Precision bubble level

[Jac@stafford.net]

All horizons are not level.

[Drew Wiley]

My 4x5 Ebony is allegedly a top-notch wooden folder, but all it took was a little bubble in the varnish to slightly skew the focus plane where the holders seat. Easy fix, but I'm glad I checked. Most of you probably already know that it only took a tiny fleck of paint underneath a calibration device to screw up the first Hubbel telescope mirror - probably the only spot they never checked first.

[AtlantaTerry]

My 4x5 Ebony is allegedly a top-notch wooden folder, but all it took was a little bubble in the varnish to slightly skew the focus plane where the holders seat. Easy fix, but I'm glad I checked. Most of you probably already know that it only took a tiny fleck of paint underneath a calibration device to screw up the first Hubbel [sic] telescope mirror - probably the only spot they never checked first.

Well, yes that. Plus there was no third party check of Perkin-Elmer's construction of the Hubble mirror.

https://en.wikipedia.org/wiki/Hubble...nd_engineering

http://www.scienceclarified.com/scit...es/Hubble.html

[Greg Y]

Ari I bought several of those levels at Lee Valley in Calgary a few years ago

[Ari]

Ari I bought several of those levels at Lee Valley in Calgary a few years ago

Hi Greg,
Same here, but they no longer stock them.
And I cannot find them anywhere but in the EU or Asia.

[Serge S]

All horizons are not level.

Very True
I see that, which adds another dimension to contend with...sometimes I can't decide how to balance it out!

[Serge S]

If your film sags or bows, the horizon line will likewise be warped a little, regardless of level. Nor does film typically lie in an exact position in the holder slots, nor the holder in the camera frame. If tolerances were too tight, there would be no margin of error for expansion/contraction stress. So you ultimately have to control the appearance of level in the darkroom. Film flatness requires some kind of precision holder (vac or adhesive).

Yes, that's exactly what is happening. I tend to tweak in the darkroom/scan, but try to get it close to right in camera if possible

[Drew Wiley]

I was directly involved with the folks who made the correction lenses for the Hubbell, but only as a supplier of machine tools and sealants. Prior to that I worked alongside the fellow who machined the Pioneer satellite optics; and he was more interested in recounting NASA shop pranks on co-workers than technical details. I was already good at pranks.

[Cor]

Coming in late here, but I usually rely/use the grid lines on my ground glass when I photograph buildings..works for me..I do not do these multiple pan thingies.

Good luck,

Cor

[toyotadesigner]

I am kind of late, but here is a link to very high quality precision bubble levels:

http://www.ehipp.de/EN/index.html

I am not affiliated with them, just using some of their bubble levels on my Arca Swiss