On Sun, 20 Aug 2017 12:31:04 -0700 (PDT), wrote:

So I can double up on 2 #11 weld lenses & Im safe?

You'll be safe but you probably won't see anything. That would be
equivalent to a shade 21 if they even make them.

For my camera setup, I'm using stacked #12 and #6 filters, equivalent
to a #15. I have the shutter speed set to 1/60 and run aperture
over-ride. As the obscuration progresses, I'm going to remove the #6
filter. As it nears totality, I'll swap the #6 in and #12 out. When
totality is complete, off comes the #6 for a shot or two of totality.
Then I'll reverse the process as the sun becomes un-masked again. All
in an effort to keep the iris from being forced wide open and
therefore underexposing that shot.

I've spent much of the day optimizing the filter vs zoom that gives me
good shake resistance. The Canon's servo controlled moving lens
element for shake reduction does a spectacular job. I got some pix
today where I can clearly make out the texture of the surface of the
sun, see some sun spots and barely see some streamers.

Fingers crossed that tomorrow will be clear.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address