Modification of TC14E, TC17E or TC20E

Last update date: Nov 7th, 2015


  1. Disclaimer
  2. Purpose of this modification
  3. Limitations
  4. Modification details
  5. Q&A
  6. More questions?


This modification will void your warranty. Although this is a very easy and straighforward modification, proceed at own risk!
OK, let's say that again:
This modification will void your warranty. Although this is a very easy and straighforward modification, proceed at own risk!

Purpose of this modification



Modification details

  1. The picture below shows you the converter before modification (actually the one you see is the TC20E, because my TC14E is already modified...).

  2. Unscrew the metal ring, by unscrewing the 4 screws (see below for some more info on the screws). The screws have locking compound on their threads, so don't worry if you have to use a lot of force. Use a good screwdriver with a big enough handle so you can apply the necessary force without stripping the screws. If possible, apply 60 seconds of heat from the tip of a soldering iron to help free each screw. The idea is to heat them to about 140 degrees Fahrenheit (60 degrees Celcius).
    Note: Most likely, the screws on your TC are JIS (Japanese Industrial Standard) screws. They differ from Phillips screws in that the slots are straight, vs. becoming wider towards the center as in Phillips screws. Ideally, you should use a JIS #0 screwdriver, however if you cannot find a shop that sells these, I've had good luck with a 3/32" Phillips screwdriver (the more a Phillips screwdriver wears out, the closer it becomes to being a JIS screwdriver!). Here's one US online shop that sells them: RJR Cool Tools ( (Disclaimer: I have never bought from this shop). One user reported that the screws that Nikon uses are Pozidriv screws. Pozidriv screws are cross slot screws which are straight cut, not tapered, vs. Phillips screws which are tapered. Make sure to check the screws on your TC and use the appropriate screwdriver. I would love to hear from you which screw type your TC has - just shoot me a quick email!

  3. Once the screws are gone, you can take of the metal ring - simply lift it up (you might need to pull a couple of times to get it off). Watch out not to damage the thin metal sheet ring that lies just below the metal ring.
    Note: some TCs have three black gaskets outside the thin metal sheet ring - make sure they don't come out (or make sure to note their position so you can put them back correctly - see below).

  4. Remove the little tab as shown in the picture below. You can file it off with a manual file, but it's much easier, quicker and cleaner to use a Dremel (or equivalent) tool. VERY IMPORTANT: make sure to you don't get any metal filings on the teleconverter, and thoroughly clean the ring after you're done. The last thing you want is scratches on your teleconverter glass!

    Ted Byrne posted some pictures and a nice video showing how he filed off the tab with a Dremel tool - check it out here.

  5. If the gasket rings came out, and you're scratching your head on how to put them back in, this may help: there are 3 dark gasket rings, and the thin metal sheet ring mentioned above. The gasket rings all have parts on the outside that extend (wider parts, extending to the outside of the ring): The rings go onto the TC in sequence: ring 1, ring 2, ring 3, then finally the metal sheet ring. For each of the rings, there's only one position that fits, so that should be easy. The picture below should help - it shows how to position each gasket ring when putting it back onto the teleconverter (simply match the red, blue and green dots):

  6. Put the metal ring back in place, tighten the 4 screws, and you're all set!
    Note: optionally you can add some blue Locktite (removable) to the screw threads.

