Cutting a fresnel lens down to size

[Greg]

Just got a fresnel lens for my 11x14. All 4 sides need to be cut down to size by around a half inch to fit the cameras back.

Anyone have and experience or suggestions on how to cut a plastic fresnel lens?

thanks

[vinny]

Straight edge and new utility knife blade. You can score both sides to keep it from chipping and sand the edges after snapping the excess off.
Otherwise, a band saw with a fence will work too.

[LabRat]

Or get a plastics knife from the hardware store + straight edge and cut like Vinny said, and snap off excess...

Steve K

[Tin Can]

Just curious which one you bought. I am also tempted to try one.

The eBay 'Deardorff' Fresnel now selling is not described well.

Currently I use a thin flexible $2 book reading plastic Fresnel I place on my DIY 11x14 GG.

[Jim Noel]

My luck with a flexible lens for reading on an 8x10 was as good as with a high priced fresnel for one of the 4x5's.

[Greg]

Just curious which one you bought. I am also tempted to try one.

The eBay 'Deardorff' Fresnel now selling is not described well.

Currently I use a thin flexible $2 book reading plastic Fresnel I place on my DIY 11x14 GG.

Fresnel lens that I bought was marked for use on an 11x14 Deardorff and measures 11x14 inches with corners cut off. I'd assume that it was made to fit in front of the GG and having to shim both so that accurate focus is to be had. I have a 4x5 that has the same configuration with its GG shimmed to account for the Fresnel mounted in front of it. To use it on my 11x14 Chamonix, I have to cut it down to 10 9/16" x 13 9/16" to be able to mount it in back of the GG.

I have an older 8x10 Sinar Norma which I (crudely) adapted a book reading plastic Fresnel to many years ago. Little while back was able to obtain an OEM Sinar Fresnel lens with correct 4 mounting clips. To be honest, comparing the book reading Fresnel to the OEM Sinar Fresnel.... didn't really see any difference to the naked eye. When I used a magnifying loupe there is a difference (OEM Sinar a finer lensed fresnel), but both are 100% useable.

[Kevin Crisp]

Greg Putting the fresnel in front of the gg is a relatively unusual position for it. There are exceptions, the most common of which is the Kodak fresnel on Crown and Speed Graphics. I'd certainly try putting it behind the gg, with the ridges pointing forward, and checking to see if it indexes properly.

[Bob Salomon]

Greg Putting the fresnel in front of the gg is a relatively unusual position for it. There are exceptions, the most common of which is the Kodak fresnel on Crown and Speed Graphics. I'd certainly try putting it behind the gg, with the ridges pointing forward, and checking to see if it indexes properly.

Also early Technikas were mounted that way.

[Tin Can]

Also early Technikas were mounted that way.

Also some Horseman. Which copied Linhof often and made some things different/better?

I'm ducking Bob!

[Greg]

Went to our local ACE hardware store and found a Plexiglass hand cutter. It cuts a "V" shape into the plexiglass. Was told not to use a utility knife blade because it only separates the material and distorts the edges. "You want to remove the material in the "V" cut to obtain a clean break." So clamped down a metal ruler and made about 12 passed with the cutter holding it at an angle so the one edge of the "V" cut at a right angle to the fresnel lens that I wanted to use. Simple bend of the plexiglass and it breaks exactly on the scored mark. Oh yes, scored the smooth side of the fresnel lens. Fresnel lens was a generic fresnel lens that I bought online. Placed it on the back of my Whole Plate camera's GG and it worked terribly. Pretty sure my fresnel was the just the wrong focal length. My 4x5 and 8x10 Sinar Normas have OEM Sinar brand fresnel lenses on them and they work excellently. I do have a slight recollection of one manufacturer offering 2 fresnel lenses for their cameras... one for use with wide angle lenses and the other for use with normal and tele lenses. Think it was the Linhof brand... maybe Bob could correct me or confirm me on this.

[LabRat]

The grooved side of your WP GG fresnel should be facing the GG smooth outside, or try flopping it over the other way to see if it helps (but not correct)...

Some fresnel's are a little hard to see through if there's a lot of light due to reflections, and lack of darkcloth... Also, try viewing at different distances to see if your FL might work at another viewing distance, so that might answer that...

Steve K

[Bob Salomon]

No, Linhof only offered one. Nikon offered special screens based on focal length for their 35 cameras, Canon might also.
We, as HP Marketing Corp., in the early 80s sold the Linhof Super Screen which replaced the gg and the Fresnel. It was our product and Linhof gave us permission to use the Linhof name on it, but Linhof themselves did not sell it. I am no longer sure but the Linhof distributor in Canada might have also bought some from us to sell up there.