High light ratio bracketing (HDR Bracketing) and Luminosity Masks (Luminosity Masks) at the blues moment of the city night scene

1. The "big light is better than the dead" in the blues moment of the city night scene

During the Blues Hour, 30 minutes after sunset, the sky is a mesmerizing pure deep blue; but by this time, the skyscraper’s powerful searchlights, LED neon signs, and road car lights are all on.

• Contrast is as high as 16 stops or more: If a single exposure takes care of the dark blue of the sky, the roads and shadows on the ground will become dead black; if a single exposure takes care of the dark parts of the ground, the signboard text on the building will be completely overexposed and explode into a dazzling white ball of light.
• The physical limit of single RAW is broken down: Even the top full-frame camera, the effective dynamic range of a single shot cannot take into account both extremes in real night scenes. Multiple bracketed exposure synthesis is the only choice for professional landscape photographers!

2. Standardized on-site shooting procedures for automatic exposure bracketing (AEB)

1. Secure the tripod on the camera and plug in the shutter release cable or mobile phone for wireless control;
2. Adjust the camera to M setting, fix the ISO to the lowest native value (ISO 64 or 100), and shrink the aperture to the best image quality f/8;
3. Turn on the [Auto Exposure Bracketing (AEB / Auto Exposure Bracketing)] in the camera and set it to 3 shots (step 2.0 EV):

• Picture 1 (-2 EV underexposure): The fastest shutter speed (such as 1/4s), specifically locking in the core details of bright and bright skyscraper neon signs and car lights, ensuring that the highlights do not have any pixel overflow;
• Picture 2 (0 EV normal exposure picture): The shutter speed is moderate (such as 1s), perfectly recording the beautiful blue gradient of the sky and the neutral gray of most building facades;
• Picture 3 (+2 EV overexposure): The slowest shutter speed (such as 4s), which is designed to completely brighten the weak details under the bridge, the shadows on the river, and the shadows of trees in the dark parts of the ground from the noise base.

3. Traceless and natural fusion of Photoshop Luminosity Masks

Many people hate HDR because the photos synthesized by many early automatic HDR software have gray edges, dirty black halos (Halo), and a cheap plastic feel.

• Pixel-level fine extraction of luminance masks:
  In Photoshop, use plug-ins (such as TK8 / Lumenzia) to directly extract the brightness channel information of the picture:
• Create a [Lights 3] selection: This selection can accurately select the overexposed and white building sign area in the normal photo with 100% pixel-level edges;
• The delicate and clear signature content in the -2 EV underexposed photo is "backfilled" perfectly and seamlessly into the normal photo through the value mask like applying oil painting;
• There are no harsh cutout marks or halos on the edges, and the final result is a pure and transparent master-level natural night scene masterpiece from the brightest luminous filament to the deepest deep blue sky!

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