[BobinKy]

Whether to choose a spotting scope with an angled or straight-through eyepiece is usually not a matter of optical performance, but more of a matter of personal preference and geography.

In his book, Pete Dunne on bird watching: The how-to, where-to, and when-to of birding (2003), Dunne states most American birders prefer the straight-through system, while Europeans favor the angled eyepiece. The reason he gives is in Europe standard birding practice frequently calls for prolonged study of birds from a hide or long-term scanning, such as sea-bird watching. On the other hand, in the United States, because of the diverse habitat and birding possibilities, birders frequently shift position quickly, moving from to bird to bird, site to site. The angled system is better suited for long-term viewing, while the straight-through system is faster, particularly for the birder with limited experience at finding birds through a scope.

Dunne also gives the following advantages and disadvantages of using scopes with angled eyepieces.

Angled eyepiece advantages

• Generally provides easier, more restful long-term viewing.
• Scope is lower than the observer's eyes, allowing the observer to scan over the scope with binoculars (not to the side as with the straight-through EP).
• Two or more observers of slightly different heights can easily share the same scope with less physical stain, fuss, or tripod manipulation.
• Observers can study birds high overhead or in tall trees without having to crouch or buy a tall tripod (which can add to the initial cost of scoping and weight that must be carried to the field).

Angled eyepiece disadvantages

• More difficult to aim and find the bird than straight-through eyepiece.
• Exposure to rain, mist, or snow (due to angle of the EP glass) may distort the image in poor observing weather.
• Difficult to use shoulder-mount or car window-mount system.
• Projects line of sight several inches below eye level; if bird is perched beyond some barrier, such as a hedge or reed bed, the lower line of sight may not be high enough.

...

As for myself, I use an angled spotting scope because, when I made my spotting scope purchase a couple of years ago, I already owned a short (and very light) tripod left over from my photography days--Bogen 3001/3126, which only entends to a height of 55", weighs 5.8 lbs, and supports 8.8 lbs. While my 3001/3126 is not as sturdy during heavy winds as my 3246/501 setup, I find the lighter camera tripod easier to take to the field and move about. I also find I like to take a short stool on many of my nature excursions and sit for long-term observing.

So, once again, existing equipment that we own determines what and how we observe, as well as our future optical purchases.

...

What about our readers--do you prefer an angled or straight-through scope? Why?

--------------------
Bob
38° Kentucky, USA

Improve your life with optics.

[Naughtymoose]

Bob,

When I bought my Opticron MightyMidget spotting scope last year at RSPB Titchwell, UK, the lady in the shop said that I must be a photographer because of the way that I automatically put the scope to my eye. It's a straight-through scope, and I love it because I can use it one-handed.

I'm now thinking of upgrading to an HR Opticron (to go with the SDF eyepiece that I have added). This will be a straight-through as well; I stop often in my company van at Hanningfield reservoir and will be able to clamp it to the window.

I tend to get a neck ache when using a 45 for any length of time.

Regards

Colin

[Alexis Powell]

Originally Posted by BobinKy

What about our readers--do you prefer an angled or straight-through scope? Why?

Straight. I like it better than angled on a window mount (which I use quite a bit), and for viewing from as high a tripod position as possible (many places where I bird have high grass or other vegetation). I see the advantages of angled for sharing views, but I generally bird alone.

--AP

[Tero]

Like I said today about 8x and 10x.

It depends. i use straight scopes, onmy second one now.

[Wachtel]

I use an angled scope, one advantage not mentioned above is stability. In windy conditions a less extended tripod is more stable. The only situation in which I can see an advantage with a straight scope is from a car.

[Alexis Powell]

It's easy enough to set a straight scope low when necessary. When height is unnecessary, I often use my straight scope from a position where I'm sitting on the ground or cross-legged on rubber boots.

--AP

[John Russell]

Originally Posted by BobinKy

I use an angled spotting scope because, when I made my spotting scope purchase a couple of years ago, I already owned a short (and very light) tripod left over from my photography days

That's a valid point. For my 190cm height the choice of lightweight, stable tripods for a straight scope was very limited and none of them was cheap.

I often wonder if the design compromises made by the manufacturers to offer both straight and angled scopes have a significant effect on the optical performance. OK, Nikon and Swarovski use Porros for the straight scopes and roof prisms for the angled, which is logical assuming they have similar glass paths. Zeiss and Meopta use roof prisms for both, with the somewhat insignificant advantage that the eyepiece on the straight scopes is not offset.
However, I once saw a cutaway straight Leica Televid 77, which had a rhomboid (periscope) prism behind the Porros to achieve the same light path as the angled, which must have had a Schmidt prism behind the Porros! That really is belt and braces.

