Wide Field Canon 300D, what fstop

[BlackWidow]

Want to do some wide field shots tonight with the Canon 300d piggy back on the LX200.. I want to take a Milky Way shot and wanted to get an idea of what F stop is best with a 18 - 55mm lense.


Regards
Mardy

[hotspur]

I posted an image here on IIS about three weeks ago,using a DSLR,I try and find a link.

I think I used F5.6,but I have used F6.3 and 7.1 all worked well.

Look forward to seeing your results.I will go through some files and get some more info for you.

[BlackWidow]

Thanks Chris.. Tonight looks really good here in Adelaide for a change. Should be a good night. I have just reached the point where I have managed to learn to be able to align my scope, guide and control all the software to use my QHY8. I have learnt each section at a time. I spent week’s just getting alignment and guiding working well.

Tonight I try to put it all together and get some images... I like to walk before I run and have spent over 12 months learning each process. It is hard to go out and go through all the steps needed to image without doing any.. Now I have it all working (I hope).. Nebulosity setup with correct offsets, Guiding working well, Alignment with Alignmaster, Starry Night directing the scope and software running exposures on the 300d at the same time... Very Exciting... Can’t wait to get some data at last and start image processing...

Thanks for your help and wish me Luck.. :D


Cheers
Mardy

[hotspur]

http://www.iceinspace.com.au/forum/showthread.php?t=78887&highlight=milky+wide+field


Here is image I took with dslr and 10-22 mm lens.

I will find all data and details and let you know,(on a different comp at present)

Think it was F 5.6 or F 6.3 14 minutes single exp on Vixen GD mount with DD1 controllers and motor,ICNR.

Was amazed how well it turned out,without all the stacking and subtraction and computer patch ups-Even my U.K press agent liked it-and it made the news!

[jjjnettie]

Like Chris said, f5.6- F6.3, the bigger the number, the tighter the stars and the less coma.
ISO 400 makes a smoother picture and more colour in your stars I reckon.
It does mean you need to take more subs, but it's well worth it.

For more instant gratification, go ISO 800 or ISO1600. Just don't be tempted to go to a faster F stop or you'll compromise the edges of your image pretty badly.

Just check your first sub, zoom in around the edges and see what your stars look like. Experiment with settings.

Good luck, you're going to have a great time. :)

[alistairsam]

Hi,

I had my first go at widefield last night with my canon 1000d and the 18-55mm lens.
didn't really check the f stop but now that you'll mention it, is there a relation between the fstop and the aperture and are both independent of each other (i'm guessing 18-55mm is the aperture size)?
bigger f stops would mean less light, longer exposures like in telescopes?

I'm new to photography concepts so lots to learn.
if I set the lens to 18mm and piggyback on an eq mount, would that be sufficient for a start at widefield?

[RB]

Aperture is your f stop, the higher the number the less light and longer exposure needed.
eg. f/1.4, f/2, f/2.8, f/4, etc.

http://en.wikipedia.org/wiki/Aperture

Your 18-55mm is your focal length range of the lens (determines your FOV) and yes 18mm is sufficient to start widefield photography.

:)

[alistairsam]

thanks. I should have looked that up. this explains it in a nutshell
http://en.wikipedia.org/wiki/File:Aperture_diagram.svg

will give it a shot.
I know dark skies are ideal but wonder how it'll turn up from outer city suburbs.
I do have an EOS UHC-S clip filter but unfortunately doesn't work with my lens.

[RB]

Try and shoot away from the light pollution obviously but being widefield it'll be hard to avoid the glare.
Give it a go anyway and see how it goes.

[RB]

Yeah unfortunately they don't work with EF-S lenses.