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 Post subject: Telescope SF vs AO question

Regional Ambassador - Multan Chapter

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Friends I need an education on relative merits and demerits on Side Focus and Adjustable Objective type telescopes.

I know that going beyond a specific range is interfered by Parallax, which can be minimized by using a scope which can be focused once the target is acquired.

But due to my ignorance in technical side (like many other sides ;) ) of scopes, I am at a loss to under stand the working of SF type scope.
Kindly also suggest which type is superior mechanically SF or AO. :confusion-questionmarks:

Best regards

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 Post subject: Re: Telescope SF vs AO question

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Mustanir bhai, i may be the last person to answer as Ghazi sb is best. However IMHO will answer in basic knowledge which i have:

Mechanically objective bell focus scopes are better in clarity since front glasses are used to focus the parallax issue; the side focus has an additional glass and its focusing setup included additionally to make it work. Additional glass means lesser light will pass when compared to front focus scope. The side focus is a bit harder to make properly as keeping the cost lower makes the scope become lesser in quality. the compromise is a bad choice. How ever this is not the case when APO glass (Apochromatic glass) is used in the lenses.

In hunting type of events where a target is acquired for a shorter period a side focus is easier and front focus is harder. There are scopes which have rear focus ring based just before the eye piece. Front focus scopes are mostly preferred by bench rest people who do not have to focus on varying lengths of field to remove parallax. It is by far easier to use side focus or rear focus. Secondly front focus can remove the parallax more crisply than side focus as finer tuning is easily possible; i.e. unless you put a large focus wheel on the side focus or use a cat tail ring attachment on rear focus.

Generally the side focus scopes of same specifications are a bit more expensive than their counter parts. example, 10x40 rear focus is 300 dollars 10x40 SF is 400 dollars.

Now the more technical thing... The light has three main beams.. red, green and blue and all the three have different wave lengths, getting all the three beams to focus at the same place is almost impossible to do with one glass. The HD or High density glass passes more light than anyother, the high the density the thinner the glass, the thinner the glass the lesser amount of material light has to pass to get to other side. ONLY two glass manufacturers used 2.21 HD glass, Schmidt and bender and Hensoldt of Zeiss line. Rest are preferring at 1.78 to 1.98 glass which is more than enough. The Apochromatic lenses and the four glasses put against each other make all the three colored light beams focus at one place, so you see something absolutely clear in them. In the non APO glasses you will see the corners of the target having either red, blue or green line shadowing the corner. THAT is the colour of light that is NOT being focused properly. Explained it this much so that we can clearly set the reasons apart.

Now this said.. back to the topic.
The good glass makers and scope makers use very good glass that is why they can afford to put in additional glass to make it SF. The lesser quality glass makers would prefer to keep it simple, use lesser quality glass and have a great scope in the price range. Not many people can afford such a risky decision. People who know the quality of glass will always say one thing "There is no alternative than to buy best scope, this is one place where you cannot compromise" said by Ghazi sb.

One other thing that keeps some of the hunters away from front focus is because when you use flip on covers on the objective bell and then try to focus the cover tends to create a hurdle and you have to shift yourself from your position to see the markings on obj bell whether you are focused at the right range. In side focus you dont even have to move cheek weld or your eye from the eye piece and can focus your left eye on the focus knob and do the ranging. THIS helps a lot when acquiring a proper shooting stance took some effort and time. The scopes which are front focus have far more brighter clarity in the dawn/ dusk time than the side focus ones; if they are from the same manufacturer. Secondly When in cloudy day the color wave length also changes so keep that in view as well. The front focus may be harder to use but imho is better in budget scopes, the side focus good quality scopes are expensive.

Last but not the least here is a list of scopes with the quality compared by someone very knowledgeable.


Image

will update on the rest of the things about scopes if it is allowed here.

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 Post subject: Re: Telescope SF vs AO question

Regional Ambassador - Multan Chapter

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Attiq brother as always you have showered knowledge, enough for me for the time being to understand the technical aspect of it,, I have three AO scopes working excellent now I was getting intrigued by the SF. But with my size of pocket I think its better to stick to AO,, till it grows large enough to house Schmidt & bender or.......

tnx again

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 Post subject: Re: Telescope SF vs AO question

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Mustanir bro, if you see the list there are two scopes that are on tops in quality,
SWFA 10x42 super sniper and Falcon menace. I have the SWFA in 12x42 with mil quad reticle and i can assure you going for top notch Schmidt and bender is NOT the best choice for the bang for buck situation. I myself am going for either of these two
Predator by Horus vision with H57 reticle (760$) or the falcon menace 4-15x44 (400 $) with B 20 reticle or the weaver tactical in 5-15x50 (700 $) or SWFA 5-15x50 (700 $).
i will rate SWFA in A class well beyond its price.
then is the Predator which is worth the cost of the reticle only. All the other big names add about 700 $ to their normal scope if they add the horus reticle in it.
then i Weaver tactical
and lastly the Falcon menace which is by the way very good for the entry into to the long range tactical shooting to 1000 yards range limit

read this second photo with the prices and the options that are included.

Image

BTW which scopes do you have???

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Graffiti in ruins of Pompeii (in the basilica): The one who buggers a fire burns his p....


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 Post subject: Re: Telescope SF vs AO question

Regional Ambassador - Multan Chapter

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I have a Redfield revenge,, Bushnell trophy XLT,, Hawke Varmint.. cheap stuff by your standards but these work for me fine,, no problems till now,, I can cope with low light plus these retain zero,, what else do I need,,, BUT I can't count ticks on my buck :twisted:

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 Post subject: Re: Telescope SF vs AO question

Sniper

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Joined: Fri Dec 31, 2010 3:54 pm
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Location: Karachi, Pakistan
sir jee, you have 3 scopes and all of them are very good.. and they are NOT cheap, learned the lesson the hard way when the cost almost broke my back with Hawke Varmint. I apologize if I made you feel that way.

I just wanted to answer a question that was also asked by someone else. So resulted in my search for the scopes and their worth according to their features and quality. I have settled for Falcon menace as my last purchase which is probably cheaper than all of your scopes. ;) hehe :P.

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I can explain it to you, but I can't understand it for you.

Graffiti in ruins of Pompeii (in the basilica): The one who buggers a fire burns his p....


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