It was not easy to obtain the Nikon TC-20E III because of high demand/short supply and after waiting for a few weeks, I decided to just rent it for a couple of weeks instead. My objective was to try the Nikon TC-20E III specifically with the Nikon 300mm f/2.8G VR II and with the Nikon 70-200mm f/2.8G VR II to see how it truly performs in an outdoor environment when photographing nature. It is one thing to shoot test charts with a lens sitting on a tripod, and another to get out and do some real shooting. Some lenses look great on paper and on test charts, but cannot perform equally well when used in an outdoor environment, especially with fast-moving subjects like birds. The primary reason is autofocus, the performance of which depends on many different factors. Teleconverters generally negatively impact autofocus performance, due to a considerable loss of light and contrast and the 2x TC is the worst in this regard. Adding a teleconverter slows down lenses and the Nikon TC-20E III slows down by two full stops. What this means, is that when the teleconverter is mounted on an f/2.8 lens, it slows down to f/5.6 and as you may know, autofocus performance on small apertures beyond f/5.6 is unreliable even in broad daylight conditions. Nikon clearly points out that autofocus does not work beyond f/5.6, so if you have an f/4.0 lens, forget about autofocus – you will have to resort to manual focus.
In addition, due to the considerable number of additional glass elements, the lens sharpness performance can suffer significantly, depending on the quality of the lens. While lenses like Nikon 200mm f/2G VR II, Nikon 300mm f/2.8G VR II and Nikon 400mm f/2.8G VR work great with 2x teleconverters, some lenses like the Nikon 70-200mm have been known to perform very poorly with any teleconverters longer than 1.4x. As I have demonstrated in this review, the new Nikon 70-200mm f/2.8G VR II works beautifully with the Nikon TC-20E III when stopped down a little, which was a nice surprise. Let’s take a closer look at the teleconverter.
1) Lens Specifications
- Enhanced telephoto versatility – affordable and portable gateway to extend telephoto reach; ideal for sports, wildlife, surveillance and more.
- Aspherical lens element virtually eliminates coma and other aberrations, especially at wide apertures.
- 2x optical conversion factor doubles the focal length of select compatible NIKKOR lenses.
- Nikon Integrated Coating (IC) enhances light transmission efficiency, improves color consistency and reduces flare.
- Mount Type: Nikon F-Bayonet
- Lens Elements: 7
- Lens Groups: 5
- Optical Conversion Factor: 2.0x
- Light Loss: 2 f-stops
- Compatible Format(s): FX, DX, FX in DX Crop Mode, 35mm Film
- Autofocus: Yes
- AF-S (Silent Wave Motor): Yes
- Dimensions (Approx.): 2.6×1.8 in. (Diameter x Length), 66x46mm (Diameter x Length)
- Weight (Approx.): 11.06 oz. (330g)
- Supplied Accessories: BF-3A front lens cap, LF-1 rear lens cap, Cl-0715 Lens Case
Nikon TC-20E III compatibility and performance chart:
|Lens Description||Effective Focal Length||Autofocus||Acceptable Sharpness||Optimal Sharpness|
|* Acceptable and optimal sharpness numbers above are estimates, based on various tests and feedback from users|
|AF-S Micro-NIKKOR 105mm f/2.8G IF-ED VR||210mm f/4.0||No||f/8.0||f/11.0|
|AF-S NIKKOR 200mm f/2G IF-ED VR||400mm f/4.0||Yes||f/4.0||f/5.6|
|AF-S NIKKOR 300mm f/2.8G ED VR II||600mm f/5.6||Yes||f/5.6||f/8.0|
|AF-S NIKKOR 300mm f/2.8G IF-ED VR||600mm f/5.6||Yes||f/5.6||f/8.0|
|AF-I NIKKOR 300mm f/2.8D IF-ED||600mm f/5.6||Yes||f/5.6||f/8.0|
|AF-S NIKKOR 300mm f/4D IF-ED||600mm f/8.0||No||f/11.0||f/11.0|
|AF-S NIKKOR 400mm f/2.8G ED VR||800mm f/5.6||Yes||f/5.6||f/8.0|
|AF-S NIKKOR 400mm f/2.8D IF-ED II||800mm f/5.6||Yes||f/5.6||f/8.0|
|AF-S NIKKOR 400mm f/2.8D IF-ED||800mm f/5.6||Yes||f/5.6||f/8.0|
|AF-I NIKKOR 400mm f/2.8D IF-ED||800mm f/5.6||Yes||f/5.6||f/8.0|
|AF-S NIKKOR 500mm f/4G ED VR||1000mm f/8.0||No||f/11.0||f/11.0|
|AF-S NIKKOR 500mm f/4D IF-ED II||1000mm f/8.0||No||f/11.0||f/11.0|
|AF-S NIKKOR 500mm f/4D IF-ED||1000mm f/8.0||No||f/11.0||f/11.0|
|AF-I NIKKOR 500mm f/4D IF-ED||1000mm f/8.0||No||f/11.0||f/11.0|
|AF-S NIKKOR 600mm f/4G ED VR||1200mm f/8.0||No||f/8.0||f/11.0|
