First or Second Focal Plane?

[brown dog]

BD,

I'm quite new to the "game", so please can you answer a question for me?

If for arguments sake I have just zero'd my Sightron (SFP )S111 6-24x50LRMOA at 100 yards using 10x mag. Then turn the mag up to 24x and shoot at the bull, will my point of aim have shifted? If it does, (and apologies if I sound dim) why does it?

Another question. If I have the same zero as in 100 yards at 10x mag and upload those details to Strelok+. If I then increase the mag to 24x and shoot at a bull at say 300 yards, will Strelok+ now give me the incorrect moa adjustment as it was calculated at 10x mag?

Thanks.

 

1st question - 'maybe, maybe not'. The only way to know for your particular scope would be to clamp it absolutely solid. Aim it at a distant aiming point and assess how much the ret wanders off the aim point as you change mag. Some do. Some don't. Some do a lot. Some do a tiny bit.

 

Your Strelok question - if I'm understanding what you're asking correctly, your computed turret corrections will be the same regardless of magnification.

[gbal]

Nothing erroneous or misleading; just simple mechanical /optical facts that you don't like

 

As regards 'savvy & demanding competition shooters' , clearly, that would depend on the type of competition. If you're thinking of the more static disciplines, have a re-read of my point about most staying on a single magnification and getting spotting shots. Such shooters don't care about the negative, because it doesn't affect the way they shoot - and is significantly outweighed by their desire for a fine ret at max power.

OK- careless of me not to specify which competitons; Bench Rest eg would notice any troublesome poor prformance for 'technical/mechanical' reasons-they don't report such,and many continue with SFP.

 

AS to the 'erroneous and misleading'-well,let other readers judge-when modern reviews and careful measurements of SFP are finding 'near perfect performance' (and also with FFP) then it seems quite clear the old statements have lost validity -both are mechanically very good indeed,so choice must look elsewhere. I have no axe to grind,or preference-if one is btter for an application,I'll buy that. I do have a bias against inaccurate claims,that are simply inconsistent with objective reviews,and currentbest technology. Whether it remains a 'fact ' that one design is less 'elegant' is not what I'm discusssing,but whether the generic claims of superiority in function for either system are tenable.

I note you are resisting so far any consideration of the findings in the reviews,so clearly know about 'facts not liked".I've presented them -pro and con for each system.I've also explicitly a said that one system (FFP)may well be a better design -and was superior in mechanical precision,but that does not make absolutely the best,since it brings other less welcome features,for some uses/users,-and even that advantage in precision has now been been lost- good FFP and SFP are not now distinguishable on mechanical quality,unless the reviews are all wrong. And lots of users.

Hollywood used to say -having it's own agenda-money-

"when the legend is overtaken by the facts,film the legacy".

We might (all) hope for better on this forum.

 

If FFP is superior,fine by me-but let's have valid reasons. Same for SFP.

I think currently there are differences,that still edge choice in some disciplines,maybe not for every participant,and less so-even reversed-in others.

 

How partisan is that. What facts have I missed ?(my bias is for test findings/user preferences ,and 'horses for courses' is what I read.

 

eg I note Vince's points about the Hensold,which didn't excell in Presicion review; but I am not so sure the reticule will be too thick for all shooting...no doubt a 'fine' one would be possible -as S&B introduced. I have no trouble acknowledging improvement in either system-and I would expect to get flak if I continued to say all FFP reticules are too thick-vorsprung happens,and evaluations should keep pace,with current facts,not shelter in out of date descriptions.

 

g

[SWShooter]

This is becoming exhausting , trying to decide if one is better than the other , I seems its horses for courses and personal preference , however I`ve just ordered a FFP Vortex , my first FFP , I`ll be trying it out on varmints and paper out to at least 600m .

[ChrisF]

The thing that really holds back the Heny/zeiss to me apart from the insane price point , is the MTC , hard click every 1 full mil , used it on 2 Premiers & not a fan of IT , as very hard to dial dead ON , always go over , then back for a click to close to a full 1 mil , like say 1.1 mil , so I would want the turret to have a option of NO MTC , firstly & secondly a better reticle .

[snc_2010]

The thing that really holds back the Heny/zeiss to me apart from the insane price point , is the MTC , hard click every 1 full mil , used it on 2 Premiers & not a fan of IT , as very hard to dial dead ON , always go over , then back for a click to close to a full 1 mil , like say 1.1 mil , so I would want the turret to have a option of NO MTC , firstly & secondly a better reticle .

