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I've heard that too. My 5D3 has 1.2.1 (and no ML yet) and I'd be willing to update to 1.2.3 and provide you with a rom dump if I had a clue how to do that. If no one else offers, and you'd like to PM me with instructions or links to instructions for doing a rom dump, I'll give it a shot.

My understanding (and be aware that I'm far from expert...) is that it would just be a matter of flashing the updater firmware in the first post of this thread to get the firmware dumped out to the memory card. I'm not sure where the source code is for that firmware file though so I can't check to be comfortable that it will run successfully/safely on 1.2.3. On top of that, the firmware also turns on the bootflag which currently can't be undone. I'm sure you don't want to enable the bootflag on your camera just yet (it slows down startup/wakeup of the camera and prevents Eye-Fi cards from working) so I'd recommend against you running it. Thanks for the offer though!

Note that you can download the firmware from Canon's European or UK sites without any reverse engineering clause:

http://www.canon.co.uk/Support/Consumer_Products/products/cameras/Digital_SLR/EOS_5D_Mark_III.aspx?DLtcmuri=tcm:14-1098601&page=1&type=download

EDIT: if anyone has a rom dump for 1.2.3 I'll be willing to have a go at updating the stubs...  (I don't want to upgrade to 1.2.3 then downgrade back to 1.1.3 as I've heard a couple of people say that can aggravate the AFMA bug)

What cable do you guys use?

The best cables by far are the ones available from Lindy. Have a look at the cables section here for more information: http://dslrcontroller.com/devices.php

that is the feature which i wanted long time ago,
but could you please edit the script instead of giving a puzzle to us?

Sure. I'd intended for engardeknave to incorporate this into the original post hence why I just posted the changes, but here's a whole copy of the modified script for you. Note I haven't tested this exact version since my local version contains a few other changes that you probably won't want and which I quickly stripped out before pasting, hopefully that didn't introduce any problems:

Code Select Expand


'------------------------------------------------------------------
dim cr2hdrpath,cr2hdrexe
cr2hdrpath="E:\Photos\Utils"
cr2hdrexe="cr2hdr.exe"

dim imgprefix,imgsuffix 'used to identify the files we're processing
imgprefix=""
'imgprefix="DUAL"
imgsuffix=".CR2"

dim movecr2s,cr2targetdir 'whether to move the original CR2 files to another directory
movecr2s=true
cr2targetdir="Dual-ISO"

dim adngcpath,adngcexe,compressdng
compressdng=true
deleteoriginaldng=true
adngcpath="C:\Program Files (x86)\Adobe"
adngcexe="Adobe DNG Converter.exe"
adngcoutputdir="Compressed-DNG"

dim maxprocs,windowtype
maxprocs=4
windowtype=7
'0 Hide the window and activate another window.
'1 Activate and display the window. (restore size and position) Specify this flag when displaying a window for the first time.
'2 Activate & minimize.
'3 Activate & maximize.
'4 Restore. The active window remains active.
'5 Activate & Restore.
'6 Minimize & activate the next top-level window in the Z order.
'7 Minimize. The active window remains active.

'------------------------------------------------------------------

dim inputfolder
if Wscript.Arguments.Count>0 then
  inputfolder=Wscript.Arguments(0) 'command line
else
  inputfolder=InputBox("Enter the path to the dual ISO shots.","Dual ISO Script")
  if inputfolder="" then WScript.Quit
end if

dim objShell
set objShell=CreateObject("Wscript.Shell")
objShell.CurrentDirectory=cr2hdrpath 'no idea why it needs this
dim fso
set fso=CreateObject("Scripting.fileSystemObject")
dim mainfolder
set mainfolder=fso.GetFolder(inputfolder)
dim file,files,filecount
set files=mainfolder.Files
filecount=0
dim cr2dngqueue,adngcqueue,deldngqueue
set cr2dngqueue=CreateObject("System.Collections.ArrayList")
set adngcqueue=CreateObject("System.Collections.ArrayList")
set deldngqueue=CreateObject("System.Collections.ArrayList")

