The TC1401 teleconverter is a good magnifier for some Sigma lenses, bringing your object by 1.4x closer than Sigma focal length can for you. If you are buying the Sigma 150-600mm f/5 – 6.3 DG OS HSM Contemporary lens, it comes quite often with it as a bundle (Pic. 1). It’s a quite good bargain in my opinion because the following teleconverter kit can be gained by about 50% it’s a regular price. Moreover for a person, like myself, who is interested in long-distance observations, this teleconverter kit is essential. In this post, I would like to take a close-up view of all the major features of the TC1401 for Sigma lenses. Before I start to do it I would like to list all dedicated sigma lenses for this teleconverter as well as the Nikon F mount.
The Sigma lenses dedicated for the 1.4x as well as 2x teleconverter are:
– 60-600mm F4.5-6.3 DG OS HSM I Sports
– 70-200mm F2.8 DG OS HSM I Sports
– 100-400mm F5-6.3 DG OS HSM | Contemporary
– 120-300mm F2.8 DG OS HSM | Sports
– 150-600mm F5-6.3 DG OS HSM | Sports
– 150-600mm F5-6.3 DG OS HSM | Contemporary
– 500mm F4 DG OS HSM I Sport
- BUILD QUALITY & DESIGN
The Teleconverter TC-1401 kit is very small (Pic. 2), and its size is very similar to its predecessor, The Sigma APO TELE Converter 1.4x DX EG. The extender is finished with metal lens mounts and the barrel is smooth and black. The final weight is 128g. Inside, the teleconverter is equipped with 1 SLD (Special Low Dispersion) glass element in order to maintain the maximum image quality. Moreover, the whole item features splash and dustproof construction, which is aimed at maintaining long-lasting durability.
If you take it to your hand and shake it a bit, you can hear some scraping (see the video below). I don’t know where it comes from, but it doesn’t impact the item usage.
However, the serious problem with the Teleconverter TC-1401 mount is not a perfect match with the Sigma 150-600mm f/5-6.3 Contemporary lens. The rigid plastic part seems to rub Sigma’s metal mount. It results in the peeling of each other, which I experienced from the very beginning of the use (Pic. 2, 3). Even if you pull the black button as much back as you can it won’t help. Something is definitely wrong here and the manufacturer should alter the metal mount a little bit. The mounting of this teleconverter kit to Sigma 150-600mm f/5 – 6.3 contemporary version is quite tough.
When the teleconverter TC-1401 kit is attached to Sigma 150-600mm f/5-6.3 Contemporary lens, then is easy to attach it to the Nikon F mount camera. The problem occurs only between the teleconverter and the primary lens, although I hope, that this issue doesn’t come out of the Sigma 150-600mm f/5-6.3 contemporary example.
The good attitude of the teleconverter TC-1401 is that autofocus works at the entire range.
2. IMAGE QUALITY & SHARPNESS
The Teleconverter TC-1401 features very good image quality. If I could make a final mark it would be something about 5/6. From the technical side, the best image quality appearance seems to be in the middle aperture range (between f/8 and f/13) and obviously in the center of the frame. Following the resolution chart test presented below (Pic. 7) the results are really good, which makes this teleconverter kit at the top of the selection.
The authors of this test found, that measured peak resolution by the MTF-50 scale tends to reach 32,4lp/mm which is very good and only a tad worse than at Sigma 150-600mm f/5-6.3 Contemporary version, where it reached about 34lp/mm. The minimum benchmark for the 840mm frame is an MTF 50 of 30lp/mm, which is almost the same as in Sigma 150-600mm C, where at the edge it reached 31lp.mm.
Translating it into a live example, there is practically no sharpness loss throughout all focal ranges (Pic. 8 – 15) caused by this teleconverter. The fuzziness and softness, known already from the smallest apertures in Sigma 150-600mm f/5-6.3 Contemporary version are simply multiplied by 1.4x (the magnification value of this teleconverter kit) and finally make some images barely acceptable. Let’s go through the major focal lengths test as I did for the Sigma 150-600mm Contemporary lens.
In all focal length ranges, we can see more or less the same moment, where the sharpness has seriously deteriorated. Because the TC-1401 removes one stop of light, we experience this problem somewhere between f/13 and f/18 and f/15 and f/20 for longer lengths.
From 300mm x 1.4 upwards, the fuzziness is noticeable even in the normal image size, which means, that they appear to be no longer acceptable.
The same as in the Sigma 150-600mm f/5-6.3 Contemporary version, the smallest apertures at the longest focal length give the worst image quality. When it’s only at the fair level in Sigma 150-600mm C, it can’t be decent with TC-1401 attached, whilst all flaws are multiplied by 1.4x.
The saddest thing is, that this practice test shows the complete opposite results to the laboratorian tests possible to check on The-Digital-Picture.com service (Pic. 16), where the smallest apertures should serve better image resolution.
Maybe at 840mm, the result is at least similar between i.e. f/14 and f/20. It doesn’t change the fact, that the widest apertures between f/9 and f/11 are undeniably the best for a whole focal length range and result in the sharpest pictures as shown in the pattern above (Pic. 6).
Let’s see how the TC-1401 image sharpness looks in terms of the text seen from some distance. There are images below, where the content was captured from about 140 – 180m distance (Pic. 17 – 19), which marks the border of the readability of this content. I guess the font size between 36 and 72 was used.
The last matter to check is the correspondence of the TC-1401 images with Sigma 150-600mm C images at the same focal length. As one of the authors said, there is no sense in using the TC-1401 attached for shorter focal lengths than the longest one offered by the given lens (i.e. 600mm in Sigma 150-600mm C). Better is to take the teleconverter down. I completely agree, but by taking photos at the same focal lengths with and without the teleconverter mounted the user can easily gauge the difference in quality. Let’s see 2 situations below. The first one shows the panorama at 600mm focal length taken with Sigma 150-600mm C and 430mm x1.4 with TC-1401 (Pic. 21). The difference is smallish and barely visible. It stresses the very good quality of the teleconverter TC-1401 itself. It has 7 elements in 5 groups, which keep the image resolution at a high level.
