ISO 1600 is possible!

[poing]

At the moment I'm trying to test the -ev option in a sort of structured way, meaning iterating from -ev 25 to -ev -25 using a python script, more on this in a future post. But at one time I found files with ISO 1000, ISO 1250 and ISO 1600. The command I used was

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./raspistill -t 1000 -sh -100 -ex sports -ev "+str(iname)+" -awb off -q 100 -o /mnt/myusb/img/"+myname

where 'iname' and 'myname' are variables in python.

Here are the resized files so you can extract the exif:
-ev 21, ISO 1000

1000.jpg (12.08 KiB) Viewed 3359 times

-ev 23, ISO 1250

1250.jpg (11.95 KiB) Viewed 3358 times

-ev 25 ISO 1600

1000.jpg (12.08 KiB) Viewed 3359 times

I tried to replicate these results from the command line later but that did not work. Maybe because of the light level as it was getting darker.

Anyway, the camera IS capable of using ISO 1600...

[lingon]

I tried out the -ex sports option and can confirm that the camera can use ISO 1600. The interesting question is why this is not used in the other modes like -ex night? ASA 1600 with 2x2 pixel binning and longer exposure times could improve the camera performance in dark significantly once the exposure bugs are fixed.

[gordon77]

Jamesh is working on manual settings l believe so hopefully it will include this

[jamesh]

Does

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-ISO 1600

not work then?

[poing]

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./raspistill -ISO 1600 -o 1600_1.jpg

= 1/24 ISO-800

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./raspistill -ISO 1600 -ex sports -o 1600_2.jpg

= 1/24 ISO-800

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./raspistill -ISO 1600 -ex sports -ev 25 -o 1600_3.jpg

= 1/20 ISO-800

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./raspistill -ISO 1600 -ex sports -ev 25 -o 1600_4.jpg

= 1/20 ISO-800 (hand in front of camera - black frame)

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./raspistill -ex sports -ev 25 -o 1600_5.jpg

= 1/60 ISO-1600 (hand in front of camera - black frame)

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./raspistill -ex sports -ev 25 -o 1600_6.jpg

= 1/60 ISO-1600

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./raspistill -ex sports -o 1600_7.jpg

= 1/60 ISO-1600

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./raspistill -o 1600_8.jpg

= 1/16 ISO-160 (light was changing a bit while testing)

To summarize:
- using -ISO has impact on the -ex sports shutterspeed; without -ISO it will not go lower than 1/60 but with -ISO it will go to 1/20.
- using -ISO will prevent -ex sports to go to 1600 while without -ISO it will; specifying -ISO 1600 will lead to ISO 800.

[jamesh]

So basically, there is a bug in the ISO setting....you should get the number you specify.

[poing]

Probably, but it's also funny that the, seemingly locked, lowest shutterspeed of -ex sports changes from 1/60 to 1/20 when you specify an ISO. Without ISO -ex sports underexposes when it needs longer than 1/60 and ISO 1600.

Seems some nice spaghetti in there

[SnowLeopard]

So basically, there is a bug in the ISO setting....you should get the number you specify.

I was trying to set a higher ISO to get better results with faster shutter speeds and have concluded that the -ISO option works as described in the README.md, that is it only sets values between 100 and 800. Any value lower than 100 gets set to 100, any value higher than 800 gets set to 800. Values in between are also changed, but to closer values (which might be normal) -- 300 became 320 and 456 became 500.

Nothing in the userland code overrides settings passed on the command line... the code is complex but something like that should be easy enough to find!

However, using "-ex sports" (without -ISO) gives an image with ISO of 1000. -ISO will take precedence and limit to >100 and <800.