At 10/12/2020 09:41 PM, Moose wrote:
>On 10/8/2020 4:42 PM, Ken Norton wrote:
>>>This is by focal length shortening and thus reduction in working
>>>distance--not always conducive to chasing critters but results in less light
>>>loss than extension.
>>There is, of course, one other method and that's to use a diopter on
>>the lens. That can be through the use of a designed-for-macro-use
>>diopter,
>
>Jim knows about that, although we haven't seen anything from his 135 Takumar
>with Olympus IS/L Lens A-Macro H. Q. Converter f=40cm dia. 49mm for a while.
>
>This is far my preferred method. So light, so quick, so easy, no lens changing
>and lens/tube/body juggling - and excellent results.
>
>In a place like a botanic garden, I may be found palming one, on magnetic
>filter holder, and popping it on and off.
>
>The problems are two:
>
>Not all AC-U lenses work well with all lenses. And there's no way to tell but
>trial and error, other than copying Moose. ;-)
>
>The selection is not ideal. Many of these lenses are discontinued, and some
>are hard to find. The Pentax 67 T132 is so important to me that I had a watch
>on the 'Bay for ages before snagging a back up.
>
>( There is an apparent difference between older and newer AC-U lenses. the
>older ones seem to generally have stronger curvatures. The diopter is simply
>the difference between front and read "powers". My suspicion is that most
>older ones are designed to minimize reflections between AC-U and main lens.
>Later ones have MUCH better coatings, and flatter curves. Oly's latest, for
>smaller µ4/3 lenses is a bit like looking into a black hole.)
>
>>or a reversed 50/1.4 sitting on the front of another lens.
>
>Optically a fine option, practically, a big, unnecessary pain.
>
>Getting Closer Moose
As you say, highly unlikely to come across a Pentax T132 (+0.76 d) or the T226
(+0.44 d).
I have the Sigma AML72-01 (+1.74 d) and is too much diopter for my use. The
less than +1.0 achromatic diopters seem to be rare indeed. Price usually puts
them out of practicality also.
I found this list of achromatic close-up lenses:
http://fuzzcraft.com/achromats.html
>From this list there is also a Minolta close-up lens (+0.33 d) 72mm thread.
>One on echBay for only $500.
For shorter focal length lenses, smaller filter thread and higher diopter,
there are more options. Perhaps the Minolta No. 0 (+0.94 d) (52mm) only $30 on
the 'Bay.
Years ago I experimented with the OM 180/2 with extension and 1.4X
teleconverter with somewhat OK results. The faster 180/2 lens helped with that
combination. Working distance was great.
Working distance is sacrificed with the diopter option. I only try using the
close-up filter option for static subjects, while working distance is more
valuable for me in the field.
For now I use my Zony zoom lens at 0.35x or PL 100-400 at 0.25x. The Olympus
50-200mm f/2.8-3.5 ED SWD has 0.21x and worked good with the E-1:
https://photos.app.goo.gl/Y7pGPkd9epLAJ9Tz6
E-1 50-200mm @ 200mm.
social bug working distance - WayneS
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|