Gran Turismo 71 back focus
- Aperture
- 71 mm
- Focal length
- 419 mm at f/5.9
- Image circle
- 44 mm
- Rear thread
- M63
- Corrector
- William Optics FLAT6AIII
Checked against the manufacturer’s documentation in September 2026.
Where to buy the William Optics Gran Turismo 71
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Cameras
| Camera | Back focus | Spacers | Result |
|---|---|---|---|
| Ares-C Pro | 64.1 mm | 30.1 mm | Exact |
| Artemis-C Pro | 64.1 mm | 46.6 mm | Exact |
| Neptune-C II | 64.1 mm | 35.1 mm | Exact |
| Poseidon-C Pro | 64.1 mm | 46.6 mm | Exact |
| Saturn-C SQR | 64.1 mm | 35.1 mm | Exact |
| Uranus-C | 64.1 mm | 35.1 mm | Exact |
| QHY183C | 64.1 mm | 30.1 mm | Exact |
| QHY183M | 64.1 mm | 30.1 mm | Exact |
| QHY268C (SBFL - Jan 2023 onward) | 64.1 mm | 28.5 mm | Within tolerance |
| QHY268M (SBFL) | 64.1 mm | 28.5 mm | Within tolerance |
| QHY294M Pro | 64.1 mm | 30.1 mm | Exact |
| QHY533C | 64.1 mm | 30.6 mm | Exact |
| QHY533M | 64.1 mm | 50.1 mm | Exact |
| QHY600M (SBFL) | 64.1 mm | 28.5 mm | Within tolerance |
| ASI071MC Pro | 64.1 mm | 30.1 mm | Exact |
| ASI1600MM Pro | 64.1 mm | 41.1 mm | Exact |
| ASI183MC Pro | 64.1 mm | 41.1 mm | Exact |
| ASI183MM Pro | 64.1 mm | 41.1 mm | Exact |
| ASI2400MC Pro | 64.1 mm | 25.6 mm | Exact |
| ASI2600MC Duo | 64.1 mm | 25.6 mm | Exact |
| ASI2600MC Pro | 64.1 mm | 30.1 mm | Exact |
| ASI2600MM Duo | 64.1 mm | 25.6 mm | Exact |
| ASI2600MM Pro | 64.1 mm | 30.1 mm | Exact |
| ASI294MC Pro | 64.1 mm | 41.1 mm | Exact |
| ASI294MM Pro | 64.1 mm | 41.1 mm | Exact |
| ASI533MC Pro | 64.1 mm | 41.1 mm | Exact |
| ASI533MM Pro | 64.1 mm | 41.1 mm | Exact |
| ASI585MC Pro | 64.1 mm | 41.1 mm | Exact |
| ASI585MM Pro | 64.1 mm | 41.1 mm | Exact |
| ASI6200MC Pro | 64.1 mm | 25.6 mm | Exact |
| ASI6200MM Pro | 64.1 mm | 25.6 mm | Exact |