Advanced fusion of landscape photography bracketed focus stacking in Photoshop and Helicon Focus

1. The ruthless iron wall of optical physics: Depth of field and aperture diffraction cannot have both.

In top-level landscape photography, photographers often long to capture a scene like this: a microscopic wildflower blooming only 15 centimeters away from the camera is so delicate and delicate, its petals are crystal clear with dewdrops, while the snow-capped mountain skyline and the bright starry sky several kilometers away are equally clear-cut and sharp as a knife:

1. Physical Achilles’ heel of optical depth of field:

• According to the optical formula, the closer the object distance is, the closer the depth of field of the picture is to zero;
• Even if you use a wide-angle lens, as long as the subject is within 30 cm from the lens, even if the aperture is minimized, the background will be completely blurred and out of focus!

2. The suicide cost of narrowing the aperture (f/22): Airy disk and optical diffraction (Diffraction):

• Many novices try to set the aperture to f/22 or even f/32 to force a large depth of field;
• When the clear aperture is smaller than the wavelength scale of the light wave, the wave nature of the light dominates, and the light passes through the tiny aperture and undergoes severe optical diffraction;
• Each point light source projected on the sensor is no longer a sharp point, but diffuses into a fuzzy Airy Disk;
• Whether it is the center or the edges of the entire photo, the resolution drops off a cliff, and all the details of the hairline become soft and gelatinous dough!

3. The solution to the problem: Focus Stacking:

• Fix the aperture at the best golden aperture (f/5.6 or f/8) with the most extreme resolution of the lens;
• Continuously change the focus point to take a series of photos, and then extract the sharpest parts of each photo for seamless pixel-level fusion.

2. Field Shooting Routine

1. Rigid physical tripod with full manual locking:

• An absolutely sturdy heavy-duty tripod and a heavy hook counterweight must be used, and the slightest movement must not occur in the breeze;
• Switch to full manual M exposure, fix ISO, aperture and shutter speed, turn off automatic white balance (lock K value);

2. Focus Stepping Sequence Shooting (Focus Stepping):

• In-camera Focus Bracketing function: Modern mirrorless cameras (Canon R5, Nikon Z8/Z9, Sony A7R5) have built-in focus bracketing exposure function, set the step span to 2 or 3, set the shooting range from 8 to 15, press the shutter button and the camera will automatically drive the focus motor to sweep continuously from near to far;
• Purely manual screen zoom shooting method (Manual Live-View Sweep):
• The first picture: zoom in and focus on the edge of the nearest foreground petal;
• The second picture: Turn the fine-tuning focus ring gently, and the focus moves to the stamen of the flower;
• Third shot: The focus moves to the mid-ground rock;
• The fourth picture: The focus moves to the foot of the distant mountain;
• The fifth picture: The focus is on the distant mountain tops at infinity;
• Make sure two adjacent photos have at least 20 to 30 percent depth-of-field overlap between sharp and sharp focal planes.

3. Software integration solution A: Photoshop has built-in automatic alignment and blending

Suitable for conventional landscape films with a small number of pictures (3 to 5 pictures) and a relatively simple structure:

1. Load layers and automatically align:

• Open all RAW files in Photoshop, select File -> Scripts -> Load files into stack, check Attempt to automatically align source images;
• Eliminate "Focus Breathing": Since the focal length of the lens will change slightly when the focus ring is rotated, resulting in a slight scaling of the picture, automatic alignment will strictly correct the composition size of each layer to 1:1 through perspective transformation.

2. Automatically blend layers:

• Select all layers and execute Edit -> Auto-Blend Layers;
• Blending method selection: Stack Images, check "Seamless tones and colors";
• Algorithm Mechanism: Photoshop will calculate the high-frequency contrast edges on each layer, automatically generate complex black and white masks, retain only the clearest and sharpest pixels, and instantly output a masterpiece with panoramic depth and sharpness from the feet to the skyline.

4. Software integration solution B: Industry benchmark Helicon Focus (King of extreme macro and complex scenery)

When the shooting sequence is up to 10 to 30 shots, or there are intricate grass or tree branches swaying in the breeze in the foreground, Photoshop can easily produce ghost patches, and professional depth-of-field synthesis software Helicon Focus must be used:

1. Three exclusive core rendering methods (Rendering Methods):

• Method A (based on average contrast weighting): most suitable for macro photography and still life with extremely smooth tones, and the softest color transition;
• Method B - based on local depth map Depth Map: most suitable for most complex outdoor scenery interspersed with tree branches, the cleanest and most efficient extraction of edge details, and almost no halo edges;
• Method C (Pyramid Algorithm Pyramid): Specializes in complex intersection overlap and large light ratio scenes.

2. Built-in Clone Repair Brush (Retouching Brush):

• Even if some leaves that are blown and swayed by the breeze appear as ghosts after synthesis, just select the damaged area in the right window, directly click on the corresponding single wind-free layer on the left, and restore it to the original state with one-click non-destructive brushing. The efficiency and image quality are superior to Photoshop.

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