• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
Feel the intensity, not your equipment. Maximum image quality. Minimum weight. The new ZEISS SFL, up to 30% less weight than comparable competitors.

Looking at this scope, opinions and a bit of help needed. (1 Viewer)

Ev4dawin

Always finding a way to go off topic...
United Kingdom
Hey all, I made a thread previously about scopes, but I have recently found one here ->

And I wanted to ask about what the numbers mean; bearing in mind I have 0 experience with scopes so a few pointers would be appreciated. So am I correct in saying the 20-60 means how far it can zoom so would it be similar to a 600mm lens? And the 80 is how high the magnification can go? This specific scope weighs 1.3kg, so does anyone use any tripods that easily support this weight? Furthermore, has anyone had any experience with this scope model? If so how has it performed?

Cheers,
Ev
 

Mike C

Emeritus President at Burnage Rugby Club
Supporter
England
20-60 = correct, this is a zoom eyepiece, 20 times magnification to 60 times magnification - no idea how it compares to a photographic lens.
80 = correct the size of the objective lens
45 = the eyepiece is angled at 45 degrees (my personal preference) to the body of the telescope.

Tripod ?
Good question. My advice would be to find your nearest Opticron stockist and go and look at the telescope. Look through it and make sure it’s right for you. Then see what tripods they stock and ask for a suggestion.

I have never looked through one of these ‘scopes.
 

henry link

Well-known member
20-60x means that objects appear 20 to 60 times larger than they appear to the unaided eye at the same distance.

80 is the size in millimeters of the large lens at the front of the scope. Theoretically the larger it is the brighter and sharper the image will be at a given magnification.

There is no direct correlation between these numbers and the focal lengths of camera lenses, but you can form a rough idea of the magnification equivalent by dividing a telephoto lens' focal length by whatever focal length is considered "normal". For instance, if a "normal" full frame lens is 50mm then a 600mm lens has a magnification equivalent of 12x compared to the normal lens, much less than a spotting scope, more like a binocular.
 

Binastro

Well-known member
With a full frame camera the 'normal 'lens is 50mm.

However the normal lens should equal the frame diagonal, which is 43mm on a 36x24mm frame.
(There were 34x24mm and 32x24mm full frames also).

So at 43mm diagonal 20x would be a 860mm lens and 60x would be 2600mm lens on a standard full frame.

If one says 50mm is a standard lens then the 20x would be a 1000mm lens and 60x a 3000mm lens.

But many now use 1.5x, 1.6x and 2x crop lenses on digital cameras.

However, these figures don't have very much meaning comparing photos to visual use.
Although they illustrate the magnification.

A clearer idea of magnification is that a bird at 200 metres distance looks to be 10 metres away at 20x and 3.3 metres away at 60x.

Regards,
B.
 

Ev4dawin

Always finding a way to go off topic...
United Kingdom
With a full frame camera the 'normal 'lens is 50mm.

However the normal lens should equal the frame diagonal, which is 43mm on a 36x24mm frame.
(There were 34x24mm and 32x24mm full frames also).

So at 43mm diagonal 20x would be a 860mm lens and 60x would be 2600mm lens on a standard full frame.

If one says 50mm is a standard lens then the 20x would be a 1000mm lens and 60x a 3000mm lens.

But many now use 1.5x, 1.6x and 2x crop lenses on digital cameras.

However, these figures don't have very much meaning comparing photos to visual use.
Although they illustrate the magnification.

A clearer idea of magnification is that a bird at 200 metres distance looks to be 10 metres away at 20x and 3.3 metres away at 60x.

Regards,
B.
Very helpful, considering how far the scope would be able to see as a 20-60, would it be a good idea to downgrade and go for the 15-45 variant of this scope? I didn't mention this in my first post, but I would use the scope for reserves such as WWT Welney or other RSPB reserves but also a bit of seawatching if I'm ever able to.
 

Binastro

Well-known member
A 15x-45x scope with ED glass would be less expensive than a 20x-60x ED scope, but may be more expensive than a non ED 20x-60x scope.

