Optiphot 66 curiosities

[blekenbleu]

A recently acquired Optiphot 66 includes a model T trinocular head.
Compared to accustomed AO 180 oculars, am pleased by CFWN 10x20 view,
first impression was that one could almost fall in...

I had read that, unlike model F head, the T is not straight-thru in nominal photo position,
but was surprised that it has optics with magnification similar to that of my eyeglasses for far vision.
This suggests that magnification will not simply be the product of objective and CF PL2.5X ratings..
I would have expected that a camera would be able to "see" the window grille thru the trinocular port.

Nikon CF objectives are reputed to not require further correction;
(1) what purpose does the model T head bottom lens serve?

The vertical illuminator lacks both Analyzer A and polarizing alternative to neutral density slider;
instructions PDF drawing of "Polarizing means" is too vague for me to identify
(2) does someone 3D-print replacement sliders?

A happy discovery:
PVC reducer from 2 inch o.d. to 1.5 inch i.d. has 42mm o.d that precisely fits the trinocular chimney
and 48mm i.d. that nicely fits an otherwise useless (to me) Pentax K/M to M42 adapter that will be epoxied in place;
an EOS to M42 adapter has yet to arrive.

[Ichthyophthirius]

(1) what purpose does the model T head bottom lens serve?

Hi,

I'm not 100 % sure which lens you mean; is it the one at the bottom of he camera port?

As far as I can tell, the trinocular type-T has a negative lens at the base of the trinocular and a positive lens at the bottom of the camera port: userpix/3229_Nikon_lightpath_1.jpg

Together, they seem to create an infinity space in which Nikon placed the beamsplitters. Together, they compensate each other, so the magnification is 1.0x!

More context here; the T seems to have the same optical arrangement as the UW; the F is different: viewtopic.php?f=25&t=33471

Regards, Ichty

[blekenbleu]

the trinocular type-T has a negative lens at the base of the trinocular and a positive lens at the bottom of the camera port

Doh! I had not realized that there actually is a pair;
optics were clear enough to not provoke immediate disassembly for cleaning.
At least, viewed thru my trifocals, there seemed to be some net magnification.
That seems the opposite of AO infinity microscopes, which convert back to finite at the bottom of the head.
Ordering RAF Camera's dovetail adapter for direct projection imaging appears to have been a lucky guess...

Thanks again!

[blekenbleu]

Having good experience with RAF camera 50.4mm dovetail adapter on AO microscopes
and having determined that was too large to fit the Optiphot, I ordered a 48.5mm dovetail for it,
but the Nikon polymer-tipped knurled screw cannot fully tighten on the 48.5mm dovetail;
should have instead ordered a 49.5mm dovetail...

[blekenbleu]

With (trincular) head removed, parfocal Nikon vertical illuminator flange to Canon EF camera body flange distance is about 58mm:


Canon EF DSLR flange-to-sensor distance is 44mm, while Canon RF mirrorless flange-to-sensor distance is 20mm.
With its chimney removed, Nikon's F trinocular head has about 76mm flange-to-flange height.
Canon RF mirrorless bodies should be able to achieve parfocality with Nikon 210mm objectives and F trinocular heads without projection ocular...

[Scarodactyl]

Yes, this is generally true of the ISO standard they follow (which Wild/Leitz also used to follow on their stereo microscppes before the Leica takepver when they tweaked it). The downside on some Nikon heads is that the lens in the head doesn't fully cover aps-c (at least the one in the UW head doesn't), even if the objectives can. That lens can be replaced though. Straight through nikon heads without the lens pair do not have this problem.

[blekenbleu]

Straight through nikon heads without the lens pair do not have this problem.

As you suggested https://www.photomacrography.net/forum/ ... 97#p282897,
an M42 to 38mm tube https://www.ebay.com/itm/274696367794
and flat EF-M to M42 mirrorless adapter https://www.aliexpress.com/item/2255800990201232.html
yields WYSIWYG APS-C images with Nikon's "F" head:

... about 4.5mm width using 5x objective displayed in 10x oculars and images.

Thanks!

[blekenbleu]

Supposing that diascopic illumination might be occasionally useful
justified getting a crippled orphan Optiphot-66 diascopic base
that turns out to have Labophot 6V 20W diascopic illumination,
which seems silly with 12V 50W episcopic illumination,
rationalizing subsequent acquisition of yet another frame,
this time a conventional first generation Optiphot.
This frame had the usual damaged fine focus gear;
investigation reveal that -1 and -66 have different planetary gears and fine focus ratios:

-1 fine focus on the left; -66 fine focus is to the right, with its fine focus shaft

• -66 has a single 26:6 planetary gear is driven from its (fragile plastic) small fine focus gear (approx 13:3)

• -1 has 15:6 plastic planetary driven from fine focus, driving a plastic idler that drives its 20:6 (approx 25:3)

Fine focus knob markings reflect this difference, with 0-100 and 0-200 scales.

Perhaps -66 fine focus is also from Labophot...
The OG Optiphot frame was actually OK, other than broken fine focus, chipped paint and missing parts.
Its rotating stage and secondary substage dovetail clamp actually makes this scope more capable and compact
than a -66 for much episcopic work, after fabricating a translating stage plate to replace its slide holder:

[blekenbleu]

My EPI DIC nosepiece is seemingly complete with prisms,
but a bundled type "L" vertical illuminator lacks polarizing filters.
Peering down into its head flange,
a slot visible at the illuminator tube end is presumably for a (fixed) polarizer,
then a pair of pins for an analyzer in a flange that rotates 45 degrees,
which seems 45 degrees fewer than wanted...?

I have not yet located any documentation for this illuminator,
but its lamp house plug mates with that in Optiophot-66 base illuminators.

"Optiphot 66" PDFs on the Internet illustrate the different universal vertical illuminator
with "A" analyzer slider and rotating polarizing filter slider in the illuminator tube.