Nifty fifty settings

[bottletopburly]

I’m currently building a imaging train which I’ll consist of a canon nifty fifty 1.8 Ef lens connected to a zwo585mc, with autofocus and guided what aperture setting would be recommended to set the lens at ?.

Edited December 4, 2022 by bottletopburly

[ollypenrice]

I would experiment with a set of inter-connecting stop-down rings (filter rings), starting with wide open and looking at star shapes and vignetting. I'd then add a ring at a time to reduce the aperture and stop adding as soon as I found the corner stars acceptable. Alternatively you could use a compass-cutter to make a set of front aperture masks of diminishing aperture and experiment in the same way. Graphics outlets have compass cutters at low prices.

Olly

[bottletopburly]

Thanks @ollypenrice  I wouldn’t have thought of doing that , half expected an F number to set lens at ,never used a lens for Astro before .

[happy-kat]

If you focus using a star where a third intersection is will even out focus rather than using a star in the centre.

[jjosefsen]

I would recommend to go down to around F3.2 or F4 to get really good star shapes.

Doing it with masks or rings as Olly suggests is a good idea, as you can get nice round stars instead of the spikes produced by the iris blades in the lens.

[happy-kat]

When I use a modern lens I use manual focus as I want to control focus and not have the camera and lens decide to adjust focus mid capturing

[ollypenrice]

The aperture you can get away with is much affected by chip size, too. The deterioration in star shapes increases as you move off axis.

Olly

[bottletopburly]

1 hour ago, happy-kat said:

When I use a modern lens I use manual focus as I want to control focus and not have the camera and lens decide to adjust focus mid capturing

Hopefully the autofocuser will sort focus out .

[happy-kat]

Just re read and you're using an ASI camera so you weren't meaning the camera auto focuser like with a DSLR, but I guess it's handy to know if you had been.