Originally posted by Flick Would you mind sharing which 500mm lens you're using
I am using a Sigma 500mm f/4.5 APO manual focus. In Pentax terms, it would be an A*500/4.5 ED(IF). It is a modern optical construction (like 10 lens elements and ED glass rather than those old and cheap 4 elements super tele primes) and is able to outresolve the K-5 sensor in the center. I use it in conjunction with a Pentax 1.7x AF converter which gives me a stabilized 850mm AF lens with focus limiter
During daytime, the 1.7x converter AF works flawlessly despite the effective aperture of f/7.7.
In this posting, I attached a 100% crop of this lens with 1.7x converter ->
https://www.pentaxforums.com/forums/1654453-post20.html
Here is a 59% crop of the same image which corresponds to a 100% crop w/o converter:
(metering rule from 52m away)
Originally posted by Flick and why?
I bought it for under $1000 from a friend and there may be no alternative in this price range.
Unfortunately, this lens is extremely rare. I never saw it offered online. You only see the AF versions ($4000+ new).
Here is a posting about the lens I use:
Sigma 500mm F4.5 APO- Nikon AiS Mount (Manual Focus)... (Page 1) - Manual Lens: Usage - Manual Focus Forum
However, mine is in white color and in K-mount and doesn't have the screw on top of the sun shade. I try to embed one of the other forum images here:
The other forum said only 500 were ever made. So, in K mount, it may be extremely rare, maybe like 50?
The lens (manual focus) appeared in 1987. In 1990, an almost identical AF version in Canon mount appeared:
->
Sigma History - 1961 to present day.
According to this info, the lens is 10 elements in 8 Groups with inner focussing and 2 ED elements in the front group which today is very expensive to buy.
Here is a 1991 test report of the lens: ->
http://www.sigmauser.co.uk/images/stories/museum/Review.pdf
It measures up to 130 lp/mm resolution limit in the center (on T-max 100 film developed in Acutol) (resolving an 24 MP APSC sensor). The manual focus Pentax K version was said to be 2450 GBP which at that time corresponded to $4730 USD which after inflation in the US would be $7870 in USD as of 2011.
The newer Sigma 500/4.5 still have the front group with 2 ED elements but add a group and 2 elements to the overall optical formula. So, the current Sigma 500/4.5 are actually good value for the money.
BTW, Adam has the more recent (legacy) EX version in his database (
https://www.pentaxforums.com/userreviews/sigma-500mm-f4-5-apo-ex.html ), but not mine. This shows how rare my lens is. More rare than any lens in Adam's database ...
BTW, the
Pentax A*600/5.6 ED(IF) is a very similiar lens (8 elements in 6 groups with ED and inner focussing and rear filter). It earns top scores from reviewers here and may be the next best option for around $2500. It would be very interesting to compare both lenses one to one. Anybody near Munich with the A*600?
Last edited by falconeye; 09-20-2011 at 04:27 AM.