Angled spotting scopes now dominate the scope market. I think that means birders are making the right decision. There is only one reason to purchase a straight scope, and that is because it is marginally easier to find birds with a straight-barreled device then one with a kink. One’s ability to get on birds with an angled scope improves with practice, but after four years with my Swarovski 80mm angled scope, I still sometimes struggle to find birds, particularly birds in flight.
I used to think there was another reason to consider a straight scope: rain. How does rain fall? Down, right? So if your scope eyepiece points up, where does the rain accumulate? That’s right, in the eyepiece. If you’re not paying attention during a shower, your eyecup can fill with water. On a straight scope, the rain falls down past the eyepiece.
If you do pay attention, you can still use an angled scope in the rain, simply by keeping your face over the eyepiece, and covering the eyepiece when you’re not looking through it. However, if you’re sharing your scope it means everyone must do this, or the eyepiece will quickly be flecked with raindrops.
Birding in the rain with an angled scope. Note that the barrel is rotated 90 degrees away from the wind direction, so rain cannot get on the eyepiece, and that the lens hood is extended to protect the ocular.
I might have remained foolishly annoyed with angled scopes and rainy days, except while chasing (fruitlessly, as it turned out) a Black Guillemot off Cape May during heavy rain, I came to what should long ago have been an obvious conclusion: If I rotated my angled scope 90 degrees, rain didn’t fall into the eyepiece anymore. Not only that, but if it was rainy and windy (it was), I could rotate the scope away from the wind, and hence away from the rain. When you do this, you have to raise the scope slightly to get it level with your eyes. I would add that another tip for rainy day scoping is to fully extend the lens hood, which will keep the objective lens (the big one) dry in any condition except birding straight into horizontal rain.
I rotate the angled scope often for other reasons, the main one being if I have a child or person of short stature along on a field trip. Rotating the scope sideways, or even so the eyepiece points down, takes away several extra inches of height. Often, that’s all you need to let the one or two shorter folks on a trip have the opportunity to use your scope.
Not all angled scopes are created equal when it comes to rotating the barrel. I actually find my Swarovski somewhat deficient in this department, because the locking mechanism on the barrel doesn’t have a positive feel or effect, and sometimes the scope tips one way or the other of its own accord. Other scopes I’ve tested have performed better, with the Zeiss Diascope and its lever locking mechanism being the best of the lot.