Thanks for the numbers chuck.....1.6 miles for infinity on my E-500, that at
least tells me that I should cut back a bit when I am shooting a hawk at
200 feet. That makes me feel better about what I felt I was experiencing
when I was trying to focus and should be able to put this data to good use
too.
A lot of my shots Saturday morning at Point Lobos were hard to focus, I
didn't like most of them, but as it warmed up the pictures became much
better, I actually have a few with the Mother Otter and her baby floating up
and down on the waves, a good foot swell and being pulled out of and back
into my field of view, that came out rather well at near full resolution.
But that was in the after noon. I understand that if I can see crap or
moisture in the air, that the lens is going to see that even more than I do.
----- Original Message -----
From: "Chuck Norcutt" <chucknorcutt@xxxxxxxxxxxxxxxx>
To: <olympus@xxxxxxxxxx>
Sent: Wednesday, March 28, 2007 7:36 AM
Subject: [OM] Re: focusing question
> Moose is correct but still underplaying the distance you need for
> infinity focus with a 600mm lens at f/8. If you're shooting 35mm (30
> lines/mm resolution) then the hyperfocal distance (the minimum distance
> at which infinity is in focus) for 600mm f/8 is 4,431 feet or more than
> 8/10 of a mile. If you put a 2X on it (still on 35mm) or have the lens
> on an E-thing (where you need 60 lines/mm resolution) then the
> hyperfocal distance doubles and moves out to 8,862 feet. If you combine
> 2X and an E-thing the hyperfocal distance doubles again and moves out to
> 17,720 feet or about 3-1/3 miles!
>
> Long lenses can be hard to use. At 200 feet this lens only has about 18
> feet DOF for 35mm and only about 9 feet on an E-thing. Good luck
>
> Chuck Norcutt
>
> Moose wrote:
>> Scott Peden wrote:
>>> A bit over a week ago I lucked into a Sigma 600/8.
>>>
>>> I noted immediately that at 200 or so feet, infinity was to far of a
>>> focus, I had to back off a bit.
>>>
>>> Last weekend It was just barely focusing all the way over to infinity.
>
>>
>> 2. 200 feet isn't infinity for a 600 mm lens I don't know the exact
>> numbers, but for a lens that long, 200 feet should focus closer than
>> infinity. You need more like half a mile to be certain of infinity.
>
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