'"adobe dng converter.exe" -dng1.4 -cr7.1 -d "C:\test\output" "C:\test\img_9242.dng"

for Each file in files 'find applicable .CR2s
  if lcase(left(file.Name, len(imgprefix)))=lcase(imgprefix) and lcase(Right(file.Name, len(imgsuffix)))=lcase(imgsuffix) then
    cr2dngqueue.add """" & cr2hdrpath & "\" & cr2hdrexe & """ """ & file.Path & """"
    if compressdng then
      adngcqueue.add """" & adngcpath & "\" &  adngcexe & """ -dng1.4 -cr7.1 -d """ & mainfolder & "\" & adngcoutputdir  & """ """ & fso.GetParentFolderName(file) & "\" & fso.GetBaseName(file) & ".DNG"""
      if deleteoriginaldng then deldngqueue.add "cmd.exe /c del """ & fso.GetParentFolderName(file) & "\" & fso.GetBaseName(file) & ".DNG"""
    end if
    filecount=filecount+1
  end if 
next

if filecount=0 then
  msgbox "No files found! Check prefix and suffix."
else
  runqueue cr2dngqueue,maxprocs,cr2hdrexe

  if movecr2s then
    if not fso.FolderExists(mainfolder & "\" & cr2targetdir) then fso.createFolder(mainfolder & "\" & cr2targetdir)
    ' find any DNG files that were created and move the corresponding CR2 file
    set files=mainfolder.Files
    for Each file in files
      if lcase(left(file.Name, len(imgprefix)))=lcase(imgprefix) and lcase(Right(file.Name, len(imgsuffix)))=lcase(".DNG") then
        fso.MoveFile mainfolder & "\" & fso.GetBaseName(file) & imgsuffix, mainfolder & "\" & cr2targetdir & "\" & fso.GetBaseName(file) & imgsuffix
      end if
    next
  end if

  if compressdng then
    if not fso.FolderExists(mainfolder & "\" & adngcoutputdir) then fso.createFolder(mainfolder & "\" & adngcoutputdir)
    runqueue adngcqueue,maxprocs,adngcexe
    if deleteoriginaldng then runqueue deldngqueue,100,"zzzzzzzzzz" 'don't wait for cmd.exe, might be running for another reason
  end if

  msgbox "Finished " & filecount & " files."

end if

set cr2dngqueue=nothing
set adngcqueue=nothing
set deldngqueue=nothing
set fso=nothing
set objShell=nothing
set objfile=nothing
Set WshShell=nothing

sub runqueue(queue,instances,exename)
  dim WshShell,myproc
  Set WshShell=WScript.CreateObject("WScript.Shell")

  dim line
  for Each line in queue
    waitfinish instances, exename
    WshShell.Run line,windowtype,false
  next
 
  waitfinish 1,exename
end sub

sub waitfinish(instances,exename)
  do
    Set myproc=GetObject("Winmgmts:").Execquery("Select * from Win32_Process where name='" & exename & "'")
    if(myproc.count>=instances) then wscript.sleep 100
  loop while myproc.count>=instances
end sub



' The Adobe DNG Converter supports the following command line options:
' -c Output compressed DNG files (default).
' -u Output uncompressed DNG files.
' -l Output linear DNG files.
' -e Embed original raw file inside DNG files.
' -p0 Set JPEG preview size to none.
' -p1 Set JPEG preview size to medium size (default).
' -p2 Set JPEG preview size to full size.
' -cr2.4 Set Camera Raw compatibility to 2.4 and later
' -cr4.1 Set Camera Raw compatibility to 4.1 and later
' -cr4.6 Set Camera Raw compatibility to 4.6 and later
' -cr5.4 Set Camera Raw compatibility to 5 .4 and later
' -dng1.1 Set DNG backward version to 1.1
' -dng1.3 Set DNG backward version to 1.3
' -d <directory> Output converted files to the specified directory. Default is the same directory as the input file.
' -o <filename> Specify the name of the output DNG file. Default is the name of the input file with the extension changed to ".dng".


Thanks! ... but what would "octave" be :-o ? Also, I guess a higher cs setting is there for reducing color bleeding on edges, or is there anything else it's good for?

Octave is presumably this: http://www.gnu.org/software/octave/

I'd like to propose a new feature - allow any CR2 files that were successfully processed as dual-ISO to be moved out to another directory (same as the compressed DNGs can be). I want this because I typically have all my shots from CF card in one directory (some dual-ISO CR2s, some normal CR2s) and I just want to throw them all at this script and let it sort them out for me. As an end result I want a directory that just contains the DNG/CR2 files that I'll be importing into Lightroom. If the dual-ISO CR2 files stay alongside the non-dual-ISO CR2 files as they currently do then I still have to filter through them manually.

