Web Analytics RiceHigh's Pentax Blog: April 2020

Monday, April 27, 2020

D FA 70-210 Had a Different Focusing Mechanism than the Original Tamron?

A Chinese full review on the lens reveals that the Pentax had a different focusing mechanism/method than the original Tamron SP lens, although the optical formula of the both lenses are the same. See the following official diagrams for the difference:



The Red Japanese words on the highlighted part just mean "focusing elements". The reviewer also writes that he tested the AF speed of the two lenses on the same objects and found that the AF of the Pentax lens was actually a tad faster. He hence suspected that it is owing to the less lens elements being moved for the AF with the Pentax lens. Note that the bodies used for the comparison test were a K-1 II and a Canon 5D III.

However, maybe owing to this change, it is also found that the Pentax lens however is less sharp when wide opened at both the wide and tele ends, which is not a good sign anyway, as image quality is affected. But it is also mentioned that the Pentax could be sharper when stopped down, on the other hand.

Nonetheless, the Pentax lens has much better coating than the Tamron, see this side-by-side comparison:


For the rest of his findings, just go read yourself. Note that Google translation is not working well as all the linked test pictures will become broken, anyway.