Home Forums Hunting & Shooting Hunting Optics FFP or SFP for DG rifle

Hi Fuchs,

I too have noticed that even with a 1X scope, the image is somehow not the same as naked eye. I thought it had to do with the diopter adjustment or eye position behind the scope (moving your eye behind the scope changes apparent magnification slightly). I have to look into this more closely..

Now here is another strange fact I recently noticed about 1-4X or 1-6X scopes: Their exit pupil is not as large as I'd hoped. Their exit pupil diameter is about 11- 12mm in various Schmidt and Bender, Zeiss or Swarovski models I checked. That is much less than 20 to 25mm I was expecting. It's funny I'd never payed attention to this when looking at such scopes at Shot Show or elsewhere (I don't own one). "Normal" hunting scopes such as Schmidt and Bender 3-12X42 have proper exit pupil diameters at their low power (42/3= 14mm) but the 1X scopes don't.

I am now looking at specs for 1.5-6X and 1.5-8X scopes.. Looks like some of these have their low-end exit pupil smaller than expected too

I'm thinking they are an American fad since range finders do a better job of ranging. They will disappear once the faddishness wears off.

Ringman,

FFP is by no means an American fad. European scopes have been FFP for generations. SFP was only used on export models in order to accomodated the American market, which didn’t know FFP. Only lately have they switched to SFP with zoom factors > 4 coming up. The classical German 4 simply became too fat at max. or too fine at min. magnification.
Further, the discussion is not on ranging but on shift of POI.

I am convinced that the future will see an increasing number of FFP models in combination with more intelligent reticels.

Omid,

In former, factor 4 zoom, scopes the exit pupil was indeed linear with the magnification setting. In current, factor 6 or factor 8, models, manufacturers are limiting the eyebox at low magnifications. I have no clue why they do this. But your observation is absolutely valid.

You are not telling me something I didn't already know about FFP and Europe. As far as SFP not holding zero that is foolishness. I think once the FFP shooters realize they can't see the reticle on low power and on higher setting the crosshairs are too large for precision shooting.

I am convinced that the future will see an increasing number of SFP models in combination with a greater variety of reticles.

http://marchscopes.com/storage/FMA-2%2024x.jpg
http://marchscopes.com/storage/FMA-2%205x.jpg

We shall see.

Those sure don't look like the FFP that I looked through. March makes both kinds. How many March scopes have I seen in my life? Zero.

An FFP scope with a more intelligent reticle? Hmm.. How about an FFP reticle pattern whose apparent size doesn't change when you change magnification?! You might think this is impossible but it is possible. I am the pround re-inventor of such a reticle. I came up with the idea in 2011 but after submitting my patent application, it turned out they were discovered by a Mr. James Benford in 1957. I have mentioned these to a couple of manufacturers (Zeiss, Schmidt and Bender) but no one has paid any attention so far.




Yes, this seems to be the case. As they tried to increase the zoom range, the designers must have limited the numerical aperture of the relay lenses which, in turn, has led to a smaller exit pupil at low magnifications.

I am fascinated. Who is the guy you are quoting?

Well, I have one. And yes, they are different to the old designs. This is why I know that the disadvantages of FFP can be overcome.

Hi Omid,

wow, I had no idea who I was chatting with. I haven't yet digged into your patent deeply enough to fully understand its fundementals, but I will do so tomorrow.

It depends on the scope as to seeing the reticle on low power settings. I'm 66 years old and I can see the reticle just fine on my S&B dangerous game scopes on low power.

I prefer FFP scopes to 2nd focal plane scope after I got used to them.

Fact is a FFP scope is much less likely to have a zero holding problem, that's not even debatable.

That's because you misunderstand current FFP reticles.

I am really ready to learn. Tell me where I see this new technology. I have been thinking about a new scope.

The Vortex Razor FFP reticles are some of the best I've seen. You might look there. Posts bold enough for use in low light on low mag, and cross hairs with markings fine enough so that they disappear on low mag, but become visible and capable of precision at high mag. Open center so as to not obscure the POA.

And FWIW, an FFP reticle is not for finding range. That's what LRF's are for. FFP reticles have more mechanical reliability, reticles that are the same subtensions at all magnifications for holdovers/offs, measuring misses and corrections, measuring target sizes, etc. I rarely have my FFP scopes on max magnification, so they are a significant advantage over SFP scopes.

Hi Omid,

I have now looked more closely to your patent. You have described exactly what Deon Optics has realized in their March Tactical FFP scopes.
It's so simple!!! I wish the European manufacturers would adopt it and go back to FFP.

Quality FFP scopes reticle don't fade out on low power in lowlight at least my S&B's don't. Correct FFP is mechanicaly supperior

The pupil of the human eye maximises at around 7mm, for some people far less.

https://www.ncbi.nlm.nih.gov/pubmed/20506961

How would an 11mm or 25mm E/P in a scope be of benefit to anyone?

If more light doesn't help, then why do I need more light to see at 66 than I did at 20? The brighter the scope the better I see

Any area of a scopes E/P over the dia. of your individual eyes pupil is superfluous.

The only way to increase or maximise the amount of useful light through the scope to your retina from that point,
is by ensuring the optical device of choice has the best possible 'light transmission efficiency'