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Canon S110 Time Lapse Advice/Recommendations

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Online reyalp

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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #50 on: 24 / March / 2016, 02:26:39 »
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Quote from: MarkB on 23 / March / 2016, 23:58:01
I have to say I am quite happy with this one. 
Yes that looks very nice :)
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If possible I would like to be able to protect this.  What setting should I play with next, reduce Overexp thresh x/100k or Overexp Ev range?
What to adjust depends on why that area was overexposed:
1) Was the threshold simply too high? (meaning the over exposed area is ~3%). If so, reducing thresh is the most direct solution.
2) Did some other limit prevent over exposure protection from staying under the 3% limit? Then those limits might need to be adjusted, or the strength of over-exposure protection increased.
3) Is the area that looks over exposed actually significantly larger than the amount the script thought was over-exposed? Then increasing overexp range might be the solution.

To determine which apply and what the best adjustment is, we need to look at the *_frac and *_weight values in the log.

In the attached plot, under_frac and over_frac are on the right scale, in %. Everything else is on the left scale.

At around frame 1600 over exposure appears and quickly reaches ~1%. At the same time, under-exposure is active around 6%. Both are below their respective thresh values, so the weights are small and they balance out.

At around frame 2500, both start increasing. over_weight is higher, so the meter value is pushed down some, but the opposite input from under exposure protection negates some of the effect, allowing over_frac to reach over 4%. Neither weight reaches it's limit, but over gets very close.

If you made the over exposure limits more strict (smaller thresh and/or larger range) over_weight would reach it's limit sooner, but the effect would be relatively minor since it almost reached max weight.

Making the under limits less strict (under thresh larger, or underexp -ev larger) would make it resist over exposure protection later.

Some suggestions:
1) Look at individual images in the exposure ranges mentioned and decide how much over exposure is OK.
2) reduce overexp thresh to a little below that amount. So if 3% (frame ~2650) looks ok, use 2.5% or 2%. This will make it max weight around your chosen limit.
3) Use less strict underexp limits, maybe underexp -ev to 6, and/or increase underexp thresh to 15%-20%. Your video doesn't look badly under-exposed when the over-exposure is happening, so letting it go further seems reasonable. You could also take c_joerg's approach and turn off under-exposure protection completely.

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  Would Meter high thresh EV change much?
No. The main effect of the meter limits is to prevent over or under exposure protection from pushing the metered area too far in the opposite direction. If you have over exposure, then the exposure is reduced, and the meter area falls below the target value. The meter low thresh and limit control how far this can go.

In your run, meter_weight was always 100, so these limits were not a factor.

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  How about Bv Ev shift base Bv? 
This has an indirect effect because it can shift the target meter value higher or lower.
In your case, the bv / ev shift was negative through whole run, ending around ~1/4 stop below neutral. Increasing the base value would increase the effect, but this probably isn't a good way to control overexposure, since it would make the earlier parts darker.
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Offline MarkB

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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #51 on: 27 / March / 2016, 14:52:41 »
Quote from: c_joerg on 03 / March / 2016, 02:22:28
Yes of course. My experience on S110 in continues mode says:
0.8s with JPG
2.5s JPG + RAW. Using DNG instead of RAW +0.8s.
I was re-reading this thread and noticed @c_joerg 's experience with interval was done with JPG + RAW, so I was wondering if I could have some time down with shooting in RAW only, using the native CR2.


I shot it a night with the thought that:
-the light wouldn't change much over the test time
-Forcing the highest ISO with the slowest shutter speed would be the longest processing time the camera would have to deal with


The interval times I tried were 3sec, 2.7sec, 2.5sec, 2.2sec, 2.0sec, 1.7sec, 1.5sec, 1.2sec and 1sec.
Other than changing the BV EV shift base BV to 10, all the other settings were the same as my last sunrise (s110test17) run.


Looking at the log, I don't start to get negative sleep readings until 1.5sec interval.  The first image in the 1.7sec run is negative  but everything that follows in around 200 (+-10).  In-between runs I turned off CHDK and photographed my hand so I had a clear delineation between runs when I looked at them afterwards, so this might have affected  the first image.


