Sunday 30 January 2011

Canon teleconverter experiments at Barnes

Cold day (1-2C) with cold NE winds hitting even central London, but not enough to kick off any bird movements at Barnes. The Shelduck is still present (as, apparently, is the Scaup although I missed it today).

I also tried out my new Canon 2x teleconverter for the camera (a Canon 7D) using it for both close targets like this Mallard. This bird was fairly close and shows up rather soft.


And more distant ones like these Peregrines (on Charing Cross Hospital taken from the WWF hide). These shots were taken with both 2x (the first photo) and then stacked 2x and 1.4x converters (the second). The stacked teleconverters combined with the 400mm lens (the f5.6 prime) add up to a focal length of 1120mm (sort of equivalent to a magnification of 22x). Basically I think the birds were just too far away for this to be any kind of useful test, but shots are included to give some idea of the difference in reach. While its hard to see on the small grey dots, the size difference between the two birds (female on the left) is immense. The birds are the small dots on the third railing down from the top and the second and sixth 'columns' from the left of the right hanbd (protruding part) of the buidling. The Peregrines perch here quite a lot, usually either on these railings or on the top of the white verticals.



A massive crop from the photo of the female with stacked teleconverters. This is, obviously, pretty rubbish, but, with a rough calculation using Google maps this is only slightly under a mile away (about 5,000 feet).


The day was pretty dull with poor light so shutter speeds were rock bottom which really didn't help photo quality.

The Siskin flock is still on site, around 14 birds around the back of the Sheltered Lagoon, but missing the Lesser Redpolls previously with the flock.

A few Snipe were also present, although fewer than at the start of the winter period. Jack Snipe seem especially thin on the ground this year. The water levels have been very high at Barnes for some time - whenever this happens the numbers of Snipe always seem to plummet. One of the few birds showing today below (taken with the 400mm and 2x converter).


Great crested Grebes seem to be in a mix of plumages ranging from some in full summer and others barely out of winter plumage - one pair were diplaying together were made up of a 'summer' and a 'winter' bird.

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