#1  
Old 28-09-2008, 06:37 AM
keppar (Graham)
Registered User

keppar is offline
 
Join Date: Aug 2008
Location: Albury N.S.W
Posts: 159
Camera control

Hi
I have a Canon 40d and would like to control exposure times etc thru the computer. The canon program does this except that it wont allow bulb exposures that exceed the time taken between shots...eg 5 min exposure you must have at least a 5 minute wait before next shot. This is not practical ...Any ideas
Reply With Quote
  #2  
Old 28-09-2008, 07:34 AM
acropolite's Avatar
acropolite (Phil)
Registered User

acropolite is offline
 
Join Date: Feb 2005
Location: Launceston Tasmania
Posts: 8,985
Could be long exposure noise reduction; when turned on, long exposure noise reduction takes equal length darks and does in camera subtraction. If you turn off Long exposure noise reduction you won't have to wait for that period equal to your exposure, but you'll have to take dark frames and manually process.
Reply With Quote
  #3  
Old 28-09-2008, 07:59 AM
keppar (Graham)
Registered User

keppar is offline
 
Join Date: Aug 2008
Location: Albury N.S.W
Posts: 159
Thanks Phil
But that still didnt work turned all noise reduction off
Reply With Quote
  #4  
Old 28-09-2008, 08:17 AM
bojan's Avatar
bojan
amateur

bojan is offline
 
Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 5,947
Then leave long exposure noise reduction ON
You will not need to take dark frames
This is what I am doing, so I do not need to bother with them
Reply With Quote
  #5  
Old 28-09-2008, 09:04 AM
TrevorW
Registered User

TrevorW is offline
 
Join Date: Aug 2006
Posts: 6,995
Keppar IMO 5 minute exposures are plenty long enough to capture what you need. I'd turn off in camera noise reduction and take darks, lights, and bias's it will speed up the process and reduce the drain on tha batteries as well. In my limited experience ISO 400 and 800 are the best settings.

Cheers
Reply With Quote
  #6  
Old 28-09-2008, 10:51 AM
Ian Robinson
Registered User

Ian Robinson is offline
 
Join Date: Jan 2007
Location: Gateshead
Posts: 2,205
TC-80n3 maybe ?

Yet to buy one , can you do long exposures in rapid fire sequences with only a second or so between with this device ?

What is the program written in (C++, Java) ? maybe if you have access to the source code you can comment out the "delay" between exposures and then recompile ?
Reply With Quote
  #7  
Old 28-09-2008, 11:10 AM
TrevorW
Registered User

TrevorW is offline
 
Join Date: Aug 2006
Posts: 6,995
Ian

Look at the one from Apeture available on E-bay works well same specs as genuine Cannon and would be 1/2 the price

Cheers
Reply With Quote
  #8  
Old 28-09-2008, 11:20 AM
Ian Robinson
Registered User

Ian Robinson is offline
 
Join Date: Jan 2007
Location: Gateshead
Posts: 2,205
Quote:
Originally Posted by TrevorW View Post
Ian

Look at the one from Apeture available on E-bay works well same specs as genuine Cannon and would be 1/2 the price

Cheers
Reply With Quote
  #9  
Old 28-09-2008, 11:30 AM
leon's Avatar
leon
Registered User

leon is offline
 
Join Date: Apr 2006
Location: ballarat
Posts: 10,812
As already mentioned the TC-80N3 is the way to go, or something similar, however you can't get a way from the extra time it takes to capture a dark for each light frame.

Although this dose double your times in taking lights, it is the best way to go, and gives you darks that are exactly the same temp as your lights.

It is a bugger to have to wait this long each time, but in the end it is well worth the effort.

Leon

Last edited by leon; 28-09-2008 at 12:12 PM.
Reply With Quote
  #10  
Old 28-09-2008, 11:50 AM
g__day's Avatar
g__day (Matthew)
Tech Guru

g__day is offline
 
Join Date: Dec 2005
Location: Sydney
Posts: 2,564
When you say long exposure noise reduction is off - you checked the C.fn bit (is it the eight bit on that model 001100000 etc) is set to 0 not one?

When you do a 1 minute shot does it go for 2 minute, does a 5 minute shot expose for 5 and subtract noise for 5 = 10 minutes - in which case the noise function is still active. Better problem diagnosis will allow better help feedback from folk here.

Matt
Reply With Quote
  #11  
Old 28-09-2008, 01:30 PM
keppar (Graham)
Registered User

keppar is offline
 
Join Date: Aug 2008
Location: Albury N.S.W
Posts: 159
Yes Matthew long exposure noise reduction is set to off.
I cannot set a exposure time that is more than the time off between shots. I have fooled around with settings that were on also
Reply With Quote
  #12  
Old 28-09-2008, 01:42 PM
Ian Robinson
Registered User

Ian Robinson is offline
 
Join Date: Jan 2007
Location: Gateshead
Posts: 2,205
Quote:
Originally Posted by leon View Post
As already mentioned the TC-80N3 is the way to go, or something similar, however you can't get a way from the extra time it takes to capture a dark for each light frame.

Although this dose double your times in taking lights, it is the best way to go, and gives you darks that are exactly the same temp as your lights.

It is a bugger to have to wait this long each time, but in the end it is well worth the effort.

Leon
Surely , since the temperature tends to be steady at night or to change very slowly , it is a case of overkill doing "darks" between each "light" of the same duration ?
I may be looking at this too simplistically , but surely you only need a "dark" every so often , say once every 5 or 6 "lights" and you'd be hard pressed to spot the difference if less frequent "darks" are taken ?
Or is this something to do with the time it takes for the CCD pixcels to loose those holes and electrons accumulated during the exposure due to the photons being captured ie it takes a while for them to diffuse out and so for the residual noise in the chip due to stray holes and electrons to disappear so you must do the "darks" to compensate for this ???

