Quick thoughts: TC-20E III

I received a Nikon TC-20E III teleconverter a few days ago.  I’ve not really been an advocate of 2x teleconverters, but this new design from Nikon contains aspherical elements (Nikon claims it is the first teleconverter with such a design) intended to drastically improve performance.

A 2x teleconverter is only intended for use on fast telephoto lenses.  In fact, Nikon’s design prevents mounting any of their teleconverters on non-AFS lenses.  Because the teleconverter robs you of light (in the case of the TC-20E III, two full stops), autofocus performance may degrade and viewfinder brightness will diminish.  Given that, I only have a couple of lenses in my arsenal that would be a good match for the TC-20E III:
  • 70-200mm f/2.8 AFS VRII (becomes a 140-400mm f/5.6 lens)
  • 200mm f/2.0 AFS VR (becomes a 400mm f/4.0 lens)
I also have a few lenses that might work ok, depending on my need for fast autofocus:
  • 300mm f/4.0 AFS (becomes 600mm f/8.0 lens)
  • 200-400mm f/4.0 AFS VR (becomes a 400-800mm f/8.0 lens)
  • 600mm f/4.0 AFS VR (becomes a 1200mm f/8.0 lens)
So far, I’ve briefly evaluated sharpness and AF ability with each of these lenses in a non-scientific manner.
Continue reading for my first impressions…


First impressions with the TC-20E III teleconverter


  • Nikkor 70-200mm f/2.8 AFS G VRII:  Autofocus works fine (effective f/5.6). Fair image quality wide-open, good image quality by f/8.
  • Nikkor 200mm f/2.0 AFS G VR: Autofocus performance is excellent (effective f/4.0), image quality is good wide open and very good by f/5.6.
  • Nikkor 300mm f/4.0 AFS: Autofocus is OK in good light, but will be sluggish at times (effective f/8.0).  I’ve had mixed results with image quality– I’m seeing good performance on close subjects at f/8 (wide-open), but I’m having a harder time getting crisp images on distant subjects unless I stop down to f/22.  Further testing is required.
  • Nikkor 600mm f/4.0 AFS VR: Autofocus performance is OK in good light, but prone to hunt or track slowly, especially in low light. Image quality is good wide-open, and very good at f/11 or above.
  • Nikkor 200-400 f/4.0 AFS VR: Autofocus performance is ok in bright conditions, but can fail to acquire a target in dim light. Image quality was good wide-open, and very good by f/11 or higher.
Conclusions
Not surprisingly, the TC-20E III does its best work on the best (read: expensive) glass.  Autofocus still operates at effective apertures of f/8, but I wouldn’t count on it in dim light or in situations where fast subject tracking is required (Nikon claims that AF is not supported at effective apertures smaller than f/5.6).
I never owned the TC-20E II, mainly because I’d never heard a favorable review of it.  If you must stop down an additional two f-stops (or more) to use a teleconverter that is already costing you two stops of light, then it won’t get a lot of use.  On the best lenses, I got good image quality by stopping down only one stop from wide-open.  In fact, with the 200 f/2 VR, I could probably use the TC-20E III with the lens wide-open; that’s a testament to how good the 200 f/2 VR is. I was surprised that the 300mm f/4 AFS lens did not perform better in my testing; this lens is very sharp and works well with the TC-14E and TC-17E teleconverters. However, for wildlife shooters, f/22 hand-held is not going to be a feasible option in most lighting conditions. Perhaps a future redesign of the 300 f/4 lens would improve its compatibility with the newest Nikon TC.
Remember, when you use a TC, you are increasing focal length.  Extra care must be taken to stabilize your lens to get sharp shots. Just because you can hand-hold it does not mean that you’ll get sharp shots using hand-held techniques!
If you are interested in purchasing the TC-20E III, check out Roberts Imaging.

5 thoughts on “Quick thoughts: TC-20E III”

  1. From your reviews here it would appear that I may be better off going for the Nikon TC-17E instead of the TC-20E III teleconverter.

  2. Tried my new TC-20E III before christmas on a 200-400 VR. I shot on a tri pod with a tethered release. It was my first attempt to shoot birds in my backyard. Since I was green at it, I choose to shot birds at one of my feeders to test my results. I had a very difficult time getting tack sharp images. I assumed it had to do a lot with ‘practice’! You can see some of my results here . Do you think locking the mirror up would make a noticeable difference?
    BTW, thanks for all the time and effort you put in on the Nikonians Podcast. I loved it! Heard the new Nikonians Podcast today (with your interview). You will be missed!

  3. A 2x TC on an f/4 lens gives an effective f/8 lens. It’s hard to get sharp images because AF is disabled, and the reduced light means slower shutter speeds. Slow shutter speeds on birds means a greater possibility of camera shake or subject motion blur.

  4. My 200-400 Version 1 works well with the tc 2.0 III at F8. AF is fast
    in good light. At F11 you need to use a D700 FX type of camera
    or a D3/D3s to fully appreciate the higher ISO requirement of taking
    photos at F11. It all depends on the subject. If the subject is mostly moving
    slowly or still, Depending on the light using Low ISO and mirror lockup will work.

    If you are photographing a high speed event, higher ISO is needed so that
    a higher shutter speed can be used.

  5. I use the TC-20E III with a D7000 and 70-200mm VRII at f/8.0. AF works fine. At its very best – i.e. on a tripod with mirror up, low ISO, and non-moving subjects that permit long exposures, it gives excellent resuits. Out in the field I often use a monopod, high ISO, and fast shutter speeds. Results are not as good, as one would expect, but are perfectly acceptable.

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