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Need bracketing shots HELP :-(

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Offline Gazza#9

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Need bracketing shots HELP :-(
« on: 07 / July / 2008, 08:07:26 »
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Hey guys!

I've been trying to take bracketing shots with my SD750+CHDK and...results aren't turning out good.  :(
May anyone help me out?

I just want a script to take 3 shots with EV(-1), EV(0) ,EV(+1).
But...I tried several of them...with no luck. I mean...I won't get a "dark" shot, an "ok" shot, and a "light" shot of the same pic.
How should I set my camera to do that?. Any script you recomend for my purpose?.

I also tried to use Self-Timer + CHDK Bracketing Continous Mode, but again I didnt get my dark - ok - light   sequence of pics.
I get ok - very light - light   sequence of shots...  :(

So...if anyone may help me out....I'd appreciate  :-[
(any help is apreciated)

Thanks in advance...

GAZZA
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Offline fe50

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Re: Need bracketing shots HELP :-(
« Reply #1 on: 07 / July / 2008, 08:27:30 »
GAZZA,

set
       * Tv bracketing value: 1Ev
       * Bracketing type:  +/-
in the "Extra Photo Operations" - "Bracketing in continuous mode" menu.


Then set the Canon custom timer to 1s delay, 3 shoots.

Now in the cameras Manual mode choose the custom timer mode, you'll see

BRACKET: +/-
TV: 1Ev

on the CHDK OSD.

And remember: if you have the "Clear Bracket Values on Start" enabled (that's the default value), after power off the settings are gone...
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Offline Gazza#9

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Re: Need bracketing shots HELP :-(
« Reply #2 on: 07 / July / 2008, 15:23:57 »
Oki dokie.
Will try again, but...seems like I'm already doing what you say, mate.... :-[
Doing like that I get an "ok" picture, and two "very overexposed" ones... I can't get the "dark" one... :(

Which "light evaluation" type should I use?? (if that may affect the bracketing): 
- Point, Overall or Center Mean ??

Mkay...If anyone has got any other advices...will be welcomed ;)

Thanks, mate!

GAZZA
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Offline LjL

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Re: Need bracketing shots HELP :-(
« Reply #3 on: 07 / July / 2008, 15:41:32 »
I think you can choose the metering method freely... but you'd better be in Av or M mode! Otherwise, the camera will re-evaluate exposure at every shot (that's how the timer mode work, it's different from "continuous" mode), which may easily end up giving weird results, I suspect.

And forget scripts, for the time being, just concentrate on getting the "built-in" bracketing to work.
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Offline r3nni32000

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Re: Need bracketing shots HELP :-(
« Reply #4 on: 07 / July / 2008, 18:28:54 »
i have found with my sd 750 that more often the scripts and settings seem to work better in kids and pets setting on the camera, dont have any idea why but it does. its a problem as you cant use macro and a few other things in this setting.
  hope this helps
jay
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Offline fe50

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Re: Need bracketing shots HELP :-(
« Reply #5 on: 07 / July / 2008, 19:26:12 »
GAZZA,

it looks like you have set the  "Bracketing type" item to [+ ], not to [+/-], so on every shot the exposure is incremented...

-> [+  ]: the first shot is "normal", the 2nd and 3rd shot is overexposed +1 / +2 Ev    (INCREMENT Ev)
-> [-  ]: the first shot is "normal", the following 2 shots are underexposed -1 / -2 Ev (DECREMENT Ev)
-> [+/-]: the first shot is "normal" (0 Ev), the 2nd will be underexpose (-1 Ev), the 3rd overexposed (+1 Ev)
          (rotational INCREMENT/DECREMENT, based on the 1st shot)

As suggested by LjL you should use the M mode...in Kids & Pets mode there are some heavy limitations, e.g. not adjustable, high ISO setting.

I use the Brackting (on my SD870) very often for "hand held" HDRs with this settings:
Manual mode, ISO <= 100, Bracketing type = [+/-], Bracketing type = [2 Ev], Custom timer mode with 1s delay and 3 shots.

