[pgerhardt]

I have a Pentax K-10D and have been using it for Aerial Photography. What mode or other settings would work best? I usually shoot from 500-1000 feet from an open cockpit aircraft. I have used the green bar and some of the other settings. Sharpness due to vibration and wind buffetting is the major problem. The other related question is how to focus. I have left the auto focus on and this usually works ok but maybe I would be better off putting it on infinity? Any thoughts on this....

Paul in Maryland

[Just1MoreDave]

You can minimize the effects of buffetting and vibration by using a high shutter speed. You can use Tv mode, which allows you to select a shutter speed and the camera to choose the lens aperture. Obviously you want to use SR.

What shutter speed is good? I don't know exactly. You can look at your previous photos to see the shutter speeds that created sharp shots. You can take some test shots in Tv, starting at one end of the speeds, taking a shot, moving the speed a couple of clicks on the control wheel and repeating through the range. At a certain shutter speed and faster, everything should be sharp. You can hedge your bets and go one or two settings faster than the minimum. My guess would be 1/500 sec., without having tried this before.

I'm guessing you have some flexibility with settings because you're doing this in daylight. The lens aperture setting will also affect sharpness somewhat - much less than vibration, but still visible. A smaller aperture (larger f number) will also increase the depth of field, the range of distances that are in focus. You want the aperture to be about f8 or f11 for good lens performance. In daylight, that should give you a pretty fast shutter speed. If it doesn't, you can adjust the ISO setting to increase the camera's sensitivity to light, maybe to ISO 400. At higher settings you might see more noise in the photos.

Your lens makes some difference here. I'm assuming you are using the lens that came with the camera, the DA 18-55mm. Vibration will be more obvious when you're zoomed to 55mm, and focus is slightly more critical. The values I suggest should work OK for most lenses.

The camera shouldn't have much trouble focusing itself in daylight. At 1000 feet, 55mm and f8, everything from 60 feet to infinity is pretty much in focus. You can put the camera on manual focus and set the lens to infinity yourself, but you should back off a bit from the limit of the focus ring travel. Auto-focus and zoom lenses will focus a little "beyond" infinity. You can test this yourself on the ground with your lens and see how much to back off.

[jmc7104]

Another methoid that I use especally with the K10 and the K20 both is with 18/55mm or simular sized lenses is to use TVA and set shutter at 250 and apature at f8, camera will pick ISO and use auto focus. If 250 doesnt eliminate motion then go up in shutter speed. jim