Here's some code to do this. Put this up near the top of the script:

Code Select Expand


dim movecr2s,cr2targetdir
movecr2s=true   'whether to move the original dual-ISO CR2 files to another directory
cr2targetdir="Dual-ISO"   'the subdirectory to move the dual-ISO CR2 files into


...and put this before the   if compressdng then   check:

Code Select Expand


  if movecr2s then
    if not fso.FolderExists(mainfolder & "\" & cr2targetdir) then fso.createFolder(mainfolder & "\" & cr2targetdir)
    ' find any DNG files that were created and move the corresponding CR2 file
    set files=mainfolder.Files
    for Each file in files
      if lcase(left(file.Name, len(imgprefix)))=lcase(imgprefix) and lcase(Right(file.Name, len(imgsuffix)))=lcase(".DNG") then
        fso.MoveFile mainfolder & "\" & fso.GetBaseName(file) & imgsuffix, mainfolder & "\" & cr2targetdir & "\" & fso.GetBaseName(file) & imgsuffix
      end if
    next
  end if


Note that this doesn't run in parallel like the rest of the script but I don't think there'll be any real performance gains from doing so anyway.

The one additional thing that I'd like to see but haven't tried implementing myself yet is to compress the DNG files in place, rather than have them end up in a different directory (so I'd end up with a single directory that I can import directly in to Lightroom).

I took this at ISO 800:

The EXIF says 1600?

This is a little ugly (and perhaps not technically feasible) but what about this:

autoexec.bin checks the camera model on startup. If it's the right camera for the binary, obviously we're all good. If it's the wrong camera, try to find the correct autoexec.bin (eg by looking for 5D3/autoexec.bin). If it finds that, copy that binary over top of itself (difficult/impossible?) and reboot the camera (or flash/beep and hang, to indicate the user needs to power cycle it). If the correct autoexec.bin is not found, boot without ML. There's a pathological case of infinite reboots if someone puts eg a 60D binary in the 5D3 location, hopefully not a big problem in practice.

This way position-independent code can be avoided for the bulk of the executable, one card could work across multiple cameras, and cards that don't have the correct version of ML won't prevent the camera from starting.

Apologies if that isn't practical and I'm just adding noise.

I'm using a custom file prefix for my images, set via the standard Canon menus (5D mark 3). When using dual-ISO I would like to use the "DUAL" prefix instead, but enabling the "Custom file prefix" option in the dual-ISO settings doesn't seem to have any effect. All my dual-ISO images are still prefixed with my custom file prefix. Is that by design or is it a bug? I'm hoping it is a bug...

[magiclantern-v2.3.NEXT.2013Sep20.5D3113.zip]

Thanks Alex,
make zip works beautifully and puts the zip file in the platform directory such as /magic-lantern/paltform/5D3.113
File name is magiclantern-v2.3.NEXT.2013Sep20.5D3113.zip

On my Desktop PC I run Windows and build ML in a VM. What I do is have Dropbox installed in Windows and share the Dropbox folder with the VM. My build script basically calls hg pull, hg update, make etc. On success it copies the output to the Dropbox folder. I then just copy ML across to SD card at my leisure from within Windows (done via a batch file, whenever I get around to inserting the SD card). The interesting part however is I can also trigger my build script remotely. Once the build is complete it automatically syncs across to my laptop via Dropbox. Great for when I'm out in the field and want to grab a current build without having a VM eat all the laptop's resources.

Possibly a bit of a niche use-case but hopefully someone will find the above useful.

+1
I shoot birds.  Mostly been using c1,c2, and c3.  I am now experimenting with M for use with ETTR and it is very useful to get the best exposure.  C1, C2, and C3 are my fast shooting methods and usually will quickly take a few shots in AI Servo plus continuous shooting for sure "killing the shutter" as Audionut puts it.  Since I shoot in AI each photo has the chance of adjusting the focus and also my exposure may change a little.  Some people make consider this improper, but who cares, it gives excellent results because you increase your probability of getting perfect shot.  Excellent Bird photography is 90% being at that magic moment and the rest is having good equipment and knowing how to use it.

Totally agree with all that. I only really apply the above to birds in flight though. If they're on a branch I'll take more time from the outset, then switch to C1/2/3 once I think/hope it is about to fly away.