Regards,
B.
 

Binastro

Well-known member
Extra low dispersion.

This type of glass reduces the chromatic aberration or false colour fringes when looking at things through a scope.

At say 30x it may not be a problem, but at 60x a non ED short scope will show false colour.

The ways to reduce false colour are to have a very long refracting telescope or a short scope with ED glass in the front.
Or maybe to have more glass elements in the front group.

ED glass comes in different qualities and different prices but ED scopes are more expensive than the equivalent non ED scope.

Regards,
B.
 
Last edited:

Ev4dawin

Always finding a way to go off topic...
United Kingdom
Extra low dispersion.

This type of glass reduces the chromatic aberration or false colour fringes when looking at things through a scope.

At say 30x it may not be a problem, but at 60x a non ED short scope will show false colour.

The ways to reduce false colour are to have a very long refracting telescope or a short scope with ED glass in the front.
Or maybe to have more glass elements in the front group.

ED glass comes in different qualities and different prices but ED scopes are more expensive than the equivalent non ED scope.

Regards,
B.
So I think that the scope I’m looking at getting has ED glass on it, but I’m not entirely sure if it does, I can’t find anything on opticrons website but I might just been going blind and have missed it. I’ll have a look but I think it does have ED glass on it already.

Edit: is there a way to tell if a scope has ED glass by looking at it? Or is it specified within its description on the website? Like someone said above, I might see if I can get to an opticron store to have a look at it.
 
Last edited:

Binastro

Well-known member
Hi,

You cannot tell if a scope has ED glass by looking at it, although an experienced observer could probably tell by looking through it at the highest magnification.

I think the Adventurer has standard non ED glass.
Opticron are very helpful and can tell you.
If it had ED glass it would be mentioned in the specifications.

If they do a 15-45x65 version, non ED glass may not be much of a problem, as the magnification and diameter of the front lens are both smaller than the 20x60-80 version.

Personally, I use non ED scopes without a problem, but birdwatchers are concerned about colour fringing.

Opticron do sell ED scopes.

Regards,
B.

P.S.
Opticron sell a 15-45x60 Adventurer II scope listed at £129.
 

jring

Well-known member
Hi,

I agree with those that have answered before that an ED scope would be better for magnifications beyond 40x or so - but significantly more expensive than the one in question. I have not found any great offers for a used ED scope around 200 quid either... but I might have missed some.

With a hard budget of 200 quid and no time to wait for a good deal for a used scope, I would prefer the 15-45x65 version as zoom eyepieces tend to have the widest apparent field of view at their high magnification end... and that is still kinda usable at 45x with a plain glass scope - if needs be, crank it down to 40x. Not so at 60x with the 80mm variant - that will be fairly blurry.

Probably best for any plain glass scope would be a fixed wide angle EP with a magnification around 30x... but since the Adventurer II series comes with a non-detachable zoom EP, that is not an option here.

Joachim
 

Mike C

Emeritus President at Burnage Rugby Club
Supporter
England
One other thing you might consider in this ED versus non-ED glass discussion is whether or not you will keep the 'scope long term.

We know it’s your first scope and as a first scope for a young birder maybe non-ED glass will be okay for you.

That then gives you the option of upgrading as you get older and more proficient as a birder.

However if you’re already an "older birder" (like me), maybe you want to go straight to ED glass now because it will be your "forever 'scope".

An interesting dilemma
 

Ev4dawin

Always finding a way to go off topic...
United Kingdom
Thank you all for the reply’s, very informative and I do think that- since I’m a young birder- I will go for the slightly less powerful (in terms of zoom and magnification) 15-45x60 scope, as I will still be able to have the fair amount of zoom at around 1900mm, which would be perfect for large reserves and bodies of water. Over time, I will no doubt want to upgrade to an ED scope to be able to get the correct colours, but for now the 15-45x60 opticron adventurer II is looking like the one I will get.

