Fresnel/Groundglass combo

[samwang]

A friend of mine who's in China has heard of a fresnel and groundglass replacement for the Ebony 4x5 and asked if it's available in the US. Can someone help me out as I can't find any store carrying it.

Years ago I came across some surplussed units made in plastic that really came in handy - very light and almost unbreakable. Is anything like that available these days - one side fresnel and the other groudglass?

Sam

[Joanna Carter]

A friend of mine who's in China has heard of a fresnel and groundglass replacement for the Ebony 4x5 and asked if it's available in the US. Can someone help me out as I can't find any store carrying it.

Years ago I came across some surplussed units made in plastic that really came in handy - very light and almost unbreakable. Is anything like that available these days - one side fresnel and the other groudglass?

Sam
Has to be the Maxwell screen. Expensive but worth it.

[Gem Singer]

The Fresnel for the Tachihara 4X5 should fit the Ebony 4X5. Plastic, with Fresnel grooves on one side, ground surface on the other.

Less expensive than Maxwell or Ebony.

Since plastic is prone to scratching, you will also need to use a cover glass. Available in plain or gridded.

Call, or Email Jim, at midwest Photo Exchange (mpex). He usually has them in stock.

[Drew Wiley]

Be aware that if working in cold or damp conditions you can get condensation between
the glass and plastic. Plastic insulates while glass conducts temperature, so this is
a particularly bad combination for certain types of outdoor work, and is a lot slower to
clear than plain groundglass. Spoken from experience.

[IanG]

The Wista's use a fresnel/screen combo and use a plastic overlay. In 23+ years in the UK I never had a condensation problem.

Ian

[Drew Wiley]

Thanks Ian. The Ebony fresnel combo is very susceptible to condensation. It's these
kinds of distinctions that people need to know about.

[Joanna Carter]

Thanks Ian. The Ebony fresnel combo is very susceptible to condensation. It's these
kinds of distinctions that people need to know about.
Having used Ebonys for several years I have never found a problem, either with the original screens or the Maxwells.

[Drew Wiley]

The glass and acrylic are separate pieces. If they aren't airtight and cemented or
gasketed (like a Kasseman polarizer for example) condensation is an inherent risk. Simple science. Maybe some of you don't encounter conditions where this is a factor, but I routinely do, and maybe others will. The first thing I did with my Ebony is to replace the groundglass. Otherwise it would be virtually useless in the mtns. I even had frost form between the two elements. Where a camera is apt to be used is very
pertinent when asking about such equipment.