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Discussion of precise time and frequency measurement

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Subject: Re: I love the smell of tantalum in the morning

SH
Scott Hamilton
Mon, Nov 7, 2016 8:17 PM

https://www.amazon.com/Donegan-OptiVISOR-Headband-Magnifier-Magnification/dp/B0068OSIIS/ref=sr_1_4?ie=UTF8&qid=1478548961&sr=8-4&keywords=headset+magnifiers

Finally, I can offer a contribution to this list. I have found the Donegan magnifiers in the above Amazon link with 3.5X lenses to be very comfortable and indespensible for SMD work. Different lenses can be obtained for other work but the 3.5X is a minimum for me.

Scott Hamilton
W3SEH

https://www.amazon.com/Donegan-OptiVISOR-Headband-Magnifier-Magnification/dp/B0068OSIIS/ref=sr_1_4?ie=UTF8&qid=1478548961&sr=8-4&keywords=headset+magnifiers Finally, I can offer a contribution to this list. I have found the Donegan magnifiers in the above Amazon link with 3.5X lenses to be very comfortable and indespensible for SMD work. Different lenses can be obtained for other work but the 3.5X is a minimum for me. Scott Hamilton W3SEH
JN
Jeremy Nichols
Mon, Nov 7, 2016 11:31 PM

Amazon indicates the different lenses simply snap in and out. Any idea how
easy/practical this is? It it better to have two completely different
visors each holding different magnification lenses?

Jeremy

On Monday, November 7, 2016, Scott Hamilton scottha@me.com wrote:

https://www.amazon.com/Donegan-OptiVISOR-Headband-
Magnifier-Magnification/dp/B0068OSIIS/ref=sr_1_4?ie=UTF8&
qid=1478548961&sr=8-4&keywords=headset+magnifiers

Finally, I can offer a contribution to this list. I have found the Donegan
magnifiers in the above Amazon link with 3.5X lenses to be very comfortable
and indespensible for SMD work. Different lenses can be obtained for other
work but the 3.5X is a minimum for me.

Scott Hamilton
W3SEH


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Amazon indicates the different lenses simply snap in and out. Any idea how easy/practical this is? It it better to have two completely different visors each holding different magnification lenses? Jeremy On Monday, November 7, 2016, Scott Hamilton <scottha@me.com> wrote: > https://www.amazon.com/Donegan-OptiVISOR-Headband- > Magnifier-Magnification/dp/B0068OSIIS/ref=sr_1_4?ie=UTF8& > qid=1478548961&sr=8-4&keywords=headset+magnifiers > > Finally, I can offer a contribution to this list. I have found the Donegan > magnifiers in the above Amazon link with 3.5X lenses to be very comfortable > and indespensible for SMD work. Different lenses can be obtained for other > work but the 3.5X is a minimum for me. > > Scott Hamilton > W3SEH > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com <javascript:;> > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > -- Sent from Gmail Mobile
CS
Charles Steinmetz
Tue, Nov 8, 2016 3:54 AM

Jeremy wrote:

Amazon indicates the different lenses simply snap in and out. Any idea how
easy/practical this is? It it better to have two completely different
visors each holding different magnification lenses?

Quite easy -- the lens plates are held onto the front of the visor by
two plastic pins that just snap in and out.  You can see the heads from
the outside (as opposed to the eye-side) at the far left and right of
the lens plate.

That said, IMO it is always more convenient to have each lens plate
mounted in its own visor.

I have to say that contrary to the original post, I find the 3.5x lenses
WAY too strong for SMD work.  The working distance is only 3-4" -- not
nearly enough to work safely with hot tools, or comfortably.  Even the
2.5x lenses, with 6-8" of working distance, are too strong for me.  For
anything that requires working on the object you're looking at (as
opposed to just examining it), I recommend staying at 2x and below (2x,
1.75x, 1.5x).

Finally, Donegan makes two series of lenses -- rectangular plastic
frames with optical glass lenses, and rectangular plastic frames with
molded-in plastic lenses.  The glass lenses are more expensive, but the
large difference in optical quality makes them the only real choice, IMO.

At substantially greater cost, you can get "surgical loupes" (a/k/a
"dental loupes").  These have compound optical systems, so you can get
longer working distances at a particular magnification than you can with
a single lens (like the OptiVisor has).

Best regards,

Charles

Jeremy wrote: > Amazon indicates the different lenses simply snap in and out. Any idea how > easy/practical this is? It it better to have two completely different > visors each holding different magnification lenses? Quite easy -- the lens plates are held onto the front of the visor by two plastic pins that just snap in and out. You can see the heads from the outside (as opposed to the eye-side) at the far left and right of the lens plate. That said, IMO it is always more convenient to have each lens plate mounted in its own visor. I have to say that contrary to the original post, I find the 3.5x lenses WAY too strong for SMD work. The working distance is only 3-4" -- not nearly enough to work safely with hot tools, or comfortably. Even the 2.5x lenses, with 6-8" of working distance, are too strong for me. For anything that requires working on the object you're looking at (as opposed to just examining it), I recommend staying at 2x and below (2x, 1.75x, 1.5x). Finally, Donegan makes two series of lenses -- rectangular plastic frames with optical glass lenses, and rectangular plastic frames with molded-in plastic lenses. The glass lenses are more expensive, but the large difference in optical quality makes them the only real choice, IMO. At substantially greater cost, you can get "surgical loupes" (a/k/a "dental loupes"). These have compound optical systems, so you can get longer working distances at a particular magnification than you can with a single lens (like the OptiVisor has). Best regards, Charles