Miscellaneous Lens Reviews and Other Tests

Sigma 1.4x TC vs Canon 1.4x TC

Even though I already have the Canon 1.4x TC, I've added the Sigma 1.4x TC to my equipment, to use it almost exclusively on the Sigma 180 f/3.5 Macro lens (the Canon TCs can not be used on the Sigma 180). Of course, I was curious to see how it compares with the Canon, so I tested it on my best lens, the Canon 600mm f/4 L IS USM, mounted on a stable support with my 20D The built quality is nearly the same - both feels very well built and pretty sturdy, even though the sigma is much smaller. The main cons of the Sigma is the lack of weather sealing - but this is not a big problem, unless you plan to use it in extreme conditions (anyway, I think that weather sealing on a TC does not make an uge difference, while it is very important on larger tools as the camera or the lens).

The Specs

The Comparision: Image Quality

The entire photo, just converted and resized. The red squares indicates the areas showed in the following 100% crops.
Sigma 1.4x -  center crop	Sigma 1.4x - corner crop
Canon 1.4x -  center crop	Canon 1.4x - corner crop

Conclusions

I've been a bit surprised: I expected the Canon to be better, instead they are practically identical. The Canon looks an hair sharper in the center, while the sigma looks very slighly better in the corner, where it shows less chroma aberration. Anyway, the differences are truly small, and it would be impossibile to tell if a photo had been taken with the Sigma or the Canon, in the field. Another small surprise has been the slight difference in magnification: the Sigma is a real 1.41x, while the Canon is closer to 1.39x.

The Canon is worth the higher price? In my opinion, it is worth its price only if you plan to use it in harsh environmental considitions, otherwise the Sigma offers the same image quality, and much wider compatibility, at a better price.

Sigma 2.0x TC vs Canon 2.0x TC

Focal lenght is never enough - so, I recently bought a Sigma 2.0x TC for my Sigma 180mm macro (the reason is the same of the 1.4x - I've already the Canon TC, but it does not fit the Sigma lens). Of course, I was curios to compare the two TCs: the Sigma 1.4x was so good that I've sold the Canon equivalent; the same will hold true even for the 2x TCs? Physically, the two TCs are similar. The Canon (here shown with a camouflaging band) is slightly bigger and heavier, and it has a better built, but both of them gives a very good impression. The main differences are that the Canon is weather sealed, and it has a protuding elements than makes impossible to use it on the majority of Sigma lenses. The Sigma instead can be used both on Sigma and Canon, and it fits even some Canon lenses (as the 100mm Macro) that don't work with the Canon TCs.

To compare the teleconvertes, I mounted them on the 600 f/4, and I toke some test shots of my usual test target. The following images are 100%, unprocessed, crops from the center of the photo, taken at f/8 (wide open).

Sigma 2.0x - 100 % (unprocessed) crop	Canon 2.0x - 100 % (unprocessed) crop

This time, the Canon TCs had a clear advantage. The magnification is slightly different - the Canon is a real 2.0x, while the Sigma looks 1.95x; other than that, the Canon looks a little sharper. It is not an huge difference, but in my opinion is justifies the higher price of the Canon; other than that, the Canon TC has a slightly better built quality and it is weather sealed. If you have only Canon lenses I won't hesitate to suggest the Canon 2x; if you have both Canon and Sigma lenses you must get the Sigma, or both if you are very picky about image quality, and you plan to use it a lot.

Sigma 10-20mm vs Canon 10-22mm

The Canon 10-22 and the Sigma 10-20 are two of the most popular wide-angles for APS-C cameras, thanks to their extremely wide angle of view (that is the equivalent of a 16mm on fullframe, and it is as wide as you can get with an APS-C camera). I have the Canon, but I have tried many times the Sigma and I have been very happy by its image quality - some time ago, I've had the occasion to test side-by-side my Canon and the Sigma of a friend. The following photos are 100% crops, unprocessed.

Sigma at 10mm, f/5.6, center crop	Canon at 10mm, f/5.6, center crop
Sigma at 10mm, f/5.6, corner crop	Canon at 10mm, f/5.6, corner crop
Sigma at 10mm, f/11, center crop	Canon at 10mm, f/11, center crop
Sigma at 10mm, f/11, corner crop	Canon at 10mm, f/11, corner crop

The differences are very small, and actually the sigma seems a little better than the Canon, in particular at f/5.6 in the corners (but it might be a problem of sample variation, maybe my Canon is not as good as it should be). Anyway, in practice I almost always use these lenses at f/11 or f/16, where the image quality is indistinguishable. Considering that the Canon is much more expensive, if I had to buy now one of these two lenses, I'd go for the Sigma, same quality at lower price!

Do you have comments or questions?

If you have comments or questions about this article, feel free to ask in the Juza Nature Photography Discussion Forum!