John

[LauraL]

I use an angled scope. I've never tried a straight but nevertheless am happy with the angled. I find it very comfortable for long viewing and that's what I like to do most. I love getting a bird in my sight and observing it for as long as possible. I find it no problem to locate birds or adjust positions quickly with the angled scope, but then again, I have nothing to compare it with. I also share my scope sometimes with my husband who is over a foot taller than I am and that makes the angled practical.

[Kevin Purcell]

Originally Posted by John Russell

However, I once saw a cutaway straight Leica Televid 77, which had a rhomboid (periscope) prism behind the Porros to achieve the same light path as the angled, which must have had a Schmidt behind the Porros! That really is belt and braces.

John

Not quite a Schmidt roof prism and a porro.

That extra prism after the porro pair is a semi-pentaprism which just deviates the light by 45 degrees.

That's exactly what it does in a roof prism assembly but it doesn't do the image inversion/reversion (there's no roof on the lower prism) that the job of the top Schmidt/Pechan prism.

The downside of adding the semi-pentaprism is more parts and two more glass/air interfaces. With multicoatings that's not bad today there is a compromise because these are both entrance/exit faces and TIR reflection faces. Plus a reflective lower surface of the prism has to be mirrored and there is either some loss there with aluminum or silver coat. Or you pay for a dielectric mirror coat (whcih I'm sure the alpha scope makers do). So overall there is a tiny loss in transmission.

I'm sure in the olden days angled scopes did have a much bigger penalty for this (and cheaper scope today probably suffer a bit more too).

But the ergonomic wins outweigh this issue for most people.

[temmie]

Angled.
You will never find the bird with a straight scope high in the canopy above your head. You will also never enjoy the close views of a raptor approaching and flying overhead. With e.g. a Nikon fieldscope, you can have a straight (angled) view because it has a clamping ring just as their lenses.
If you put a strap on the objective side of the scope, you have a pointer that works as wel as having a straight scope, so you will never miss a bird because you have an angled scope.
Please do not justify the choice between angled and straight based upon birding from a car. I know it works better for some birds to approach when just sitting in that piece of metal, but cars kill birds and roads make birds go extinct.

[John Russell]

Originally Posted by Kevin Purcell

That extra prism after the porro pair is a semi-pentaprism which just deviates the light by 45 degrees.

OK, Kevin, I stand corrected. If you happen to have that link with all the prism illustrations, I would appreciate it if you could post it here.

John

[Alexis Powell]

Originally Posted by temmie

Please do not justify the choice between angled and straight based upon birding from a car. I know it works better for some birds to approach when just sitting in that piece of metal, but cars kill birds and roads make birds go extinct.

Ha! Cars are also the only practical way for humans to get around some parts of the world. I don't use my car to closely approach birds in my neighborhood, or favorite hiking areas, but Kansas birding can easily involve (should a birder choose to consume resources in such fashion, which I do) a 20-200 mile drive to a lake or two, or to a wildlife refuge where one might drive along the dam/shoreline or refuge/dike roads for many (20-100 miles) miles in day. A scope on a window mount is very handy for this "safari style" birding of open country.

--AP

[Kevin Purcell]

Originally Posted by John Russell

OK, Kevin, I stand corrected. If you happen to have that link with all the prism illustrations, I would appreciate it if you could post it here.

John

For the SP roof prism (that's a semi-pentaprism at the entry point)

http://en.wikipedia.org/wiki/Schmidt-Pechan_prism

and for more prisms than you can shake a stick at ...

http://www.tecplusplus.de/ManualLu/prisms.htm

And you can see it described in this Alulla review of a Kowa scope

I'm pretty sure you can imagine a porro erector followed by a semi-pentaprism.

[BobinKy]

If you put a strap on the objective side of the scope, you have a pointer that works as wel as having a straight scope, so you will never miss a bird because you have an angled scope.

... Temmie

Interesting. Do you have a photo of this technique? Can you tell us more?

... Bob
Kentucky, USA

[temmie]

here you go:
http://birdforum.net/showthread.php?t=99084

My excuses for the harsh words if some felt offended (see my last message in this thread).

[BobinKy]

Temmie...

Thank you for the link to the cable tie finder. I remember seeing cable ties on spotting scopes before--but never asked why. A very simple, cheap, and accurate finder.

. . .

812,713 raptors sighted in 2008 is amazing!

...Bob
Kentucky, USA

[BirderSean]

I was interested in picking up a scope and was going to post the
exact same question- so I'm glad someone else did to start the dialogue.

I must admit, though, after reading the responses I'm still unsure what
to get.

[Alexis Powell]

Originally Posted by BirderSean

I must admit, though, after reading the responses I'm still unsure what to get.

Well, both types do the job, so you can't really go wrong with either _unless_ you have a strong preference, perhaps based on your typical patterns of use--but only you can know that, through personal testing.

--AP

[BobinKy]

BirderSean...