|AF-S NIKKOR 600mm f/4D IF-ED II||1200mm f/8.0||No||f/8.0||f/11.0|
|AF-S NIKKOR 600mm f/4D IF-ED||1200mm f/8.0||No||f/8.0||f/11.0|
|AF-I NIKKOR 600mm f/4D IF-ED||1200mm f/8.0||No||f/8.0||f/11.0|
|AF-S NIKKOR 70-200mm f/2.8G IF-ED VR||140-400mm f/5.6||Yes||f/11.0||f/11.0|
|AF-S NIKKOR 70-200mm f/2.8G ED VR II||140-400mm f/5.6||Yes||f/5.6||f/8.0|
|AF-S NIKKOR 80-200mm f/2.8D IF-ED||160-400mm f/5.6||Yes||f/8.0||f/11.0|
|AF-S NIKKOR 200-400mm f/4G IF-ED VR||400-800mm f/8.0||No||f/11.0||f/11.0|
|AF-S NIKKOR 200-400mm f/4G ED VR II||400-800mm f/8.0||No||f/11.0||f/11.0|
The lenses with f/11 for both “Acceptable” and “Optimal” sharpness produce very unreliable results.
2) Lens construction and handling
Similar to other Nikon teleconverters and its predecessor, the Nikon TC-20E III has a rugged all-metal exterior and a metal mount that is built to last a lifetime. The solid construction, along with a whopping 7 elements make it one heavy teleconverter, weighing a total of 330 grams without a lens attached. As a comparison, the Nikon 50mm f/1.4G lens weighs only 280 grams. The Nikon TC-14E II and TC-17-E II weigh 200 and 250 grams, respectively. While the number of optical elements has not changed between the new and the older 2x teleconverters, two key differences to note are the redesigned layout/lens groupings and replacement of a regular lens element with an aspherical one. The aspherical element was added to improve image quality by increasing sharpness, decreasing coma and other aberrations. Like other teleconverters, the Nikon TC-20E III has fixed lens elements that do not move when focus ring or zoom ring are touched on the lens. This means that the lens is protected very well against dust and moisture.
3) Focus acquisition speed and accuracy
When it comes to autofocus performance, the Nikon 2x teleconverters have always been the worst (when compared to other Nikon teleconverters), since they slow down lenses by two full stops and degrade image quality. The quality of light that reaches the autofocus sensor is often poor and only large aperture lenses that pass through lots of light can focus well enough with the TC-20E III. For example, the Nikon 200mm f/2.0 works very well with the TC-20E III and autofocus is often both fast and accurate. Slower f/2.8 prime lenses are a little worse, but still accurate enough in bright conditions. As lighting conditions worsen, the autofocus performance gets less accurate and lenses might start “hunting” – that’s when the lens goes from infinity to close focus, unable to stop at a particular focus mark. When the TC-20E III is used with slow f/4 aperture lenses, autofocus stops working completely or becomes extremely unreliable. With the exception of the new Nikon 70-200mm f/2.8G VR II, zoom lenses also start acting up in daylight with very mixed results. The Nikon 70-200mm f/2.8G VR II works surprisingly well with the TC-20E III and I found the autofocus performance to be good in bright conditions, although the lens also works very well with the TC-14E II and TC-17E II teleconverters. The same cannot be said about the older 70-200mm f/2.8 lens – it is only known to work well with the TC-14E II. The above table chart outlines which lenses perform best at what aperture with the TC-20E III. When photographing sports, wildlife and other fast-action photography, you have to be extremely careful when using the TC-20E III. Not only will it take some time to get used to, but you also need to know how to get the best out of your autofocus system on the camera. For example, choosing anything but the center focus point will often result in focus hunting and you might need to manually pre-focus the lens before trying to acquire focus on your subject. In addition, using the focus limiter switch on telephoto lenses also helps, as lenses do not have to go through the full cycle of focusing back and forth. So if you are frustrated with the TC-20E III, I recommend taking your time and experimenting with the AF system on your camera. It goes without saying that AF performance will suffer even more on lower-end DX cameras, so I suggest using the TC-20E III on pro-level bodies like Nikon D300s and above.
