Graflex.org

[JimBarbour]

I just obtained a pre-Graflok Pacemaker Speed Graphic.

From what I have read, it should have a fresnel lens. It doesn't. Are these readily available? Can I use a generic fresnel?


Thanks

[t.r.sanford]

If memory serves, the "Ektalite" field lens always was an option, not standard equipment. I had one installed in the focusing panel of a "Century Graphic" in 1961, and over the decades, I've purchased a couple of "Pacemakers" with "Graflok" backs that don't have the Fresnels installed.

The "Ektalite" is not to everyone's taste. It does a fine job of brightening the image right out to the corners, but the raster is fairly coarse, and can make accurate focusing a bit more challenging.

They are around; check the large-format dealers who have Graflex listings.

I don't see why any Fresnel of about the same focal length and thickness, cut to the correct size, wouldn't work.

Back when Fresnel condensers for groundglass focusing screens were new, there were some third-party ones made for TLRs that installed on top of the GG, not underneath it. This might be worth exploring.

There is some useful discussion on this site of the correct spacing of a Fresnel condenser when installed under the focusing screen.

[Les]

the answer is.

It might have had a Fresnel, it might not.

And putting one where one hadn't been before can be troublesome.

Here's how it works.

there are two frame out there.

The one without the fresnel has a fairly tall raised boss or rail that the ground glass sits on.
When they introduced the fresnel this boss was machined down to allow for the thickness of the fresnel and the effect the fresnel has on the focused image, because Graflex put their fresnel in between the ground glass and the lens.

If your frame never had one, then putting one in will shift the ground glass and you won't be focusing where the film will be.

If your frame did have one, then it either needs spacers or the original fresnel to get the ground glass back where it's supposed to go.

Now I don't have any experince with aftermarket screens. I know some of the top end cameras....Sinar, wisner, etc put the fresnel between you and the ground glass. As long as the ground glass is in the right place you should be able to put one of these in without a problem.

BTW: I recently found factory records that state the amound of machining was equal to half of the thickness of the fresnel. So they determined/believed the fresnel lens does have an effect on the focus.

les

[Rangemaster]

You might want to read Ron Wisner's article on ground glass and fresnel screens before you endevor to install one, I have graphics with fresnels and with out them and I prefer the ones without due to the courseness of the fresnel when focusing. I grind my own screens and far prefer them without the fresnel than with.

Dave

[JimBarbour]

Thanks guys. My main concern was that in absence of the fresnel, my GG would be out of position. In my opinion the glass was bright enough, and I thought focusing was pretty easy. I guess I'll run some tests to see if the GG is properly positioned. If it is, I'll leave it alone.

Thanks

Jim