Originally posted by Lowell Goudge I have 6 different TCs
vivitar MC-22 2x and 3x
Takumar 2x in KA mount
Pentax 1.7x AF adaptor
Sigma EX 1.4x and EX 2x DG
I have been quite pleased with the sigma 1.4x and the pentax 1.7x (note they are expensive)
I have just gotten the sigma 2x
I have not tried enough with the TAK and vivitar reciently.
Hi, Lowell, it is good to learn a person that has so much TC experience
I consider buying one, but I have some doubts and questions about
Sigma's TCs, especially about 2x TC. Unfortunately I couldn't find any convincing information - you might know the answers, thanks to your practical experience. Please, could you tell me?
My first question concerns the way how the TC handles the focal length of the attached lens. I heard that it doesn't convert it appropriately. Is it the truth? And if it is, what are the practical impacts? I assume that EXIFs contain then bad focal length (annoying, but I can survive that). I'm afraid more that this also influences the shake reduction system of the body. What is your experience?
The second point is about HSM support. According to the press release on DPReview (
Sigma 70-200 and 50-150 f/2.8 APO EX DG for Pentax and Sony: Digital Photography Review) it seems that the TCs already incorporate the electric contacts for powering SDM (and also power zoom and HSM etc.) and therefore even HSM lenses should operate with them without problems. Could you confirm that or do you understand it in the way that only the newly made TCs will support HSM as well? (OK, there were other threads where the support of Tamron's TCs was mentioned, but the situation with Sigma was not explicitly clarified - I'm interested in Sigma now.)
Thanks for your (or anybody's) reply in advance. Knowing the answers would help me a lot