Camera lens or an apo refractor?

Ask your fellow astronomers to solve your telescope queries

Camera lens or an apo refractor?

Postby dave.b » Sun Jun 11, 2017 11:21 pm

The new Sigma 100-400mm f5-6.3 looks interesting and has received excellent reviews. It's currently retailing for £799. I figure you could get a 2.5" triplet apo refractor for the money. The lens of course offers autofocus and stabilisation on top of the variable focal length. But the refractor would have better contrast for astronomy work.

Thoughts? (I've already got a 66mm doublet refractor.)

Dave B.
Last edited by dave.b on Fri Jun 23, 2017 11:23 pm, edited 1 time in total.
dave.b
 
Posts: 760
Joined: Mon Feb 13, 2012 6:35 pm
Location: Staffordshire

Re: Camera lens or an apology refractor?

Postby Gfamily2 » Wed Jun 14, 2017 9:36 am

dave.b wrote:The new Sigma 100-400mm f5-6.3 looks interesting and has received excellent reviews. It's currently retailing for £799. I figure you could get a 2.5" triplet apo refractor for the money. The lens of course offers autofocus and stabilisation on top of the variable focal length. But the refractor would have better contrast for astronomy work.

Thoughts? (I've already got a 66mm doublet refractor.)

Dave B.

Apparently the Sigma is prone to internal reflections (understandable really, with so many more optical components), so it may well be disappointing in that regard.
Also, CA wouldn't be as well managed as a true APO of course. Just my 1/2p
Scopes: Meade 8" SCT, Skywatcher 127mm Mak
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
Gfamily2
 
Posts: 249
Joined: Thu Jun 25, 2015 10:38 pm

Re: Camera lens or an apo refractor?

Postby dave.b » Fri Jun 23, 2017 11:30 pm

A zoom lens will never be as good as prime (fixed focal length) lens. But then the zoom offers versitility, and of course the motors and sensors for autofocus (which is of considerable use in the day time).

I thought the LensTip review was quite favorable since they are usually quite blunt about deficiencies.
dave.b
 
Posts: 760
Joined: Mon Feb 13, 2012 6:35 pm
Location: Staffordshire

Re: Camera lens or an apo refractor?

Postby The Man with the Corrugated Iron Roof » Thu Aug 03, 2017 11:02 pm

I have found that autofocus does not work well with astronomical objects. You can buy a 70-300mm zoom camera lens for much less money. I get the point that the camera lens is better for non-astro use but my money would be on the APO, which you can use with an eyepiece or webcam.
How can I be one with the universe when we don't know what 96% of it is.

My website: http://www.philippughastronomer.com/

My blog: http://sungazer127mak.blogspot.co.uk/
The Man with the Corrugated Iron Roof
 
Posts: 345
Joined: Sat Nov 23, 2013 1:53 pm
Location: Wiltshire but can be just about anywhere up to 41 000 feet


Return to Equipment Advice

Who is online

Users browsing this forum: No registered users and 1 guest