Pentax F* 300mm f/4.5 On Terns


My family visited Mountain View Shoreline Park and for the first time, I met this unfamiliar bird that hovers over the air like an helicopter. Others have told me that this bird is related to "Terns" and it may either be Common Terns or other variants in Bay Area as in Forster's Terns. It flies very fast and circle around area above a lake looking for food. Once it hovers a spot, it dive down to the water and quickly come back up and nowhere found in my viewfinder.

My skills, AF.C, auto select AF point, center focus all foul up on me with this bird. There are moments that I seriously worry about the AF motor from the nervously grinding noise from my Pentax F* 300mm f/4.5 and Pentax K20 D in obtaining focus. And there are moments after few shots, the AF motor won't AF at all. It goes as if the AF halts after 4 shots are taken. I have been shooting in single drive and it is probably my first time hitting the focus halt problem in daytime shooting. I have to point the lens down to ground and half press to reset things to normal.

There is a lot of "damn it", "good grief", "you silly bird", "bummer" that go with each shutter. The birds ability to fly and hover over water for feeding are very much breath taking. If you live in bay area from California, you have to come to Mountain View Shoreline to look for this bird. I have the most excitement with this bird, I need to re-shoot the series in another time with more study on taking smaller number of shots with better precision. I ended the shootout in shifting to manual focus as the tree and some neighboring background have confused the AF and the less noise from the AF motor keep me calm in picturing the birds


Pentax F* 300mm f/4.5 on Terns


Pentax F* 300mm f/4.5 on Terns


Pentax F* 300mm f/4.5 on Terns


Pentax F* 300mm f/4.5 on Terns


Pentax F* 300mm f/4.5 on Terns


Pentax F* 300mm f/4.5 on Terns

Impressions & Notes

  • AF.C with auto select AF points work reasonably better than center focal point when the background has no distracting objects as in trees and background mountain.
  • AF motor tend to grind more in Auto Select focal points. AF actually grind down to a halt in a series of shots, I don't really know what happens. Half-pressing has no movement from AF and I end up pointing my lens to ground floor and half-press to reset focal point.
  • The noise from the AF motor bother me quite a bit in the shooting
  • AF has a difficult time to get focus on first shot.
  • I find manual focus does a quicker job in obtaining the first shot in focus. But when I am shooting, I can't mix the mode together quickly as I have to toggle Auto Focus ring to MF and switch on body from AF to MF. I am in either mode but not mix in between the two.
  • In MF, I lose the trap focus capability. I only manage to hear the beep for focus confirmation. I mostly hit the shutter after the beep and there is undoubtedly some delay in the reaction to the shot
  • I turned off SR in all shooting and make sure shutter is close and faster than 1/1000 sec. I shot mostly in f/6.3 to f/9.0 in iso 400 to iso 640.
  • It is easier to picture the bird in a horizontal flying path. If the bird is approaching me heads on, I have more problems in both AF and MF mode as the bird are moving at a rapid pace. The bird is just way too fast and when the bird is really close, I mostly cut the bird by the wings. I need to practice on the timing.
  • In MF, I can hardly rely on pre-focus on neighboring objects as the bird move in a large area. The best time to pre-focus is perhaps the time when it hovers over water for few seconds. I should attempt MF for the diving sequence when the tern is going straight down for the feeding.



LightBug said...

You can program the "OK" button to enable/disable auto-focus. That may be easier than the MF/AF switch.

Hin Man said...

Thank you for the suggestion. I have set the "AF" button to disable AF. Maybe I should look up to use the OK button instead. Thanks!

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