Sigma 1.4x Teleconverter Review

This is a detailed review of the Sigma 1.4x Teleconverter EX APO DG for the Nikon mount. I had a chance to test out this teleconverter, along with the 2x Sigma teleconverter when working with the Sigma 120-300mm f/2.8 lens (review to be published within the next week), so I wanted to share some of my findings and compare the teleconverter to its Nikon counterpart, the Nikkor TC-14E II. In this review, I will go over the optical characteristics of the Sigma 1.4x teleconverter and talk about its performance when using both Sigma and Nikon super telephoto lenses.

Sigma 1.4x EX DG Tele Converter

Unfortunately, due to compatibility issues with using Nikon teleconverters on Sigma lenses (see below), I had to obtain a copy of both Sigma teleconverters to test the optical performance of the new Sigma 120-300mm f/2.8 Sport lens. Having a constant aperture of f/2.8, the Sigma 120-300mm sounds like a very interesting choice, especially when coupled with teleconverters. It is also an intriguing choice price-wise, since with its $3,600 MSRP price (as of August 2013), the Sigma 120-300mm is significantly cheaper than the comparable Nikon 200-400mm f/4G VR lens ($6,800) or the Canon 200-400mm f/4L IS ($11,800). With the Sigma 1.4x teleconverter, the lens essentially becomes a 170-420mm f/4 lens, which covers even more range than the 200-400mm lenses from both Nikon and Canon at the same constant aperture of f/4. While detailed test results from the teleconverter will be published in the upcoming Sigma 120-300mm f/2.8 review, I will share some Imatest data with our readers from this lens and compare the performance of the teleconverter to the Nikon TC-14E II, mounted on the Nikon 300mm f/2.8G VR II lens.

Elk #1

NIKON D3S @ 420mm, ISO 800, 1/800, f/5.6

1) Lens Specifications

Main Features:

  1. Dedicated teleconverter lens
  2. Multi-layer coating reduces ghost & flaring
  3. Carrying case, body & rear caps

Technical Specifications:

  1. Mount Type: Nikon F-Bayonet (available for other mounts)
  2. Lens Elements: 5
  3. Lens Groups: 3
  4. Optical Conversion Factor: 1.4x
  5. Light Loss: 1 f-stop
  6. Autofocus: Yes
  7. Dimensions (Approx.): 68 x 19.5mm
  8. Weight (Approx.): 160g

Detailed specifications for the teleconverter can be found in our lens database.

2) Lens Compatibility

One of my biggest frustrations with the Sigma 120-300mm f/2.8 Sport lens, was the fact that it will not take any of the Nikon teleconverters – they simply will not physically mount. I am not sure if there is a technical reason for not allowing that, but given that teleconverters are mostly “pass-through” lenses for magnification purposes, I initially did not think that I would be faced with any cross-brand compatibility issues. It turns out that teleconverters are very brand-specific. Nikon teleconverters are designed to only work well with Nikkor lenses, while Sigma teleconverters are designed to only work well with Sigma lenses. So if you were thinking of buying a Sigma 1.4x teleconverter to be used for a Nikon telephoto or super telephoto lens – forget about it. Even though the Sigma 1.4x will physically mount on any Nikon telephoto lens that can take teleconverters and it will perform well optically, it will cause all kinds of lens communication and autofocus issues. For example, when I mounted the teleconverter on the Nikon 300mm f/2.8G VR II lens, it confused my camera into thinking that the maximum aperture of the lens was still at f/2.8 (the correct max aperture is f/4 instead, since 1.4x teleconverters lose one full stop of light). When I mounted the teleconverter on my Nikon 70-200mm, it incorrectly communicated the focal length of the lens. I also lost the ability to autofocus. The teleconverter caused both Nikon 300mm and 70-200mm f/2.8 lenses to go to an AF loop and my 70-200mm sounded like it would break if I kept on trying to acquire autofocus. In short, only use this teleconverter with Sigma lenses!

Sigma maintains a full list of compatible lenses for the 1.4x teleconverter on their website, so make sure to check that your lens is listed on that page before you try to mount the teleconverter.

3) Construction and Handling

Thanks to its all-metal construction, the Sigma 1.4x teleconverter feels like a very solid lens. Both sides of the mount are metal and there is a red dot on the mount itself, which is what you would use to align the lens and the camera. From the usability perspective, I prefer markings on teleconverter’s barrel instead, like on all Nikkor TCs. It is easier to look at the side of a TC when mounting it, rather than looking for the red dot on the mount. Being about 20% shorter than the Nikon TC-14E II, it is hard to believe that such a small unit could accommodate 5 high quality optical elements in 3 groups. Yet Sigma managed to do it and the teleconverter does indeed work quite well for its small size. The spring-based single lever on the side of the teleconverter allows to easily detach it from the lens and it seems to be made to last for years. Overall, the teleconverter is built very well.

