# Reasoning Chain

## Dimension 1: Video Resolution & Sensor Quality

### Fact Confirmation
The Z40K uses a Panasonic 1/2.3" CMOS with 25.9MP total, recording 4K (8.29MP effective) video. (Fact #1, #2)
The USG-231 records Full HD (1920×1080, ~2MP effective) from a CMOS sensor. (Fact #8)

### Reference Comparison
4K contains 4× the pixel count of Full HD (8.3M vs 2.1M pixels). A 1/2.3" sensor is physically ~30% larger in area than a 1/2.8" sensor (if that is what USG-231 uses). Larger sensor = more light per pixel, better dynamic range, less noise. (Fact #21)

### Conclusion
The Z40K delivers dramatically higher resolution. At any given zoom level where both cameras share coverage, the Z40K captures ~4× more detail. This translates directly to better target identification, better image crispness, and more usable footage for post-mission analysis.

### Confidence: ✅ High

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## Dimension 2: Optical Zoom Range

### Fact Confirmation
Z40K: 20x optical zoom, narrowing FOV to 3.45°. (Fact #3, #5)
USG-231: 30x optical zoom, narrowing FOV to approximately 2.1°. (Fact #8)

### Reference Comparison
The USG-231 reaches 50% more optical magnification. In pure optical zoom terms, the USG-231 can bring distant targets closer without digital quality loss. At 30x, you see objects at roughly 1.5× closer than Z40K's 20x maximum.

### Conclusion
USG-231 wins on raw optical zoom reach (30x vs 20x). For long-range surveillance where maximum optical magnification matters and you cannot fly closer, the USG-231 has an advantage.

### Confidence: ✅ High

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## Dimension 3: Effective Detail at Maximum Zoom (Resolution × Zoom Trade-off)

### Fact Confirmation
Z40K at 20x optical zoom captures 3840×2160 pixels (8.29MP) across a 3.45° horizontal FOV. (Fact #2, #3)
USG-231 at 30x optical zoom captures 1920×1080 pixels (~2MP) across a ~2.1° horizontal FOV. (Fact #8)

### Reference Comparison
Effective detail = pixels per degree of FOV.
- Z40K: 3840 pixels / 3.45° ≈ 1,113 pixels per degree (at 20x, 4K)
- USG-231: 1920 pixels / 2.1° ≈ 914 pixels per degree (at 30x, FHD)

Even though the USG-231 zooms 50% further optically, the Z40K still delivers ~22% more pixels per degree of angular coverage due to its 4K sensor. The Z40K's pixel density advantage persists even when the USG-231 is at full optical zoom.

### Conclusion
The Z40K produces sharper images at max optical zoom despite zooming less far, because its 4K resolution compensates for the zoom difference and then some. For target identification, the Z40K's 4K at 20x is effectively crisper than USG-231's FHD at 30x.

### Confidence: ✅ High

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## Dimension 4: Stabilization — Wobble Effect

### Fact Confirmation
Z40K: 3-axis gimbal (pitch + roll + yaw) with ±0.02° accuracy, plus 5-axis OIS in the lens. (Fact #4)
USG-231: 2-axis gimbal (pitch + roll only) with digital EIS. (Fact #8, #9)

### Reference Comparison
2-axis gimbals leave yaw rotation uncompensated. On fixed-wing drones, wind gusts and turns cause yaw movements that create visible horizontal wobble/jello in footage. (Fact #12) Digital EIS attempts to correct this by cropping and shifting the frame, but this: (a) reduces effective resolution, (b) can introduce warping artifacts, (c) fails with fast vibrations. (Fact #14)

3-axis gimbals mechanically compensate yaw, eliminating the primary source of wobble. Combined with OIS, even small high-frequency vibrations from the airframe are absorbed without resolution loss. (Fact #13, #15)

### Conclusion
The Z40K has categorically superior stabilization. The 3-axis gimbal + 5-axis OIS architecture eliminates wobble at its physical source. The USG-231's 2-axis + EIS approach is fundamentally limited — uncompensated yaw will produce visible wobble on fixed-wing drones, especially during turns and in wind. The wobble becomes more pronounced at higher zoom levels because angular errors are magnified.