Here are a few questions for you to consider. If you like, you can post your answers in this thread and others can give you their opinions.

Q1: How do you plan to use the scope?

Q2: What type of birds do you plan to observe and in what environment?

Q3: Will the birds be high in trees, high in sky, or flying above you? (Think in terms of altitude degrees: zenith or directly overhead--90°, horizontal or level with you eyes--0°, some altitude such as in trees--30°, high altitude such as high in trees or sky or atop mountain--60°.)

Q4: Do you like to sit or stand when you observe?

Q5: Do you plan to observe from inside your car?

Q6: Will you observe overtop hedge or tall pond reeds?

Q7: Do you plan to use the scope to observe other targets (i.e., large land animals such as deer, small animals such as squirrels at a feeder, ships at sea, whales in a bay, landscapes, sports, targets at a shooting range, etc.)?

Q8: Do you have back or neck problems?

I hope these help.

...Bob
Kentucky, USA

[Chris Oates]

I bought a straight scope and endured 2 years of terrible neck pain (don't know why I put up with it) - angled copes might be harder to aim but you soon learn how to compensate automatically...or use the cable tie trick.
Angled scopes are so much more versatile, easy to share, work on a small tripod.
I went on to buy an angled Opticron ES80ED and traded my MMII straight for an angled MMII ED - excellent little scope which takes nice pics with my Fuji F30 & S8000fd.

[Kevin Purcell]

Neck pain with a straight scope means your tripod is too short (which of course is a downside of a straight scope). But you should have the EP at eye level to look straight into it ... no neck bending needed (or wanted).

Same to some extent with angled scopes except there is a head tilt though not a neck crik to a slightly lower EP.

[stbear]

I chose the angled scope. It took a few days to get used to location birds quickly but now it is second nature. I chose it because of the height distance between my wife and myself. With the swaro scope I can just roll the eyepiece to the side and she can look right in. No fiddling with the tripod and we can both view comfortably. It is a little awkward when viewing from the truck but I do not do that very often.

[jmepler]

stbear,

What many people don't think of doing with an angled scope when viewing from a vehicle is precisely what you describe doing with your scope to allow your wife to view comfortably.

If you rotate the eyepiece toward you it will allow you to look straight out of your vehicle's window without needing to turn your head the full 90 degrees. This actually makes the angled scope more comfortable to use than a straight scope.

I personally use a straight scope, almost exclusively from a tripod. My first scope was a straight model and I guess I got used to it.

I find that for the majority of my viewing I am more comfortable with a straight scope. When birds are high in trees or flying overhead an angled scope would be nice, but that is a small percentage of my viewing.

If I am somewhere that there may be other people viewing with my scope I will set my tripod with the legs not fully extended and raise the center column to bring it to a comfortable level for me. Then if I want to lower it to allow someone to look through it I need only drop the center column. Doing this doesn't change the view and allows them a comfortable look.

Sometimes I will attach my digital camera to let a large group view the image on the camera's display. This also is a good way to protect expensive optics from the accidental smudges that surely come with many viewers, particularly inexperienced ones.

Mike

[The Kerreran]

I have a straight Nikon ED82 - for me holding my head at an angle for any length of time = neck pain. I chose and use the scope primarily for observing from a fixed position for periods of time - mostly seawatching, waders, and waterbirds - and find it does the job very nicely [the big zoom is very good for this, but that's another discussion! ]. It was my first proper scope, and I partially chose straight as I knew I'd have trouble getting on stuff [I'd tried out a few scopes and realised just how big a difference it makes being able to point straight at a moving bird, rather than line up with a sighter, then look and find you're already off-target]. Another advantage of straight not yet mentioned is being able to look down on things [from a hilltop/cliff etc.] much more easily.
I also have an ED50, which is straight too, and is my 'mobility scope'. I don't even use a tripod with it - either in the Grippa case in the top of my rucksack when walking, or on a shoulderpod for close terrain - great for treetop warblers! Again the straight helps with handheld, as you can pretty much look down it [though the eyepiece is slightly offset, its easy to compensate]. A factor with the ED50 is that due to the different prisms the straight body transmits a few % more light than the angled [I'm waiting to be corrected here, aren't I?], but I'm sure that's not the case with all scopes [again awaiting correction!].
After babbling on, I'm going to conclude with the famous birding optics cliche - try out both, and see what works best for you, and what you want to do with your scope.

[RAH]

I use an angled scope. It is a big advantage when more than one person share a scope. Dunne is understating it when he says, "Two or more observers of slightly different heights can easily share the same scope with less physical stain, fuss, or tripod manipulation." We have 3 people, heights 6', 5'5" and 5'2" all comfortably sharing the same scope.

Only trouble I've ever had is when trying to see over a wall that is almost the height of the scope. Even here, you can raise the scope and rotate it sideways to bring the eyepiece to the same level as the scope barrel.