Have one; use it often.

[Oom Julius]

Sharp, light, sharp and did I say sharp? I use it often for bird photography. The other lens in my bag is a Tamron 70-200 so with these two very sharp lenses, I am almost complete but I am looking forward to using it with the new 1.4x extender.

 

[Craig R K]

Sharp, light, sharp and did I say sharp? I use it often for bird photography. The other lens in my bag is a Tamron 70-200 so with these two very sharp lenses, I am almost complete but I am looking forward to using it with the new 1.4x extender.

Have you had a chance to use this lens with the new 1.4TC? Still sharp? AF performance? I am considering purchase of either this lens or the new 150-450mm, and performance of the 300mm with the 1.4TC and K-3 may be the deciding factor. Any insight would be appreciated. Thanks.

 

[Craig R K]

Sharp, light, sharp and did I say sharp? I use it often for bird photography. The other lens in my bag is a Tamron 70-200 so with these two very sharp lenses, I am almost complete but I am looking forward to using it with the new 1.4x extender.

Have you had a chance to use this lens with the new 1.4TC? Still sharp? AF performance? I am considering purchase of either this lens or the new 150-450mm, and performance of the 300mm with the 1.4TC and K-3 may be the deciding factor. Any insight would be appreciated. Thanks.

I have just reviewed the product feedback on the Pentax 1.4TC, and pretty much have the answer to both issues (no loss of sharpness, AF function A-OK). No further response is needed, but I am unable to delete/edit the post from my day-job.