raspistill - exposure

[chrisla9]

Has anyone had any luck with playing with the exposure setting using raspistill?

I've tried a few settings and the picture hasn't altered at all! Frustrating.

Here is the command line I'm using:

raspistill -w 1296 -h 972 -t 0 -ex night -e jpg -q 15 -o test
raspistill -w 1296 -h 972 -t 0 -ex auto -e jpg -q 15 -o test1
raspistill -w 1296 -h 972 -t 0 -ex verylong -e jpg -q 15 -o test2

Everything dark and horrible at 6pm but nice and light at 4pm

Ultimate aim is to use it on a bird table or bird box so I need something with a long exposure time

Any help appreciated

Thanks

Chris

[gordon77]

Has anyone had any luck with playing with the exposure setting using raspistill?

I've tried a few settings and the picture hasn't altered at all! Frustrating.

Here is the command line I'm using:

raspistill -w 1296 -h 972 -t 0 -ex night -e jpg -q 15 -o test
raspistill -w 1296 -h 972 -t 0 -ex auto -e jpg -q 15 -o test1
raspistill -w 1296 -h 972 -t 0 -ex verylong -e jpg -q 15 -o test2

Everything dark and horrible at 6pm but nice and light at 4pm

Ultimate aim is to use it on a bird table or bird box so I need something with a long exposure time

Any help appreciated

Thanks

Chris

Try

Raspistill -t3000 -ex night

Night seems to a reasonably long time to build up the image.

Gordon77

[gordon77]

Raspistill -t3000 -ex night

You must be on older firmware where that still works. A month or two ago it stopped working.

I only got the camera this week, downloaded the latest raspbian, did an update and an upgrade, is that old firmware ?

This is genuine question as l am confused exactly what you do need to do to get the latest firmware / software as raspbian is dated July.

Gordon77

[jamesh]

I cannot see why the update broke exposure. Weird. I hadn't been working in that area. Hopefully will get some time to look at it next week.

[gordon77]

I cannot see why the update broke exposure. Weird. I hadn't been working in that area. Hopefully will get some time to look at it next week.

If you don't mind me asking...if the camera is a supported and marketted raspberry product why does it need you to do it in your spare time ?

[jamesh]

I cannot see why the update broke exposure. Weird. I hadn't been working in that area. Hopefully will get some time to look at it next week.

If you don't mind me asking...if the camera is a supported and marketted raspberry product why does it need you to do it in your spare time ?

Because the Foundation has no camera experts (or at least, people who know about this part of the code). Much of the stuff you see the Foundation bring out is done like this - they have only a very few employees, and there are working pretty hard on other stuff. Some of which is 'quite interesting' and should be announced soon...

I do occasionally get time at work to look at stuff like since the Foundation are a customer of Broadcom, but they are fairly low volume, so therefore a relatively low priority. I hope to get some time next week, as long as my Raspi monitor gets replaced, as it's gone titsup.

[jamesh]

I cannot see why the update broke exposure. Weird. I hadn't been working in that area. Hopefully will get some time to look at it next week.

Thanks. Maaaaaaybe it's only an EXIF problem where the reported value is always the same but the actual setting does change? Or the setting does change but some sort of auto-compensation pulls the effective exposure back to a fixed value?

Although I do seem to remember images being darker in low-light all of a sudden, ie. after after a certain update.

There definitely seem to be a problem, I just don't know what I've done that may have caused it. Debugging on the GPU will be required which is a PITA.

[poing]

I tried and also see a problem that wasn't there before.

@jamesh, if you're diving into the exposure stuff on the GPU could you please take a look if manual exposure and white balance is feasible? Me and others are desperately waiting for that functionality since we can't use auto exposure and auto wb in our projects. Thanks. This also has an educational angle as learning photography with only auto modes is like learning programming with forced auto-complete

[wallarug]

I was wondering why my pictures where not coming out with the exposure settings. I knew that there was a problem but no clue how to fix it.

The best setting I found was the 'auto' exposure mode.

I was wondering how the 'fixedfps' mode worked. I thought it could be the manual exposure setting? Could someone please explain this to me?

[jamesh]

I was wondering why my pictures where not coming out with the exposure settings. I knew that there was a problem but no clue how to fix it.

The best setting I found was the 'auto' exposure mode.

I was wondering how the 'fixedfps' mode worked. I thought it could be the manual exposure setting? Could someone please explain this to me?

It appears that auto is the only setting working correctly at the moment - I hope to look at this bug next week.

[jamesh]

OK, think I have found the problem. For those that can rebuild the raspistill code...

change the line in the function raspicamcontrol_set_defaults in raspicamcontrol.c that sets the ISO to 400, and set it to 0 instead.

Would welcome feedback as to how well this fixes the issue.