Elk #2

NIKON D3S @ 420mm, ISO 400, 1/800, f/4.0

4) Focus acquisition speed and accuracy

Like I pointed out above, forget about trying to get this teleconverter to focus on Nikkor lenses. On Sigma lenses, however, it is a whole different story – autofocus operation is fully maintained and the teleconverter does not seem to negatively impact the AF speed of the Sigma 120-300mm f/2.8, which is good news. Accuracy also does not seem to be impacted, although mileage might vary from lens to lens. Obviously, AF performance and accuracy will surely suffer on slower lenses, with fast lenses being the best candidates to be used with the extender.

5) Sharpness, Contrast and Color Rendition

Similar to AF performance, lens sharpness, contrast and color rendition will depend on the lens the teleconverter is coupled with. When I used the teleconverter on the Sigma 120-300mm f/2.8 Sport, contrast and colors looked superb. Sharpness-wise, as expected, there is definitely a drop of sharpness across the frame, but it is not outside of specs or abnormal. As you will see from the below comparisons, the Sigma 1.4x loses about the same amount of sharpness in the center as the Nikon 1.4x TC.

First, let’s take a look at the resolution capabilities of the Sigma 120-300mm f/2.8 when measured by Imatest:

The Sigma 120-300mm f/2.8 Sport starts out weaker at its maximum aperture of f/2.8. Its performance improves significantly at f/4 and peaks at f/5.6, where it gets very high center resolution. Corner resolution is pretty weak for a telephoto lens, looking about twice worse than the center in resolving power. Let’s now take a look and see what happens when the 1.4x Sigma teleconverter is mounted for additional reach (making it a 170-420mm f/4 lens):

Although the overall sharpness is dropped by about 15%, the center resolution at f/5.6 looks very good. The lens resolves more than the Nikon 300mm f/4G + 1.4x TC, which is impressive! However, the performance at the maximum aperture is rather weak, so I would highly recommend to stop down to f/5.6-f/8 range to get the maximum performance. In comparison, the Nikon 300mm f/2.8G VR II has noticeably better wide open performance, but the center resolution is about the same at f/5.6 and smaller. Where the Nikon 300mm f/2.8G VR II shines is its sharpness consistency throughout the frame – it is much better in mid-frame and the corners (see below)!

Finally, here is an interesting test that I conducted, which compares MTF performance of the Sigma 1.4 and Nikon 1.4 teleconveters. Both were mounted on my reference lens, the Nikon 300mm f/2.8G VR II and I measured sharpness differences between the two in a lab environment. Take a look at the result from the Nikon 1.4x:

And now take a look at the MTF performance of the Sigma 1.4x:

Looks like the Sigma 1.4 is about as good optically as the TC-14E II in the center. However, its performance quickly deteriorates outside the center area, with mid-frame showing slightly worse performance and the extreme corners showing much worse performance, as shown in the above graphs. Also, the Sigma 1.4 seemed to cause a lot more diffraction in my shots starting from f/8. I am not sure if this is another compatibility issue, or some other problem that might have affected the results. In short, it looks like the Sigma should really be used on Sigma lenses only…

6) Summary

The Sigma 1.4x teleconverter seems to be a pretty solid choice for Sigma lenses. As you can see from this review, it works very well with the new Sigma 120-300mm f/2.8 Sport lens and shows impressive performance when stopped down to f/5.6 range and smaller. It is a very compact teleconverter that only weighs 160 grams, so you could leave it on the 120-300mm f/2.8 lens without adding much more weight. Optically, it seems to be as good as the Nikon TC-14E II teleconverter in the center, but it clearly is not suited to be used with Nikkor lenses. Not only does it break the communication between the lens and the camera as noted earlier in this review, but it also makes autofocus go in a loop, causing the focus to go back and forth erratically. This brings up a whole different issue – lens and cross brand compatibility. It looks like none of the Nikon teleconverters will work with Sigma lenses, and none of the Sigma teleconverters are designed to work with Nikon lenses either! So if you already own Nikon lenses and teleconverters and you are getting yourself the Sigma 120-300mm, you will also have to purchase a Sigma teleconverter with it as well…

7) Where to buy and availability

B&H is currently selling the Sigma 1.4x teleconverter for $224 (as of 08/25/2013).

Big thanks to our friend John Lawson for providing sample images!

