I have the Sigma 105 mm f/2.8 MACRO, its build quality is pretty good, not
up to FA* standards, optically its very sharp with what i would consider to
bev not bad bokeh. Im unsure wether i like the manual/auto focus clutch
mechanism, but thats only because i'm comparing it to the ones on the FA*
lenses.
----- Original Message -----
From: "Ayash Kanto Mukherjee" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, June 25, 2001 11:42 PM
Subject: Re: Macro lens: Some insight needed!
> On Mon, 25 Jun 2001, Terence Mac Goff wrote:
>
> > Hi.
> >
> >
> > as someone who shoots a lot of macro stuff, I'd seriously recommend the
> > Tamron 90/2.8, which is 1:1, and is a fabulous portrait lens to boot.
>
> The minimum focussing distance for this lens is 11.4 inch. Is it enough
> to take shots of butterflies, bees and other insects without scaring them
> away? Mark Casino has always used 200mm f/4 Macro to take shots of
> sensitive insects which has a minimum focussing distance of 18 inch. If
> you try to get any closer than that, what really happens with the insects,
> I don't know.
>
> What about Sigma 105 mm f/2.8 MACRO (1:1) in terms of optical quanlity?
> Any thoughts?
>
> Regards,
> Ayash Kanto.
>
>
> > Its
> > exceedingly sharp edge to edge, and has a 55mm front end, which fits
most
> > ring flashes out of the box. It comes in Manual and autofocus versions.
> > Having had both, there is nothing between them in optical terms, but I
have
> > found that the manual focus lens required a decent focusing screen when
you
> > are in real close.
> >
> > However, I don't as a rule use ring flashes, as I have found it next to
> > impossible to get a TTL unit to fit pentax here in Ireland at any sort
of a
> > reasonable price. I generally use two metz 45 bracket flashes on
standard
> > light clamps. Its ungainly, but works ok. it also requires a large
degree
> > of co-operation from the subject :)
> >
> > Hope this helps,
> >
> > T.
> >
> >
> >
> > At 14:18 25/06/2001 +0530, Ayash Kanto Mukherjee wrote:
> >
> > >Hi Jon!
> > >
> > >You are absolutely correct. Therefore, the final decision is to go for
a
> > >macro lens having magnification of 1:1.
> > >Yep, I need a long working distance of about 1 feet but not less than
10
> > >inch so that a macro ring flash can be attached on the lens. A 100mm
> > >Macro lens will do that for me.But wait a minute, I have a
> > >question. Suppose I need a longer working distance than 1 feet, then
you
> > >should ask me to go for 200 mm Macro lens. In order to solve the
problem
> > >in cheaply, suppose I use a teleconverter of 2x ratio. That will
convert
> > >the present lens (100 mm MACRO) to 200 mm with a loss of two stops of
> > >aperture. What happens to the Macro magnification ratio? Does it
remains
> > >1:1 or it decreases. I think remains as it is.
> > >
> > >Any comments?
> > >
> > >Cheers,
> > >Ayash Kanto.
> > >
> > >
> > >On Mon, 25 Jun 2001, Jon Hope wrote:
> > >
> > > > 1:1, always. A 1:1 macro lens will do 1:2 on it's nose, but a 1:2
macro
> > > > will only go to 1:1 with adapters of some sort. The real question
> > > regarding
> > > > macro lenses is how much working distance you want, and therefore
how much
> > > > focal length you need. At 1:1 the working distance on a 50mm macro
is a
> > > > couple of inches from memory. It is roughly twice that for 100mm,
and
> > > > roughly twice that again for 200mm. The working distance is
important for
> > > > things that move, more than for things that don't. It is also easier
to
> > > use
> > > > a flash at longer working distances.
> > > >
> > > > I hope that helps a tad.
> > > >
> > > > Cheers
> > > > Jon
> > >
> > >
> > >-
> > >This message is from the Pentax-Discuss Mail List. To unsubscribe,
> > >go to http://www.pdml.net and follow the directions. Don't forget to
> > >visit the Pentax Users' Gallery at http://pug.komkon.org .
> >
> >
> > -
> >
><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><
><
> > Terence Mc Goff | [EMAIL PROTECTED]
> >
> > If its worth doing, Its worth Overdoing.
> > John William Corrington, Shreveport, 1956.
> >
> > PLease report all problems and flames to mailto:/dev/null ...........
> >
><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><
><
> >
> > -
> > This message is from the Pentax-Discuss Mail List. To unsubscribe,
> > go to http://www.pdml.net and follow the directions. Don't forget to
> > visit the Pentax Users' Gallery at http://pug.komkon.org .
> >
>
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>
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