[mikerr]

Changed the ISO default from 400 to 0 and after a quick compile here's the new version:

Code: Select all

-rwxr-xr-x 1 pi pi 49957 Sep 23 14:26 raspistill

Download it:

Code: Select all

wget https://www.dropbox.com/s/7g3ps83a2rrxtp0/raspistill
chmod a+x raspistill

[jamesh]

Changed the ISO default from 400 to 0 and after a quick compile here's the new version:

Code: Select all

-rwxr-xr-x 1 pi pi 49957 Sep 23 14:26 raspistill

Download it:

Code: Select all

wget https://www.dropbox.com/s/7g3ps83a2rrxtp0/raspistill
chmod a+x raspistill

But is it better??????? (thanks Mike)

[poing]

Changed the ISO default from 400 to 0 and after a quick compile here's the new version:

Code: Select all

-rwxr-xr-x 1 pi pi 49957 Sep 23 14:26 raspistill

Download it:

Code: Select all

wget https://www.dropbox.com/s/7g3ps83a2rrxtp0/raspistill
chmod a+x raspistill

Thanks Mike. I got it, but now what? I tried to copy it to first /usr/bin, then to /opt/vc/bin but it doesn't work. Had saved a copy of the original so I got it back to work again but I'd like to know where to put the new file...

[jamesh]

Wherever you like (downloads folder?) - then run it using

./raspistill

[thsBavR10]

Code: Select all

sudo cp raspistill /opt/vc/bin/raspistill

[jbeale]

Changed the ISO default from 400 to 0 and after a quick compile here's the new version:

Code: Select all

wget https://www.dropbox.com/s/7g3ps83a2rrxtp0/raspistill
chmod a+x raspistill

Thanks! I can confirm that with this new version, ./raspistill -ex night -o test.jpg in a dark environment does indeed give me an ISO 800, 1/4 second exposure according to the EXIF tags, and the image looks somewhat noisy, so I think the EXIF tags are correct. As far as I can tell, -ex verylong still does not ever return (killed it after a few minutes). It also leaves something mis-configured, no further invocations of raspicam work until system is reset.

Setting both ISO 100 and also -ex night does not work; exposure stays at 66 msec (1/15 sec).

Code: Select all

pi@raspberrypi:~/camtest$ ./raspistill -ISO 100 -ex night -o test3.jpg
pi@raspberrypi:~/camtest$ identify -verbose test3.jpg | grep exif:ExposureTime:
    exif:ExposureTime: 65924/1000000

[geekinthesticks]

On ArchLinux this gives me 0.25sec exposure and ISO 500 (from EXIF tags). Can also confirm that verylong never returns and causes the camera to lock up. Will do some more exepriments.

[geekinthesticks]

Manually setting ISO as in:

Code: Select all

./raspistill -ex night -ISO 800 -o test_night800.jpg

Results in an ISO of 800, but an exposure of 1/20 sec and an underexposed picture. Don't know if this is expected behaviour. Maybe --ISO and -ex are mutually exclusive.

[jbeale]

Maybe --ISO and -ex are mutually exclusive.

I believe that is correct. The '-ex night' mode is enabled if and only if ISO is not explicitly set. The code bug that was just fixed, was the ISO getting set to 400 by default, instead of leaving it in auto-ISO mode.

Of course, many of us would like to be able to set all the controls including ISO and exposure time, to permit full manual exposure. That is apparently a project for another day. It seems the existing mobile-phone code base in the GPU camera code covers the common use cases, and full manual exposure control in a mobile phone is not a common use case.

[poing]

Yes, with '-ex night -ISO 800' I get 1/25 while with only '-ex night' I get 1/4 (but also ISO 800!)

[jamesh]

Changed the ISO default from 400 to 0 and after a quick compile here's the new version:

Code: Select all

wget https://www.dropbox.com/s/7g3ps83a2rrxtp0/raspistill
chmod a+x raspistill

Thanks! I can confirm that with this new version, ./raspistill -ex night -o test.jpg in a dark environment does indeed give me an ISO 800, 1/4 second exposure according to the EXIF tags, and the image looks somewhat noisy, so I think the EXIF tags are correct. As far as I can tell, -ex verylong still does not ever return (killed it after a few minutes). It also leaves something mis-configured, no further invocations of raspicam work until system is reset.

Setting both ISO 100 and also -ex night does not work; exposure stays at 66 msec (1/15 sec).

Code: Select all

pi@raspberrypi:~/camtest$ ./raspistill -ISO 100 -ex night -o test3.jpg
pi@raspberrypi:~/camtest$ identify -verbose test3.jpg | grep exif:ExposureTime:
    exif:ExposureTime: 65924/1000000

Cool. Looks like a good fix for the exposure issue. I,ve pushed to userland github.

Not sure about very long though. I thought that worked for me.

[gordon77]

I agree verylong locks up my camera, and needs a reboot

[jamesh]

If someone has time can you add the -ex verylong issue to the userland github bug tracker so I don't forget it. Ta.

[geekinthesticks]

If someone has time can you add the -ex verylong issue to the userland github bug tracker so I don't forget it. Ta.

Added to Github.