### Confidence: ✅ High

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## Dimension 5: Image Crispness During Zoom

### Fact Confirmation
Z40K: Uses OIS (no resolution loss during stabilization), 4K base resolution. At 25x iA zoom (4K mode), quality begins to degrade due to digital crop but remains at ~4K equivalent through sensor oversampling. (Fact #3, #15)
USG-231: Uses EIS (crops frame, reducing effective resolution from already-FHD). The effective resolution while EIS is active is less than 1920×1080. At 30x optical + EIS crop, the actual visible pixels are reduced. (Fact #14, #8)

### Reference Comparison
The DJI Zenmuse Z30 (similar sensor to USG-231) shows "sufficient sharpness for inspection work" at 30x but "slight loss of quality" when digital zoom engages. (Fact #19) At maximum zoom, atmospheric distortion becomes the limiting factor for both cameras. (Fact #18)

### Conclusion
The Z40K maintains significantly crisper images during zoom due to: (1) 4K base resolution, (2) OIS not consuming resolution, (3) higher pixel density even before zoom. The USG-231's crispness degrades more noticeably because EIS crops from an already-lower resolution. However, the USG-231's optical glass reaches further, which partially compensates in scenarios where distance is the primary constraint.

### Confidence: ✅ High

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## Dimension 6: Low-Light Performance

### Fact Confirmation
Z40K: 0.05 lux minimum illumination at F1.6, 65dB dynamic range. (Fact #7)
USG-231: If using Sony STARVIS sensor, minimum illumination could be as low as 0.00008 lux. (Fact #24)

### Reference Comparison
Sony STARVIS sensors are specifically designed for surveillance with exceptional low-light performance. The USG-231's minimum illumination (if STARVIS) would be ~625× better than the Z40K's.

### Conclusion
The USG-231 likely has significantly better low-light performance if it uses a Sony STARVIS module. This matters for dawn/dusk and night reconnaissance. The Z40K is adequate in daylight and moderate low-light but is not in the same class for near-dark conditions.

### Confidence: ⚠️ Medium (USG-231 sensor identification not confirmed)

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## Dimension 7: Weight & Integration

### Fact Confirmation
Z40K: 595g all-in-one, needs custom integration (PWM/TTL/SBUS/UDP). (Fact #6, #23)
USG-231: 840g total (590g camera + 250g VPB), plug-and-play with Pixhawk/Ardupilot. (Fact #10, #22)

### Reference Comparison
The Z40K is 245g lighter as a total system. For a fixed-wing UAV at 10-15kg MTOW, 245g is ~2% of total weight — meaningful for flight endurance. However, the USG-231's plug-and-play Pixhawk integration is a significant engineering advantage if the airframe uses that autopilot.

### Conclusion
Z40K wins on weight (595g vs 840g) but loses on integration simplicity if the platform uses Pixhawk/Ardupilot. For custom builds, the Z40K requires more integration work but saves weight. The USG-231 is purpose-built for the Shark ecosystem.

### Confidence: ✅ High

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## Dimension 8: Field-Proven Track Record

### Fact Confirmation
USG-231 has extensive combat deployment on Shark UAVs in Ukraine. Defense Express noted good image quality and effective auto-tracking. (Fact #16, #17)
Z40K has no publicly documented combat deployment.

### Reference Comparison
Combat-proven systems have demonstrated reliability under vibration, temperature extremes, EW interference, and time pressure. The USG-231 has survived this test. The Z40K has not been publicly evaluated under equivalent conditions.

### Conclusion
USG-231 has a significant advantage in proven reliability and real-world validation. The Z40K is untested in comparable conditions. However, this speaks to platform reliability, not inherently to video quality.

### Confidence: ✅ High