Once i get a couple of shots I will switch to M mode and fire a few slower shots (AIServo) with AETTR (which I have to enable via ML menu).

Me too - AETTR is great once you've got a shot or two under your belt already and there's time to spend a bit more time to try and get a better shot. Not that it matters but I don't really think of M+AETTR as true "manual". I tend to think of it as a very smart Av/Tv hybrid instead. Manual to me means the camera has no say in the exposure whatsoever, rather than the dial being set to M. Semantics.

When using ETTR use the option to link to Canon shutter, it allows you to quickly change the Slowest shutter speed.  This is very useful when things change rapidly and you do not have time to go into ML menu and adjust Slowest shutter speed: Bird on the ground 1/100, bird in flight 1/2000, etc 

Yep I do already, love it! One thing I was wondering though, is there any particular downside to linking to the Canon shutter? For me at least I couldn't come up with a reason to ever want to turn it off.

Also playing with SNR settings.  I typically use C2 with a +2 EC and use it for back-lit bird-on-a-tree shots.  If you set SNR at 6-2 or 7-2, ETTR will compensate for the backlit situation, I am still paying with this to optimize results.

I haven't had a chance to experiment with that yet so that's good to know, thanks for the tip.

I need to go outside now and shoot some more..

+1

Each ISO is captured with 14bits at best.  It's my understanding that bitdepth (all but) = DR.
But we have 2 captures, that are by design increasing the DR (bitdepth).  We are not just mapping 11bits (9 useable) of signal into a 16bit container with it's greater precision, we are actually mapping 14.5 (or so) bits into a 16bit container.  Here, the greater precision is helping with the accuracy.  Because our shadows which would otherwise be mapped into 1-4bits of tonal precision (in a 14bit container), are now being mapped into a higher bitdepth.

Higher bitdepth is higher accuracy.  And we are mapping actual detail into a higher bitdepth.  Start tone mapping that data (especially the shadow data), and the increased precision will allow much greater freedom.

Well... yes and no. I haven't worked through all the math (and don't intend to) but it's more complex than what you're stating above. For example, mapping 14.5 bits into a 16 bit container makes the accuracy worse. It's similar to the problems faced with representing a decimal number like 0.2 in binary. You end up with 0.00110011... recurring, so have to truncate it somewhere. That introduces roundoff error and you lose some accuracy in the process (yet you gain precision). Of course in some cases that might mitigate the additional quantisation error introduced during the ADC process, in some cases it may make it worse. With regards to bit depth, yes it is somewhat related to dynamic range but again it's not a straightforward relationship since noise plays a very important role too. There's a couple of good articles on the topic here:

http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html
http://francoismalan.com/2011/10/raw-12bit-or-14bit-lossy-or-lossless/

Personally I'm not too fussed about trying to understand exactly what gains and losses there are in terms of accuracy, precision, noise, dynamic range or whatever. If anyone wants to debate it or even prove it mathematically then be my guest but I'm staying out of it. The basic theory is sound and the results of dual ISO speak for themselves which is good enough for me!

I don't understand how the high ISO data is being underexposed?

Sorry, my fault for being sloppy with my terminology. By "underexposed" I meant the process of cr2hdr pulling down the high ISO data by a few stops (and discarding the low order bits in the process), such that it is now exposed correctly.

I get the full time manual thing. I'll do that too fairly often - generally when I have plenty of time such as landscapes, when I know I can't rely on Canon's metering, or sometimes when I don't want the exposure to change (situations like the cloudless days you point out). However I'm not exclusively M, I often prefer Av + EC depending on what makes the most sense (or simply feels right...) to me at the time.

You clearly go to a lot of trouble to avoid being under any pressure in the first place, by determining your exposures in advance as much as possible. That makes sense. I'll do that when I can but for me at least it often doesn't feel practical. In fact I think if I was to do that as standard, I'd spend more time preparing my camera (for shots that often wouldn't even materialise) than I would trying to spot my subjects or simply enjoying the nature I'm in. Even if I was prepared for both sun and shade I am certain I'd miss shots because it simply isn't possible to be ready for everything in advance. Think white birds vs grey vs black birds on bright vs dark backgrounds, shooting into or out of the sun. Any combination of the above or more could and does happen at any time. That's where I think trying to reconfigure full manual on the fly is going to be a curse (for me at least). Here's a concrete example:

