DA* 16-50 Zoom Damping

*AlanR* · 03-05-2008, 06:32 PM

My new DA* 16-50 requires more pressure while zooming past 28mm. Is this normal? It is new just out of the box along with a K20D - still charging the battery, so haven't tried anything else. This is my first Pentax camera and lens. Thanks

*Canada_Rockies* · 03-05-2008, 07:03 PM

Originally Posted by AlanR

My new DA* 16-50 requires more pressure while zooming past 28mm. Is this normal? It is new just out of the box along with a K20D - still charging the battery, so haven't tried anything else. This is my first Pentax camera and lens. Thanks

If you watch the lens as you zoom, you will find that the second tube starts to move at about 28 mm. The slight change in feel is normal.

*AlanR* · 03-05-2008, 07:57 PM

Thanks for the quick reply. High anxiety with the new camera.
There seems to be a bit more than slight change in feel. If I'm not thinking it can come to a halt at about 27mm. Much less of this going back to wide.
I will see if it loosens up, or I get used to it, after a few days.

*Canada_Rockies* · 03-05-2008, 10:10 PM

Originally Posted by AlanR

Thanks for the quick reply. High anxiety with the new camera.
There seems to be a bit more than slight change in feel. If I'm not thinking it can come to a halt at about 27mm. Much less of this going back to wide.
I will see if it loosens up, or I get used to it, after a few days.

You will need more effort to move the zoom ring on the weather sealed lens than with non sealed lenses. You will get used to it. Just take lots of images - as if I have to even mention that!

Lowell Goudge · 03-06-2008, 06:29 AM

As others have posted, there is a change in motion of the elements in the lens.

In fact, this seems to be a particular aspect to pentax wide to tele and wide to normal zooms.

I own 3 different pentax zooms, FA 28-105 , AF 28-80 (both power zooms) and FA-J 18-35.

All these lenses have the front group moving in as you zoom from maximum focal length, but they go through a point where they stop, and begin moving back out again, as you approach minimum focal length. As a result, as the direction of the front group changes you feel a change in the resistance of the zooming ring.

This is different from Tamron, for example, where my 28-75 has the front group extend out from minimum to maximum focal length.

I believe what youo see is just a result of pentax's approach to optical design, which compared to some other makers results in a more compact overall design.

This topic has been discussed before in the forum, but It was a while ago and I don't have reference to the posting easily available

*AlanR* · 03-09-2008, 10:41 PM

Thank you Lowell and CR
I have now had my new equipment for a few days and the lens has loosened up to what I had hoped for. Now it just gently tells me when I am at 28mm. The camera, K20D and lens DA*16-50 are fantastic.
I've run through some focusing tests, and brick walls and the lens is great.
I am as excited about photography as I was with my first new camera in 1974, a Nikkormat.