Reprocessed Corona Australis

[CometGuy]

Bert,

I have seen some of the images Scott has producing with that lens and it seems to have a similiar problem with bright stars that the Sigma 300 2.8 lens has (witness his M42 image). At the same time I think the Sigma has a bit more coma on one side but at the same time has less CA. I am not sure I would gain anything apart from going to the 300 EF non-IS.

Your EF lens is a cut above, even taking into account the larger pixel size of the 5DH. The level of aberations are very well controlled for f2.8.

The latest IS version seems to be a step back (its not just Jerry Lodriguss saying this either). I would be pretty upset shelling out $6-7 K only having to use the lens at f4 for astrophotography!

For the sort of work I do (comet searching) its important to have reasonably sharp images edge to edge whilst maintaining maximum possible aperture.

Terry

[avandonk]

I always had a gut feeling that IS will only produce aberrations compared to non IS, even when turned off. Unless the 'park' position is perfectly aligned and this is highly unlikely.
You are correct the only lenses for astro that start to approach pefection at F2.8 is the Canon Super Telephoto series with NON IS. The sweet spot bang for buck is the Canon 300mm F2.8L.

I have not seen any astro images with the new Nikon F2 200mm (?) but this costs even more than a Canon.

Bert