http://redyeti.net/extra/IMG_4816.jpg

It's a photo from a few years back but is probably the first time I really became aware of the issue and it gave me a lot to think about afterwards, so I think it's a good case study. When I took this I was lining up for a landscape shot with the sun behind me. The landscape was fairly bright. I was on aperture priority f/16 or so, ISO 100, fairly slow shutter, possibly a small amount of EC. I happened to spot the monkey in my peripheral vision, in deep shade at the time but scampering quickly towards the thin beam of light you see in the photo (it was the sun streaming through a gap in a wall). From that moment I had probably something like 2 or 3 seconds to:

a) turn around
b) change my zoom and frame the monkey
c) increase my ISO
d) open the aperture wide
e) dial in some EC (I should have dialed it down a bit but in fact I overlooked it for this shot, my brain wasn't quick enough to think it through properly. The histogram ended up quite a way right but fortunately didn't blow the highlights - kinda a best case scenario but certainly a bit lucky)
f) change to high-speed continuous shooting and AI servo
g) fire off a burst of 3 shots

Of the 3 shots, only this one caught him with the full backlighting, and it was the first shot in the sequence, the other two were too late. If I was in full manual I'd also have to have changed my shutter speed too which alone would probably have meant I'd have just missed the shot. There would also be a high chance I'd have screwed up the exposure calculation in my head badly enough that it would have ruined the shot anyway. If you can reliably predict and prepare for a situation like this then reconfigure your camera in time my hat is off to you. For me, that's too busy, I'd rather stick with the devil I know which is Canon's metering and override it as needed based on my experience of how it behaves.

Of course the above steps don't apply to me anymore anyway, it is now much quicker and simpler. These days I only ever use AI servo combined with back button focus since it works well in all situations. Then I have preset custom modes to reduce the steps above to the following:

a) & b) stay the same
c) turn the dial to the appropriate custom mode. I have them all set a bit different (eg Av, Tv, M + auto ISO) and constantly fine-tune them but generally they set high-speed continuous shooting, higher (or auto) ISO, high shutter speed, some EC, custom AF tracking options etc
d) potentially override the ISO/shutter/EC somewhat if I think the scene warrants it (generally not required but perhaps one or two clicks of a wheel)
e) start shooting

That reduces my response time to unexpected action to somewhere in the region of a second or so. It has earned me many shots that I don't see how I could have taken any other way. How can full M possibly compete with that in terms of speed in getting set up? There's simply no way. I know I'm at the "mercy" of Canon's metering, but I understand it's behaviour well enough that it rarely causes me serious issue these days.

Note also that I'm only talking about wildlife/action photography. When I'm purely shooting landscape etc, I often take an approach similar to the one you've described. I'm not quite as hardcore though since it can be a tossup for me on whether I go full manual or just Av+EC. For wildlife I'm still going to stick with my current setup, I still can't see the upside to using M sorry.

As for dual ISO... I fully agree with what you're saying about dual ISO making exposure decisions easier due to the increased leeway it gives and I certainly intend to try and use it the same way as you've described. The limitation I have with it currently is that ML settings do not get swapped out with the custom modes. That means I'd still need to enable dual ISO through the menus when needed, which makes it impossible to use for time-limited scenarios like the above. If ML settings were tied to the custom modes I'd be incredibly happy but that doesn't sound very easy to implement just yet. A couple of other concerns I have with dual ISO is the extra step it adds to the workflow (no big deal really) along with the small loss in vertical resolution. With wildlife I often have to crop because it's not always possible to get close enough to the subject - resolution can really start to matter.

I'm going to continue to experiment and adjust my workflow based on what you've said and what dual ISO offers. Thanks for splitting off the thread, this is a good discussion.

I use it for tone mapping in camera.  As I am predominantly a portrait shooter, skin tones are very important for me, but I also like to respect the highlights in the scene (not blow them to white).

Interesting, thanks for explaining that, makes sense. I don't do much in the way of portrait shooting so didn't appreciate the issue with underexposed skin tones but I can see how the same reasoning would apply to similar situations. Basically whenever the subject is at the lower end of the scene's dynamic range, even if the entire DR is within the sensor's capabilities since more signal (via higher ISO) can give better S/N - as per standard Auto ETTR without dual ISO.

We then have both ISOs mapped into 16bit DNG (16bit image files have 65,536 levels of tone) with it's greater precision.

