Improving CHDK ND filter support

koshy

1096

Re: Improving CHDK ND filter support

« Reply #70 on: 08 / June / 2018, 14:09:28 »

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Quote from: reyalp on 07 / June / 2018, 22:28:53

Quote from: koshy on 07 / June / 2018, 20:38:17
On srsa's codegen build I can't obtain aperture info on IXUS 1000:
You need a build with
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#undef CAM_HAS_IRIS_DIAPHRAGMremoved from platform_camera.h

srsa kindly did that.

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> !local minav,maxav=con:execwait([[return get_min_av96(),get_max_av96()]]) printf('%0.1f %0.1f\n',exp.av96_to_f(minav),exp.av96_to_f(maxav))

zoomed in: 5.7 18.6
zoomed out: 3.5 11.3

the following are in the archive http://www.filedropper.com/ixus1000:

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> rs -av=5.7
> rs -av=18.6
> rs -av=3.5
> rs -av=11.3
> rs -nd=in
> rs -nd=out

There is no iris. Large 10x lens. I figured I'd override TV (and it crashes on ETR > 30 sek. Nafraf fixed that for the old (non code_gen) build I think to recall). Anyway with the override and "rs -av=18.6" I looked for the iris ,saw the sensor and nothing in between. Script time out, camera didn't stop shooting, removed the battery but no iris ;-).

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reyalp

14079

Re: Improving CHDK ND filter support

« Reply #71 on: 08 / June / 2018, 23:13:42 »

Quote from: koshy on 08 / June / 2018, 14:09:28

the following are in the archive http://www.filedropper.com/ixus1000:
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> rs -av=5.7 > rs -av=18.6 > rs -av=3.5 > rs -av=11.3 > rs -nd=in > rs -nd=outThere is no iris. Large 10x lens. I figured I'd override TV (and it crashes on ETR > 30 sek. Nafraf fixed that for the old (non code_gen) build I think to recall). Anyway with the override and "rs -av=18.6" I looked for the iris ,saw the sensor and nothing in between. Script time out, camera didn't stop shooting, removed the battery but no iris ;-).

I'm confused by these results.
032 and 033 are different, indicating the camera does respond in some way to AV override, but don't look anywhere close to the normal ~3 stops of a canon ND filter.
034 and 035 appear essentially the same as 032 and 033 respectively. This would make sense if the actual limits are smaller than the requested range.
036 and 037 show no change at all, indicating the camera doesn't respond to ND overrides. They appear similar to 032 and 034

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koshy

1096

Re: Improving CHDK ND filter support

« Reply #72 on: 10 / June / 2018, 13:38:32 »

Quote from: reyalp on 08 / June / 2018, 23:13:42

I think I'll re-shoot and put overrides into place on Time / ISO and maybe Subject distance.
I'll post what happens.

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reyalp

14079

Re: Improving CHDK ND filter support

« Reply #73 on: 10 / June / 2018, 15:14:29 »

Quote from: koshy on 10 / June / 2018, 13:38:32

Quote from: reyalp on 08 / June / 2018, 23:13:42

I think I'll re-shoot and put overrides into place on Time / ISO and maybe Subject distance.
I'll post what happens.

Thanks.

One other observation, the examples with aperture control do seem different beyond just exposure. The cactus to the right is noticeably wider in the darker shots (33 and 35) than the lighter ones (32 and 35). It doesn't look the DOF changed much. It might be clearer what's happening in a scene with more depth. We have seen previously that ND filters cause some optical changes (examples at https://chdk.setepontos.com/index.php?topic=13228.msg134454#msg134454) but this seems different.

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koshy

1096

Re: Improving CHDK ND filter support

« Reply #74 on: 11 / June / 2018, 17:16:14 »

Quote from: reyalp on 10 / June / 2018, 15:14:29

One other observation, the examples with aperture control do seem different beyond just exposure.

Yes the actual thing there seems to be that I can't turn AF off. No matter what I do the camera tries to get the focus. Overriding that to "Inf"inity via CHDK doesn't do it. Setting Infinity on the Canon FW doesn't change it either; focus pumps before shooting. I think all we saw before is due to that focus action.

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koshy

1096

Re: Improving CHDK ND filter support

« Reply #75 on: 11 / June / 2018, 17:17:45 »

I spent a long while on this today and what I'm seeing does not make an awful lof of sense.
Here is one item I prepared first but then followed up on as it did not seem sensible.

