Teleconverter Disappointment
May 10, 2017 10:20:33 #
I recently picked up a used Nikon TC-20E lll teleconverter in like new condition to use with my 70-200 f2.8 lens. According to Nikon this converter is fully compatible with the 70-200 lens. Such was not the case. Without the converter the lens autofocus is fast and accurate. With the converter the autofocus is slow as molasses, hunts all over the place and cannot get a focus lock. I tried using it with both a full frame and a cropped sensor camera and with a few other f2.8 lenses I have, all with the same result. Needless to say(but I'm saying it anyway) I'm very disappointed.
May 10, 2017 10:26:06 #
Sorry to hear this, I have a Sigma 2x and it works with my Fx lenses but does the same thing as yours with DX lenses
May 10, 2017 10:28:54 #
jkm757 wrote:
I recently picked up a used Nikon TC-2E lll teleco... (show quote)
Is it the TC, the camera, or the combination?
I have no knowledge of Nikon, but with Canon all three function as a system and need to be 'mated' physically and electronically to be compatible. It can become complicated.
May 10, 2017 10:36:44 #
Which camera model are you using it on?
jkm757 wrote:
I recently picked up a used Nikon TC-2E lll teleco... (show quote)
May 10, 2017 10:39:54 #
jkm757 wrote:
I recently picked up a used Nikon TC-2E lll teleco... (show quote)
What aperture are you using? I think this converter will only work when you are using large apertures, like f2.8-4.0 If you are using f8 or something like that this is just a normal problem with about every teleconverter.
May 10, 2017 10:43:45 #
Peterff wrote:
Is it the TC, the camera, or the combination?
I have no knowledge of Nikon, but with Canon all three function as a system and need to be 'mated' physically and electronically to be compatible. It can become complicated.
I have no knowledge of Nikon, but with Canon all three function as a system and need to be 'mated' physically and electronically to be compatible. It can become complicated.
Since autofocus works fine without the TC, I have to assume it's the TC that's causing the problem. My camera bodies and lenses are Nikon and according to the Nikon website the TC is fully compatible with the 70-200 lens.
May 10, 2017 10:44:14 #
May 10, 2017 10:46:06 #
I suspect it's an electrical/connectivity issue. Perhaps, a thorough and careful cleaning of the contacts will help. Subtle damage or prior misuse is also a possibility with a used lens. Rarely, even Nikon produces a lemon. At the end of the day, teleconverters are designed to work best with prime lenses and even then, some, usually small, degree of optical loss can often be seen but not the level of malfunction you're seeing. I sometimes use a TC-2E lll with a Micro Nikkor 105. It's not listed as compatible but it works well enough.
May 10, 2017 10:47:29 #
Maybe you need to ask for a definition of "fully compatible." That may mean different things to different people.
May 10, 2017 10:48:53 #
JPL wrote:
What aperture are you using? I think this converter will only work when you are using large apertures, like f2.8-4.0 If you are using f8 or something like that this is just a normal problem with about every teleconverter.
It is only the wide open aperature that matters as automatic lenses focus with the aperture wide open. A 1.4 TC adds one stop. A TC 2 adds 2.
Most older cameras can only focus with f5.6 or wider. So you need a lens with f2.8 max aperture for it to focus reliably with a 2 TC.
Newer cameras focus with an aperture down to f8 so you can add a 1.4 to a 5.6 lens and it will still autofocus. But not a 2.
May 10, 2017 10:49:52 #
jkm757 wrote:
Since autofocus works fine without the TC, I have to assume it's the TC that's causing the problem. My camera bodies and lenses are Nikon and according to the Nikon website the TC is fully compatible with the 70-200 lens.
That was my point. It depends upon the successful interaction of all three. Each may be individually OK, but the combination may not deliver for numerous reasons.
May 10, 2017 10:51:01 #
JPL wrote:
What aperture are you using? I think this converter will only work when you are using large apertures, like f2.8-4.0 If you are using f8 or something like that this is just a normal problem with about every teleconverter.
Wide open on an f2.8 lens.
May 10, 2017 10:52:20 #
jkm757 wrote:
Wide open on an f2.8 lens.
Again it does not matter what f-stop you set for the image as the cameras uses wide open to focus. Should work.
May 10, 2017 11:01:11 #
JPL wrote:
What aperture are you using? I think this converter will only work when you are using large apertures, like f2.8-4.0 If you are using f8 or something like that this is just a normal problem with about every teleconverter.
Respectfully, the aperture you are using has absolutely no effect on focus speed of any modern lens. That aperture only comes into play when the shot s taken and the lens is stopped down. The maximum aperture of the lens in question is the important item here. Best of luck.
May 10, 2017 11:02:58 #
optic wrote:
I suspect it's an electrical/connectivity issue. P... (show quote)
When I tried it with my macro lens (Nikon 105 f2.8) it wouldn't open any wider than f8.
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