PDA

View Full Version : Astro shooting with the 20D (non A version)


gus
Nov-30-2005, 12:46 PM
Im heading out bush sat night & have a moonless night so i intend to get some star trail photography in as ive never done it.

Just need some help

I have set custom function 12 to mirror lock up. So i hit the remote & i can here the shutter lockup...i press it again & i can hear (i assume) the shutter open. But it still wont bulb ? I cant find this info in google...can anyone help please ?

Please give a long winded drawn out reply on the best method...i promise to read it.

Shay Stephens
Nov-30-2005, 01:02 PM
Adjust the shutter speed past 30 seconds, it should show 'bulb' and you are all set.



Im heading out bush sat night & have a moonless night so i intend to get some star trail photography in as ive never done it.

Just need some help

I have set custom function 12 to mirror lock up. So i hit the remote & i can here the shutter lockup...i press it again & i can hear (i assume) the shutter open. But it still wont bulb ? I cant find this info in google...can anyone help please ?

Please give a long winded drawn out reply on the best method...i promise to read it.

gus
Nov-30-2005, 01:15 PM
Adjust the shutter speed past 30 seconds, it should show 'bulb' and you are all set.Just did that & have not got 'bulb'..im doing something wrong here.

John Mueller
Nov-30-2005, 01:31 PM
Gus,I think its in the setting mode,AV,TV,M Bulb,etc.Not for sure as I dont have a 20D anymore

gus
Nov-30-2005, 01:48 PM
Gus,I think its in the setting mode,AV,TV,M Bulb,etc.Not for sure as I dont have a 20D anymore
been through them all john but still cant get bulb. thanks anyway.

John Mueller
Nov-30-2005, 02:24 PM
Gus,are you holding down the shutter release for the desired time of exposure?

gus
Nov-30-2005, 02:34 PM
John i assumed it would stay open until i hit it the remote button 2nd time ..im talking about a 2 hour exposure here so i will have to give holding it a miss.

John Mueller
Nov-30-2005, 02:36 PM
Mirror lock-up push once for mirror up,2nd time will open the shutter,but you must hold it down.

On the remote I have,it locks pushing it forward.

gtc
Nov-30-2005, 02:37 PM
gus

in mirror lock up when you hit the button the first noise is the the mirror lifting and the shutter firing,the next time you hit the button you will hear the mirror drop down so that your viewfinder operates again.

try shutter priority and wind the shutter speed dial all the way back until you get bulb.

it may be a firmware glitch-try clearing all camera settings and then switch off and back on again.


Im heading out bush sat night & have a moonless night so i intend to get some star trail photography in as ive never done it.

Just need some help

I have set custom function 12 to mirror lock up. So i hit the remote & i can here the shutter lockup...i press it again & i can hear (i assume) the shutter open. But it still wont bulb ? I cant find this info in google...can anyone help please ?

Please give a long winded drawn out reply on the best method...i promise to read it.

gus
Nov-30-2005, 02:56 PM
ooooookkkkkk...it has to be on M !! Now i get it.


Final question. To avoid the shutter shake initially i read that you can aim at a star let her focus & then set to manual focus and hold a hat etc over the front of the lens (not touching) hit the remote button & once you hear it open then remove the hat & let the image start.

Sound feasible ?

John Mueller
Nov-30-2005, 03:03 PM
Go for it,cant wait to see what you come up with:):

gus
Nov-30-2005, 03:26 PM
Go for it,cant wait to see what you come up with:):I'll come home with something thats for sure john. Im staying in the tree house (http://wadjelaphotography.smugmug.com/photos/3371994-M.jpg) for the night & there is always a yowie or 2 about (http://www.yowiehunters.com.au/index.php?option=com_content&task=view&id=201&Itemid=106) up that way.

Gets a bit uncomfortable up there by yourself somenights. Once they start stamping their feet & hitting rocks together you dont get back to sleep.

gtc
Nov-30-2005, 03:31 PM
thats the way they used to do it in the olden days before shutters were invented!
ooooookkkkkk...it has to be on M !! Now i get it.


Final question. To avoid the shutter shake initially i read that you can aim at a star let her focus & then set to manual focus and hold a hat etc over the front of the lens (not touching) hit the remote button & once you hear it open then remove the hat & let the image start.

Sound feasible ?

tmlphoto
Nov-30-2005, 03:34 PM
Gus,
I don't think you really need to worry about mirror lockup for such a long exposure although it couldnt hurt to use it. My understanding is that mirror lockup is helpful for a certain range of slow, but less that one second exposures. Around 1/15th or so. Good luck with your star quest.

gus
Nov-30-2005, 03:35 PM
thats the way they used to do it in the olden days before shutters were invented!
Ive got 5 pinhole cameras sitting beside me & i have made wooden shutters for 2 of them & the others i just use duct tape.