Sigma 1.4x Teleconverter
  • Optical Performance
  • Features
  • Build Quality
  • Focus Speed and Accuracy
  • Handling
  • Value
  • Size and Weight

Photography Life Overall Rating



  1. 1) Eric laquerre
    August 27, 2013 at 11:25 am

    It is the sigma 120-300 2.8 SPORTS lense not ART lense!! :-)

  2. August 27, 2013 at 12:06 pm

    If Sigma only works with Sigma, and Nikon only works with Nikon (and I’ve read that before, so I didn’t find it surprising), performance kind of becomes moot, doesn’t it?

  3. 3) KnightPhoto
    August 27, 2013 at 12:53 pm

    Excellent details in your review. Makes me wonder if there is a tab or something that could be ground off the Sigma lens to allow it to mount the Nikon TC14 which appears to be superior.

    To be honest, the wide-open stats for the lens both native and with TC, are a bit underwhelming given the weight commitment for carrying this lens, but I thank you for reviewing and showing what you found! And I should recognize that this lens really is a bargain so there is that :-)

    Hmmm bring on the Nikon f/2.8-4 50-30mm VR (that was patented)…

    • 3.1) Rob
      August 27, 2013 at 4:38 pm

      I suspect that it’s the usual issue of the “extra” tab on the TC14E mount which would have to be removed……. Then it may well fit the Sigma, as it does many other lenses once modified.

      • 3.1.1) RobHu
        August 27, 2013 at 4:56 pm

        I tried this (removing the tab) with my Nikon TC17-E II and a Sigma 180mm macro lens. It had the same ‘AF loop’ effect Mansurov experienced using the Sigma TC with a Nikon lens. It became impossible to use AF because it would focus (or over focus) then under focus, and repeat (very very fast).

        I wonder, technically speaking, what the cause is?

        • Rob
          August 28, 2013 at 4:51 am

          Aside from the electronic issues with AF, how didthe Sigma 180mm (which one?) perform with the TC17E?

  4. 4) Carlo
    August 27, 2013 at 3:06 pm

    Have you ever tried the KENKO Teleplus Pro 300 DGX 1.4X ….. it is cheaper than other teleconverters and it works on my Nikon lens (AF-S 80-200 f/2.8 , 50 f/1.4, 105 macro, etc.)

  5. August 27, 2013 at 4:34 pm

    Nice review…..I too wish that the Sigma TC’s worked with Nikon lenses and vice-versa,as it is I keep a 1.4 Sigma TC almost exclusively mounted on my Sigma 150mm f/2.8 and a Nikon TC-14E II practically super glued to my Nikon 300mm f/4 ;-)

  6. August 27, 2013 at 6:56 pm

    Nice review, Nassim. Do you know if the 1.4 teleconverter will autofocus with the Sigma 50-500 and a D800? Bit the bullet last December, and bought the D800, 24-70 2.8, 14-24 2.8, and 70-200 2.8. I also have the Sigma 50-500, and it was great to have in Antarctica in January.

  7. 7) hsrurs
    August 28, 2013 at 9:21 am

    HI Nasim,

    This was a good test!

    Just out of interest what happened with your Nikon super telephoto review?


  8. 8) Warren Drohman
    August 28, 2013 at 4:34 pm

    Hi Nasim,

    You may be interested to know that the Sigma 1.4 teleconverter works wonderfully with the Nikon 70-300 VR lens on my Nikon V1 utilizing the FT-1 adapter! It focuses seemingly as quickly as the lens alone on my D300 and the latest firmware update for the V1 allows it to continuously AF although, with the FT-1, only in the center. The lens and teleconverter also work on the D300, but with audible “stuttering” as it obtains focus and it is not as consistently accurate as the V1. The V1 focusing is amazing. Personally, I sincerely hope Nikon enters the APS-C market with a camera matching, at least, the V1/V2 capability. I’m an owner if they do!

  9. 9) Diego
    August 29, 2013 at 12:48 am

    Hi Nasim,

    Good research with clear findings ! The Sigma 2x TC combined with a 120-300 OS is a complete different story: it is only usable in the 10 – 15 mtr range. Beyond that sharpness is unacceptable. One negative on all TC’s (Sigma, Nikon, Kenko): using it in the field after a while will loosen the screws. Also the superb quality of the 120-300 has nothing to do with the reliability of the system. Both my AF and OS part have been replaced within two years so I decided to sell. Sigma 120-300 OS ? Not recommended for daily use.

