit and a 14-bit file.
My guess is that the real advantage of this app is the raw conversion itself, involving dead pixel line handling, shadow detail and colour, etc.
 
Great tool!
Now 1250 is perfectly usable, even in color. Noticed no difference at 160 or 320, but 640+ results in much less noise and better colors.

Only if someone could modify the firmware to have RAW mode available after power off....
 
So I've noticed some recent threads and posts suggesting people still like the M8 (including me). Now, I'm curious if anyone is still doing anything with the 16(14)-bit raw files possible with the M8 after the "button dance"?

While I do love my M8, I continue to have disappointment with higher ISO, and sometimes loss of highlight detail that I don't get with other digital systems that I sometimes use (Nikon DSLR and micro4/3). I'm not sure if high ISO can be addressed by using the 14-bit files, but highlight detail does seem to benefit from their use.

However, 14-bit on the M8 means: button dance, no power-off, and conversion to DNG (software linked in this thread) before PP in Lightroom. That's not trivial.

So, I'm in a phase where I'm doing the button dance every time I pull out the M8. Its a pain because the setting isn't saved (we lose it whenever there is a power-off) and I wrestle with the value of the hassle. Of course, that's until I get a rather nice image that (in my head at least) seems nicer in tonal gradient and highlight detail than the 8-bit version would have been.

So: Who else? Anyone? And how about high ISO?
 
Another of Arvid's discoveries is shooting everything at ISO 160 Raw and letting the Photoshop or other processor handle the image. There are some wonderful shots on the Leica forum showing how well this works. I've been doing it for about a month now and it's made the M8 a useable tool for low-light shooting. You do have to keep the M8 set at ISO 160. Doing it this way gives very decent - no noise - shots at the equivalent of 2500 and higher. You can use it on automatic exposure if you set the compensation at -3 or you can just meter independently. It works, and works well. Thanks, Arvid.
 
Interesting presspass.
So, if I'm using the aperture priority mode (I often do), I can set the exposure compensation to...say -3 and I'm in essence shooting at ISO 1250? I get to that as 3 steps off from 160 (160 -> 320 -> 640 -> 1250, but of course thats not necessarily actual "stops"). And then I slide "exposure" up in postprocessing? I'm excited to try this... Do I have this right?

High ISO noise is probably my greatest dislike with the M8. I'd love to find a way to reduce that.
 
That's how it works. Adobe CR makes the adjustment automatically when you open the raw file. I've also tried it with Capture 1 LE that comes with the camera, but that doesn't work as well. Keep in mind, when you look at the image on the camera screen, it looks bad - too dark, etc. The info button will also indicate vast underexposure. You won't be able to tell what the photo looks like until you open it in Camera Raw. Give it a try; it's turned the M8 from a very occasional tool into a camera I can use every week shooting for a chain of small weekly newspapers and the papers' website. I've even shot high school basketball with it - no flash - and it works. Not as well as the Canon DSLR, but it does give good images.
 
I am just starting to try this underexposure method with my M8, recalling discussions here about doing the same with the M9. I have set User Profiles #2 for -2 stops compensation, and Profile 3 for 3 stops. Lightroom does adjust exposure on DNG import, usually overdoing it on the + side. Interested to see how this works out.
 
Using the M8/M9 cameras in DNG mode as if they were ISOless works because the data shows Leica uses a two stage analog amplifier.

There's data published on LULA and on this blog-scroll to the bottom for the summary (for the M9) that shows Using ISO 160 and pushing the exposure in post-processing produces the best analog signal-to-noise ratio. The most significant benefit is observed in shadow regions. The M8 has a similar data stream design.

In any case, the decrease in signal-to-noise ratio becomes much worse above ISO 640 (when the second ISO DC signal amplifier kicks in).

Since I only use raw, I typically use the lowest possible ISO setting with all my digital cameras and increase exposure in post-processing. At base ISO (a sensor system's native gain) the analog dynamic range is achieved. This technique is not appropriate for many Canon cameras because their analog-to-digital converters require high signal levels and the signal-to-noise ratio actually improves as ISO increases.

The M-P 240 CMOS data stream behaves as SONY, Nikon, FUjifilm, etc as it has a single-stage signal amplifier and a high-performance analog-digital converter. The only reason to underexpose and increase brightness in post-processing is when the scenes dynamic range challenges the analog data stream's dynamic range.
 
OK, now I'm excited. Have the camera with me at work today....going to try out some low-light shots and see how things go. Doug, I like the idea of setting up User Profiles as surrogates for ISO settings. This could all work out quite nicely.

I do hope Lightroom will manage the exposure increase nicely. I don't have ACR or Capture 1. Lightroom has met my very amateurish needs so far.
 
I would love to use this to improve the M8s files, and have several goes without success. Full kudos to the guy who wrote the software. I hate to be rude but I take it he does not have English as a first language. The explanations on his web page do not help. (They may assists a programmer but not someone who is just a user. What is needed are concise examples step by step)

I have downloaded the file for my operating system (Windows 8) and I have unzipped the downloaded zip file which produces two files - one labelled lensdb.ini, the other M8RAW2DNG.exe. So far so good. But then my understanding goes to crap.

Also I have opened a command prompt in Windows and tried to get it to point at the directory where the M8raw2dng.exe file is located (which in my case is C:\Users\Peter\Downloads\M8 JPG_RAWCONVERSION TOOL\m8raw2dngv11win) but I just get an error message. I did this by copying and pasting the address of the directory from the address bar of my PC then appending the name of the exe file to it so the command line would point to the exe file itself.

His web page talks about "droplets" which seems to be some other tool which runs in conjunction with the above tool but there is no download link and the instructions about using them are even more arcane.

For example these instructions are meaningless to me and I have no idea what is required.
  1. change the path in the line set TheApp="C:\Path\To\The\Executable\m8raw2dng.exe" to where your m8raw2dng executable is
  2. change the line set Params= -b -p -v -r -c -o "C:\Path\To\Pictures\" as you wish (see below)
  3. change the line set NoParams= -b -p -v -r -c as you wish (see below)
So failure all around. I take it that to someone versed in the technicalities of computers this is child' play. To ordinary mortals who have to intuit whats required, its near impossible.


Can someone please provide a step by step instruction on whats needed? Many thanks.

Yours in frustration, Peter
 
Peter_S said:
Interesting discussion. Any follow-ups on noise and higher ISO? I may use an M8 again for a photo project, higher ISOs are needed.
Click to expand...

Yes, I my reply was incomplete. Use raw and never exceed ISO 640. Then push the raw rendering brightness during post-production.

The M8/9 camera read-noise contribution increases above ISO 640. The lower noise levels at ISO 640 result from the use of two-stage analog signal amplification between the sensor and the ADC. The switch to the second stage occurs above ISO 640.

ISO only brightens the image after the shutter closes. Your project requires the sensor to be underexposed (shutter speed is too high for the ambient light).

Here is a general description of this method that applies to shooting raw in low light that applies to all digital cameras.
 
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