Quote from: LjL on 07 / July / 2008, 15:41:32
I think you can choose the metering method freely... but you'd better be in Av or M mode! Otherwise, the camera will re-evaluate exposure at every shot (that's how the timer mode work, it's different from "continuous" mode), which may easily end up giving weird results, I suspect.

Hmm, ok - the metering doesn't matter, i always use Manual mode; but i'm not sure with the re-evaluation: on my SD870 the bracketing works in Auto mode just as well as in the manual mode, the exposure only depends on the first shot of the row...

I made a fast test (3 shots, +/- 2Ev, room with bad lights):
[Manual mode, ISO 80]           (0"8 / F2.8 )  (3"2 / F2.8 )  (1/5  / F2.8 )
[Auto Mode, ISO Auto=200]       (1/8 / F2.8 )  (0"5 / F2.8 )  (1/30 / F2.8 )
[Auto Mode, ISO 80 by CHDK]     (1/8 / F2.8 )  (0"5 / F2.8 )  (1/30 / F2.8 )
[Kids&Pets Mode, ISO Auto=250]  (0"3 / F2.8 )  (1"3 / F2.8 )  (1/13 / F2.8 )
[Kids&Pets Mode, ISO 80 by CHDK](1/5 / F2.8 )  (0"8 / F2.8 )  (1/20 / F2.8 )



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Offline LjL

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Re: Need bracketing shots HELP :-(
« Reply #6 on: 07 / July / 2008, 19:32:22 »
I thought that in continuous mode, there's no re-evaluation, while in timed mode (even with 0 seconds delay set between shots) there is. I could be wrong, though, or at least it might not apply to all models.
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Offline fe50

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Re: Need bracketing shots HELP :-(
« Reply #7 on: 07 / July / 2008, 20:23:14 »
Quote from: LjL on 07 / July / 2008, 19:32:22
I thought that in continuous mode, there's no re-evaluation, while in timed mode (even with 0 seconds delay set between shots) there is. I could be wrong, though, or at least it might not apply to all models.

On the Ixus series (or at least on the Ixus 860/SD870) you can only set the delay before the first shot, the time between the shots is not adjustable (maybe it is on the "A" & "G" series ?), for me it looks like there's no re-evaluation, but i'm not sure about this.

I think that the CHDK settings always override the Canon ones, so if the camera does a re-evaluation this doesn't matter at all - the CHDK settings (in our case the incremented or decremented Ev) wins the war  8)
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Offline Gazza#9

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Re: Need bracketing shots HELP :-(
« Reply #8 on: 08 / July / 2008, 07:57:03 »
Uhmm...first of all, thank you guys for trying to help me out.
I tried now some of your tips and...damn!, now I get an "ok" pic, and then two "underexposed" exactly_same.  :blink:

I tried to use LjL's settings on the "Bracketing in Continuous Mode" and...I got this: 
  1 ok and 2 underexposed (but exactly same underexposure).

I'm kinda getting mad at CHDK now!!!, jajaja!!   :D
I also tried "Kids and Pets" but...same result.  :-[


Here you have a try I have made right now in my room: 
Manual mode, ISO <= 100, Bracketing type = [+/-], Bracketing type (AV) = [1 Ev], Custom timer mode with 1s delay and 3 shots.

 

As you see...the first two pics are same, and last one is Underexposed.  :blink:
(which is not what I got on my first test  :blink:, Actually is opossite!!. Two ok sames, and 1 underexposed)

Any more help??. I wanna do my HDR's!!!!!   :(

Thanks,

GAZZA
« Last Edit: 08 / July / 2008, 08:00:09 by Gazza#9 »
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Offline fe50

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Re: Need bracketing shots HELP :-(
« Reply #9 on: 08 / July / 2008, 08:20:53 »
Seems like you have a very headstrong Ixus  :haha

What you also can do:
- delete your config file on the card (chdk.cfg)
  or better: use a fresh formatted card (e.g. the 16/32 MB shipped with the camera) & install CHDK again
- use a 2Ev step to check whether something is changing

Perhaps there's a little bug in the +/- loop in the code, so it only works in one direction...

We should have another IXUS 75 user testing the +/- bracketing & report the results...
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