  10. 10) Lawrence Nieland
    September 4, 2013 at 10:43 am

    Ostensibly, your tests with the Sigma 120-300 were on full frame ?? but, you do not actually say … If that is so, then the results look much better for crop frame ! ………Larry

  11. 11) Per Laursen
    September 16, 2013 at 7:00 am

    I use the Sigma 120-300/2,8OS on D800. Results are great all-over – also with the Sigma TC1,4 APO DG at f 5,6 or smaller. I have machined a Nikon TC20EIIIasf. to fit all lenses ( including 120-300/2,8OS ). Results ar no better than with the Sigma 2X TC APO DG. The Nikon2X TC can NOT be used with ordinary optical AF, because of horrible constant hunting unable to lock on any motiv. Using Live-View and Cary-Speed VF-3 there is no problem – besides mediocre picturequality….

  12. 12) Paul Evans
    December 26, 2013 at 4:22 pm

    I went and bought a Sigma 2x teleconverter today and mounted it on my Sigma 70-200 f2.8 lens. I use it on a Nikon D3200. I was greatly disappointed in this lens. I get better results at 150 yards without the converter than I do with it. I ran throught all the combinations of aperture and shutter speed that I could do. I finally settled on f14 at 1/2500 of a second in bright light with 800 iso. I would not recommend this converter to anyone. Maybe the 1.4 does a good job, but you need lots of light, and a high shutter speed to make up for any shake or vibration and all of my shots looked soft. On another note, do not order a Promaster, they do not function on the sigma lens, it keeps searching and will not lock onto your focal point. I tried that before I bought the Sigma for almost $300. I feel I just wasted a lot of money. Trying to focus on flying eagles today was useless with the converter.

  13. 13) asamdisalpr
    March 2, 2014 at 10:50 am

    What about canon lenses and Sigma Teleconverters. I recently acquired a Sigma 70-200 Apo OS f/2.8 lens.

  14. 14) oeriies
    April 30, 2014 at 6:28 pm

    I own the Siggy 120-300 OS and both the Siggy and Nikon 1.4 TCs. If you grind the extra tab off the Nikon TC it will fit on the Siggy. I believe it is sharper, but it communicates the wrong f stop and hunts a bit for focus. So Siggy on Siggy and Nikon on Nikon is the TC rule.

    Nasim’s review is very helpful because you’ll look in vain to find TC and lens combos run through Imatest anywhere ele. That said, you should look at the resolution results at Dpreview and DxO for the lens itself. They are quite a bit different than reported here. To be specific the MT50 chart at the center at 300mm generates 2500 lp/mm at f2.8 and doesn’t budge through f5.6 at Dx0 and DPreview whereas Nasim reports substantial increases in resolution when stepping down from f2.8 to f5.6. Different copies? Different test procedures? I don’t know. My copy of the lens seems as sharp wide open as stepped down, consistent with the DxO results. Also, for whatever it is worth, if I crop to obtain the same small field of view at about 30 feet from a D800 and D7100 the D7100 resolves better — more pixels on the target makes a difference.

  15. 15) Ulrich Drescher
    May 3, 2014 at 10:17 am

    I have the Sigma 120-300 f2.8 (Non OS) lens, and also a Sigma 2x Teleconverter…

    I am looking at purchasing the Sigma 1.4x Teleconverter and think this will cover a lot of bases for me…

    I use a Nikon D90 and so far my results have been very good, I have no issues with the lens even on the 2x converter the autofocus performs very well…so I can only think that the with the 1.4 there should be no issues at all…

    Thanx for the review…

    • 15.1) ChuckL
      August 15, 2014 at 1:17 am

      Ulrich: I’d be very interested to hear what you think of the Sigma 120-300 non-OS with the Sigma 1.4 TC. I borrowed that combo from a friend a year ago, and I was amazed at the results. The 120-300 is very sharp by itself, and I couldn’t see any drop in sharpness using the Sigma 1.4 TC with it.

      On the other hand, I’ve used the Sigma 2.0 TC a few times, and the results were far less sharp then the Sigma 1.4 TC.

  16. 16) Pedro Vilela
    September 16, 2014 at 4:09 pm

    Hello to all
    I have a SIGMA 120-300 mm D APO HSM EX , i work a lot with SIGMA 1.4 TC
    The lent alone is very Sharp. using it with TC 1.4 TC you will notice a small drop on quality .
    Autofocus Speed will decrease a little, not very much
    I use it with D90 and D2XS .
    on the other hand i notice the same TC 1.4 with Nikon 400 mm Af-S don´t work, a lot o loops and f stays at 2.8 instead of f4

Comment Policy: Although our team at Photography Life encourages all readers to actively participate in discussions, we reserve the right to delete / modify any content that does not comply with our Code of Conduct, or do not meet the high editorial standards of the published material.

Leave a Comment

Your email address will not be published. Required fields are marked *