So if I am interpreting this correctly, does this indicate if I am shooting RAW only  I can get an interval as short as 1.7sec, or is there something else I should also be looking at?   I might try 1.6sec run to see what the results are since the 1.5sec run was 0 for most of the run.



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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #52 on: 27 / March / 2016, 15:14:20 »
Quote from: MarkB on 27 / March / 2016, 14:52:41
I was re-reading this thread and noticed @c_joerg 's experience with interval was done with JPG + RAW, so I was wondering if I could have some time down with shooting in RAW only, using the native CR2.

As long sleep is greater 0, everything should be OK. I let sleep always greater 200ms because sometime the SD cards made jitter into saving.

There is an option in the script that’s turns an LED on or made a Peep, when sleep goes under 0.

On JPG, I expect that the processing needs the most time. For RAW I think the most impact is writing to the SD card.

Native RAW’s are also compressed. When it is dark, there are much smaller so this might be change the timing as well.
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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #53 on: 27 / March / 2016, 15:26:31 »
Quote from: MarkB on 27 / March / 2016, 14:52:41
So if I am interpreting this correctly, does this indicate if I am shooting RAW only  I can get an interval as short as 1.7sec, or is there something else I should also be looking at?   I might try 1.6sec run to see what the results are since the 1.5sec run was 0 for most of the run.
That makes sense to me.  If you want to maintain a steady interval, 100ms margin is probably about as low as you want to go. You may still get the occasional frame that goes over, but it shouldn't happen too often, and probably depends on the card.

I hadn't thought about it before, but the Canon firmware may not do as much processing at high ISO if you are shooting CRW only, so you might be able let ISO go higher without affecting interval. OTOH, the Canon firmware does create a ~2MP jpeg for the embedded thumbnail, so may do all the normal processing anyway.
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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #54 on: 03 / April / 2016, 12:13:53 »
Quote from: c_joerg on 27 / March / 2016, 15:14:20


As long sleep is greater 0, everything should be OK. I let sleep always greater 200ms because sometime the SD cards made jitter into saving.

There is an option in the script that’s turns an LED on or made a Peep, when sleep goes under 0.

On JPG, I expect that the processing needs the most time. For RAW I think the most impact is writing to the SD card.

Native RAW’s are also compressed. When it is dark, there are much smaller so this might be change the timing as well.


I never realized there was some compression with CR2's.  It seems common rhetoric that that RAW's are uncompressed, so this is interesting to know.


I did another RAW only speed test on a fairly bright but intermittent cloudy day.  The intervals I shot at were 3,2.7,2.5,2.4,2.3,2.2,2.1,2.0,1.9,1.8,1.7,1.6,1.5 and 1.4 


Much to my surprise the sleep at the 1.4 sec interval fell around 360 +-10 ms.  Judging by the trend I am assuming a 1.3 sec interval would fall around 160ms.


Interesting that the night shooting 1.5 sec interval was getting a sleep of 0 and during the day I would be getting 0 or minus results at 1.2 sec interval.


So unless my logic is flawed I would assume the shortest interval to keep at least a 200ms margin of error to do a sunrise/sunset would be 1.7 sec for this particular camera and SD card combination.







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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #55 on: 03 / April / 2016, 13:12:47 »
Quote from: MarkB on 03 / April / 2016, 12:13:53
I never realized there was some compression with CR2's.  It seems common rhetoric that that RAW's are uncompressed, so this is interesting to know.
I think it’s just a lossless compression like ZIP. It works only good, when you have large uniform areas…
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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #56 on: 03 / April / 2016, 14:11:46 »

Hopefully people are not too bored of my view off the balcony.  Sorry it is  easy to set up a test and go back to sleep.


This one came out very well. Maybe a bit too bright overall when the sun is up but it is overcast  and I need to be a bit more aggressive with the noise reduction, but these could be adjust in post.

