Concentric circles in viewfinder?

jds · 10-02-2009, 12:47 PM

Hello all. I am new here and just purchased an old Spotmatic. In looking into the viewfinder, I notice a series of concentric circles that fill the viewfinder side to side and top to bottom. The lines are faint in some areas, bolder in others. Somewhat distracting. Is this normal? Thanks.

Nowhere Matt · 10-02-2009, 01:02 PM

Originally posted by jds

Hello all. I am new here and just purchased an old Spotmatic. In looking into the viewfinder, I notice a series of concentric circles that fill the viewfinder side to side and top to bottom. The lines are faint in some areas, bolder in others. Somewhat distracting. Is this normal? Thanks.

Maybe a improperly installed focus screen. Throw it against the wall really hard and... No don't! I'm just kidding about the throwing part. But I will wager someones else mentions the focus screen and not the part about throwing it.

pbo · 10-02-2009, 01:41 PM

Are you talking about fresnel? That's made to aid you in manual focusing; without them, it'll be harder to tell if the image is in focus or not - particularly in the areas outside of center microprism, where you have to judge/guess by looking at the picture of the viewfinder (as opposed to relying on split and microprism band).

jds · 10-02-2009, 03:34 PM

These are concentric rings that are outside of the center microprism. In reading the manual, it says " Fresnel lens consists of many concentric rings which provide the brightest possible image on the ground glass". Is that what I am seeing? Almost like a target without the center circle. Thanks.

Marc Sabatella · 10-02-2009, 04:03 PM

Which camera? Using the focus screen that came with? I find I don't even notice this, unless the light is *just* right (or just wrong, depending on your perspective. As others have said, it's on purpose; without this, manual focus would be impossible. But you stop noticing it after about a day.

Wheatfield · 10-02-2009, 04:42 PM

It's normal. They used to sandwich a fresnel lens onto the groundglass to make the screen brighter.
You might be seeing a bit of delamination of the two components with the bolder rings.

10-02-2009, 12:47 PM	#1
jds Inactive Account Join Date: Oct 2009 Posts: 2	Concentric circles in viewfinder? Hello all. I am new here and just purchased an old Spotmatic. In looking into the viewfinder, I notice a series of concentric circles that fill the viewfinder side to side and top to bottom. The lines are faint in some areas, bolder in others. Somewhat distracting. Is this normal? Thanks.

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10-02-2009, 01:02 PM	#2
Nowhere Matt Veteran Member Join Date: Nov 2007 Location: Nowhere Land Photos: Gallery \| Albums Posts: 2,357	Originally posted by jds Hello all. I am new here and just purchased an old Spotmatic. In looking into the viewfinder, I notice a series of concentric circles that fill the viewfinder side to side and top to bottom. The lines are faint in some areas, bolder in others. Somewhat distracting. Is this normal? Thanks. Maybe a improperly installed focus screen. Throw it against the wall really hard and... No don't! I'm just kidding about the throwing part. But I will wager someones else mentions the focus screen and not the part about throwing it.

10-02-2009, 01:41 PM	#3
pbo Veteran Member Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 891	Are you talking about fresnel? That's made to aid you in manual focusing; without them, it'll be harder to tell if the image is in focus or not - particularly in the areas outside of center microprism, where you have to judge/guess by looking at the picture of the viewfinder (as opposed to relying on split and microprism band).

10-02-2009, 03:34 PM	#4
jds Inactive Account Join Date: Oct 2009 Posts: 2 Original Poster	These are concentric rings that are outside of the center microprism. In reading the manual, it says " Fresnel lens consists of many concentric rings which provide the brightest possible image on the ground glass". Is that what I am seeing? Almost like a target without the center circle. Thanks.

10-02-2009, 04:03 PM	#5
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,686	Which camera? Using the focus screen that came with? I find I don't even notice this, unless the light is just right (or just wrong, depending on your perspective. As others have said, it's on purpose; without this, manual focus would be impossible. But you stop noticing it after about a day.

10-02-2009, 04:42 PM	#6
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,108	It's normal. They used to sandwich a fresnel lens onto the groundglass to make the screen brighter. You might be seeing a bit of delamination of the two components with the bolder rings.

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