This I'm not so convinced about. Data is only captured with 14 bit precision at best. There's still noise which probably shaves off a couple of meaningful bits from the low ISO data, plus the high ISO data ends up underexposed by a few stops, each stop shaving off a bit (which was probably also noise anyway). cr2hdr interpolates the data into a 16 bit DNG but that doesn't mean you end up with 16 bits of accuracy in the resultant DNG, just precision.

I realise I am dumping everyone into 2 groups here, but in my experience there are 2 kinds of photographers.

Those who shoot auto/semi auto modes and perhaps do not place enough thought into exposure, and those who place exposure towards the top of their priority list.
To often I see people who explain the need for fast captures, and in my opinion, probably actually use it as an excuse.  "I couldn't check my exposure because I was to busy killing the shutter"!

To give you an idea of where I sit between the two extremes you described - on a three week trip to Antarctica I came back with 1,200 photos (that's a lot for me on a trip of that duration). Compare that to one person I met on that trip who finished up with over 50,000(!). Generally speaking I'm pretty closely aligned with your approach and I prioritise exposure pretty highly over "spray and pray" when I can. I'm just saying that it's not always possible to do so.

I haven't yet met some who materializes into a scene with their finger on the shutter button ready for that split second moment.  In other words, when walking to the scene, unpacking equipment at the scene, setting up tripods or whatever, these are perfect opportunities to observe the scene and make exposure decisions.

In the past 12 months I've spent roughly 16 weeks on safaris. It's a a constant battle to anticipate what might happen next. Perhaps a large bird might swoop past - is it likely to be white or dark? What will the backdrop be like, bright sky or dark trees? What if there's a fleeting glimpse of a leopard? A zebra bursts out of the bushes with a lion in hot pursuit? Even an animal walking slowly through mottled light against a changing background is extremely hard to expose correctly for in advance. To make things worse, sometimes two or more of the above can happen at the same time!

My current way of dealing with these situations is to have the C1,C2,C3 custom modes preconfigured for various combinations of fast shutter speeds, AF tracking options and exposure compensation. I'll quickly switch to whichever custom mode I think is most suitable for the given event, often adjusting the exposure comp based on experience/intuition as I'm lining up the shot(s). Not ideal but being a bit out on the exposure is far better than missing the shot completely. If you know a better way I would genuinely love to hear it, I know my approach isn't perfect.

Regarding wanting the histogram while reviewing later. Take the mottled light example above - I might well end up with 2-3 shots that are similar in terms of composition and aesthetic appeal, but because of the changing light between shots the quality of the exposure might become a deciding factor on which I choose to keep. I don't think anyone mentioned retaking shots. For me at least it's generally just to help decide which to keep. Having said that, I do make mistakes at times and I'd rather find out I'd screwed up an exposure during review on camera than once I finally get it back to my PC, I might have time to try again if I catch it early.

Anyway, I think we're going on a bit of a tangent here. There's no doubt in my mind that a RAW histogram in the picture viewer would be incredibly useful - even just for those cases when I accidentally half-press the shutter again before I've had time to review the histogram properly It doesn't seem like I'm the only one who feels this way, and as Marsu42 pointed out Canon included the histogram during review for a reason. Having a RAW one would be better.

Thank you for this, it's fantastic. I picked up quite a few useful snippets of information and I'm sure I'll be referring back to this regularly while I figure out all the various options in detail.

One small typo: "You may want to put 8 or 8 second so you can see the results in the ..."  You haven't finished the sentence.

Would it be possible for you to expand a little on the SNR limits, in particular the pros/cons of the different values and when you might prefer one over the other?

Finally, am I right in thinking the main use case for Auto ETTR + Dual ISO be a scene where there is high dynamic range but there is also some movement in the scene (people, etc) that makes it unsuitable for bracketing + HDR/blending/Exposure Fusion etc instead? Are there other cases where it might be useful too?

I honestly don't understand why you would need to check for overexposure well after a shot has been taken.

When shooting wildlife and action it's often not possible to check the exposure carefully before, during, or immediately after shooting - doing so might mean missing "the" shot. I'll often shoot a lot of images over the course of a two week trip, without a laptop, and in the evenings I want to whittle down my images to save processing time later and/or free up some CF card space. Having the RAW histogram available at that point would be invaluable to me. Currently I often find myself keeping two similar photos with slightly different exposures because I can't be sure if I've blown highlights or not.

