Gary Fairhead wrote in post #2295941
Beautiful Birds here Romy and excellent photographs as we have come to expect. That Kingfisher is just superb.....I see you now also use the Sigma 1.4X TC. Does it also allow auto focus on F5.6 lenses and how do you find it compared to the Tamron?
Thanks, Gary.
Per tests on my copies, the ranking according to sharpness among my TCs :
1.4x
1. Sigma 1.4x (non-DG)
2. Canon 1.4x II
3. Tamron 1.4x (standard version)
2x
1. Canon 2x II
2. Sigma 2x (non-DG)
3. Tamron 2x (standard version)
The sharpness difference is very small though, that I consider it virtually undetectable after PP. I choose which TC to mount depending on the property I need for the situation (fast AF, correct EXIF data or weather-sealing).
The Sigma 1.4x behaves like a Canon 1.4x II - no AF at f/8 for non-1Dxx bodies. Even if I tape the pins, the 1.6 CF body will attempt to AF but it's always hunting. The standard Tamron 1.4x is the king of AF speed with any body, at the cost of incorrect EXIF data (focal length and AV) and a small hit in IQ (negligible to me).
Romy