At 10/14/2020 04:07 PM, Moose wrote:
>On 10/13/2020 7:57 AM, Wayne Shumaker wrote:
>>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=40cmÃ? 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
>
>I have, or have used, a significant subset of these:
>
>Brand    Model Diopter  Thread
>Olympus   MCON-P02      ~+3.6   46 & 37
>Olympus   iS/L Lens A-Macro H.Q. Converter f=40cm.       2.50  Â
> 49
>Olympus   iS/L Lens A-Life Size Macro H.Q. Converter f=13cm.   7.70 Â
>Â 55
>Olympus   iS/L Lens B-Macro H.Q. Converter f=40cm.      2.50  Â
>55
>Olympus   Close-up Lens 80mm Macro f=170mm      5.90   49
>Nikon    3T      1.50   52
>Nikon    5T      1.50   62
>Nikon    6T      2.90   62
>Canon    500D       2.00   72
>Minolta  No. 0     0.90   55
>Minolta  No. 1      2.00   55
>Minolta  No. 2      3.80   55
>B&WÂ Â Â Â Â 67E NL 0,5 Â Â Â Â Â Â Â Â Â 0.50Â Â Â 57
>Pentax   T132       0.76   67
>Pentax    T226       0.44   67
>Sigma    Achromatic Macro Lens AML 72-01     1.74   72
>
>I returned the Canon 500D when testing showed it didn't resolve as well on the
>PLeica 100-400 @ 400mm as the Pentax T132. Whether downsampling the Canon or
>upsampling the Canon to the same size, the Pentax was better.
>
>The B&W was an experiment to see if, at very low diopters a single element
>lens might work - no.
>
>>>From this list there is also a Minolta close-up lens (+0.33 d) 72mm thread.
>>>One on echBay for only $500.
>
>Having tried the various AC-U lenses on various primary lenses, I think I can
>safely say that there is a fairly narrow range of really useful diopter for
>each primary lens/FL.
>
>One factor how close the primary lens focuses on its own. For the PL 100-400,
>0.44 diopter is so weak that it adds nothing to using the lens alone. On an
>old MF lens with poor minimum close focus, it might be of value. This means
>the expensive 0.33 diopter lens is not a good choice for the 100-400.
>
>OTOH, as you point out, Sigma AML72-01 (+1.74 d) is too much diopter, and
>perhaps not as well matched for optical performance as the T132. Using it side
>by side with the T132, I found
>the shorter working distance problematic for bugs, and had trouble getting
>good shots.
>
>>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.
>
>The Minolta no. 0 works well on a Panny ZS200, using the Lensmate adapter to
>get a filter thread.
>
>The Nikon 5T is perfect on the PLeica 12-60; 6T is too strong. The PL has
>quite good close focus on its own.
>
>>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.
>
>Mileages vary . . . Of course I'm using the semi-unobtanium T132, but I use
>it extensively in the field. As Jim has confirmed, magnetic filter holders are
>an integral part of the package for field use.
>
>BTW, working distance at infinity primary lens focus of an AC-U lens is its
>focal length - from the front of it. So add distance from front of lens to
>focal plane to that, to compare to other options.
>
>>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:
>
>These are not comparable numbers. Shoot a US quarter, 24 mm diameter with a
>.35x lens on FF and again with a .25x lens on 4/3 sensor. Print the full
>frames on 8x10. The FF quarter is 2.8" in diameter, the 4/3 is 3.7"
>
>It gets weirder, when Mega-Pickles are considered. Testing the OM 600/5.6, I
>found that the pixel dimensions of the target on 24 MP FF were almost
>identical to those of a shot @ 400 mm on 20 MP µ4/3. The interaction of
>different physical and MP dimensions of the sensors and of actual, vs.
>nominal, FLs of the lenses made them in effect equivalent.
>
>Relative Sizes Moose
Thanks Moose.
Interesting point about working distance with lens at infinity. I hadn't
thought of that. Also using 5T on the 12-60.
WayneS
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