The setting I used are;
Interval 25  2.5 sec
Max EV change ⅓
Ev shift ¼
Bv Ev shift % 15
Bv Ev shift base Bv 10 ½
Max Tv Sec/1000 500  ½ sec
Min Tv sec/100k  10   1/1000 sec
Target ISO 80
ISO adj Tv sec/1000 125    ⅛ sec
Max ISO 400
Meter high thresh Ev 1
Meter high limit Ev 1 ¾
Meter low thresh -Ev 3 ¼
Meter low limit -Ev 6
Overexp thresh x/100k 2500   2.5%
Overexp range ¾
Underexp thresh x/100k  15000  15%
Underexp -Ev 6

Quote from: reyalp on 24 / March / 2016, 02:26:39

Some suggestions:
1) Look at individual images in the exposure ranges mentioned and decide how much over exposure is OK.
2) reduce overexp thresh to a little below that amount. So if 3% (frame ~2650) looks ok, use 2.5% or 2%. This will make it max weight around your chosen limit.
3) Use less strict underexp limits, maybe underexp -ev to 6, and/or increase underexp thresh to 15%-20%. Your video doesn't look badly under-exposed when the over-exposure is happening, so letting it go further seems reasonable.

I took your suggestions and reduced the overexp thresh to 2.5%, underexp -Ev to 6  and increased underexp thresh to 15%  and the results were great.  Thanks.

My next tweak would be to reduce the overall brightness once the sun is up but it is overcast.  Not sure if this is something the script can control, but if so, where should I look first?   Bv Ev shift base BV since now my current concern is more in the mid range of the exposure as opposed the the extreme ends?  Or is there somewhere else I should look.

Quote from: reyalp on 24 / March / 2016, 02:26:39
You could also take c_joerg's approach and turn off under-exposure protection completely.

While @c_joerg's moonrise time lapses are amazing, that look is a bit too extreme for what I am looking for.  I am looking to get a decent general purpose time-lapse script that will handle most situations comfortably.  Hence I am experimenting with sunrise or sunsets since that will give me the most extreme lighting changes I will encounter.


I am also thinking of upping the Max ISO in the next sunrise/sunset run, as this might help with the noise issue I am getting from underexposure. 

Again any advice or suggestions are greatly appreciated.



« Last Edit: 03 / April / 2016, 14:15:02 by MarkB »
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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #57 on: 03 / April / 2016, 17:05:07 »
That run looks very good too me, and as far as test scenes go, you balcony is quite nice :)

Quote from: MarkB on 03 / April / 2016, 14:11:46
My next tweak would be to reduce the overall brightness once the sun is up but it is overcast.  Not sure if this is something the script can control, but if so, where should I look first?   Bv Ev shift base BV since now my current concern is more in the mid range of the exposure as opposed the the extreme ends?  Or is there somewhere else I should look.
As usual, the first thing I'd suggest is looking at the log and see what is driving the exposure in that part of the run.

It's a bit hard for me to be sure which part of the run you are talking about. If you can give frame numbers and/or or a time range in the youtube video, that would be helpful.

There is some over-exposure in the brighter parts of the run (~2200-3500, 4000-5000) so stricter over-exposure limits would reduce the overall exposure in these parts of the run.

If you set your Bv/Ev shift base to a higher value, this would make overcast push exposure down more. However, it would also make the earlier parts of the run darker too. With your current setting of 10.5 (=Bv 1005), the shift is ~0 in the brighter parts of the run, because the meter has reached about that value (Bv = ~ 960)

A larger Bv/Ev shift % would also have have some impact, but again will have other side effects.

Fundamentally, the script can't distinguish between clear, twilight sky can overcast daytime sky.

You can adjust what portion of the scene contributes to the meter, but at the moment it's always centered. Allowing more control of the meter area (different positions, multimple meters) is on my TODO list.
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I am also thinking of upping the Max ISO in the next sunrise/sunset run, as this might help with the noise issue I am getting from underexposure.
Note that "sleep" never falls below about 1000 in this run (except for after the first shot, which is often slow), so you could increase the allowed exposure time up to something like 1.4 seconds. I would do this before increasing the ISO limit.

