Help?

[mod1968]

Hello all,

I am a absolute beginner in astrophotography and was wondering if anyone could help me or give me some tips on how to take pictures of stars. I have a canon EOS 400D 10.1 megapixel digital camera with EFS18-55mm lens and EF75-300mm lens and tripod. Where do I start? What settings do I need on the camera? Aperture / Speed? Any help would be greatly appreciated... even just a quick set up so I can take a picture would be fine. Thanks you in advance.

Marcelo

[jjjnettie]

Here is a link to Canon's EOS Digital Astrophotography Guide. It may be a little dated, but it's a good place to start.
http://web.canon.jp/imaging/astro/pages_e/01_e.html

[iceman]

Hi Marcelo, welcome to IIS!

The Canon 400D is a great camera, and a great astro camera. The low noise and high sensitivity make it perfect for astro use.

The stock lenses are "ok" to start with. They're not great, and have some imperfections but they'll be enough to get you started. The 18-55 is worst at the 18mm end especially when it's not stopped down. The corners will show a lot of coma (stretched stars) and there's a bit of CA (Chromatic Abberation) on the bright stars. The 75-300mm is a great zoom lens for long focal length stuff, but may not be suitable for what you want to do.. let me explain further.

You've got a fixed tripod, so you'll be looking at a fixed piece of sky. As the Earth turns, the stars move. The longer the focal length, the quicker the apparent motion of the movement of the stars.

At 18mm on a fixed tripod, you'll be able to do a long exposure of around 15-20 seconds without getting star trails, but any longer than that and you'll start getting trailing. At longer focal lengths, for example the 75mm lens, you may only get 5 seconds exposure before you start getting trailing. It also depends which area of the sky you're pointed at. Best to just do some trial and error.

Regarding settings,
- Set the lens to the desired focal length (for eg: around 20mm on the 18-55).
- Set the lens to autofocus and point it at a bright star and hold the shutter halfway until it finds focus. Then change to manual focus, taking care not to change the zoom or focus. If you can't lock on autofocus, you'll have to try and manually focus it - this can be difficult and may need a series of test exposures to see if you're focused.
- Set the camera to Manual mode
- Change the exposure to f/4 or so - 1 or 2 stops down from wide open
- Change the shutter to 20s exposure.
- Change the ISO to 800.
- Leave White Balance on AUTO.
- Set the Quality to RAW if you normally shoot in RAW. If you're unsure what that means or how to process RAW, set it to Highest Quality before RAW.
- Click away!

Once you've got a bit of practise, you can do some more advanced settings like In-Camera Noise Reduction ON (in the custom functions) and also mirror lockup ON (again in the custom functions).

Do you have a remote?

If you do, set the camera to remote and then you can do your own timed exposures, from 15s to a minute or more, and you can see the effect of the star trails at different focal lengths and different exposure times.

I hope that helps, keep asking questions and make sure you post your results so we can help further!

Where is Carrum Downs? What's the sky like? Dark or light polluted?

[erick]

Hi Marcelo

Sorry I have to speak from the knowledge of a film SLR, but here are the concepts:-

Start with simple goals. How about some star trails? Find a dark sky location. Put the camera on a tripod, point it to the South Celestial Pole (about 40 deg up from due south) get it to the "B" setting, turn off flash, set focus to infinity, open to wide angle and hold that shutter open for anything up to a hour or two, and nothing less than about 15 min
- see what you get.

Then have a go at the Moon - not only at full Moon, but a cresent and at various phases before full. On a tripod again, no flash, let the camera decide the exposure and see what you get. Zoom in, zoom out. Try that 300mm lens - but exposures need to be short, the tripod solid, no wind and careful of any camera shake. We have a full Lunar eclipse coming up on 28 August (if I remember correctly). Lovely photos of a red/brown moon during the eclipse are possible then - probably longer exposures.


There's a few thoughts to get you started. Now, we need to here from the DSLR experts who can correct my old-fashioned thinking! Eric :D


(edit - yep, Mike beat me to the "send" button. Listen to him, not me!)

[iceman]

Your advice is spot on, Eric! :thumbsup:

Although leaving the shutter open for an hour or two might give you a completely white image, depending on where you live ;)

And on a DSLR, you may need to hook it up to more power - at least make sure the battery is fully charged.

[erick]

Yes, at Carrum Downs I expect all white will result, now I think about it. In defence, I did say find a dark sky location. :P

I was recalling my best star trails on film - they were an hour plus exposure - but they were in the middle of Central Queensland away from any towns!

[PCH]

Erick,can you tell us what speed film you use in your regular SLR for astro use?CheersPaul

[erick]

Paul

I'm not particularly experienced and only recently went back into this.

I photographed Comet McNaught with Kodak EliteChrome 400ASA slide film. Had to go to the big shops to purchase and it took me a while to find a suburban photoshop who still processed slide. See this thread for pics:-

http://www.iceinspace.com.au/forum/showthread.php?t=16990

Then more recently I went for widefield shots of the stars on a little tracker I set up. I didn't expect much so just pulled some Fuji 400ASA colour print film out of the fridge where it had been for a few years. Results were better than I had anticipated so I put them here:-

http://www.iceinspace.com.au/forum/showthread.php?t=19735 (http://www.iceinspace.com.au/forum/showthread.php?t=19735)

My suggestion is that you use no less than 400ASA film. Slide is reportedly the best choice. If you search the web - probably "astrophotography film", I'm sure you'll still find some historic sites that talk about film work and choice - I've read several some months ago. However, I suspect the days of hypersensitising film with reforming gas :scared: are now long gone! Try this site from 2004:-

http://www.covingtoninnovations.com/astro/films.html

However, I'm going digital as soon as I can afford to! :)

[PCH]

Erick,

I followed your various links and read all your stuff, - so I got the full thread of what you've acheived there. I must say the photos look very impressive to me as a beginner. And I don't mean that in a patronising manner, - just that I'm not qualified to offer any constructive criticism as has been requested on the forum recently.

I would be extremely happy if my own results were anything like as good in time. However, from your very final comment about going digital when you have the readies, and also with the increasing unavailability of the film/slide type services, I'm tempted to agree with you and possibly go for the digital option too - when the readies are there !

Keep up the good work and thanks for the reply.

Cheers,

Paul