My understanding is SAM is not like SSM which is silent.
What SAM feature is really takes away the mechanical drive out from the lens and rely on the electronic contact for the information like SSM lens without its silent mechanism.
My guess is SAM feature is incorporated because all along, SONY was planning the release of E mount (NEX camera) and hence would be beneficial for them in this regards.
SAM or normal, the noise of the gear movement shouldn't be an issue.
Lets face it, Minolta 50mm f1.7 was built some decades ago and as the technology improve, the processes and quality improve as well. But in terms of future-proof, should you want to go into Full Frame DSLR in the future, Minolta 50mm f1.7, Minolta 50mm f1.4, Sony 50mm f1.4 and Sigma 50mm f1.4 will be your choice.
With crop sensor DSLR such as A2xx, A3xx, A5xx, A700 series, SONY DT 50mm f1.8 will be a good choice for now given that the initial outlay will be small.
By all mean, not everyone need a FF and some are more than happy with the crop sensor, hence the SONY DT 50mm f1.8 will be better investment as compared to older Minolta 50mm f1.7 lens.
If you are choosing the two, Minolta 50mm f1.7 and Sony DT 50mm f1.8, by all mean, it make sense to buy the later because price is about the same, and you get the full 15 months warranty for peace of mind as well as it is one the the sharpest 50mm that you could buy at that price at the moment.
I hope it helps.
Regards,
Hart