Anyone know ?

Note - I'm yet to turn my 40D onto the heavens , even to get it out of the box so though I've many many many years of astrophotography experience behind me (35mm film) , I'm new to this digital game.
Reply With Quote
  #13  
Old 28-09-2008, 01:48 PM
RB's Avatar
RB (Andrew)
Moderator

RB is offline
 
Join Date: Aug 2005
Posts: 21,982
Quote:
Originally Posted by keppar View Post
Hi
I have a Canon 40d and would like to control exposure times etc thru the computer. The canon program does this except that it wont allow bulb exposures that exceed the time taken between shots...eg 5 min exposure you must have at least a 5 minute wait before next shot. This is not practical ...Any ideas
Guys it's got nothing to do with ICNR, as keppar explained, the software does not allow you to set a shorter interval than the exposure interval.
That's it, it's how the software is designed and last time I looked Canon were not offering their code as Open Source.

The quickest and best solution is to get a TC-80N3 or equivalent and use it with your 40D.
You may want to google for a control app for the 40D but I've yet to see one apart from Images Plus.
DSLR Focus had the feature but only supports up to 20D from memory with no further updates available.

Hope this helps.
Reply With Quote
  #14  
Old 28-09-2008, 01:53 PM
leon's Avatar
leon
Registered User

leon is offline
 
Join Date: Apr 2006
Location: ballarat
Posts: 10,812
Surely , since the temperature tends to be steady at night or to change very slowly , it is a case of overkill doing "darks" between each "light" of the same duration ?


I can see where you are coming from, in regard to this, and I too was thinking that the transition of 35 mm into digital was a piece of cake, so to speak.

As you, I figured how hard could it be, gee I had been doing 35mm film stuff for ever, I have this experience, so this can't be that hard surly.

Well no, it really isn't hard, but I soon learn't that to get the best out of the digital world there were a few things that I should do to make the results as good as possible, and taking darks and flats etc, was one of them.

It dose make a big difference to get the temp right, and ICNR is also the best way to go, I know it is a pain in the arse, but thats life.

Leon
Reply With Quote
  #15  
Old 28-09-2008, 01:54 PM
RB's Avatar
RB (Andrew)
Moderator

RB is offline
 
Join Date: Aug 2005
Posts: 21,982
Quote:
Originally Posted by Ian Robinson View Post
Surely , since the temperature tends to be steady at night or to change very slowly
Not necessarily, you'd be surprised the difference it makes to the final image.
Try it first before forming an opinion, temp differentials in darks causes horrible black dots everywhere in the image.
The closer your darks are in temp to your lights the better.
Reply With Quote
  #16  
Old 28-09-2008, 01:55 PM
keppar (Graham)
Registered User

keppar is offline
 
Join Date: Aug 2008
Location: Albury N.S.W
Posts: 159
Thanks all will get a TC 80 nc
Reply With Quote
  #17  
Old 28-09-2008, 10:00 PM
vash's Avatar
vash (Ashley)
Registered User

vash is offline
 
Join Date: Nov 2005
Location: Gold Coast
Posts: 420
I'm thinking of getting one of these for my 450D, or maybe just a longer usb cable because the stock one doesn't reach the top of the 10" Newtonian.
Reply With Quote
  #18  
Old 28-09-2008, 10:12 PM
dugnsuz's Avatar
dugnsuz (Doug)
to baldly go...

dugnsuz is offline
 
Join Date: Aug 2005
Location: Hahndorf, South Australia
Posts: 4,200
Quote:
Originally Posted by keppar View Post
Yes Matthew long exposure noise reduction is set to off.
I cannot set a exposure time that is more than the time off between shots. I have fooled around with settings that were on also
Don't know if this is the problem, but I had something similar a wee while back.

The EOS utility software wouldn't let me set exposure times over a certain value due to the amount of available storage space left on my CF card.
I wanted to take 10 exps and I neglected to observe that I only had 4 left!!!
Perplexed me for ages until the penny dropped.
Might help.
All the best
Doug
Reply With Quote
  #19  
Old 28-09-2008, 10:49 PM
Terry B's Avatar
Terry B
Country living & viewing

Terry B is offline
 
Join Date: Mar 2006
Location: Armidale
Posts: 2,759
Quote:
Originally Posted by keppar View Post
Thanks all will get a TC 80 nc
You seem to have a problem. Using the supplied software I can take a 5 min exposure every 5 mins and 15 secs. This is pretty close to continuous exposing. I take darks after I've finished as they can be taken unsupervised when I'm in bed.
The use of ICNR is controversial and different people will use or not use it. The theoretical advantage of combining darks compared to the ICNR that essentially subtracts a single dark is that you can median combine multiple dark frames and this will reduce the non thermal noise in the darks.
Reply With Quote
  #20  
Old 29-09-2008, 08:38 AM
keppar (Graham)
Registered User

keppar is offline
 
Join Date: Aug 2008
Location: Albury N.S.W
Posts: 159
Yes Terry .It will allow you take exposures that are a less time than the duration between then ,this is not practical for me. The program Nebulosity 2 I have just found allows me to do what I want
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 09:45 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
OzScopes Authorised Dealer
Advertisement
Lunatico Astronomical
Advertisement
Celestron Australia
Advertisement
Meade Australia
Advertisement
Bintel
Advertisement
SkyWatcher Australia
Advertisement
NexDome Observatories
Advertisement
Astronomy and Electronics Centre
Advertisement