[SOLVED] Exposure drift when using HDR and timelapse

[kenc3dan]

When using 3-exposure HDR and the intervalometer I find that the shutter speed drift as time passes.
As I look at the triplets of sequential images I see something like this...


Frame 1   Frame 2   Frame 3
1/15      1/50      1/125

Frame 4   Frame 5   Frame 6
1/15      1/50      1/125

...

Frame 97  Frame 98  Frame 99
1/50      1/125     1/400


The shutter speeds of the frames drift, presumably as the lighting changes (not sure of this).
This means I can't use them for time-lapse video because the "underexposed" aren't equally dim and so on.
Is there some method I can use to make sure my under/mid/over-exposed frames keep all the same shutter speeds for the duration of a timelapse?

Thanks for any help!
Relative noob here,
Ken
...

[a1ex]

Did you have any exposure ramping enabled?

[kenc3dan]

I had no Bulb Ramping selected under Intervalometer. Nor anything similar anywhere else I can see in the menus. Is there something I may be missing buried in a submenu someplace?

[kenc3dan]

Back in the standard Canon menus there's Auto Lighting Optimizer under red camera menu 2. This was on. As was Evaluative Metering and ISO Auto. Exposure Compensation was on zero, no EV spread there. Does the Canon firmware even matter to Magic Lantern?

[a1ex]

Was this in M mode?

[kenc3dan]

EXIF data says every one was in Manual mode.

[a1ex]

Can you attach your ML config file?

[kenc3dan]

I'll try to send it tomorrow. Thanks for all the diagnostics help!

[kenc3dan]

Here's my config file, I've since turned off HDR but most everything else should be the same.

# Magic Lantern 2011Dec22.550D109.alex (394c773262f4 (unified) tip)
# Build on 2011-12-22 19:47:23 by alex@karmic
# Configuration saved on 2012/07/28 19:04:38
menu.upside.down = 0
debug.menu-timeout = 1000
menu.advanced = 1
menu.first = 9345774
debug.timed-dump = 0
prop.k = 0
prop.j = 0
prop.i = 0
dm.enable = 0
audio.monitoring = 1
audio.draw-meters = 2
audio.disable-filters = 1
audio.input-choice = 4
audio.alc-enable = 0
audio.o2gain = 0
audio.lovl = 0
audio.mic-power = 1
audio.dgain.r = 0
audio.dgain.l = 0
audio.mgain = 4
buffer.warning.level = 70
bitrate.indicator = 0
time.indicator = 3
h264.bitrate-factor = 10
h264.bitrate-mode = 1
h264.qscale.plus16 = 8
digital.zoom.shortcut = 1
swap.menu = 0
play.lv.button = 1
quick.delete = 1
play.set.wheel = 2
crop.playback = 0
play.quick.zoom = 2
af.frame.autohide = 1
burst.auto.picquality = 0
lv.metering = 0
expsim = 2
dof.preview.sticky = 0
crop.info = 0
movie.log = 0
shutter.display.degrees = 0
lcd.release = 0
lcd.sensor.shortcuts = 1
display.dont.mirror = 1
electronic.level = 0
defish.preview = 0
idle.rec = 0
idle.display.gdraw_off.after = 0
idle.display.dim.after = 0
idle.display.turn_off.after = 0
spotmeter.position = 1
spotmeter.formula = 0
spotmeter.draw = 0
spotmeter.size = 5
clear.preview.mode = 0
clear.preview.delay = 1000
clear.preview = 0
waveform.bg = 38
waveform.size = 0
waveform.draw = 0
hist.log = 0
hist.warn = 2
hist.colorspace = 1
hist.draw = 1
focus.peaking.color = 7
focus.peaking.thr = 10
focus.peaking.method = 0
focus.peaking = 1
zoom.overlay.lut = 0
zoom.overlay.split = 0
zoom.overlay.pos = 1
zoom.overlay.x2 = 1
zoom.overlay.size = 1
zoom.overlay.trig = 3
zoom.overlay = 0
falsecolor.palette = 0
falsecolor.draw = 0
crop.movieonly = 1
crop.index = 0
crop.enable = 0
zebra.rec = 1
zebra.level.lo = 5
zebra.level.hi = 95
zebra.mode = 1
zebra.draw = 0
global.draw = 1
transparent.overlay.y = 0
transparent.overlay.x = 0
transparent.overlay = 0
disp.mode.xxx = 589888
disp.mode.ccc = 557200
disp.mode.bbb = 2707457
disp.mode.aaa = 2641985
disp.mode = 0
lv.disp.profiles = 0
picstyle.rec = 0
iso.round.only = 1
quick.review.allow.zoom = 0
bulb.ramping.percentile = 70
bulb.ramping = 0
motion.trigger = 1
motion.release-level = 3
mlu.auto = 0
bulb.duration.index = 1
bulb.timer = 0
zoom.sharpen = 0
zoom.disable.x10 = 0
zoom.disable.x5 = 0
zoom.enable.face = 0
silent.pic.slitscan.skipframes = 1
silent.pic.sweepdelay = 350
silent.pic.highres = 0
silent.pic.submode = 0
silent.pic.mode = 0
silent.pic = 0
interval.movie.duration.index = 0
audio.release-level = 10
focus.trap = 0
interval.timer.index = 3
hdr.iso = 0
hdr.seq = 1
hdr.delay = 0
hdr.ev_spacing = 12
hdr.frames = 3
hdr.enabled = 0
bv.av = 48
bv.tv = 111
bv.iso = 88
bv.auto = 1
rec.notify = 0
screen.layout.ext = 1
screen.layout.lcd = 0
shutter.lock.value = 0
shutter.lock = 0
enable-liveview = 1
movie.rec-key = 0
movie.mode-remap = 0
movie.restart = 0
wbs.ba = 100
wbs.gm = 100
wb.kelvin = 6500
hdmi.force.vga = 0
focus.patterns = 0
movie.af = 0
focus.follow.rev.v = 0
focus.follow.rev.h = 0
focus.follow.mode = 0
focus.follow = 0
focus.step = 5
focus.stack = 0
focus.wait = 1
focus.delay = 1
focus.stepsize = 2

[kenc3dan]

I can confirm that using the latest firmware (decided to contribute) I don't seem to have this problem any more. I shoot fully manual, turn on HDR and set the over/under values, turn on Intervalometer and it seems to lock in those initial +/- EV figures no mattter what I point at - bright, dark doesn't matter.