cheat code for Mt. Rainier zoom shots: phone case with 17mm thread and a screw-on zoom lens (under $50 total)

If you want to take pretty-good-but-not-pro zoomed in shots of Mt. Rainier from Seattle, the photos on this post were taken with a snap-on phone case with a 17mm threaded screw hole, and a screw-on zoom lens kit with a 22x zoom. (The numbers on such things are misleading, and the lens does not actually make things “22 times bigger” on your screen, but it was good enough for this.) Rules probably prohibit linking directly to specific products, but you can find these and similar products on Amazon.

I had somehow just absorbed the notion over the years that it cost hundreds of dollars to get a camera with any kind of decent zoom capability, but apparently (for manufacturing reasons I don’t understand), what’s expensive is an *adjustable* zoom lens. Lens with a fixed zoom are pretty cheap, especially if they’re just a novelty to attach to your phone.

Most zoom lenses come with a clip to hold them over your phone lens, but I always found that they didn’t hold them very firmly in place, so it was worth the extra $15 to get a snap-on phone case. (Make sure to get the right case depending on your camera type; e.g. the iPhone 15 and the iPhone 15 Pro have the main camera in different places, so the snap-on case has to be for the right model.)

The trick that works for me to get the focus as sharp as possible in the center of the frame:

1. with the zoom lens attached and pointed toward the subject of the photo, pinch-zoom on the screen to digitally zoom in as far as possible
2. adjust the focus on the zoom lens until the details appear sharp on the pinch-zoomed-in image on the screen
3. pinch-zoom back out

The caveats with a cheap screw-on lens are that (a) straight lines close to the edge of the picture will appear bent inward (you can see that in pic 2 which is Mt. Rainier through the fence of the Aurora Bridge) and (b) even when the center of the picture is in focus, the outer areas appear blurry. I don’t know if there’s a free app that can un-bend the curved lines at the edge of the photo, and presumably there’s nothing that can fix the blur around the edges without “cheating” (i.e. filling in information that wasn’t in the original image).

But sometimes you might get lucky and it looks like there’s an in-world “reason” why the outer parts of the picture are blurry — e.g. in the first picture, maybe the sailboats at the bottom are out of focus because they’re closer? 🙂 On the other hand that doesn’t work for the Gas Works photo, because all of the people are equally distant from the camera, so it makes no sense for the ones at the edge of the picture to be blurry. (On the other hand it gives the picture an otherworldly feel like you’re taking a photo of a miniature.)

But in any case you can also just pinch-zoom in by a factor of 2x and that removes most of the bent and blurry portion of the photo, which is what I did for the first picture.