Nikon TC-14E III, TC-17E II teleconverters

On another page of this site, I discussed some of the legacy and current Nikon 2x teleconverters in F mount. The present page complement this subject by discussing the TC-14E III and TC-17E II. The TC-14E III is still marketed by Nikon, while the TC-17E II is discontinued.

TC-14E III

The TC-14E III is an AF-S compatible teleconverter that increases the focal length of a compatible lens by 1.4x and adds one stop to the effective lens speed. See below for details about the compatibility of this teleconverter, which is more limited than other current and recent Nikon teleconverters.

This teleconverter was released in 2014. My specimen is made in Japan.

The optical scheme uses 7 elements in 4 groups and is a total optical redesign, compared to earlier models. This scheme is remarkably compact, resulting in an almost solid block of glass front-to-rear. The total spacing between separate optical groups is much less that the total thickness of the elements. The rear element of this teleconverter is a little recessed, compared to other Nikon teleconverters of the same age.

Unlike the TC-20E III, this model does not use aspheric elements. Coupled to an objective of good quality, like an AF-S Nikkor 300 mm f/2.8, this teleconverter gives excellent results. The rear mount of this teleconverter is surrounded by a weartherproof rubber gasket.

The preceding model (TC-14E II) uses a simpler optical formula (5 elements in 5 groups) and is said to be optically very slightly worse than version III.

The distance between front and rear mounting flanges of the TC-14E III is 24 mm, with a barrel diameter of 63.5 mm. The weight without caps is 185 g. The front optical group projects moderately out of the front mount, and this teleconverter comes with a special front cap (BF-3B) similar to those used by other modern Nikon teleconverters.

This teleconverter is equipped with only 8 electrical contacts on its rear mount, not 10 like the TC-20E III, TC-17E II and TC-14E II. The front mount has 10 contacts, as usual for AF-S teleconverters.

The external appearance follows the style of the TC-20E III. However, under the hood, Nikon introduced a mechanical change that makes this teleconverter incompatible with 13 reasonably recent models of Nikon AF-S and AF-I prime lenses of focal lengths between 300 and 600 mm, plus the AF-S Zoom-Nikkor 80-200mm f/2.8D IF-ED (see the list at Nikon). All the incompatible lenses possess a physical aperture ring.

Nikon removed from the TC-14E III the maximum aperture coupling ridge and the minimum aperture signal post (a.k.a. EE servo coupling post), present in all other recent Nikon teleconverters (above figure). This change prevents the camera from recognizing a lens equipped with an aperture ring, and causes the camera to lock up and display an FEE error message until the lens is removed. This is the same error message displayed when the aperture ring has not been turned to its maximum value and locked, but of course the cause is different when using the TC-14E III.

The TC-14E III is compatible with only 16 models of AF-S lenses, all of them either currently marketed or recently discontinued. The Micro Nikkor 105 mm f/2.8 VR G is among the compatible lenses, albeit, according to Nikon, autofocus is not available with this lens and teleconverter combination. However, I tested this lens on the TC-14E III, FTZ/FTZ II lens adapter and Z8 camera, and this combination does autofocus (a little more reliably, in fact, than on the TC-17E II and TC-20E III, probably because the TC-14E III "eats" only one stop of lens speed).

This intentional incompatibility with numerous recent Nikon lenses is particularly remarkable, because it does make the TC-14E III less likely to be purchased by photographers. The TC-20E III, also currently marketed, has no such limitations. There seems to be no particular reason for this, other than a desire to selectively make lenses equipped with a physical aperture ring less desirable for photographers to use, as part of a long-term strategy to "kill off" the use of all such lenses.

