Ride with Daniel from Romania thru Gilford Pinochet Forest Jun 22, 2024


I met Daniel on the TransAlpina in Romania. Daniel is visiting and working in Kent Washington near Seattle for a few months. Two weeks ago (June 9), I stopped by to say "Hi" after my Capitol Forest ride and invited him to visit and go for a ride someday.

This is a loop I quickly put together to show off some of the sights: Washougal River Road, Dougan Falls, the Bonneville Dam, Carson Guler and Curly Creek roads from Carson, Swift Reservoir and Cougar, Moulton Falls, Livingston Mountain Rd, and back to The Chalet. Too bad I missed the turn in Chelatchie. I'm sure those roads would have been interesting, but lunch in Yacolt at Taco's Sensacion was good too. Now I have a good excuse to go back and explore those roads (8220, 8320, 8590, 8750, NF-42) near Amboy and Chelatchie again.


The whole loop (165 miles)

Ride Log

TimeMinuteskmkph avgComment
10:33am0.7 Leaving The Chalet
10:33am10.714 km80Leaving The Chalet
10:45am2.5 topping up the gas at Arco in Washougal
10:47am26.528 km64Washougal River Rd
11:14am6.0 Dougan Falls
11:20am28.434 km73Salmon Creek Rd and Hwy 14 east
11:56am0.3 Bonneville Dam lookout
11:56am36.942 km68Bonneville Dam lookout
12:36pm0.1 Carson Guler Rd and NF-65, checking the map
12:36pm33.426 km48Carson Guler Rd and NF-65, checking the map
1:10pm14.9 Curly Creek Rd, checking the map
1:25pm63.872 km68unpaved
2:32pm0.1 Yacolt
2:33pm56.0 Lunch at Taco's Sensacion in Yacolt
3:29pm5.55 km50
3:34pm6.3 Moulton Falls
3:41pm40.942 km62a few miles of unpaved roads
4:25pm10.88 km42
4:38pm29.6 Arriving back at The Chalet
6h36m4h39m moving272 km58.6 kph70% moving, 117 minutes of breaks

This PHOTOSPHERE taken by Google Android Pixel 6, Daniel Filip's stitching code, 9.8 MiB, 8704x4352, 2.17 bpp — quality is significantly better
This panorama (20240622_191438_261.jpg) taken by insta360 X3, processed with ONE R PureShot, 17 MiB (twice as big), 8000x4000, 4.456 bpp
Full Pano Height Pixels : 4352
Full Pano Width Pixels : 8704 — blurred trees and less detail in the snows on Mt. Saint Helens

This is a test image from insta360 X3 72Mp auto exposure
This is a test image from insta360 X3 HDR — I honestly cannot see any improvement. Conclusion: do not use HDR on the insta360 X3

Comparing Pixel 6 PhotoSphere panoramas with the Insta360 X3

Pixel 6

The Google Pixel 6 camera is 50 Mp, 1.2um pixels. A standard Pixel 6 .jpg image is 4080x3072 = 12.5 Mp (50.1 Mp ÷ 4 = 12.5e6 Bayer groups). Default FOV is 82°, thus 0.0201° or 0.01° before Bayer calculations. The PHOTOSPHERE output is 8704x4352 so 0.041° per pixel.

A Google Android PHOTOSPHERE is a 2:1 equirectangular projection 8704x4352 ( 6.25% over 8Ki x 4ki ). The 50Mp camera takes 1+8+11+8+1 = 29 shots to make a PHOTOSPHERE for a total of 1450 Mp but with a lot of overlap. In fact the equirectangular image contains only about 1/9th of the pixels from the 29 source images.

insta360 X3

The Insta360 X3 sensors are quoted to be 72 Mp, 1/2", 5.7k and the raw images are 5984x5984 or 35.8 Mp per sensor.

When shooting video in single lens mode, the FOV depends on the different shooting modes of resolution and in-camera stabilization, horizon-lock, etc. MaxView provides 170° FOV. But the actual field of view on the sensor seems to be about 6% wider than 180° or 190°. That would make the angular resolution 190/5984 = 0.032°, and after quad Bayer it might be as bad as 2× (0.064°) or 4x (0.128°). An exported equirectangular panorama is 8000 pixels wide or 0.045° per pixel, similar to a Google Pixel 6, but the quality of the image is much worse. Like at least 2× or 3× worse.

Subjective quality comparison

I took two pictures at the same place and time at the McCellan Viewpoint looking at Mount Saint Helens on a sunny, very clear day.
Here's a side-by-side extracted directly from the images

Left: Pixel 6 Photosphere         ————     Insta360 X3 PureShot exported Photoshpere :Right

PXL_20240622_201134254.PHOTOSPHERE.jpg was taken by Google Android Pixel 6 in Photosphere mode, 9.8 MiB, 8704x4352, 2.17 bpp
The quality is significantly better. Notice the treeline, hills in the distance, snows on the volcano, and clouds in the sky.

20240622_191438_261.jpg was taken by insta360 X3, processed with ONE R PureShot. It is 17 MiB, 8000x4000, 4.456 bpp
The trees are relatively blurry and the snows on Mt. Saint Helens show less detail, and even large features such as the distant mountains and clouds in the sky are flat or missing.

I tried Gaussian Blur and Bicubic downsampling followed by upsampling and I could not find a way to make the Google image comparable to the Insta360 image. So I don't have a quantitative measure of the relative image quality. But somehow, it seems "half as good" while using twice as many bytes.


If you have the time to take an Android Photosphere, do it. The quality is much better. But for quick shots, the insta360 grabs a pano much more quickly. Also, don't think you can use the insta360 to get quality stills by exporting reframed shots. The angular resolution is perhaps 1/3rd as good as snapping a picture with your phone and the phone is much faster with no post-processing.