Nikkor 105mm F2.8 VR Macro + TC-14 E ll

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Pete
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Nikkor 105mm F2.8 VR Macro + TC-14 E ll

Post by Pete »

According to the Nikon lens compatibility chart, the TC-14 E ll will work with the 105 VR macro, but without autofocus.

I just tried mine on for the first time, and the autofocus (and everything else) works fine.........
:smt017

Pete

ray_parkhurst
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Post by ray_parkhurst »

It may be that it will operate "strangely" in some ranges of focus, so Nikon does not want to warrant it for normal operation. Modern macro lenses shorten focal length as they near 1:1 magnification. This is due to the odd characteristics of extension vs working distance that occur in this region. The AF algorithm is optimized for the lens' characteristics to give best performance, though due to the focal length changes there are still a few odd behaviors such as "focus breathing" and such. When a TC is added, these algos are perturbed, and the lens may go through the critical 1:1 region when the focal length has not changed enough to offset the effects. A 2x TC would be even farther from the algo's optimum, passing through 1:1 at what the algo "thinks" is 1:2.

So I think bottom line is that the AF indeed functions, but may not function as intended, and in some cases may even hang up or fail to find correct focus.

Pete
Posts: 14
Joined: Sun Oct 15, 2017 3:18 am
Location: Hants., UK

Nikkor 105mm F2.8 VR Macro + TC-14 E ll

Post by Pete »

Thanks for your reply............I haven't tried it in anger yet, I just put it on to see if it de-graded the image noticeably.
If it focuses reliably, it will be a useful combination.
The lens alone is tack-sharp.

Pete

clarnibass
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Re: Nikkor 105mm F2.8 VR Macro + TC-14 E ll

Post by clarnibass »

Pete wrote:I just put it on to see if it de-graded the image noticeably.

The lens alone is tack-sharp.
Did it? Because my previous model Nikon 105mm micro lens, which is also tack sharp and just excellent at x1, degraded very significantly when adding extensions, to the point of pretty much unusable at about x2 (well depends on the size you want to view the result). Though a TC is different anyway so maybe better (or worse?).

Lou Jost
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Post by Lou Jost »

There's often a huge difference between the results with extensions versus TCs. Modern lenses have floating elements designed to correct for the focused magnification. Add extension and you can wreck that correction, since the lens thinks it is still focused at the distance which was in focus before you added the extension; the floating elements will be in the wrong place for the new WD and sensor distance.

Adding a TC expands the accurately-corrected image without changing the WD of the lens, so the floating-element corrections are still doing their job properly. So in theory, a really good TC is generally going to be much better than empty extension for modern lenses.

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