 

 

It might be possible to modify MTC clicks out.

[Shuggy]

Having a play with that $7000 6-24 Hensold last weekend. It suffers from what most FFP scopes suffer from - the reticle is too thick at max power. Also, the turrets - really strange - it was very difficult to turn just one division - it always jumped two or three. I know that sounds daft but it did - anyone else handled one?

Too thick? The centre cross lines on the P4F reticle on my PMII subtends 0.035 mils, which I believe means it will subtend 1.3 inches of the target at a 1000 yards. The Hensoldtt looks like a fairly standard Mildot reticle, so I expect that the lines are 0.05 mils, which if my maths is right means that they will subtend 1.8 inches at a 1000 yards. The F class V bull at a 1000 yards is 5 inches I believe? How fine does the reticle need to be to quarter the bull?

 

Max power on a FFP also won't affect the thickness of the reticle on the target. It will subtend the same angle whatever the power is!

[terryh]

Vince,

 

think the 'big click' at a mil is a militarty thing, in the dark you can 'count' easier. Personnaly so long as you can feel the click adjustments, if not sure you can always 'look'

 

I'm also puzzled at this ret thickness thing, older FFP's possibly but recent FFP's I cannot see it (no pun!). I've a couple of March FFP's and the Ret is nice and simple, no clutter of Chrismas trees etc. The centre floating dot covers less than 2" at 1000 yards = less than a bunnies head. There are some very good F-Class shooters who are realising the advantage of FFP I beleive?

 

Any for the 'moa only' folks you can get moa/moa FFP's with both 1/4 & 1/8 moa adjustments should you so wish.

 

But the bottom line is you buy what you will feel confident with, even if the scope was 'better', if you have psychologically written it off then it will not work for you, belief in your kit is essential.

 

Terry

[brown dog]

OK- careless of me not to specify which competitons; Bench Rest eg would notice any troublesome poor prformance for 'technical/mechanical' reasons-they don't report such,and many continue with SFP.

 

AS to the 'erroneous and misleading'-well,let other readers judge-when modern reviews and careful measurements of SFP are finding 'near perfect performance' (and also with FFP) then it seems quite clear the old statements have lost validity -both are mechanically very good indeed,so choice must look elsewhere. I have no axe to grind,or preference-if one is btter for an application,I'll buy that. I do have a bias against inaccurate claims,that are simply inconsistent with objective reviews,and currentbest technology. Whether it remains a 'fact ' that one design is less 'elegant' is not what I'm discusssing,but whether the generic claims of superiority in function for either system are tenable.

I note you are resisting so far any consideration of the findings in the reviews,so clearly know about 'facts not liked".I've presented them -pro and con for each system.I've also explicitly a said that one system (FFP)may well be a better design -and was superior in mechanical precision,but that does not make absolutely the best,since it brings other less welcome features,for some uses/users,-and even that advantage in precision has now been been lost- good FFP and SFP are not now distinguishable on mechanical quality,unless the reviews are all wrong. And lots of users.

Hollywood used to say -having it's own agenda-money-

"when the legend is overtaken by the facts,film the legacy".

We might (all) hope for better on this forum.

 

If FFP is superior,fine by me-but let's have valid reasons. Same for SFP.

I think currently there are differences,that still edge choice in some disciplines,maybe not for every participant,and less so-even reversed-in others.

 

How partisan is that. What facts have I missed ?(my bias is for test findings/user preferences ,and 'horses for courses' is what I read.

 

eg I note Vince's points about the Hensold,which didn't excell in Presicion review; but I am not so sure the reticule will be too thick for all shooting...no doubt a 'fine' one would be possible -as S&B introduced. I have no trouble acknowledging improvement in either system-and I would expect to get flak if I continued to say all FFP reticules are too thick-vorsprung happens,and evaluations should keep pace,with current facts,not shelter in out of date descriptions.

 

g

 

Right, I'm about to give up, because I simply don't care enough.

 

Benchrest as assessors of a scope's consistent zero when zooming. Hmmm.

Do they change power a lot in benchrest? (I should say, Do they change power at all in benchrest?)

Do they get spotters in bench rest?

