Cruising airliners and experiments with teleconvertors

Hi All,

I've been interested in photographing cruising airliners since somebody showed me this site link where it looks like they're using astronomical telescopes.

I wanted to see how well I could do with the photo gear I have, which is a K-5, a Tamron 500mm f/8 mirror lens, a couple of teleconvertors (Teleplus 7 element KA 2x & Vivitar K 3x) and a Uni-Loc 1700 system tripod. All of the photos below are full APS-C frames for comparison, I've boosted the contrast on most of them and sharpnd them all.

First a straight handheld shot with the 500mm f/8, 1/350, ISO 160:



Secondly a handheld shot with a Teleplus 2x, 1/250th, ISO 400:



At this point I was a little disappointed, zooming the images in camera and computer to 'full size' and seeing all sorts of artifacts. It looked like camera shake or that the mirrors had been knocked out of alignment. After some thinking I thought it might help if the image was larger, I wouldn't have to zoom quite so much. I bought the Vivitar 3x teleconvertor with the aim of taking the lenses out and using as an extension tube, but the thought of getting a usable image out of it seemed remote.

With the Vivitar 3x I got the following: 1/2000th ISO 6400:



and 1/1500th ISO 6400:



Along way from the photos in the link at the top, but gives some idea of the focal lengths required (I suspect they're using eyepiece projection on the scopes their focal lengths are unlikely to be over 1000mm and it looks like they're using much longer than my 1500mm f/22.

My technique for the shots with the 3x was to use the tripod to take the weight off, unlocking the ball head and framing by hand. The head wouldn't hold the weight at the angles of elevation required and the subject is moving very quickly. Framing & focussing were the biggest problems.

As a further experiment (and I expected this to fail), was stacking the TCs (Vivitar 3x closest to the camera). Obviously this pushes my aperture out to 'tiny'. I didn't get a chance to try this on an airliner, but found a ladybird, tripod mounted about 3m away, 1/750th ISO 12800:



I haven't looked at trying to change/apply noise redution on this yet, but still far better than I expected.

I hope this is of some interest to somebody.

John.

John - I just clicked on one of the photos in the link you provided. If you then scroll to the very bottom of the page, there's your clue!

Hi Steven,

Yes I saw the line of telescopes, but from the scale, these are unlikely to be longer than 1200mm focal length. Their images are shot at a much higher magnification than mine with the 500 x3 TC. So instead of using the 'scope as a 1200mm f/8 mirror lens they must be using eyepiece projection (getting magnified image in the 'scope eyepiece and photographing that through a camera & lens combination).

As I undestand it, this is where you set the camera lens focus to infinity and get the camera-eyepice distance just right.

This is one of my attempts with my old EI-2000 (which has a fixed zoom lens) through my 4.5" Newtonian 'scope, (which is 900mm f/8 optically) :