4) Lens sharpness, contrast and color rendition
Similar to AF performance, lens sharpness, contrast and color rendition will depend on the lens the TC-20E III is coupled with. Fast prime lenses generally yield the best performance, but still require stopping down in order to get optimal results. No matter what lens you use the TC-20E III with, image quality will be degraded in all cases to a certain extent, even with top-of-the-line lenses like Nikon 200mm f/2G and Nikon 300mm f/2.8G. Sharpness improves dramatically as you stop down on the aforementioned lenses, but still does not reach the same level of sharpness you would get without a teleconverter, which is expected. Colors and contrast are OK at maximum aperture and also improve when stopped down. I personally would not use apertures faster than f/8.0 (except on Nikon 200mm f/2G, which is very sharp at f/5.6) when using the Nikon TC-20E III if you want to get the best results.
Sharpness Test – Nikon 70-200mm f/2.8G VR II
Sharpness Tests on FX Sensor
Some technical junk:
- White Balance: Auto, changed to “Custom”: 3400 Temp, +22 Tint in Lightroom
- ISO: 200
- EXIF information is preserved in the images
- Lens was mounted on Nikon D3s Camera and Gitzo tripod
- Focusing was performed through Live-View Contrast Detect. After each successful focus acquisition, focus was switched to manual to prevent camera refocusing
- Mirror Lock-Up mode with Exposure Delay set to “On” and remote cable release to completely eliminate camera shake
- Long exposure NR: Off
- Image Format: RAW
- Lightroom settings: Default settings, but exposure had to be slightly adjusted (-.20 to +.033) to make sure that all images have the same brightness level
- Lightroom export: sRGB JPEG Quality 80
- Nothing was moved during testing
5) Sharpness Test – Nikon 70-200mm f/2.8G VR II with TC-20E III Center @ 400mm
A couple of notes and observations before moving on to sharpness tests. I found the TC-20E III to work very well with the Nikon 70-200mm f/2.8G VR II for stationary and slow subjects. For fast-action photography (birds in flight, running wildlife), the autofocus on the 70-200mm was the bottleneck – I did not get many sharp images due to focus errors. The experience I had with the TC-20E III on 70-200mm VR II was very similar to the TC-17E II on 70-200mm both in terms of sharpness and AF accuracy, although the TC-17E II produced slightly better results with fast moving subjects. Unfortunately, the previous generation Nikon 70-200mm f/2.8G VR does not pair well with the TC-20E III or the older TC-20E II (in my opinion, the older TC-20E II is basically unusable with any lens as there is too much image degradation and loss of contrast). So if you own the older 70-200mm f/2.8G VR and want to try the TC-20E III, you will most likely be disappointed. It almost feels like Nikon “tuned” the 70-200mm for the TC-20E III before they released it. Overall, I am very pleased with how the TC-20E III performed with the Nikon 70-200mm f/2.8G VR II.
I only tested the Nikon 70-200mm @ 200mm (400mm effective) for two reasons: the lens is incredibly sharp at all focal lengths and those who will be using the 70-200mm with a 2x TC will be using it at the longest focal length to get the maximum reach. Wide open at f/5.6, the Nikon 70-200mm f/2.8G VR II shows pretty good sharpness. Stopping down the lens to f/8 improves the situation significantly, as can be seen below:
As you can see, stopping down to f/11 does not improve sharpness and anything smaller than that shows the negative effects of diffraction.
6) Sharpness Test – Nikon 70-200mm f/2.8G VR II with TC-20E III Corner @ 400mm
The first image is darker due to visible vignetting at the largest aperture. If I brighten up the image a little, there is no difference between the two images. This means that stopping down the lens does not result in improved sharpness in the corners. Let’s see if the situation improves at f/11 or f/16:
I cannot see any improvements at smaller apertures at all.
7) Nikon 70-200mm f/2.8G VR II + TC20E III vs Nikon 200-400mm f/4G VR
Obviously, the Nikon 200-400mm is much sharper wide open without a teleconverter. Once you use the TC-20E III with the 200-400mm, the performance goes down the drain, as can be seen in other tests of this review. Here is a more meaningful comparison with the 70-200mm at f/8:
As you can see, the TC-20E III yields surprisingly good results with the 70-200mm at f/8, which is pretty close to the 200-400mm at f/4 (without a TC) in sharpness. Obviously, there is a loss of two full stops of light and larger depth of field, but still pretty impressive.
Sharpness Test – Nikon 300mm f/2.8G VR II
8) Sharpness Test – Nikon 300mm f/2.8G VR II with TC-20E III Center Frame
The Nikon TC-20E III was specifically designed to pair well with lenses like Nikon 300mm f/2.8G. I had a very pleasant experience with the TC-20E III both in terms of sharpness and AF speed on the 300mm f/2.8G VR II. I was able to photograph birds in flight with this combo and images were sharp enough wide open and very sharp at f/8. If you have an older version of the 300mm f/2.8 lens, you can safely assume that the TC-20E III will give you similar results. As I have already noted in my Nikon 300mm f/2.8G VR II Review, I would rather use the Nikon 300mm f/2.8 with the TC-20E III than the Nikon 200-400mm f/4 with the TC-17E II or the TC-14E II.