Do they shoot for group rather than target centre in benchrest?

 

They wouldn't notice - or wouldn't care (about this single 'zoom' issue), as it doesn't affect their shooting style, and reticle and glass choices etc far outweigh the negative of a feature/flaw that is entirely irrelevant to the way they shoot..

 

I'll say no more because I've said it all twice (three times?) already.

 

 

Here's the key point:

 

Since the mechanical parts that hold the power changing lens system slide inside each other, (some allowances are made for temperature changes, manufacturing tolerances and wear), there must be some movement made to accommodate this.

 

So note this. IT ISN'T ABOUT 'MECHANICAL QUALITY'

 

Even if the set up were to be machined to within 1 nanometer, there has to be space for it to move. And move as well at -10deg C as at +40 deg C.

 

It's becoming obvious to me that you are confusing mechanical precision with tolerances (ie gaps left on purpose) necessary for movement. (I think you're also then muddling this in to talking about turret scope clicks).

 

So, whilst some brands may mitigate the flaw to the lowest level they can; in terms of ensuring that it is IMPOSSIBLE for zero to wander as a result of changing zoom setting, there are only two ways to render that mechanical movement irrelevant / unimportant:

 

1. Have a fixed power scope.

2. Dislocate the reticle from the movement (by putting it in front).

 

I have no ideas what (other) reviews you're talking about.

[John MH]

Here's all you need to know.

 

If your are going to range a target, spot for some one using a similar scope or want to use the ret to estimate corrections from spotted shots then get a FFP.

 

If you don't intend to do any of the above now but might later on get a FFP.

 

If definitely are not going to do any of the above ever, get either a FFP or a SFP.

[brown dog]

Here's all you need to know.

 

If your are going to range a target, spot for some one using a similar scope or want to use the ret to estimate corrections from spotted shots then get a FFP.

 

If you don't intend to do any of the above now but might later on get a FFP.

 

If definitely are not going to do any of the above ever, get either a FFP or a SFP.

 

Yes. I'd add: If you're ever likely to change zoom power settings between shots, get FFP.

[John MH]

All makes sense, odd that all my scopes are SFP but I like to make things difficult for myself.

[gbal]

Matt, yes a bit tedious,no doubt for all.

A Professor of Educatuon used to say on such occasions that an educator who ubderstood could explain,repetition alone was what parrots did. :-)

 

I accept what you say about optical syatems,specifically SFP tube in tube,which the FFP does not have in its design. Zoom zero wander was sometimes found years ago on cheaper SFP scopes.

However ,as reviewers of scopes now find,this is no longer true of the better top end SFP scopes,at least.The Precision Shooting review was specifically used as it is closer to what sems yourprefered shooting-ie varied distance targets,with a bit of zooming-targets seem smallish-around 1moa,one shot hits to count mostly.So no dice loading in favour of Bench Rest,or anything else- on the contrary-top end scopes used in their best application-practical/Precision shooting (save government work,where a thick reticule would have advantages at shortish distances-Hensold?-all your comments assume only some shooting disciplines/applications-Varminting is probably closer to Precision;Bench Rest isn't-it's just true precision shooting-I accept that .05 for five shots at 100y isn't the Holy Grail for everyone-and with fixed x scope!)

OK Sorry to parrot,here's the nub: the reviewer-and the shooters asked-all top 'Precision' shooters ( as above-they are not 5 shots in .1 moa-ie ultimate precision) rated the couple of modern SFP scopes (NF and Leupold) in the mid field,right beside latest S&B- top were the PM11 and NF FFP.The important point is that these scopes were NOT deficient in any mechanical test-and the SFP were actually better than many FFP (all were pretty good).

So whatever deficiency old/cheap SFP had,and still accepting that the design is not as good as FFP (but suggesting it retains advantages the FFP cannot share) this evidence says that the SFP scope can be made indistinguishably as good as FFP in realistic use. A major disadvantage it is not,indeed at the high end,it is none at all.

 

Other pros and cons then come into play- the modal view seems the eminently balanced' "it's horses for course/horses vary within courses".... choose what works for you.

 

When technicalities nudge apart,pragmatism restores.

 

OK I'm back in my Ivory Tower cage,but have read the latest research,superseeding the old hat fashions.

"SFP,FFP,SSP,FFP....just don't go cheep"

 

g polly bal.