I overrode TV to 0.03333 (1/30th) and ISO to 125. Still I found no difference in the below:

Code: [Select]

> !local minav,maxav=con:execwait([[return get_min_av96(),get_max_av96()]]) printf('%0.1f %0.1f\n',exp.av96_to_f(minav),exp.av96_to_f(maxav))
3.5 11.3
> rs -av=3.5
> rs -av=11.3
> rs -nd=in
> rs -nd=out
> !local minav,maxav=con:execwait([[return get_min_av96(),get_max_av96()]]) printf('%0.1f %0.1f\n',exp.av96_to_f(minav),exp.av96_to_f(maxav))
5.7 18.6
> rs -av=5.7
> rs -av=18.6
> rs -nd=in
> rs -nd=out

http://www.filedropper.com/ixus1000again

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Koshy had a little ELPH which wasn't white as snow but everywhere that Koshy went the ELPH was sure to go. (actually an SD, but that detail ruins the rhyme...)

koshy

1096

Re: Improving CHDK ND filter support

« Reply #76 on: 11 / June / 2018, 17:52:25 »

After that I started messing with a bright lamp. Depending on how close I move the camera to it I get different TV/AV combinations listed. The interesting thing is that when zoomed out this varies on getting closer to the lamp:

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1/25th f 3.4 (small lamp, dark room)
1/1000th f3.4
1/2500th f 4.5 
1/3200th f5.0 (bulb at full frame height)

ok, we have +/- EV adjust
I set it to - 1EV and stay close up / go even closer

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1/4000th f 6.3
1/4000th f 7.1

I set it to - 1EV and I get RED typography on

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1/4000th f 7.1
The camera mimics Iris in these listings. I can half press the shutter at each position and then shoot whatever I want. While it was still day outside I tried doing that with an override for ISO at 125 and Exposuretime (I think 1/15th) and shot out of the window. That is the camera said f 3.4 or f 7.1 before taking the shot, neither AV nor ND filter were being overridden.

I blurred one image by accidental shake but exposure is identical between the two. I know don't trust the Exif but it matches what the camera said, too.

Here is a download: http://www.filedropper.com/weird1

Then returning to the above but zoomed in the aperture range presented by the camera changes.

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1/50th f5.6 (bulb adjacent to frame)
1/2000th f6.3 RED (bulb fully in view)
a position where the exposure computed is 1/2000th f6.3 - that is in white type can be found

The claimed aperture range is much narrower. At only a little zoom it is f 4.0 to f 6.3.

« Last Edit: 11 / June / 2018, 17:55:24 by koshy »

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koshy

1096

Re: Improving CHDK ND filter support

« Reply #77 on: 11 / June / 2018, 18:03:49 »

Whatever it is doing I'm still of the opinion that there is no aperture. There is no DOF change between test shots.
Still I tried shooting remotely with the aperture values the camera used, too => identical images again in terms of DOF.

Then it gets weird. I set overrides for ISO / Exposure time and ND filter in camera.
With "ND in" I get a much darker live view upon half press and hold than with "ND out" but the actual photos with all three overrides are identical. Even removing the overrides for ISO and Exposure time I do not get a dark final image for "ND in" while I do get a dark live view on the camera.

I thought the overrides may be broken but I ascertained that I can under expose by setting an override of 1/2000th of a second and shooting out of the window etc.

So, to sum it up, is it conceivable that IXUS 1000 has neither ND filter nor Iris and all it displays in terms of AV/TV in reality is being done by shutter? That the ND filter effect gets simulated in live view does not mean that there is a physical ND filter. All it proves is that the camera Firmware knows what the effect of such a filter would be.

It stays weird.

One of these must be with ND and one without ND due to override.
I Forgot which was which: http://www.filedropper.com/weird2

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Koshy had a little ELPH which wasn't white as snow but everywhere that Koshy went the ELPH was sure to go. (actually an SD, but that detail ruins the rhyme...)

srsa_4c

4451

Re: Improving CHDK ND filter support

« Reply #78 on: 12 / June / 2018, 12:38:42 »

Quote from: koshy on 11 / June / 2018, 17:16:14

No matter what I do the camera tries to get the focus. Overriding that to "Inf"inity via CHDK doesn't do it. Setting Infinity on the Canon FW doesn't change it either; focus pumps before shooting.

Is the cam in P mode, and if it is, is "servo af" turned off in the Canon menu?
If servo AF is active, CHDK overrides usually fail.

The cam's specification says the following about the aperture:
Aperture Type Blade (x2) f/number f/3.4 – f/7.1 (W), f/5.6 – f/9.0 (T)

Not the values we usually see on ND only cameras.

« Last Edit: 12 / June / 2018, 12:41:07 by srsa_4c »

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koshy

1096

Re: Improving CHDK ND filter support

« Reply #79 on: 12 / June / 2018, 13:04:35 »

Quote from: srsa_4c on 12 / June / 2018, 12:38:42

Is the cam in P mode, and if it is, is "servo af" turned off in the Canon menu?

Yes to both.

Google:

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site:https://global.canon/en/c-museum/product/ "Blade (x2)"Whatever "Blade (x2)" is, it seems unique to this model.

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Koshy had a little ELPH which wasn't white as snow but everywhere that Koshy went the ELPH was sure to go. (actually an SD, but that detail ruins the rhyme...)