The second test unveils the real TC-1401 image quality, as we are focused on some texts, visible from about 70m distance (Pic. 22, 23).
Looking at the very last image, there is no brainer that TC-1401 doesn’t degrade the sharpness. The difference between Sigma 150-600mm f/5 – 6.3 C performance and teleconverter TC-1401 attached is very little, at least up to 600mm (430mm x1.4).
The distortion in the teleconverter TC-1401 is very minor. It’s a barrel distortion with an average value of 0,25% (Pic. 24).
The difference between the Sigma 150-600mm C and TC-1401 mounted is quite big. I mean, that the presence of TC-1401 reduces the distortion flaw. Obviously, the biggest distortion remains at 210mm but remains barely visible at further focal lengths.
The biggest distortion is to be seen at 210mm and 280mm. From 350mm is almost completely gone.
The teleconverter TC-1401 kit reduces vignetting flaws in the Sigma 150-600mm f/5 – 6.3 Contemporary lens when using it with the APS-C sensor combination. I found, that the light-fall at the longest focal length can be even 4x fainter at 840mm than at 600mm, without a teleconverter mount (Pic. 33).
It was found, that at the widest aperture and the longest focal length (600mm; f6/3 and 840mm; f/9 accordingly), the vignetting is strongly reduced with TC-1401 attached. The Sigma 150-600 C’s light fall exceeds -0,2EV in the corners, whereas the TC-1401 teleconverter attached makes our frame virtually equally illuminated. The biggest vignetting is to be observed at the left edge of the frame when reaches -0,06EV only, which is nothing. On top of that, this difference applies only to the widest apertures down to f/11. From f/13 the vignetting wasn’t observed for Sigma 150-600mm + TC-1401 combination (Pic 34).
Looking at the image above (Pic. 34) you can see almost no vignetting from f/13. This is amazing!
5. CHROMATIC ABERRATION
The chromatic aberration issue appears to be a bit emphasized in TC-1401 mounted to a Sigma 150-600mm f/5 – 6.3 Contemporary lens. It’s clearly visible up to 420mm. Afterward, it looks like is a bit fainter, which is driven by a higher astigmatism flaw, which emerges at longer focal lengths.
This chromatic aberration obviously varies throughout the aperture range, but knowing the image resolution problem in Sigma 150-600mm f/5 – 6.3 Contemporary version we can assess, that it won’t directly impact our image at smaller apertures. Another issue worth mentioning is the contrast difference between captured objects. The most eye-catching chromatic aberration takes place between the opposite colors (Pic. 36, 37), whereas in other cases might be not visible at all (Pic. 38).
Any higher contrast between objects and surroundings results in the visibility of the chromatic aberration (Pic. 39 – 41).
Concluding, chromatic aberration is somewhat multiplied by 1.4x in this case. Proportionally it’s still the same if we compare the percentage of frame height. You cannot spot it in normal images, but you definitely can see it in cropped versions.
6. COMA & ASTIGMATISM
The coma aberration in the TC-1401 is very small likewise in the Sigma 150-600 f/5 – 6.3 Contemporary version. The teleconverter TC-1401 kit doesn’t boost the coma aberration, which is great news for night distant watchers. You can see the example images below (Pic. 42 – 43).
Astigmatism is visible at the longest focal length. It’s unfortunately increased by TC-1401. In turn, some fuzziness is noticeable, especially at the high contrast borders i.e. in the case of dark text at the white background and so on (Pic. 43).
7. BOKEH & NEAREST DISTANCE
The bokeh feature looks good (Pic. 44), which is a derivative of the Sigma 150-600mm Contemporary lens.
Images captured from the minimum distance look sharp, although there is some slight fuzziness produced by the teleconverter TC-1401 kit, especially at the longest focal length. Regarding the distance itself, sharp images can be gained from about 270cm distance. This is the threshold, for which autofocus works without problems. The difference between the Sigma 150-600mm f/5-6.3 Contemporary lens and the TC-1401 attached is about 20cm only. This is definitely good news for someone dealing with macro-like images of birds, insects, etc. (Pic. 45, 46).
8. SUMMARY & SAMPLE IMAGES
In general, the teleconverter kit TC-1401 for Sigma lenses is a very good choice. I haven’t spotted any major flaws, that could make my image worse than gained from the sole Sigma lens. Unfortunately, there is one noticeable demerit, which might affect our image. It’s astigmatism, which makes the image a bit blurry eventually. It goes side by side with a slightly deteriorated image resolution. These differences aren’t big. We can’t say that TC-1401 works as the digital zoom mostly because it’s absolutely not true. Well, most of the cons listed in Sigma 150-600mm f/5 – 6.3 DG HSM Contemporary lens are simply multiplied by 1.4x, but it’s not a direct teleconverter action. On top of that, the autofocus works throughout the entire zoom range, which is great. I would recommend purchasing this teleconverter because it’s worth having. The best way to do it is by buying it with Sigma 150-600mm f/5 – 6.3 DG HSM Contemporary lens as a bundle.
- Sigma 1.4x and 2x teleconverter compatibility
- Teleconverter TC-1401 test on Sigma 50mm f/1.8
- https://www.uglyhedgehog.com/Sigma 1.4X Tele Converter TC-1401
- Sigma Tele Converter TC-1401 and TC-2001 Compatibility
- A Sigma 100-400 C + a TC-1401
- Sigma 150-600 C with a teleconverter?