I can think of only a few possible technical reasons for this artificial incompatibility, none of them quite convincing, except perhaps the last one:

- Eliminating the couplings reduces the production cost of the teleconverter. True, albeit by a minor amount. If Nikon is saving any money in this way, they are certainly not passing the savings on to the buyers.
- Eliminating the couplings makes the teleconverter sturdier, and less likely to be damaged by an accidental fall on a hard floor. This type of damage does occur and I have seen examples, but a fall hard enough to deform the mechanical couplings is likely to also crack or decenter the optics.
- Eliminating the couplings provides more space for large rear optical elements. However, there is unused space around the rear element of this teleconverter, actually quite enough for accommodating the missing couplings. Also, the aperture actuator lever is still present, and takes the same space as in earlier teleconverters.
- Eliminating the couplings allows the addition of weather-proofing around the rear mount of the teleconverter, and forms a weather-proof seal around the front mount when the teleconverter is attached to a weather-proof lens.

Purchasing a new TC-14E III from Nikon is remarkably expensive. This model is not difficult to find on the second-hand market, but its second-hand price, at least in Europe, can be twice as much as the TC-20E III and other recent Nikon teleconverters. In fact, I started to look for a reasonably priced second-hand TC-14E III at the same time as four other models of Nikon teleconverters in F mount, and the TC-14E III was the last I purchased, after unsuccessfully waiting for a specimen to appear on eBay at a price comparable to the other teleconverters. The limited range of Nikon lenses compatible with this teleconverter does not seem to put a damper on its second-hand price.

A PDF of the documentation of the TC-14E III can be downloaded from Nikon.

TC-17E II

The TC-17E II is compatible with AF-S and AF-I lenses. It increases the focal length of a lens by 1.7x and adds 1.5 stops to the effective speed of the lens. The model II is the first of the TC-17 series, and there never was a TC-17E model I. The TC-17E II was introduced in 2004 and is now discontinued. There never was a TC-17E III, either. The specifications of the TC-17 are intermediate between the TC-14 and TC-20 series of teleconverters, and sufficiently different from both to constitute a feasible compromise between the two teleconverter types.

This teleconverter was released in 2004. My specimen is made in Japan.

The distance between rear and front mounting flanges is 31.5 mm and the weight without caps 245 g. This teleconverter is not weather-proof.

The optical scheme uses 7 elements in 4 groups. I have been unable to find a picture of this optical scheme, and cannot say how similar it is to the TC-14 II or III. Image quality with this teleconverter and a lens of good quality is roughly intermediate between the image quality provided by the TC-14E III and TC-20E III.

This teleconverter is comparable to the TC-20E III in possessing a full complement of AF-S mechanical couplings and signal posts, and supports the large majority of AF-S and AF-I lenses equipped with a teleconverter-compatible lens mount.

The TC-17E II is not so well known, and is often eschewed by buyers. Its second-hand price is typically far less than those of the TC-14E III and TC-20E III, albeit the quality is comparable. The 1.7x increase in effective focal length and the "loss" of only 1.5 stops are a good compromise between the much more popular 1.4x and 2x models. This teleconverter was typically used with fast telephoto lenses of focal lengths 300 mm and 400 mm.

Conclusions

The Nikon TC-14E III teleconverter does provide AF with the Micro Nikkor 105 mm f/2.8 mounted on a Nikon Z8 camera via FTZ/FTZ II lens adapter, even though Nikon declares that this combination of lens and teleconverter does not provide autofocus.

The TC-14E III is the only 1.4x teleconverter in F mount still marketed by Nikon.

Nikon removed two mechanical couplings from the mount of the TC-14E III, which makes it incompatible with 17 current or recent models of Nikon AF-S and AF-I lenses equipped with physical aperture rings. With these unsupported lenses, you must use a legacy TC-14E II, only available on the second-hand market. This intentional incompatibility is particularly dumbfounding, because the current TC-20E III has no such limitations.

The Nikon TC-17E II teleconverter also provides AF with the Micro Nikkor 105 mm f/2.8 mounted on a Nikon Z8 camera via FTZ/FTZ II lens adapter, even though Nikon declares that this combination of lens and teleconverter does not provide autofocus.

The Nikon TC-17E II teleconverter multiplies the lens focal length by 1.7x and adds 1.5 stops to the lens speed. It provides an excellent image quality when attached to a good lens (usually a telephoto lens of 300 mm or higher focal length), and is a sensible compromise between the 1.4x and 2x teleconverters. There never was a TC-17E model I, nor a model III successor.