Mysteries, Chemtrails, Aerosols :: Mysterious NZ New Zealand based Discussion Forums The strange & mysterious, archaeological anomalies, modern oddities... Current affairs, health & medical issues, Aerosol Spraying in NZ... ...and general interest: ARCHIVES
Its very hard to tell the hight of a plane. but using a bit of trickery we can get close(ish).
There is a few methods of calibrating your lens at full focal lenght and then seeing how many pixels long or wide the plane is. You would need to use raw format to do this but i always shoot in raw anyway.
One other thing to concider is that lenes dont stay fixed at one focal lenght when the focus distance changes so calibrating a lens for counting pixels is very hard and the result is not linea.
What i have done so far and this is only rough is to take a photo of a few buildings about 20,000 - 30,000feet away.
I know from other pics of the same korean airlines plane on the same parth that the lenght of the plane fits in 118 pixels at 250mm zoom.
We know that this plane is a boeing 777-200 and that it is 209ft long.
We can now take a crop of that photo of the buildings 118pixels long, now just using google earth you can see how far back you need to go on your phot to find and object that is 118pixels wide and also 209ft wide.
I wasn't being picky when i did this but somewhere around 26,000-29,000ft looked about right.
I searched the net for rates of climb for the 777-200 and it looks to be about 1,700ft/min, it takes 30min for them to get to us after the departute time so even if we say they have been climbing for 20min thats gives us an altitude of 34,000ft by whangarei. I don't know what they are targeting so they might slow their rate of climb as they get closer.
If someone has an old screen shot of Flight Explorer it would be very handy to know for sure.
Its funny but i still arn't sure but yet some people like to outright guess and base serious statments on that guess.
It would be interesting to find out for sure but i would say no lower than 26,000ish ft.
I wish i could help more but am yet to find a perfectly accurate way of doing it.
Posted: Thu Jul 29, 2010 6:48 am - RAC
Posted: Thu Jul 29, 2010 7:13 am - Milutiche
At the very least it could be said that you guys work very long hours in each other's company 8-[ Let's just leave it at that then. Current investigation closed
Just wondering if you can detail your photographic hardware that your are using to image these aircraft at altitude. Can you resolve an aircraft adequately at say 36,000 ft for identification purposes? cheers'
All i'm using is a canon 20d camera and a canon 55-250mm lens.
Cheap setup really, the lens is about $250-400 and the camera second hand on TM goes for around the $500 mark. It takes good shots of the kids too as a bonus.
By the way a 250mm lens on a 1.6 crop camera is the same as a 400mm on a 35mm camera.
This is shot from Parahaki Whangarei looking at the portland cement works.
This is a 100% crop of the cement works building.
As you can see from google earth it is about 34,000 feet away.
And about 1/3 of the building is the lenght of a boeing 777-200.
So yes i think it would be no problem to id the planes from 36,000ft Infact i was looking at some other shots and it looks like they could be as high as this. Its truly amazing how low they look when just looking at them, i can see how guessing their heights is never going to work.
