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Forward Focal PLane?

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/14/2010 at 00:22
YakAk View Drop Down
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What is a forward focal plane?  Advantages and disadvantages.

Thanks,
Steve
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/14/2010 at 00:42
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Forward or first focal plane (associated with objective lens) allows for utilization of mil-dot or BDC at any power, but the reticle and target size increases as power is increased/gets smaller as power is decreased vs 2nd Focal plane (associated with ocular lens)where reticle size remains constant with power increase/decrease, target size increases or decreases, but mil-dot or BDC is only calibrated for one power setting, commonly 10x or the highest power setting.  
I prefer FFP to SFP, but many like the SFP's better... 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/14/2010 at 07:34
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If you use the search function with the terms "first focal plane" and/or "FFP, " you should get a huge amount of material to read on this.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/14/2010 at 08:33
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The only real disadvantage to a FFP is while using it in low light situations with the magnification turned down, the reticle might be hard to pick-up. But this depends on the reticle type, and whether or not the reticle is illuminated.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/14/2010 at 11:54
YakAk View Drop Down
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O.K.  I am looking at a 1.5-6x42 with a 4A reticle and FFP.  My typical hunting shots would be 20-300 yards. Any advice would be appreciated.

Steve
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/14/2010 at 16:10
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With all due respect, I don't see where FFP would matter in a scope that's so low on the high end (6X) or for shots that are (for most rifles) within max. point blank range. The only scenario I can think of is that because the reticle in an FFP scope is relative to the size of the object you could use the reticle to lead or to correct on a follow-up shot. However, a 4A reticle doesn't have any useful gradations for this.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/14/2010 at 18:57
YakAk View Drop Down
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jonoMT,

I see your point.  The more research I do, it seems a SFP would be much better for 1.5-6x42.
Thanks for the help.

Steve

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