Re: [APML]: 300mm F2.8 lenses..which brand?

["Jim Barclay" <cosmos@fan.net.au>]

The Astro-Photography Mailing List
------------------------------------

Wil,

Hi mate, in regards to your 300/2.8 lens, does this lens give a flat field
at 2.8,  or do you have to stop down a bit to get a sharper image at the
edges. There may be a time I will need to print the entire neg, hence the
question.

Secondly, have you or others compared the results between this and say, the
Nikon or a Sigma?

I am looking into the options of this size lens since I missed out on the
Pentax 800/4 sale.
And if you ever think of coming Down Under one of these days for some Sth
sky shooting, let me know, as I have a dark rural site at my Stuart Range
Obserevatory where naked eye is at least 6.5. It is here, I will be setting
up a GT-1100 mount within the next few months, along with a C11 and an ISDN
line of 30 channels. This gives a bandwidth of 2 megs.

Best regards,

Jim
-----Original Message-----
From: Wil Milan <wmilan@airdigital.com>
To: astro-photo@nightsky.com <astro-photo@nightsky.com>
Date: Tuesday, 22 September 1998 17:01
Subject: Re: [APML]: 300mm F2.8 lenses..which brand?


>The Astro-Photography Mailing List
>------------------------------------
>
>Philip Perkins wrote:
>
><< The big problem with the Tamron is the slop in the Adaptall mounting
>system. This is a potential killer and means that the camera body really
>needs mounting too.  In portrait format, this can be a big problem. >>
>
>Philip:
>
>My 400mm f/4 Tamron also exhibited some slop. It turned out to be loose
>screws near where the tripod collar mates to the lens. I tigtened them and
>have had no problems since. It might be worth checking if that's all it is
>on yours.
>
>
>Wil Milan
>