One for the camera experts.

[+Graham]

Just purchased a remote control for my canon eos 1300 D so I can do long exposure stuff. 

It requires the camera to be set on manual to use the bulb function. 

Not a problem so far.

Here's the question. 

What do I set the F stop to.

I am using my new 70 - 300 zoom lens.

Thanks in advance. 

[Alec]

I’m no expert but the following have served me well :-

 

Shoot in RAW

Select a fast aperture F/2.8 - F/4

White balance to daylight

ISO 400 - 1600

Manual mode

[+Graham]

Thanks Alec. 

It was the F number that had me puzzled. 

[MeadeUser]

Just open it up as far as it will go....that way the exposures can be shorter...just like using a very fast scope.. ?

[+Ibbo]

I usually stop the lens down one stop sometimes 2 depending on the lens

[Craig]

If you are shooting to infinity, which you will be (as close as) when shooting the night sky, then the widest (lowest) is likely going to be fine. The narrower (higher) the more depth of focus, increasing the likelihood of sharpness of the focus point, but at infinity this matters very little.

 

Lenses do typically have a known sweet spot for sharpness, though, so you may want to Google the lens to see if there's agreement on what it is.

[andyboy1970]

Google your lens and look at tests, you usually find stopping it down prevents blurring at the edges and corners.

For example my 50mm F1.8 Canon lens works better at F3.5.

[Doc]

I agree I would step it down a few stops to get a sharper image.

[+Bino-viewer]

I agree too.

I've tried a 30s night sky exposure from home before with one of my lenses wide open at F1.2

and iso 1600 and all i got was a white image ☹️

I'm guessing thats my rather dire light pollution telling me something....?