A tiptoe into Bft5

After some pretty sad testing with a 2m Delta Conyne kite in about 20mph wind speed (it sort of folded up and lost all lateral stability at peak gust)  I fret over the Bft 4/5 KAP options and return to the high speed KAP favourite: the PFK Nighthawk.
It’s a lively kite but I have learned to give a long lead deep into the wind before I attach the camera and to be ready to haul line quick in lull (anything under 10mph with an 800g load) . The PFK is very active as it  ‘hunts’ the wind and because of this I have given up viewfinder work with it and opted for AutoKAP.
I have noticed the 50 mm F1.8 ‘Pancake’ Nikkor lens lens is really sharp (as well as light at 120g) on the D5100 so I thought it would be a good test for the PFK on the basis of making the best of the available paltform in 15 -20mph windspeed. Pan gear is by Brooxes, shutter relase and intervalometer is by GentLed. Neat eh?

At the risk of boring you here is an example of the surface of the earth near me taken from 60m AGL.

Camera Nikon Corp D5100
Image size 3264 x 4928
Exposure 0.016 sec (1/60)
Aperture f/22
Focal Length 50 mm
ISO Speed 320
Exposure Bias -0.3 EV
Flash Off, Did not fire
Exposure Program: Manual
Date and Time (Original) 2012:10:17 10:52:57
Subject Distance unknown
Manual focus pre set to infinity
Kite: PFK Nighthawk
Line: 250 DaN Dacron
Rig: Fixed tilt, AutoKAP pan /shutter
Windspeed 10-21mph
I’m trying to get an idea of the image resolution achievable so I was thrilled to get a shot with a reference object in:
and here is the resolution of the reference object :
From this you can get an idea of how much work can be involved in getting over the lull (and also that lull is when the ridiculouly slow shutter speed I’d set pays off too)  that’s me on the run to keep the line tight.
I get roughly 30 pixels to the metre or 90 Pixels/m2. This is at an estimated height of 50m AGL.
I got some hints of what some good AutoKAP shots would be like but they are ruined by the slow shutter:
I now know I have a high speed KAP method with potential. Next time I’ll up the ISO and shutter speed, I got far too many shots ruined by motion blur !



About billboyheritagesurvey

Heritage worker
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4 Responses to A tiptoe into Bft5

  1. Marty says:

    Why f22?
    With that tiny an aperture your shutter speed is going to have to be much slower.

    • Why indeed, I got the whole camera set up wrong! I have become far too used to Auto settings and reverted to ‘donkey’ mode when I set up the camera..for years I have always begun with 1/60 at f8 and then test..I got the aperture fine at f22 for test shots on the ground! The D5100 will do ISO 6400 and shutter speeds up to 1/4000 so I have no excuse for such a poor set up- even with fixed focus I should be able to run with 1/500 at f8 on ISO 1000 if needs be…It’s a case of needing to learn new ways with old lenses!

      • Marty says:

        I was flying my Olympus Pen last weekend, in some crazy gusts, 4-6. Rig bouncing all over the sky (it even managed to get a shot of its own carrier-kite).
        Had it set to “S” shutter priority, with 1/1000 selected. The camera decides then what aperture to use for a correct exposure, especially if you’ve set ISO to auto.
        Every single shot was in sharp focus, even the ones with the 45 degree angled horizon!

  2. Ah the joy of ‘auto’ yes the EP1 does a good job of auto exposure- I’m trying to get the best of a set up with no auto on this one. Not all cameras do as well as the EP1 on the auto ISO though, the X1 is baised to wide stops for some reason unless I peg the ISO.

    I’d like to see some of your Bft 4-6 shots Marty, it sounds like a heart stopping flight!

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