It's probably possible, but I'm not curious to try it

(it's hard and I guess it will be very slow, since it will have to decompress the CR2)

What about the possibility of writing a sidecar file with the required information when the photo is taken? It wouldn't need to be much, just the bare minimum required to reconstruct the histogram (128 pixels * four channels (RGB + luma) * 6 bits + a small amount of additional metadata). Presumably that sidecar file could be used for other purposes too.

Using the ML Alfa release for 5DIII and very happy with it (thanks).  I note the release notes imply that the Timelapse feature will come in the future.  Wondering, is there a ballpark timeframe you are thinking about?  In short, should I go buy a suitable shutter release or shall I just chill for another month or two.

The alpha release is very old. Try one of the 5D3 nightly builds, intervalometer has been supported for a long time. Do be aware however that if you enable the bootflag on the 5D3 you currently can't disable it again.

In the fine print it says "65MB/s minimum sustained write speed", so it might not be as good as it appears to be for 1080p RAW. Having said that, my 32GB 90MB/s SanDisk CF card was just able to handle sustained 1080p RAW in the one and only test I tried with it (5Dmk3).

and I bet I've used his suggestions but my idea is totally different than what he put in magic lantern!

You seem to be suggesting that knowing the approximate sunrise/sunset time would help the camera decide what to do? Determining the correct exposure is impossible from that - you'd still need to allow for current sky conditions, moon phase and location, streetlights/light pollution, altitude (since it affects sunrise/sunset times), shadows from landscapes or buildings, latitude, camera direction (into/away from sun), ...

If you simply want to know when sunrise or sunset is on a given day so you know when to go out shooting, you'd be MUCH better off with a mobile app like Sun Surveyor to help you plan ahead for the sun and moon conditions. Those apps are far more flexible and powerful than anything that could be built into the camera.

Having said that, I can see a little bit of merit in being able to lookup sunrise/sunset times on camera. I just don't see what it would have to do with the timelapse functionality.

fixed now?

It's not fixed, or if it was fixed it is back again

Note that an easy way to check for its presence without worrying about any side effects is by looking here: http://sitecheck.sucuri.net/results/www.magiclantern.fm

I've been trying to track down the memory location on the 5D3. So far I've found:

0x268DC - changes when rolling the rear dial.
0x2E770 - changes when rolling the rear dial.
0x2E780 - changes with the scene's brightness. Values are between -7000 and +9000 or so.
0x2E7C0 - ranges between 250 and 500 or so. Doesn't seem to map to brightness directly but is somehow related.
0x323F8 - possible?
0x323EC - possible?

I tried copying the 5D2 code that's in consts.h and using the address 0x2E780 but that froze the screen (top LCD and camera buttons still worked, wouldn't take a photo). I was going to play further but my camera batteries all need charging and it's 2:30am. Will try some more tomorrow.

In the meantime, I have a couple of questions:
What range of values should I be looking for? Is -7000 to +9000 reasonable?
How do I know whether to look for an int16 or an int8? It seems the 5D2 is an int16 but all other Canon cameras are int8?
When I think I've found the right address, what exactly should I do to test it?

Apologies for my lack of understanding, I'm new to this.

One small bug I noticed in mem_spy. The call to bmp_fill() should take FONT_SIZE rather than a hard-coded 12 (I noticed this because I had to make the font bigger so I could read the output!).

looks amazing! how did you find focusing on the night sky? because I can't see much I can never get a decent focus

The best way I've found is to pick a bright star and use 10x liveview to help you focus on it manually. It's well worth spending time trying to get the focus as precise as possible as it makes a big difference to how sharp the stars look in the final image.

If you're having trouble seeing it clearly on the camera, consider using a mobile app like DSLR Controller. With that you can view 10x liveview on your phone or tablet (bigger screen), and you can also step the focus motor in tiny increments without having to physically touch/bump the lens. Even with this approach it can be a little tricky to get right but with a bit of practice you should get the hang of it pretty quickly.

Finally, to get the sharpest stars you want to keep your shutter speed as fast as possible to prevent star trails due to the rotation of the Earth. The rule of thumb is 600 / (focal length) seconds on full frame or 600 / (focal length) / 1.6 seconds on a Canon crop camera.

Have you tried the "steady hands" feature?