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-   -   Using Camera With Long exposure (https://talk.maemo.org/showthread.php?t=63344)

deyons 2010-10-04 15:06

Using Camera With Long exposure
 
I live in the city and I cant take pictures of the stars. I would need to take pictures with a long exposure of around 4 seconds. Is there a Script or any App that would let me do this?

Khertan 2010-10-04 15:15

Re: Using Camera With Long exposure
 
I think FCam can do that

dqm 2010-10-04 15:29

Re: Using Camera With Long exposure
 
FCam offers the opportunity to do that but I haven't seen anything that anyone has written to do it. It would be great though, light painting with an N900!

deyons 2010-10-04 19:51

Re: Using Camera With Long exposure
 
Thanks..I will have to think very hard about this as how last time FCamera drivers some how stopped my keyboard lights and notification lights from working.

handaxe 2010-10-04 22:07

Re: Using Camera With Long exposure
 
fcam is updated to fix the led issue.
Apparently the makers of blessn900 have an in-house version with timed exposure. hope they release it....

ahmadamaj 2010-10-04 22:27

Re: Using Camera With Long exposure
 
i don't think fcam can get exposures more than 1 sec. if it can, can somebody teach me how plz.

TiagoTiago 2010-10-04 22:53

Re: Using Camera With Long exposure
 
the Fcamera example program only goes to 1 second

and it seems Fcam is screwing with the autolocking of my N900 (somtimes it won't engage, seemed to work normally when i uninstalled Fcam, and then stopped workign again after i reinstalled, though somtimes it stay working for a while even with it installed so i don't know for sure if it's really Fcam's fault)

edit:seems it turned out it was Shake-N-Surf's fault

ossipena 2010-10-05 06:22

Re: Using Camera With Long exposure
 
Quote:

Originally Posted by ahmadamaj (Post 833379)
i don't think fcam can get exposures more than 1 sec. if it can, can somebody teach me how plz.

could you paste the code and possible error messages when compiling?

hint: fcam = api
fcamera = the application you can run with your n900

azkay 2011-03-22 03:27

Re: Using Camera With Long exposure
 
Anyone found something for this yet? FCamera only has 1 second as the longest exposure.

handaxe 2011-03-22 07:26

Re: Using Camera With Long exposure
 
I think there is no solution to this. The sensor is quite noisy so that would pose a problem on long exposures, don't you think?

azkay 2011-03-22 11:02

Re: Using Camera With Long exposure
 
Quote:

Originally Posted by handaxe (Post 972894)
I think there is no solution to this. The sensor is quite noisy so that would pose a problem on long exposures, don't you think?

100 iso, long exposure. One way to find out.

mishmich 2011-03-22 12:45

Re: Using Camera With Long exposure
 
If the chip is CMOS, rather than CCD, then long exposures will be noisy. In astrophotography, people tend to use CCD chips because of this. CMOS chips are improving. I'm not sure what the n900 has, but I expect it is CMOS, as these are cheaper (CMOS are what you get in webcams). The chip seems quite small as well. I have used webcams and DSLR's. Webcams have small chips, and can produce reasonable results for planets - although CCD is better (Phillips used to make one, but they are hard to get hold of now). DSLR's are OK for Deep Sky Objects - although I have managed to use a Russian software hack to get reasonable images of Jupiter with one. the DSLR has a larger sensor. My guess is that you would get results with planets, but stars would be difficult. Light sensitivity is another problem - and with longer exposures you would need to start tracking accurately, otherwise you will get star-trails. I forget now how long my exposures were for something like Pleiades or Orion, but it was an hour of 30 second exposures to start getting any nebulosity out. 4 seconds without tracking, I'd have thought you'd be lucky to get a blur.

Edit: Just checked - yeah, it is CMOS

mishmich 2011-03-22 13:01

Re: Using Camera With Long exposure
 
1 Attachment(s)
This is one I prepared earlier - taken with a Canon EOS1000D, using a 4" ED refractor on an EQ mount

mishmich 2011-03-22 13:07

Re: Using Camera With Long exposure
 
1 Attachment(s)
This was with a Sony Alpha, I think, and the ED refractor. The moon is the best place to start, because it is big and bright - but it does move faster relative to the stars and planets. Needs shorter exposures, less sensitivity.

mishmich 2011-03-22 13:19

Re: Using Camera With Long exposure
 
3 Attachment(s)
This is the best I managed for Jupiter using the EOS 1000D with the video hack. Took a lot of post-processing to bring out any detail. I never thought of trying the n900 - as I attach the camera direct to the telescope and just use the sensor (avoiding the camera lenses). You can use anything with a sensor - I rigged up a CCTV camera to take these images of Mars & Saturn.

There might be another way of approaching this - with the CCTV camera, I hooked that up to a HDD recorder, then processed the video. You might find taking video with the n900 produces better results - you take the frames recorded and put them into something like Registax to stack them and average them to produce a better image. You'd still need to track the object quite accurately though.


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