JakTrax
Topic Author
Posts: 4654
Joined: Thu Jun 30, 2005 3:30 am

Anyone Know About The Sigma 170-500 F/5-6.3 APO?

Mon May 16, 2011 4:35 pm

Hi all,

A friend of mine - who incidently isn't computer-qualified enough to do this himself - has asked me about the above lens and to be honest I haven't a clue!

I did a quick search and I know the lens is discontinued; most likely replaced by the 150-500. I also know that it isn't an EX, and it doesn't offer HSM, so I've no idea what quality he can expect. How is the lens generally? Same build, etc. as the Bigma and 150-500? Results on a par?

Cheers,

Karl
 
yankeezephyr
Posts: 14
Joined: Sun Sep 21, 2008 11:38 am

RE: Anyone Know About The Sigma 170-500 F/5-6.3 APO?

Thu May 19, 2011 12:38 pm

Hi
I have that lens for Pentax and I find it's hot and cold (I'll blame the equipment here   )

Seriously, I have found it's not very forgiving, but once you work out what it's truly capable of, it gives some good results

I have used it for spotting on a few occasions, and have been happy with it up to about 400, over that and it's definitely soft
I have also found it's optimum f-stop is around f8 to f13, below that and it's soft, above that and the only word I can use to describe it is 'funky'
Also, on the Pentax it slow, very slow, to focus
So it's not really ideal for jet displays, spitfires, or anything that moves at a reasonable clip

I have found it's great to attach to a tripod, and take photos of the moon, or anything else that is, relatively, not moving

Interestingly, I found it gives great results when it's coupled with a Kenko 2X converter, where the auto focus works fine between 170 and about 300, and is then sporadic above that. It also seems to be sharper than without

It's built well, though, but is pretty heavy
I have found that manually focusing it can be a mission due to the weight, so you do rely on AF a lot

I have seen on other forums that the Bigma is definitely better all round, and streets ahead when it comes to IQ
I understand that the 150-500 is much the same

The biggest issue I have with it is, I guess due to the weight of the front elements, it will extend to full zoom in about 3 seconds if you hold it at any angle past horizontal (it moves so fast you can hear the 'thunk' as it gets to the end)

If I were to buy again, knowing what I do now, I'm not sure I would buy it again, but would probably spend the extra on the 50-500

If you are after anything more specific, let me know

Paul
 
JakTrax
Topic Author
Posts: 4654
Joined: Thu Jun 30, 2005 3:30 am

RE: Anyone Know About The Sigma 170-500 F/5-6.3 APO?

Thu May 19, 2011 9:24 pm

Thanks for the reply - and also to 'the other guy' who pm'd me (you know who you are).

Karl

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