I had a request to provide unprocessed full resolution images from the airshow I went to recently where I used the K-5, DA* 300mm f4, and Kenko 1.5x Pz AF teleconverter together. I’ll be providing a few images with 100% crops straight from camera raw default settings for your viewing pleasure.
First, here is some detail on the teleconverter if you don’t know about it:
http://photographybanzai.com/2011/01/29/kenko-pz-af-1-5x-teleplus-shq-with-sdm-auto-focus/
The first image shows some movement blur and how well I did on tracking with AF. This isn’t a representation of absolute sharpness, but rather what type of result you might get in extreme conditions as long as you gained decent focus on the subject:
The UPS plane was stationary, so this is a better representation of sharpness (long distance from subject):
This person’s t-shirt is also a good representation of sharpness (close distance from the subject):
I still see some motion blur in this shot, but most of the text is readable:
Another result which might have benefited from a faster shutter speed:
Doing a little math that combination gives me around 680mm in full-frame terms. I think in absolute sharpness terms, the UPS tail fin and National Air and Space Museum t-shirt really show just how sharp the combo can be hand-held. I think in situations where I was panning while taking photos of planes in flight could have benefited from faster shutter speeds. The camera was basically set to automatic exposure control with either manual focus or AF.C auto-focus. I was also having that strange shutter/mirror issue with the K-5 which might have a slight negative impact on some of my shots.
As I mentioned before (and demonstrated in my linked Kenko article above), the combo focuses slower with the TC is attached. This was a bit challenging with extremely fast planes like jets, but I managed okay overall. I have devised a few methods to get the best shots possible. I basically start on my subject of interest as far out as possible and pan my lens around to follow it until some type of object obstructs my view, or I get the shots I wanted. In some instances I need to switch to manual focus as I just can’t get some shots with AF enabled. That case is especially true when I want my focus on a specific area or when the frame has multiple objects that could take focus away.