Note that you may need to disable canon dark frame subtraction to maintain interval. IIRC this often kicks in around 1.3 seconds.

edit:
updated chart, accidentally left off meter96 the first time
« Last Edit: 04 / April / 2016, 03:09:11 by reyalp »
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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #58 on: 04 / April / 2016, 00:41:15 »
Quote from: reyalp on 03 / April / 2016, 17:05:07


As usual, the first thing I'd suggest is looking at the log and see what is driving the exposure in that part of the run.

It's a bit hard for me to be sure which part of the run you are talking about. If you can give frame numbers and/or or a time range in the youtube video, that would be helpful.




The part I am talking about start around 2:40 in the video which is approx. image 3840,  It seems to keep getting brighter until the light changes (break in cloud) and the exposure changes.



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If you set your Bv/Ev shift base to a higher value, this would make overcast push exposure down more. However, it would also make the earlier parts of the run darker too. With your current setting of 10.5 (=Bv 1005), the shift is ~0 in the brighter parts of the run, because the meter has reached about that value (Bv = ~ 960)




That might not be a bad thing actually

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Fundamentally, the script can't distinguish between clear, twilight sky can overcast daytime sky.




This I realize, I just find that when the images is fairly flat, (low contrast) and the light is not changing,  the exposure is a bit on the high side.



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Note that "sleep" never falls below about 1000 in this run (except for after the first shot, which is often slow), so you could increase the allowed exposure time up to something like 1.4 seconds. I would do this before increasing the ISO limit.

Note that you may need to disable canon dark frame subtraction to maintain interval. IIRC this often kicks in around 1.3 seconds.


Actually  I would prefer to increase ISO over shutter speed.  The slowest shutter speed I would want to use is ½ sec.  Most things I would shoot would have movement, cars, pedestrians etc, and I find I have too much motion blur as it is at ½ sec at night so I would not want to go any longer. 


Not sure if this will factor in with the script, but when shooting without CHDK, in either Manual or Av mode and regardless of whether  Auto ISO  is set or not, once the shutter speed falls below 1 sec the ISO switches to ISO 80.  You can't even change the ISO setting unless you change the shutter speed in Manual mode, or open the stop or get more light on the scene in AV mode.  So if the script/CHDK doesn't override this, any time the shutter speed is 1.3 or more the ISO will be 80, which in turn leads to longer shutter speeds.


Since I found the camera could handle an interval of 1.7 sec at ISO400 ½ sec when shooting at night,  I figured I would start with that setting and slowly up the ISO and find out when the sleep goes into the negative.
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Re: Canon S110 Time Lapse Advice/Recommendations
« Reply #59 on: 04 / April / 2016, 03:37:24 »
Quote from: MarkB on 04 / April / 2016, 00:41:15
The part I am talking about start around 2:40 in the video which is approx. image 3840,  It seems to keep getting brighter until the light changes (break in cloud) and the exposure changes.
Up to around shot 3500 (frame/csv line number, exp count ~5200), exposure was being pushed down by over exposure. From there to about 4000 it was closer to the target value.

Overall brightness went down down. You can see bv/ev shift pushed down a little bit there, but the effect is pretty small. A higher base or larger % would have made things darker in this section.

A smaller overexp thresh would not have helped much in that part, because there wasn't much over exposure. A larger overexp Ev range might, but you already have that set fairly high, and it would prevent the sky from getting bright in other situations.

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Actually  I would prefer to increase ISO over shutter speed.  The slowest shutter speed I would want to use is ½ sec.  Most things I would shoot would have movement, cars, pedestrians etc, and I find I have too much motion blur as it is at ½ sec at night so I would not want to go any longer.
That makes sense.

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Not sure if this will factor in with the script, but when shooting without CHDK, in either Manual or Av mode and regardless of whether  Auto ISO  is set or not, once the shutter speed falls below 1 sec the ISO switches to ISO 80.
IIRC CHDK overrides work on cameras like this, but I could be wrong. It should be easy to test.
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