Transplanting TC14E-III Optics Into A TC14-II Body . .

[Erik Lund]

Easy to test, shim the TC14E Mark III until it's 24.7mm and see what happens. It's well within the pins of the contact blocks tolerances to move the male F mount on the TC out.

[Roland Vink]

When a TC is used on a unit focusing lens, the lens elements move much more than 0.15mm during focusing.
Granted, most telephotos used with TCs are IF ...

[jhinkey]

Well, as any hard-core lens modder can tell you, while 0.15 mm might not appear to be much, it is also many times larger than any factory tolerance of the flange distance. So is bound to generate troubles.

Obviously someone needs to measure the E-III accurately to see what the dimension actually is.
0.15mm is 0.0059" BTW for us English unit challenged.  Two pieces of somewhat thin-ish paper.

[Bjørn Rørslett]

Thinnish maybe, but that is about the depth of focus of say a 400 mm f/2.8 lens wide open. Should give the proper perspective of things.

[PedroS]

Correct dimensions of the TC-14E III

Front element protrudes - 2,5mm (including protective rubber)
Front to rear mount - 24,11mm (with compressed rubber seal)

Don't have here the vII

[Erik Lund]

Thanks Pedro. Please measure at the indicated point on the flange that's the mating point of the Nikkor F-mount.

The Mark I and Mark II are identical length and optics.

Edit. I'll upload a new image!

[Erik Lund]

When a TC is used on a unit focusing lens, the lens elements move much more than 0.15mm during focusing.
Granted, most telephotos used with TCs are IF ...

When you mount a unit focusing lens on a TC the new combined lens becomes a lens with floating elements similar to an IF lens. Thus also you loose Focal length as you focus closer with a TC attached, for some lenses especially IF lenses a lot of focal length is lost as you focus up close actually!

Please see 1.4.2 and for instance Fig. 25 on this amazing reference page

http://www.pierretoscani.com/echo_focal_length.html

[PedroS]

Thanks Pedro. Please measure at the indicated point on the flange that's the mating point of the Nikkor F-mount, you can also see that's where lenses get 'brassing' from wear,,,

The Mark I and Mark II are identical length and optics.

Hi Eric,
That measures 25,07mm

[Erik Lund]

Sorry Pedro, I think I was wrong, I will upload a new drawing! I think your first measurement was about right, I got thrown off by the stated 24.5mm!

[Erik Lund]

Here is the 85mm 1.4 showing M B f 46.5mm, top right of the drawing, to the wide surface of the mount, so that's where we should measure.

The measurement of 24,5mm  is an overall length of the housing, has nothing to do with the optics,,,

Sorry for the confusion! I was calibrating Leica lenses last night so my head was in Leica mode 

[Erik Lund]

24.71mm - 24.74mm is the TC14E Mark I and II

[jhinkey]

My TC14EII measures 24.63 to 24.66mm depending on where you take the measurement - yes that's 0.0012 of an inch non-parallel.

[Erik Lund]

Thanks, well I'm measuring with a cheap digital caliper and an old-school one of good quality,,,

[jhinkey]

Thanks, well I'm measuring with a cheap digital caliper and an old-school one of good quality,,,

My quick measurement is with my not-so cheap digital caliper (supposedly good to 0.0005 inch resolution) that should be close.
I will re-check with my 0.0001 inch resolution caliper later today . . . .

[Bjørn Rørslett]

My TC14EII measures 24.63 to 24.66mm depending on where you take the measurement - yes that's 0.0012 of an inch non-parallel.

If these firgures are accurate, they imply the mount(s) are warped and well outside factory tolerance.