Straight and Angled Scopes: Pros and Cons of Each

So, you’re thinking of buying a spotting scope, or upgrading your current one?  That’s a great idea! We love scopes, and we want you to learn from our mistakes and make fewer of your own.  I alone made enough mistakes for a whole bird club.  But let’s dive right in and I’ll save tales of my early mistakes for a postscript at the end.

I bought my third scope about 1980. It was a straight 60 mm Bushnell Spacemaster.  And you know what? It wasn’t bad!  They made a 15-45x zoom eyepiece, but even at 15x the field of view was narrow, optical quality deteriorated quickly as you zoomed, and there was too little eye relief for eyeglass wearers (me, since third grade). So, I got the fixed 22x wide angle eyepiece and saw many a lifer with it. The Spacemaster wasn’t waterproof but with a little care I used it in rain and snow, even on Attu.  In my opinion it was a better field scope than either of its early ‘80’s contemporaries, the Swift Telemaster 15-60x60 or Bausch & Lomb Discoverer 20 to 60x60 mm, which had built-in zooms in the middle of the barrels. They were great-looking scopes but both longer and heavier and always dim and unsharp. Better to have a more compact, lighter weight scope that was reasonably bright and sharp with a functional field of view at a fixed 22x.

My fourth scope was a Kowa Prominar TSN-4 with 20x and 40x fixed eyepiece. It was also straight, and bright and sharp. I enjoyed it for 28 years, later adding a 30x wide eyepiece, and eventually a 20-60x zoom. Hundreds of field trip participants enjoyed fine views of birds and mammals through it.

Let’s consider the ADVANTAGES of STRAIGHT spotting scopes:

• Easy to aim – just point it directly where you’re looking.
• Eye-level height may help see over vegetation which might obstruct the view, or to get a half second longer view in the trough behind the wave crests. (Nope, it’s not a Labrador Duck...).
• Works well with an automobile car window mount.

• In precipitation, easier to keep the eyepiece dry.

Any DISADVANTAGES to STRAIGHT scopes? Consider:

• the eyepiece must be at your eye level to be comfortable, and it must be stable at that height, which might require a larger tripod
• If you are birding with just ONE other person, the chance that their eye is the exact same height above the ground as yours isn’t great: if you’re birding in a group it’s almost zero. That means lowering the scope to the eye level of the group’s shortest participant (who may be the best birder), which is only fair. It also means that in order to look through the eyepiece, anyone taller than that may need to bend over uncomfortably far. If you bird alone, disregard this.
• Due to standing higher it may be less stable in the wind, and at greater hazard of blowing over.

• When looking at something at a steep angle, either high in a tree or a raptor near the zenith, you’ll need to either put the scope way up high (a challenge if you’re 6’4”) or yourself very low, or both-oh sorry, that could’ve-been-count-first Marsh Harrier is gone.
• Since both eyes are looking in the same direction, the subordinate (non-scope) eye tries to intrude and bring the horizon into focus, so most people will close the non-scope eye. This is OK for a little while but can lead to eye fatigue if you’re scoping for hours.

Next, the DISADVANTAGES of ANGLED spotting scopes:

• Since the eyepiece must be below your eye level, you might have a phragmites-obscured view, and compared to a straight scope, each view in the wave trough could be a half-second shorter (in other words, you’ve lost the advantage of height).
• It can take a little practice to aim an angled scope, though 99% of people master it in minutes.

• If it starts to drizzle, it’s harder to keep the angled eyepiece raindrop free.
• While they can be used with a car window mount, that often requires rotating the barrel 90° so the scope will be aimed 45° from the direction you’re looking [Note that while this is often the case, there may be some scope/viewer/vehicle combinations that permit an angled scope to be use as you would on a tripod].

ADVANTAGES of ANGLED spotting scopes:

• When birding in groups, set the scope so that the shortest person can use it; then everyone taller can too, simply leaning forward. No contortions required. All 16 people on the two-van tour get their lifer look as fast as musical chairs. As a trip leader, you’ll be best served by an angled scope.
• Set below your eye level, your tripod is more stable and less prone to tipping over.
• Easier to look up at steep angles; if you set the eyepiece at your eye level and you look straight ahead, the scope is looking up 45° from the horizon, with 60° in easy reach.
• One main advantage that is perhaps least obvious, but important for long-term scanning: with an angled scope, the scope eye is focused on a distant object near the horizon, while the other eye is looking at the ground nearby. It intrudes less (your brain knows you don’t want to look at the ground) so long-term viewing is more relaxed and restful.

So, straight and angled each have their advantages, either might work in specific situations, and I’ve used both for years. But consider this: at one time, every manufacturer made every model in both straight and angled versions; many still do. But now some are only available in the angled version, and over the past decade the ratio of angled to straight in the birding market has gone from about 5 angled:1 straight, to more like 49:1. I finally joined the angled crowd last year and haven’t looked back. So, although we sell more angled scopes, there are still valid reasons for a straight scope, and we’d be happy to special order one for you if we don’t have it in stock.

Addendum: My Early Misadventures in Scopes

My first scope, purchased in 1970, was angled. But it doesn’t count, because it was an Edmund Scientific “Palomar-Type” 4 ¼" Newtonian reflector with a 90° angled eyepiece. The lowest power was 45x, and the closest focus was a distant back-neighbor’s chimney, which filled the upside-down field of view. No one cares if Betelgeuse is upside down, but some folks don’t like legs-in-the-air sandpipers. Clearly it was nothing a birder would buy even after drinking pints at the C-View Inn until closing time. But wouldn't you love to see people’s reactions as you drive the dikes at Forsythe NWR, hauling that four-foot optical tube on and off of the 40 pound equatorial mount and in and out of your car (ideally a Mercury Bobcat or Ford Pinto), every hundred yards? “Hey buddy, what’s the close focus on that?” “Uhhhh.... The Borgata?”

My second scope was a surplus thingy with about a 3.15” objective (they weren’t importing millimeters back then) and a rotating turret with three oculars. You read that right; the eyepiece end was like the objective end of your biology class microscope. You know how makers have grades of quality like “good, better, best”? These were “bad, horrible, and OW MY EYE!!” If the lenses were coated at all, it was with pre-Clean Air Act air, which as I recall was nearly opaque and when the wind was from the northwest smelled of the plastics plant fifteen miles away across the river. The eyepiece was at a 45° angle, but the view was so bad who cared?

It took me several more years to figure out how important a good tripod is, but you’ve likely figured out that that I may not be the sharpest tack in the office supply closet. Still, I just saved you THREE BAD SPOTTING SCOPES, so I hope you’ll shop New Jersey Audubon when you’re in the market!