[brown dog]

Show zoom apparatus 'technology change' over last 10 years.

Show 'latest research'.

Show Longitudinal Testing (effects of use over time).

[gbal]

Show zoom apparatus 'technology change' over last 10 years.

Show 'latest research'.

Show Longitudinal Testing (effects of use over time).

You'd have to ask NF etc. But I explicitly said there may well be some intrinsic second place design in SFP scopes-BUT the current crop at least are found indistinguishable in practical shooting from the FFPs.If a difference cannot be seen in use,I would hesitate to insist it is a 'huge' disadvantage,but I'm happy to suspend semanics and agree in the name of getting onto something more tangible.

 

Of course it does depend on it remaining so for a reasonaable service life-that will have to wait,since the scopes on test have not had time to be long term checked.It is a general weakness in much testing-will it last-all that I can offer at this time,is the long term sustained precision of the better scopes-NF do seem to sustain well- grounds for optimism but not there yet-how many zooms do you need? :-)

There is some reliable data on Zoom tests in post 41. If we get to the literal 'hairs breadth' per click that NF admit to,it is almost impossible to detect any POI change at short range (really needs a tunnel test)-and even slightly thicker reticules would make any very small changes very hard to detect.... if undetectable ,I'd not be too concerned-especially in the context of "precision gong shooting"-it's not really a hair's breadth context,though it could add to a few inches at very long range.

 

For realistic testing,what do you reckon the zoom range really is- 5-25 seems the modal sort of scopes specs,but the used range is probably less. It seems,currently,that any POI changes seem very small-but it may not be known absolutely. It os odd that eg new S&B did a bit less well,though stillvery good-all this 'Precision" review is understood as vey top end and all the scopes did pretty well,but some were better,of course.Even within the prefered design,there may be differences-which no one has denied,if not mentioned.

If there really were substantial practical advantages,with only small disadvantages, between the designs (F or S fp) it would be helpful to many shooters to know,and they could make a more informed choices.

While this may/not be so for scopes,differences without clear advantages are promoted elsewhere-fast straight pulls eg,undeniably in skilled hands fast reloading,by a fraction of a second (I'll be kind and exclude the Scandinavian fast bolters),but of vriable field advantage given the aiming time in seconds for any action. A lever action would come close,too.I use all three,seem about the same.

OK,just a diversion into 'distinctions without differences/differences without distinction"-never sure the Prof's comment was/not just a repeat. For the pragmatist-and that's what shooting is-pragmatic not perfect-the simple question remains "In what scenario does it make a difference I need to know about?"

This has been another long pint,Matt.

g

[That bald headed Geordie]

FFP v SFP. Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaarrrrrrrrgghhhhhhhhhhhhhhhh

Enough already my brain hurts!!!!

[gbal]

Show zoom apparatus 'technology change' over last 10 years.

Show 'latest research'.

Show Longitudinal Testing (effects of use over time).

Shortish and sweet:PrecisionRifle blog test seems about the best available.*41 post by vInce on here might suggest little problem;no-one seems to have done zoom testing. Old discussion post just repeat-cheap old scopes sometimes had problem,recent better ones do not (I suspect cheap old scopes had all sorts of problems!)The PR tests do show very impressive performance for both F and S fp.Long term testing on new scopes has to wait.

As bryanBryan Litz says,"assume nothing-measure everything you can measure,take nothing as given." **

I'll look forward to the critical zoom/POI measures in contemporary High end scopes,but I don't have this data,maybe no one does-which would be hugely odd ,but possible (as its well overdue).

 

One interesting finding though is that even some-most-of these top end scopes dont track exactly in the vertical turrets. If not,that might bear on the repeated complaints here that ballistic engine solutions do not fit field test data.Well,they won't if the vertical tracking on the turrets isn't accurate.Other reasons too,of course,and Vince usually does a box test-at 100y?

** Litz:check turrets

Oh,and the % of shooters holding off instead of dialling is now 41%,and rising (slowly?)...laser etched reticules will be more precise than mechanical turrets,and definitely faster,if that is relevant.(forr both F&S fp ).

 

 

gbal

[ds1]

I think most companies would not report results - not the way marketing works. I do know R and D folks at Meopta and repeatability of 1/2 moa for 2fp scopes through the zoom range is broadly achievable from a manufacturing vs cost perspective. Over the last 20 years I have not seen 1fp Schmidt Pm2 scopes fail to function at temperatures down to -20, on the other hand I have seen Leupold 2fp scopes lock the zoom ring up at these temperatures.

