As others have commented, there is the A* 200mm f4 macro, FA* 200mm
macro and Sigma 180 f 3.5 macro. These all go to 1:1. The A* is manual
focus, the other two are AF. On ebay and in the Pentax forums I have
seen a couple other brands of 180 macro's pop up but if I recall
correctly, they were not A compatible (no auto modes) and were 1:2
lenses, not 1:1.
I have two A* 200 macros - one is worn out and the aperture does not
stop down reliably, but it works fine for studio work in stopped down
mode. The new one is my workhorse for field macros now.
When my first A*200 was in the shop I did some experiments and found
that the DFA 100 macro plus the AF converter 1.7x was pretty sharp. A
summary of my experiments is here:
http://www.markcassino.com/b2evolution/index.php/the-blackthorn-wand
When it comes to macro lenses the main consideration for me is the
working distance - i.e. the distance between the front of the lens and
the subject. Reading the specs on some of the Sigma lenses, their 150
f2.8 was as good or maybe better than the A*200 in this regard. As far
as I know, the Sigma 150 macro was never released in Pentax mount - I
watched for it but never saw it.
I'd suggest going with a 100mm macro and teleconverter as a first
option. The problem with this is that you won't know for sure what you
will get until you try the optics in combination. Second choice would be
to go with a good standard 200mm and a Raynox macro adapter. You will
lose infinity focus but I've been using a Raynox DCR 250 and am
surprised at how well it works, though I've mostly been using it for
greater than 1:1 macro on medium format film.
There's no technical reason limiting the production of longer macros.
Like many specialty lenses the demand is low and I assume Pentax can't
justify making them. For nature photographers, a 300mm f2.8 is a fairly
basic piece of equipment, more basic than a 200mm macro, and Pentax not
longer make those. So I think we have a ways to go before we see a
re-emergence of true specialty lenses. (Not so long ago Pentax made a
greater diversity of lenses than any other major camera manufacturer.)
Hopefully Ricoh will be successful in resurrecting the Pentax brand and
will expand the range of lenses offered.
Mark
On 4/29/2016 4:52 PM, Larry Colen wrote:
It seems that the longest macro currently produced for K-mount might
be about 100mm. I've heard mention of a 200mm, and I have an old
manual focus 135 1:2 macro.
Two part question:
What are the options for long focal length macros? How are they
optically? Are there any teleconverters that do well? Or, am I just
better off cropping tighter?
In a similar vein, are there technical reasons for the dearth of long
macro lenses? Or is it just that the market for them is too small for
them to be commercially viable?
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