  7. The result looks like this:


Question Answer
Do I really need to remove the metal ring from the TC to file off the tab? Leaving the metal ring on the TC while filing off the tab is a recipe for disaster: you could inadvertently touch the TC lens element with your file/dremel and completely ruin it, or the metal filings could (and will) get in the TC mechanism or on the lens element and severely scratch not only the TC but potentially also the lens you mount on the TC. So, I guess that would make the answer 'Yes'!
So what's the purpose of that tab?? Well, I guess that's a question only Nikon can really answer. However, as far as I'm concerned, the only reason for that tab is to physically prevent non AF-I/AF-S lenses from being mounted on these TCs. Since these TCs don't have the screwdriver connection for the AF motor, Nikon really never intended them to be used on those lenses.
Does filing off the tab change/break anything as far as functioning of the TC with AF-I and AF-S lenses? Not that I'm aware - I've been using a modified TC14E since 2000 and haven't had a single problem. There's absolutely no change in function when mounted on an AF-I or AF-S lens (I'm using the following lenses myself: 80-200mm f/2.8 AF-S, 300mm f/2.8 AF-I, 200-400mm f/4 AF-S VR).
Can I maintain AF with a modified TC14E or TC20E on e.g. a 80-200mm f2.8 AF-D or 300mm f4 AF (non AF-S)? No. Only AF-S/AF-I lenses maintain AF (if the maximum aperture is f8 or better, and only in ample light on a high-end body). If you want to use a teleconverter on an AF-D lens, you should look into the Kenko Pro series of teleconverters
Can Sigma lenses be used with a modified TC? I do not have any Sigma lenses myself, but users have reported the following:
  • Sigma 70-200mm f2.8 EX HSM: does NOT work (rear lens element hits TC front element)
  • Sigma 100-300mm f4 EX IF HSM: works OK with TC14E - at least 1 report of non-AF with a modified TC17E
  • Sigma 120-300mm f2.8 EX IF HSM: works OK with TC14E - at least 2 reports of erratic AF behaviour or even non-AF with a modified TC17E and TC20E
  • Sigma APO 120-300mm f2.8 EX DG HSM: at least 2 reports of hunting AF (TC14E II on D200 used by one user) and 1 report of no AF-lock at all (TC20E III on D3)
  • Sigma 50-500mm f4-6.3 EX RF HSM: does NOT work
  • Sigma 300-800mm f5.6 EX DG APO HSM: works OK with TC14E (user reported AF functional on D200)
  • Sigma 500mm f4.5 EX APO HSM: works OK with TC14E - at least 1 report of erratic AF behaviour with a modified TC17E and TC20E
  • Sigma 800mm f5.6 EX APO HSM: works OK (user reported AF functional on D100, D1, D1x, D2x)
  • Sigma APO Macro 150mm f2.8 EX DG HSM: does NOT work
  • Sigma APO Macro 180mm F3.5 EX IF HSM: works OK (user reported AF can be jittery)
  • Sigma 150-500 f5.6-6.3 DG AF OS: user reports issues with TC20E III - while stabilizer, light measurement etc. seem to be working fine on this configuration, AF just can't lock on target - it goes back and forward forever. On very bright scenes (ie. photographing a light bulb) the focus movements are near the actual focus; on lower light, it just goes back and forward the whole focusing range. Also, the TC does not allow me to get much more detail out of the scene, but that's just because the Sigma 150-500 isn't that sharp - after all it's one of the cheapest zoom lenses of that length. The body I used is a D7000 - without the TC, AF works perfectly until very low light. (Editor's note: this is to be expected since effective aperture is f/11 at best which is too slow for proper AF).
Note that aperture and focal length reported to the camera are not modified, so a f2.8 lens will show as f2.8 in the EXIF data, and the focal length reported will be the focal length of the lens without TC. No compensation necessary though.
When stacking TC's, do I need to following a specific sequence of mounting everything? No, I have never noticed any difference or had any trouble, regardless of mounting sequence: Camera + TC1 then TC2 then lens, or TC1 + TC2 then camera then lens, etc.
Can I put a modified TCxxE on a Nikon 18-200mm f/3.5-5.6G IF-ED AF-S VR DX, Nikon 70-300mm f/4.5-5.6G AF-S (VR or non-VR) or Nikon 55-200 f/4-5.6G AF-S (VR or non-VR) DX?

Short answer: No

Long answer: the TC may physically fit - I don't know, I haven't tried. You'll probably have an issue with the front TC element bumping into the lens rear element on the short end of the lens. However, even if it does fit, you'll most likely be very disappointed with the result - these are fine lenses in their category, however a TC will lead to decreased contrast, decreased sharpness, etc. Also, using these lenses at the long end means you're at f/5.6. Add a TC14E and you're at an effective f/8, so autofocus is highly unlikely to work. So you're back to manual focus, which is not evident with a viewfinder as dark as you'll have at f/8, especially with today's focusing screens which are optimized for AF.

I have an old TC14B and an unmodified TC14E. Can I use the ring of the TC14B on the TC14E so I don't have to grind off the tab on the TC14E ring? No, the ring from a TC14B will not mount on a TC14E. The rings are same size, but the ring from the E seats slightly differently into the TC body.

More questions?

Check out the forums and post your question if you can't find the anwswer in there!
You may also email me. I will update the Q&A section or add a forum topic for those questions that are of interest to everyone.