[tennjed]

I own a Tamron 70-200 2.8 for Nikon F mount, and like the lens a lot. Yesterday, I was looking at an identical lens for Pentax and was surprised by how much louder the Pentax mount lens was. It is a bit of an exaggeration, but not much, to say that the thing sounded like a zip-tie being pulled through every time it focused. The Pentax lens was new. Is this normal? The Nikon mount lens, while not perfectly silent when focusing, is pretty quiet.

I am curious, did I just get lucky with the Nikon mount lens?, or, is there likely something wrong with the Pentax mount lens.

Like others have, I am also considering getting the Pentax 50-135 2.8 instead of the Tamron. but everything I have read about focus motor troubles with this lens has me a bit concerned. Is this an ongoing problem with the lens? do the optical qualities of the 50-135 justify the %100 price premium when the lens is considered against the Tamron 70-200?

Size and weight are the things that attract me to the Pentax 50-135. If I purchased it, I would use it with a 1.4x TC.

[southlander]

The Tamron 70-200/2.8 in Pentax mount utilises the screw focus motor within the camera to focus. With the Nikon, is the focus motor built into the lens? If so, that is likely to explain the noise difference. At least with screw drive, there's one less thing in the lens to break and need to be repaired!

[virusn3t]

I believe the Nikon have the built-in motor on the lens, the Pentax use the screw motor from the camera and make that noise.

[skunktail]

That's normal.

I find that my tamron lenses seem to be slightly louder than the others, not really sure why.
I think it may be the screw drive combined with the relatively long focus throw.

[kiwi_jono]

Reviews I have seen for Tamron on Nikon state its a built into lens auto focus motor.

Also a lot of people on Nikon complain in their reviews that AF is too slow. I have a Tamron 70-200 on Pentax and, sure its a bit noisy, but I find the auto focus speed pretty good. Other reviews I have read say that AF is faster on Pentax with the screw drive AF than on Nikon with build in motor.

Its a great lens - can't believe how sharp it is for a zoom. Its put some of my primes to shame.

[clackers]

The IQ of the 50-135 is gorgeous It's what you'd hope a top zoon lens would be, and yet it's small.

I have the Tanron 70-200 as well, and really like it for portraits and sports.