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Ground glass & fresnel lens
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AuthorMessage
ron8748
Joined: 16 Jun 2007
Posts: 6
PostPosted: Mon Jul 16, 2007 5:13 pm   Post subject: Ground glass & fresnel lens

I've seen some Graphics with the fresnel and GG and others with only glass. Did all Graphics come with both or were some equiped with only glass? Is one set up better than the other?
thanks,
Ron
Les
Joined: 09 May 2001
Posts: 2682
PostPosted: Mon Jul 16, 2007 9:49 pm

The "Ektalite field screen" as it was call when it was introduced gave a brighter image on the ground glass particularly at the edges. I believe it was introduced in 1950 or '51 so there are several years that didn't have them.

I've used cameras with and without. Both will work, it just depends on how fussy you are. If you are intent on seeing exactly what's in the corners the fresnel might help.

On the other hand, if you use a loupe stronger than say 5x, the rings of the fresnel interfere with the image, and some say make it much harder to focus the image.
Henry
Joined: 09 May 2001
Posts: 1662
PostPosted: Wed Jul 18, 2007 11:24 pm

What Les said. I got ahold of an Ektalite screen from Robert Pins in NJ and kluged an installation on my Century. Knowing what I now know, it probably wasn't worth the effort/expense, IMO. A good loupe is more important; I use a Toyo 3.8x from B&H Photo in NYC. And yes, the fresnel lines definitely show up in the loupe and make focussing more, uh, "challenging," shall we say?, especially when using a wide-angle lens (in my case, a 65mm Optar). These already present more of a focussing chore than the normal 101. I and others have referred to it as the "least worst" method.
ron8748
Joined: 16 Jun 2007
Posts: 6
PostPosted: Thu Jul 19, 2007 5:44 am

Henry wrote:
What Les said. I got ahold of an Ektalite screen from Robert Pins in NJ and kluged an installation on my Century. Knowing what I now know, it probably wasn't worth the effort/expense, IMO. A good loupe is more important; I use a Toyo 3.8x from B&H Photo in NYC. And yes, the fresnel lines definitely show up in the loupe and make focussing more, uh, "challenging," shall we say?, especially when using a wide-angle lens (in my case, a 65mm Optar). These already present more of a focussing chore than the normal 101. I and others have referred to it as the "least worst" method.
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Thanks to both of you for the information. I think I'll just buy a new gg and a good loupe and call it good.
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