Cameras and Lenses

Focus rotation for 3m to infinity for a range of binoculars

[QUOTE=kabsetz;1405652]When comparing focus speed, it would be useful if people would specify two things to make the reports easily comparable. One is of course the amount of turning of the wheel, in rotations and fractions thereof (e.g. 1 1/4 turns) or in degrees (450, 205, whatever it happens to be), but the other and equally important one, often missing, is the distance range which that amount of turning covered. For the latter, I would suggest using 5 meters to infinity as a practical range that would give meaningful information, although the ones among you who have good memory and have read my previous stuff may recall that I have thus far used 10m-1km as the range.

[...]

I'm suggesting this because it is cheap, fast and easy to do, and makes different users' reports meaningful and comparable from model to model. And, as long as the range is mentioned by the person reporting the focus speed, it doesn't even matter if the range is the same or different from what I or anyone else uses - one can always take their reference binoculars and check how fast they focus over the range someone else had reported.

Kimmo[/QUOTE]

and I responded

[QUOTE=Kevin Purcell;1406111]I do just what Kimmo suggests but I'd suggest use decimal notation for the turn counting. It's less restrictive ... is that 1 3/8 or 1 1/4 turns or 1.3 turns ... tenths are easy to estimate too.

And use 3m/10 feet to infinity which I feel is a more typical distance range for people who bird over a range of habitats (from woodland to open spaces). It's also a typical maximum focus distance for "older" bins. I think most people would agree 3, as a "maximum" minimum close focus for a birding bin.

Which is what I use in all of my reports (including the one on this thread )[/QUOTE]

So here's a thread for people to report these rotation measured from their own binoculars to change focus from 3m/10 feet/3 paces to infinity in decimal notation.

Multiple reports are good (are we consistent?).

Collect the set.

Swift Eaglet CFT 7x36 0.4 turns

Pentax DCF HS 8x36 0.9 turns

Zen Ray ED 8x43 1.3 turns
Hawke Frontier ED 8x43 1.3 turns
Promaster Infinity ELX ED 8x42 1.3 turns

Great idea Kevin. One thing I would like to see added is the direction of the turn from close to infinity. Clockwise (CW) or CounterClockwise (CCW)

My contribution:

Canon 12x36 IS II (from minimum 6 meters) to infinity 0.9 turn CW
Nikon 8x32 SE 1.0 turn CW

Cheers Peter

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