On 6/28/2021 5:42 AM, DZDub wrote:
On Sun, Jun 27, 2021 at 11:23 PM Moose <olymoose@xxxxxxxxx> wrote:
On 6/27/2021 2:22 PM, Mike Gordon via olympus wrote:
<>
Here is one image from the count. It is all I could get to today out of the
slim pickings.
https://www.olyendomike.com/Macro-2017/i-pdTRvGL/A
Beautiful!
One winner worth the trip.
Fluttering Moose
I had the same thought, though I understand Mike's disappointment, too. If
you go to Disneyland, you're probably hoping there's more than one ride
working.
I have what is probably a stupid question. I would use a lens like the DZ
50-200/2.8 or the floater DZ 40-150 to get a respectful working distance,
and I'm satisfied with the IQ (whether I should be or not).
Why should I be investigating the use of a diopter? Tick the boxes:
* Allows use of a desired lens not otherwise serviceable in the
situation/setting
Uh, OK. If I want to use a longer lens that has inadequate
magnification/closest focus.
* Improves working distance
It's only the COMBINATION of longer lens and C-U lens that increases working distance, for the same magnification. And
that is the whole POINT, closer focus!
* Allows use of a lens of better quality not otherwise useable for the
capture, especially desirable because of the speed of the lens or the
characteristics of the glass.
Nope, I don't see that. I suppose if I had a crappy 300 mm lens that focused to 2' and a great one that focused only to
5', that could be true.
But here there be dragons. How does the specific lens react with the specific C-U lens? I carefully tested my PL 100-400
@ 400mm with both a Canon 500D and a 5T, everything else identical. Although the stronger diopter of the Canon produced
a larger image, it was distinctly inferior in resolution whether the 5T was upsized or the Canon downsampled, to match
magnifications.
You might think all achromatic diopter lenses are created equal. But it's not true. Single element ones and older
achromats seem to use bigger curves. I didn't check the Canon 500D before returning it. The power is the combination of
the front element front curvature and the rear of the rear element. +4 and - 3 = 1 diopter. But so does +2 and -1. The
Nikons use weaker curves than, for example, the old Minolta series. With very complex lens designs, even primes with
many elements, I think it's impossible to say how any particular combo will perform without trying it. (As good an
excuse as any for owning 15 different ones. 😉 )
I mostly use the rare Pentax T132 for the PL 100-400 lens; lower mag, but much better working distance. The 5T works
well on PL 12-60.…
* Allows some marriage of non-native glass to foreign camera body
Huh?
* Allows a lighter kit
Doesn't really apply to me and the 100-400 mm lenses, as there is nothing
longer to be larger and heavier.
The big thing for me is ergonomics and practical field use. Extension tubes are also light, if a little bulkier, and
also achieve the desired closer focus. I tested them back when my long lens was the Oly 75-300. With that particular
lens, they worked very well, optically.
But they have drawbacks in the field:
1. Switching them in and out sometimes requires more limbs, with hands on the end than I possess. In a field, with only
grass and wet soil around, it gets tricky.
2. Switching them is slow. The critter is likely to be long gone, the light changed, my companion(s) far ahead of me,
whatever. I've recently become newly very aware of this. My new Oly 100-400 has matching tele-converters. I have juggled
the 1.4x one in the field. As it's tiny and light, not impossible with two hands and nowhere to put anything down. But
still slow. When tracking a Great Blue Heron, waiting for it to do something photogenic, not good. Fortunately, I had
only just started to disconnect the combo when it flew. I got the in-flight shots, but if it had taken off a few seconds
later, no dice.
3. Switching them opens up the camera. By almost never switching lenses, PL 12-60 on one Panny body, 100-400 on another.
I have had no problems with dust on my sensors, in spite of working in places with lots of wind blown dust.
4. They add multiple additional contacts to the lens-body connection. The inexpensive ones I've used have hollow brass
contacts that fit over springs. Where direct lens to body connection involves one pressure contact, with a tube, there
are four, most not gold plated. Stack tubes and the connection becomes unreliable. Hot and damp? Bad Juju.
The advantages of achromat C-U lenses:
1. They have none of the problems listed above.
2. Used, as I do, with Xume magnetic filter holders, putting them on and off is nearly instantaneous. I often literally
pop the C-U lens off and palm it while taking a shot or several, then pop it back on for other(s).
3. AFAICT, when they work with a lens, they work optically just as well as extension tubes. I haven't tested this
carefully, because I'm just not going to use tubes on the road and in the field.
* Esoteric qualities, approaches unobtanium standards
That's in your hands and brain, not the glass. 😁
* Other -- please specify
I think that's it, leaving out any cool/not cool factors. The point is to allow closer focus in a way that's practical
and optically good.
Inquiring minds -- are lazy. I know I could look something up, but I like
the conversation. Thanks in advance.
YWIA. It's generally useful to review what I know once in a while. It leads to fewer mistakes on my part. Esp. so after
so long with a limited range and amount of photography.
Long Winded Moose
--
What if the Hokey Pokey *IS* what it's all about?
--
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