Jump to content


Photo

Canon EOS 1000D strange noise pattern

  • Please log in to reply
8 replies to this topic

#1 N_DD

N_DD

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 21 Oct 2012
  • Loc: East Germany

Posted 29 September 2013 - 04:46 AM

Hi,

I recently got an astromodified Canon EOS 1000D (Rebel XS). I tried shooting some test images and I always get a strange noise pattern (see image: 2 min. at ISO 800, camera without lens and closed with lid, LCD off, contrast stretched). There is amp glow visible (low left), but what worries me is the dark band at the bottom. The pattern does not change if I use APT or the canon EOS utility or if I manually depress the shutter button... any idea about what could it be?

Thanks a lot!

Posted Image

#2 mmalik

mmalik

    Fly Me to the Moon

  • *****
  • Posts: 5369
  • Joined: 13 Jan 2012
  • Loc: USA

Posted 29 September 2013 - 11:58 AM

Not sure if you bought it modified or modified it afterwards; if later, I would consult with the modifier. Regards

#3 wasyoungonce

wasyoungonce

    Messenger

  • -----
  • Posts: 476
  • Joined: 07 Jun 2007
  • Loc: Land Downunder

Posted 29 September 2013 - 07:42 PM

You might want to read this thread and look at a link I provided in post #5512214. Looks a lot like I experienced.

Also check the shutter isn't jamming or you have the viewfinder fully covered. Cannon give a little rubber shoe to fit over the viewfinder...you can use this or tape.

Also try to take "darks" with aluminium foil over the lens cap. A lot of plastic caps pass infrared which can be seen on the sensor as photons.

Hope this helps

edit:
Oh one last thing...check the mirror lockup is fully going up out the light path way.

#4 N_DD

N_DD

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 21 Oct 2012
  • Loc: East Germany

Posted 30 September 2013 - 03:43 AM

Hi Brendan,

thanks a lot for the link: I was aware of both the mirror lockup and the "live view" issues, so I disabled the ML on the camera side and on APT and did not shoot using "live view". However, I still get that dark band at the bottom of every image I take... I am still using "virtual" exposure control, might that be the culprit?
Interesting point the aluminum foil, I will try again with better light shielding.

Nico

#5 N_DD

N_DD

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 21 Oct 2012
  • Loc: East Germany

Posted 01 October 2013 - 05:56 PM

Ok, seems that there is no explanation for the strange dark band... the problem is similar to what people have experienced when shooting with live view, but I have disabled it!!! The LCD screen is off, the viewfinder capped, and in APT the mirror lockup is disabled and the anti vibration pause set to 0... anyone has an idea? I am starting to consider selling the camera as partially malfunctioning :( ...

#6 mmalik

mmalik

    Fly Me to the Moon

  • *****
  • Posts: 5369
  • Joined: 13 Jan 2012
  • Loc: USA

Posted 01 October 2013 - 06:02 PM

Modifier should own this and take care of the problem in my opinion. Thx

#7 jsines

jsines

    Mariner 2

  • *****
  • Posts: 256
  • Joined: 06 Sep 2011
  • Loc: Berkley. Michigan

Posted 01 October 2013 - 07:00 PM

My hunch is that your shutter isn't opening all the way. Try the cleaning sensor option on your 1000D, where you take off the lens, press the shutter button, and the shutter opens all the way. If you look in there and the shutter doesn't open all the way, that's probably the problem.

My hunch is also that the shutter isn't opening all the way because of how it was modified. The modifier should fix this.

#8 wasyoungonce

wasyoungonce

    Messenger

  • -----
  • Posts: 476
  • Joined: 07 Jun 2007
  • Loc: Land Downunder

Posted 02 October 2013 - 01:13 AM

Yep as said check the shutter is opening fully...maybe do a 5 sec exposure or open shutter with lens off.

Also check the flip mirror is fully moving up out the way. It does look like a light leak around the flip mirror.

Other than that...it's back to the modifier.

#9 N_DD

N_DD

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 21 Oct 2012
  • Loc: East Germany

Posted 02 October 2013 - 01:15 PM

Ok, thanks guys. I will try to troubleshoot with the previous owner (I purchased the camera used and was already modified). My bad I didn't ask for flats before buying. Anyway I checked the shutter, as already suggested by Brendan and jsines, and it seems it's opening ok. On the other hand, I am getting the noise pattern even without any light entering the camera, so it must be something electronic. Subtracting the noise pattern as bias in DSS restores the images.

Nico






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics