Originally posted by BruceBanner
- from around 200-250mm the rotation is smooth, however the actual difference of zoom/reach between say 210mm-250mm is very little difference. You can even see it physically on the lens as it is not internal focusing, it shifts out/extends perhaps only 5mm between 200-250mm, whereas the other leaps between the focal lengths feel like they cover more distance.
The DA* 60-250 is most certainly internal focus, something that does not affect how much or whether a lens extends to zoom. The fact that it extends on zoom indicates that it is not able to change focal length purely by moving the internals around. With modern two-touch zooms, a change in extension does not directly translate to the change in focal length.* The total extension from 60mm to 250mm being only about 60mm. If you have doubts about the focal length at the 250mm mark, compare FOV at infinity (200m is probably far enough) to a 250mm prime at the same subject distance. Do not compare at closer distance because it is quite likely that your lens may have some degree of focus breathing resulting in wider than expected FOV at moderate to close subject distance with longer focal lengths.
As for the effort required to move the zoom ring, that was noted as a characteristic of the lens in the detailed review here on PF.
Pentax DA* 60-250mm F4 Review - Construction and Handling | PentaxForums.com Reviews
Steve
* In much the same sense, the overall length of a long prime is almost always significantly less than the focal length due to telephoto design.
Last edited by stevebrot; 02-17-2020 at 12:21 PM.