Edit: When it comes down to magnification, is it a bit like exposure with different light levels where you would use the higher magnification if there was more light coming in and the lower magnification would be when there’s less light? Or is it the other way around?
 

Binastro

Well-known member
Generally more light higher magnification.

But it depends on the amount of magnification one feels is needed and the distance of the bird.

The atmosphere is generally the limiting factor, but in the U.K. the air is steadier than in many countries with more extreme temperature variation.

Generally young eyes are much better than old eyes, but experience comes with age also.

The 15-45x60 is not too expensive and if there is a tripod handy one doesn't need anything extra.
Also the weight is less than a bigger scope.

Regards,
B.
 

Ev4dawin

Always finding a way to go off topic...
United Kingdom
Generally more light higher magnification.

But it depends on the amount of magnification one feels is needed and the distance of the bird.

The atmosphere is generally the limiting factor, but in the U.K. the air is steadier than in many countries with more extreme temperature variation.

Generally young eyes are much better than old eyes, but experience comes with age also.

The 15-45x60 is not too expensive and if there is a tripod handy one doesn't need anything extra.
Also the weight is less than a bigger scope.

Regards,
B.
Yes those factors are important as well. Amazon does a “bundle” where you can get the scope and a tripod for £135 which I think is what I might be getting for Christmas
 

Essex Tern

Member since 2006
Supporter
England
Yes those factors are important as well. Amazon does a “bundle” where you can get the scope and a tripod for £135 which I think is what I might be getting for Christmas
As a starter setup I don’t suppose you could easily find a better value kit. The tripod has a hook at the bottom which would be a good idea to make use of by hanging a bag on with a bit of weight in to give you your steadiest view. An alternative tripod could possibly be found on ebay, plenty of used Manfrotto 055 will likely come up which would likely be an upgrade at not too hefty a price point.
 

wllmspd

Well-known member
The 055 is overkill unless you have a very large scope. I use a 190 with a heavy 80mm and it’s fine. Cost is one consideration, but so I weight… lugging extra kg of scope or mount about can get tiring. For seawatching and other wide sites like Welney sometimes you want as much power as you can. Chromatic aberration tends to be most obvious as a purple fringe round high contrast objects, especially in sunlit conditions.

Peter
 

Essex Tern

Member since 2006
Supporter
England
The 055 is overkill unless you have a very large scope. I use a 190 with a heavy 80mm and it’s fine. Cost is one consideration, but so I weight… lugging extra kg of scope or mount about can get tiring. For seawatching and other wide sites like Welney sometimes you want as much power as you can. Chromatic aberration tends to be most obvious as a purple fringe round high contrast objects, especially in sunlit conditions.

Peter
Yeah but maybe future proofing for scope upgrade if cost difference isn’t too great - lots to consider, but if either are found at a bargain price I’d snap it up myself 👍 Think 055 is taller for legs only, so if OP is tall 055 might be preferable. A lighter 190 is totally valid too. Like a lot of birding and photography gear you have to weigh up what’s best for you 😊
 

Ev4dawin

Always finding a way to go off topic...
United Kingdom
Yeah but maybe future proofing for scope upgrade if cost difference isn’t too great - lots to consider, but if either are found at a bargain price I’d snap it up myself 👍 Think 055 is taller for legs only, so if OP is tall 055 might be preferable. A lighter 190 is totally valid too. Like a lot of birding and photography gear you have to weigh up what’s best for you 😊
I'm 5'8 so idk if that woulda class as tall :ROFLMAO:, but I will likely upgrade the tripod that comes as a "bundle" within a few years or so.
 

Essex Tern

Member since 2006
Supporter
England
I'm 5'8 so idk if that woulda class as tall :ROFLMAO:, but I will likely upgrade the tripod that comes as a "bundle" within a few years or so.
Same height as me, a good height 😂

I now use a carbon 055, having used an aluminium one for many years - they are a good height without extending the column much at all…..an advantage of not being too tall!

The bundle will certainly get you up and started 👍 Just keep a casual eye open for any bargain upgrades.
 

Users who are viewing this thread

Top