Pentax K20D + Sigma 17-70/2.8-4.5 autofocus speed

[rumvodkaf1]

Sounds cool. Who the hell cares about HSM or USM when all the motor does is rotate the lens a few mm to the right or to the left.

[klechetor]

@rumvodkaf1

HSM = quietly = silence is very important in nature photography.

[rastislavstanik]

@klechetor

dont the animals hear the ultrasound?

[klechetor]

@rastislavstanik

haha Dogs - Yes, other animals - Idont know ?? Do they ?

[flyguyga321]

Does the lens stay at f/2.8 maximum aperture throughout the entire zoom range?

[xmeda]

@flyguyga321

obviously not if it has 17-70/2.8-4.5