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300mm f4 pro focus limiter accuracy?

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vass

vass

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Received my 300m f4 pro today on a miserable cloudy day with a little rain and was just testing the focus limiter switch to see what it does.
I found that if it is set from 1.4-4m it was fairly accurate in focusing those distances but when set to 4m-infinity it focuses from 2.4m to inifinity.
Anywayone else can try this? Just get a measuring tape and lay down low with camera mount area at start of tape and try focusing on it.

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[URL]http://www.flickr.com/photos/14869355@N07/ [/url]
 
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I tried it when I first got the lens, but haven't really needed it for things farther away. I like to be able to use auto focus for close or distant stationary targets without moving the switch. So I always first set the manual focus with the snap ring at a distance where I might expect any BIFs (moving targets) and then just snap the ring back and forth to instantly refocus at that distance when needed. I expect that I will use the focus limiter a lot more for close targets. When I start photographing my hummingbirds eating from flowers and butterflies in the garden, I will not need the longer focus distances.
 
I found there was a bit of an overlap with my lens as well. My measured limits were 1.4-5m and 3.5-Infinity. I haven't had to used the 1.4-5m setting yet. The 3.5-Infinity setting works well with any of the birding that I do.
 
I'm happy with what it is as long as it's reliable and does the same all the time. Just wanted to be sure my lens isn't faulty in any way.
What would of been better would be able to set the limits yourself by camera settings. By that I mean just be able to change 1.4 to 4 and the 4 to infinity. The middle setting would not need to be tampered with and id'e say it will be 80-90% of my go to.

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[URL]http://www.flickr.com/photos/14869355@N07/ [/url]
 
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vass said:
Received my 300m f4 pro today on a miserable cloudy day with a little rain and was just testing the focus limiter switch to see what it does.
I found that if it is set from 1.4-4m it was fairly accurate in focusing those distances but when set to 4m-infinity it focuses from 2.4m to inifinity.
Anywayone else can try this? Just get a measuring tape and lay down low with camera mount area at start of tape and try focusing on it.
Click to expand...
 
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vass said:
I found that if it is set from 1.4-4m it was fairly accurate in focusing those distances but when set to 4m-infinity it focuses from 2.4m to inifinity.
Click to expand...
Interesting. Does the margin change depending on aperture (depth of field)?

I think it makes sense to have some overlap, particularly in the foreground. And it's the first few meters that slow down focussing the most, so I don't think it will impact speed in the 4m-infinity part much.
 
vass said:
Received my 300m f4 pro today on a miserable cloudy day with a little rain and was just testing the focus limiter switch to see what it does.
I found that if it is set from 1.4-4m it was fairly accurate in focusing those distances but when set to 4m-infinity it focuses from 2.4m to inifinity.
Anywayone else can try this? Just get a measuring tape and lay down low with camera mount area at start of tape and try focusing on it.

--
[URL]http://www.flickr.com/photos/14869355@N07/ [/url]
Click to expand...
I just checked mine and found some overlap, which is good in my opinion.

With limiter set to 1.4-4 approximate focus was 1.4 to 5.5

With limiter set to 4.0-infinity, approximate focus was 3.0 to infinity

Temperature can have an effect on telephoto focusing, so possibly this is a factor in the differences. I will check again when the weather warms up outside.

I'm good with this and find that I have yet had the need to move the switch off the center position (1.4-infinity) as both near and far focus is always quick.
 
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Have never tested my SHGs (150 and 35-100) with a tape but notice the limit switches seem to affect where the lens comes to rest rather than providing a hard cutoff, but it does prevent unwanted excursions to infinity like the 50-200 seems to love when shooting nearby.

Will be curious how the 300 actually functions.

Cheers,

Rick
 
jimbeaux said:
vass said:
Received my 300m f4 pro today on a miserable cloudy day with a little rain and was just testing the focus limiter switch to see what it does.
I found that if it is set from 1.4-4m it was fairly accurate in focusing those distances but when set to 4m-infinity it focuses from 2.4m to inifinity.
Anywayone else can try this? Just get a measuring tape and lay down low with camera mount area at start of tape and try focusing on it.

--
[URL]http://www.flickr.com/photos/14869355@N07/ [/url]
Click to expand...
I just checked mine and found some overlap, which is good in my opinion.

With limiter set to 1.4-4 approximate focus was 1.4 to 5.5

With limiter set to 4.0-infinity, approximate focus was 3.0 to infinity

Temperature can have an effect on telephoto focusing, so possibly this is a factor in the differences. I will check again when the weather warms up outside.

I'm good with this and find that I have yet had the need to move the switch off the center position (1.4-infinity) as both near and far focus is always quick.
Click to expand...
+1 Thanks.
 
Thanks for all the replies everyone. Seems I have nothing to worry about :-)
 
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