Monday, October 28, 2013

The right tool for the job. Part 3: Coasts and estuaries.

Large flocks of waders on mudflats are an impressive spectacle
but are often at long range.
Viewing birds or ships out to sea or across mudflats and wide river mouths requires good magnification and a reasonably bright image. In general the high magnifications offered by spotting scopes are more useful for seeing detail at long range, but binoculars are still very useful for scanning across large areas and being easily portable.

Whilst high magnification is useful at longer range the usual problems of holding powerful binoculars steady and the restricted field of view come into play. The highest practical magnification for most people is 12x. A good specification to look for in this power is a 12x50, the 50mm lenses letting lots of light which is essential for use in lower light. A more general purpose model would be a 10x42, being lighter in weight and having a wider field of view.

The Hawke Naturtrek 12x50
If you are able to do most of your viewing seated or from somewhere you can rest your elbows then a higher magnification can be used (e.g. 15x56 or 20x60 etc.) but these will be relatively heavy and bulky.  Tripod mounts are available for most types of binocular that can make these higher magnifications more practical.

Some models to consider are: The Hawke Naturetrek 10x50 or 12x50, or at the top of the range, the Swarovski EL 10x50 or 12x50.

Scopes take over where binoculars leave off, zoom eyepieces typically starting at 15x or 20x and giving up to 50x-70x depending on manufacturer. The highest practical magnification is 60x-70x, and depending on the conditions, even this can be too much. If there is a heat haze, fog or heavy rain it doesn’t matter how good the quality of the optics is, the weather you are looking through will be the limiting factor. However, in clear, still conditions a top quality scope can be a real treat at high power, even in low light.  The best results can be obtained from scopes with larger objective lenses (77-95mm).

There are many larger scopes available both new and second hand right across the price range that can zoom up to 60x or more, from the Acuter 20-60x80 at under £200 to the Swarovski ATX 95 at £3000.

As good as it gets.
The Swarovski ATX 95mm has an impressively wide field across the zoom range of 30-70x