[CameronWilson]

How do I post image links on this forum – I keep getting a message saying I can't...

[gbal]

David,correct as far as has been enquired-the excellent Precisionrifle blog top end scopes test did ask,but only NF replied (.007 per click,from memory-hairsbreadth anyhow-even that does accumulate over 30 moa into inch(es).Other didn't. It is of course checjkable by the shooter on something like a ladder test-but needs very accurate measures and some distance.When tested,many of even the top end (all tactical scopes-though I doubt that 'competition BR etc would differ) were out by small 1-3 %

This just won't show in most useage and will be included in general '' noise-" ie other error effects,mostly not the scope (wind etc). 1-2% is probably pretty good manufacturing tolerance-some were better,so it can be done (not exactly price correlated,but these were all pricey scopes).

 

Temperature seize/freeze up at -20 isn't a UK issue,but could well be in some shooting zones-central Europe (as you can attest) and areas of USA/Canada.

 

John-I think-as does Bryann LItz,ec,that the choice is a genuine one-save for a few quite specific applications,where one focal system has an edge-as shown by shooter preferences: because:

 

Ranging-use a laser-it's accurate- using any reticule is not,the more so the f;longer the range,smalller the target,and lower the mag. SFP can be used at specific setting if this need arises.Make sure you have your target size in cms 9metric) if using mils,and of course in inches if SFP,otherwise you need a calculator,or a predone conversion chart. Gongs eg are often non metric...it's doable if lasers are not allowed-by both systems,FFP is more flexible wrt mag.But you are better with high mag to reduce error....

 

Shooter buddy: when in Rome- agreed,if two/more shooters are exchanging info,or spotting it is eminently sensible for both to use the same system;can't see any clear reason to think either focal plane or mil/moa has any advantage though,given consistency within the system(reticule/turrest) and between shooter/spoters.

 

Correction if fall of shot is seen-ditto- either mil/moa work equally well- if shot is 2 units low and one unit right,EITHER hold 2 units high and one left OR dial in 2 up,1 left on the turrets. What the units are does not matter( let's not go into the possible precision differences in mils,moa-small and mostly eliminable by sizes of hatches/click values.ONly fine targeteers worry about 1/4 moa clicks being less satisfactory than 1/8th-but of course precision matters for some).

Many target competitions,not all, use scoring rings that are moa based-moa scope helps.

 

I know and empathise with users in variuos disciplines-there are are,as some keep suggesting,choices-and some applications nudge,maybe quite significantly,one system rather than the other.

For some,there probably is no choice-eg military experience will be mil-though by no meand all FFP?;as above ring target shooters esp will probably be more used to moa and FFP. Tactical shooters who may need quick ranging on the fly understandably like FFP. etc etc.Europeans have more tradition of FFP,USA and probably UK hunters of SFP.

 

All systems have pros and cons-known target size is a essential for ret ranging,but you could say so is a battery for the laser.Agreed,in such cases,the single mag calibrated SFP will do as good enough a job as the FFP. The only question is whether such "tennis rallies" are short or longer-very few issues are yes/no-or perhaps that should be 'very few issues that really matter to most shooters are yes/no.'

( FFP/SFP and mil/moa are of course quite seperable issues).

 

Get what you think best,by all means.I'm just saying that good accurate appraisals of both systems,and pros/cons (and taking on board expert preferences,as it's reasonable data),help everyone make a more informed choice for their eyes/use/context/budget and even predilections.Almost,but not quite like magnification range.( shooting a couple of days ago in rather overcast light,42x NF was not dazzling on 500y fig 11s,but very well good enough to pick which corner of the 4x6" white centre paste on to hold for wind etc...someone else was shooting a modest chinese variable,and at 4x it was so much brighter...but the cross hair covered the entire white,and then some,and fall of shot in the grass(longer ranges) was a complete mystery (ditto every scope there) ....how could it be otherwise.Winding the NF down to 12x,restored brightness and strike seemed to be 'adequately close' to 42x POI.But I'd like a lot more evidence on this issue-surprising it is not readily to hand-but I haven't checked systematically,over large mags and distances ( would it be lost in 'noise'?).

 

gbal