I have no way to check my work up in the scrub so i want to make sure my methods work 1st before i waste a night cowering up a tree throwing rocks at the yowies.

gus
Nov-30-2005, 03:36 PM
Gus,
I don't think you really need to worry about mirror lockup for such a long exposure although it couldnt hurt to use it. My understanding is that mirror lockup is helpful for a certain range of slow, but less that one second exposures. Around 1/15th or so. Good luck with your star quest.tks thomas...i hope to in the very least learn something anyway.

gtc
Nov-30-2005, 04:53 PM
take a flash and get a shot of a yowie and you won't have to worry about gear prices for a very long time...


Ive got 5 pinhole cameras sitting beside me & i have made wooden shutters for 2 of them & the others i just use duct tape.

I have no way to check my work up in the scrub so i want to make sure my methods work 1st before i waste a night cowering up a tree throwing rocks at the yowies.

Shay Stephens
Nov-30-2005, 05:19 PM
Having the camera auto focus on stars can be hit and miss. Mostly miss with me.

If possible, try to auto focus on infinty by aiming at trees lit by something or even before the sun goes down. Maybe manual focus. Or maybe even shooting some short exposure test shots that are auto focsued on the stars first to try and verify the focus before you commit to a 2 hour exposure only to find it misfocused ;-)

And shoot a 15 minute exposure first to verify that the noise isn't going to destroy the photo. Nothing more heart breaking than spending all that time only to find the photo is nothing but noise.

gus
Nov-30-2005, 05:36 PM
Having the camera auto focus on stars can be hit and miss. Mostly miss with me.

If possible, try to auto focus on infinty by aiming at trees lit by something or even before the sun goes down. Maybe manual focus. Or maybe even shooting some short exposure test shots that are auto focsued on the stars first to try and verify the focus before you commit to a 2 hour exposure only to find it misfocused ;-)

And shoot a 15 minute exposure first to verify that the noise isn't going to destroy the photo. Nothing more heart breaking than spending all that time only to find the photo is nothing but noise.Thanks shay but i always get good results aiming at a planet 1st...venus atm. After the storms go over the sky to the west clears & venus does not sink below the horizon until about 2100. I lock onto it & then go to manual & swing the camera east to get the lightning coming from the back of the storm. I misled you a bit...its a lot brighter than a star.

Yep noise is something im interested in finding out about. All i can do is sit on iso 100 & see what i get.

Shay Stephens
Nov-30-2005, 10:16 PM
I could see Venus working better because it has a non zero diameter. The problem that can happen with stars is that the contrast of a partially unfocused star can be greater than a focus one. Many cameras use contrast to guess at the focus and so often misfocus in such situations.

So my advice is to just really pay attention to the preview before commiting to a really long exposure http://www.digitalgrin.com/images/smilies/mwink.gif

And ISO 100 is good, but warm weather and long exposures can do some pretty wicked things. So ramp up the exposure time. I like to do a 15 minute test first. If it looks good, then I go for it, if it is really noisy, then there is no point. I wound up with a photo that was nothing but noise and I was devestated to say the least. I was on location, late at night, and nearly had nothing to show for it save for the shorter exposures I took after the big long exposure. Now I do the short ones first http://www.digitalgrin.com/images/smilies/mwink.gif

Thanks shay but i always get good results aiming at a planet 1st...venus atm. After the storms go over the sky to the west clears & venus does not sink below the horizon until about 2100. I lock onto it & then go to manual & swing the camera east to get the lightning coming from the back of the storm. I misled you a bit...its a lot brighter than a star.

Yep noise is something im interested in finding out about. All i can do is sit on iso 100 & see what i get.

RichardBrackin
Dec-01-2005, 07:43 AM
Probably stating the obvious here but:

Make sure sure sure you have sufficient battery power.
You don't want the battery to go out with the shutter still open or the 20D gets to take a little trip to a Canon service center.

DoctorIt
Dec-01-2005, 09:38 AM
Probably stating the obvious here but:

Make sure sure sure you have sufficient battery power.
You don't want the battery to go out with the shutter still open or the 20D gets to take a little trip to a Canon service center.Really?

When I did star trail shots with my DRebel (300D), I left it outside unattended once, and the battery did in fact die. I don't recall now whether the shot was saved or not (I seem to think it was), but there was definitely no trip to the service center.

Strange that the 20D would be different.
:scratch

ChrisJ
Dec-01-2005, 11:22 AM
Not much to offer, my astro shots have been limited to about 5 mins of exposure time... but I'm looking forward to seeing your shots!

This is an area where the beefier remote (http://www.canoncompanystore.com/epages/annex.storefront?ProductDetail=2465A001AA) can come in handy.