Canon compatible camera lens for widefield imaging.

[peeb61 (Paul)]

Hi All,

Bit of a drawback on imaging with my stock Canon lens...

Canon EF 28-80mm
Canon EF-S 18-55mm

Using the ZWO to DSLR filter draw adaptor and the above Canon Lens I found and just to add, I was expecting coma and other issues... And I got them.... What do you expect from Camera kit lens?

So.... What is a good and not to break the bank Lens that would give me less frustration and something to work on and keep me happy for a while purchase??

I will be using a ZWO183MC Pro.

Many thanks in advance.
Paul

[JA]

Hi Paul,

Did you try both of the lenses you listed? I suspect the full frame EF lens might be better, but you never know. Did you try stopping down the lenses to reduce coma or did you use them wide open? Stopping down one or two stops should make a considerable difference (improvement) in coma, sharpness and most other aberrations.

Otherwise a Sigma Art 35mm f1.4 or 50mm f1.4 are very sharp and have low coma. The 40mm even lower, but it's heavy and expensive and you need to find a way to operate the aperture with these lenses when not used on a DSLR.

Best
JA

[peeb61 (Paul)]

Originally Posted by JA

Hi Paul,

Did you try both of the lenses you listed? I suspect the full frame EF lens might be better, but you never know. Did you try stopping down the lenses to reduce coma or did you use them wide open? Stopping down one or two stops should make a considerable difference (improvement) in coma, sharpness and most other aberrations.

Otherwise a Sigma Art 35mm f1.4 or 50mm f1.4 are very sharp and have low coma. The 40mm even lower, but it's heavy and expensive and you need to find a way to operate the aperture with these lenses when not used on a DSLR.

Best
JA

Thanks JA for your reply... Stopping down the lenses? Can you please explain this? Will also have a look at the ones you suggested...
Very much appreciated.

[Leo.G (Leo)]

I have no idea with Canon lenses and required operation (JA knows a lot more than I do about this stuff) but I do know with my little CMOS camera I can use some of my older Nikon lenses with full manual operation which are still suitable for my Nikon. I don't even know if I'd have any old Canon lenses but if you're using an adapter for the 183MC you really don't have to limit yourself to Canon lenses, a different adaptor for Nikon mount or possibly (I don't own a ZWO camera so I'm guessing) like my player one Neptune which has a standard M42 mount thread (or M48, I forget) which will should a standard old Pentax/Practica/other M42 lens screw mounts and many of the older lenses are available used for reasonable prices in good condition (I always check Salvation Army and St Vinnies if I'm passing and pick up some surprising camera stuff for a donation. The pawn shops are worth taking a peek in too if passing.

HOWEVER, buying dedicated to suit your Canon DSLR when not doing Astro is a smart financial choice if buying new lenses (sorry, I know I'm stating the obvious but I like my collection of old lenses and have a range of different brands and focal length/apertures to play with (I also collect old cameras)).

Stopping down the lenses? Can you please explain this?

Sorry, obviously not JA but just happened to be here in this thread.
If you are using an f2.8 lens you could try stopping it down from the widest aperture to a narrower aperture, f3.3/f4.5/f5.6/f8.....
Stopping a lens down gives better depth of field (more depth (a larger focal area instead of like a portrait where only the face is in focus).
I know a few of my larger f1.4/f2.8 lenses are much better stopped down. If you can't take longer subs due to less light coming in through the smaller aperture (depending on guiding) more subs of the same time period is a good substitution.

Originally Posted by Wikipedia

As a lens is stopped down from its maximum (widest) aperture, most lens aberrations (spherical aberration, coma and astigmatism) are decreased, but lens diffraction increases

https://en.wikipedia.org/wiki/Stopping_down


There's a lot of good information available with benefits and drawbacks online.

[peeb61 (Paul)]

Originally Posted by JA

Hi Paul,

Did you try both of the lenses you listed? I suspect the full frame EF lens might be better, but you never know. Did you try stopping down the lenses to reduce coma or did you use them wide open? Stopping down one or two stops should make a considerable difference (improvement) in coma, sharpness and most other aberrations.

Otherwise a Sigma Art 35mm f1.4 or 50mm f1.4 are very sharp and have low coma. The 40mm even lower, but it's heavy and expensive and you need to find a way to operate the aperture with these lenses when not used on a DSLR.

Best
JA

Originally Posted by Leo.G

I have no idea with Canon lenses and required operation (JA knows a lot more than I do about this stuff) but I do know with my little CMOS camera I can use some of my older Nikon lenses with full manual operation which are still suitable for my Nikon. I don't even know if I'd have any old Canon lenses but if you're using an adapter for the 183MC you really don't have to limit yourself to Canon lenses, a different adaptor for Nikon mount or possibly (I don't own a ZWO camera so I'm guessing) like my player one Neptune which has a standard M42 mount thread (or M48, I forget) which will should a standard old Pentax/Practica/other M42 lens screw mounts and many of the older lenses are available used for reasonable prices in good condition (I always check Salvation Army and St Vinnies if I'm passing and pick up some surprising camera stuff for a donation. The pawn shops are worth taking a peek in too if passing.

HOWEVER, buying dedicated to suit your Canon DSLR when not doing Astro is a smart financial choice if buying new lenses (sorry, I know I'm stating the obvious but I like my collection of old lenses and have a range of different brands and focal length/apertures to play with (I also collect old cameras)).





Sorry, obviously not JA but just happened to be here in this thread.
If you are using an f2.8 lens you could try stopping it down from the widest aperture to a narrower aperture, f3.3/f4.5/f5.6/f8.....
Stopping a lens down gives better depth of field (more depth (a larger focal area instead of like a portrait where only the face is in focus).
I know a few of my larger f1.4/f2.8 lenses are much better stopped down. If you can't take longer subs due to less light coming in through the smaller aperture (depending on guiding) more subs of the same time period is a good substitution.





https://en.wikipedia.org/wiki/Stopping_down


There's a lot of good information available with benefits and drawbacks online.

Thanks Leo and JA for your valued information... Understanding the term "Stopping Down" and JA I will try the full frame lens, I did use them wide open at its highest possible f value so I will try the full frame as you suggested...

[gregbradley]

Stopping down to a higher aperture number
Reduces the aperture.

50mm prime lens should work as long as it’s set to the right distance from the sensor.

On a Canon it’s something like 44mm. It’s called back focus and you can look up what that distance is.

I just looked it up, yes it is 44mm.
That means the distance from the back flange of the lens to the surface of the sensor has to be 44mm.
Your adapter needs to be the right thickness so this 44 is achieved.
Greg

[DebinOz (Deborah)]

How about the Samyang 14mm f2 XP AE? I use one for Milky Way with a full frame camera. Beautiful shots.

[brianramsey]

I've had pretty great success with a Sigma 18-35mm f1.8. They come up for a good price 2nd hand from time to time. Lots of cinematographers use them, so lots exist in the wild.

I've mostly done basic stuff like star trails but never had bad artefacts.