Stopping down the lens to f/11 does nothing and at f/16 diffraction kicks in and makes the image look a little softer:
If you want the best results, I recommend keeping your aperture at f/8. Larger apertures between f/5.6 and f/8 can also yield fairly good sharpness in the center. Let’s take a look at the corners now.
9) Sharpness Test – Nikon 300mm f/2.8G VR II with TC-20E III Corner Frame
Sharpness Test – Nikon 300mm f/4 AF-S
10) Sharpness Test – Nikon 300mm f/4 AF-S with TC-20E III Center Frame
I love my Nikon 300mm f/4 AF-S, because it is a very sharp and lightweight lens that I take with me when I do not feel like taking the big bazookas with me. While it pairs very well with the Nikon TC-14E II, I find it to be unreliable with any other teleconverter. I have tried the TC-20E II with the 300mm f/4 AF-S in the past and found it to be completely unacceptable, so I decided to try it again with the new TC-20E III. The Nikon TC-20E III slows down the Nikon 300mm f/4 AF-S to f/8. As expected, the small maximum aperture of the lens caused the AF system to be completely unreliable and often inoperable – the lens would hunt in almost all cases. I quickly gave up using the TC-20E III. Let’s see how sharp the optics of the Nikon 300mm f/4 AF-S are with the TC-20E III if you were to manually focus:
The wide open performance of the 300mm f/4 AF-S @ f/8 is slightly worse than when stopped down to f/11.
Stopping down the lens further to f/16 does not improve the sharpness.
11) Nikon 300mm f/4 AF-S + TC-20E III vs Nikon 300mm f/2.8G VR II + TC-20E III
As you can see, the Nikon 300mm f/2.8G VR II + TC-20E III is much sharper at f/8 when compared against the Nikon 300mm f/4 AF-S + TC-20E III. If you compare both lenses wide open (at f/5.6 and f/8.0), then they look very similar as seen below (Left: Nikon 300mm f/4 @ f/8, Right: Nikon 300mm f/2.8G @ f/5.6):
I am not going to provide test results from the Nikon 300mm f/4 AF-S in the corners, because it performs very similarly to the Nikon 300mm f/2.8G.
Sharpness Test – Nikon 200-400mm f/4G VR
12) Sharpness Test – Nikon 200-400mm f/4G VR with TC-20E III Center Frame
I had a negative experience with the TC-20E III mounted on the Nikon 200-400mm – not only did autofocus not work, but I could not get good sharpness out of this lens, period. Without a teleconverter or with the Nikon TC-14E II, the 200-400mm is extremely sharp from center to corner across the zoom range. But it just does not play well with the Nikon TC-17E II, Nikon TC-20E II and the new Nikon TC-20E III. Take a look at the performance of the lens at 600mm:
As you can see, the wide open performance at f/8 is weak and stopping down the lens to f/11 does nothing to improve the sharpness – the same goes for f/16:
The corner performance is very similar to the center performance.
13) Nikon 200-400mm f/4G VR + TC-20E III vs Nikon 300mm f/2.8G VR II + TC-20E III
Again, the Nikon 300mm f/2.8G is much sharper and the two would be comparable wide open.
Summary and Image Samples
Without a doubt, the new Nikon TC-20E III is a huge improvement over the Nikon TC-20E II. While I have not had a chance to actually test both side-by-side, I have tried using the Nikon TC-20E II in the past and was very disappointed with the results, even when used with fast lenses like Nikon 300mm f/2.8G. As can be seen in the previous pages of this review, the new TC-20E III is capable of producing excellent sharpness and contrast with most fast prime lenses and the Nikon 70-200mm f/2.8G VR II. Even though the lab tests show that the sharpness is relatively good with slower f/4 lenses, I personally would not recommend using the TC-20E III with any of those, unless you will be heavily stopping down and focusing manually on a tripod. You will need to be careful in selecting the right lens to pair with the TC-20E III. Again, it is one thing to shoot test charts in a controlled environment and completely another to shoot subjects like birds in challenging light. The TC-20E III is not an easy tool to master – it will take some time to get used to and you will have to first learn how to properly use the autofocus system on your camera.
Overall, if you own a fast prime lens or the Nikon 70-200mm f/2.8G VR II and need the maximum reach, the Nikon TC-20E III is definitely worth looking at. When photographing distant subjects such as wildlife and birds, the Nikon TC-20E III can be an invaluable tool that will let you enlarge your subjects without approaching and disturbing them.
15) Where to buy and availability
16) More image samples
All Images Copyright © Nasim Mansurov, All Rights Reserved. Copying or reproduction is not permitted without written permission from the author.