The Pentax Q7 uses the Pentax Q mount with a 4.60× crop factor (about 7.8 × 5.2 mm sensor). Below: equivalent focal lengths, maximum shutter speeds for sharp stars, a hyperfocal distance chart, compatible lenses and how to check the shutter count.
Equivalent focal length & field of view
| Lens focal length | Full-frame equivalent | Diagonal FOV | Horizontal FOV |
|---|---|---|---|
| 8 mm | 37 mm | 60.7° | 52.0° |
| 10 mm | 46 mm | 50.2° | 42.6° |
| 12 mm | 55 mm | 42.7° | 36.0° |
| 14 mm | 64 mm | 37.0° | 31.1° |
| 16 mm | 74 mm | 32.7° | 27.4° |
| 18 mm | 83 mm | 29.2° | 24.5° |
| 20 mm | 92 mm | 26.4° | 22.1° |
| 24 mm | 110 mm | 22.1° | 18.5° |
| 28 mm | 129 mm | 19.0° | 15.9° |
| 35 mm | 161 mm | 15.3° | 12.7° |
| 50 mm | 230 mm | 10.7° | 8.9° |
| 85 mm | 391 mm | 6.3° | 5.3° |
| 135 mm | 621 mm | 4.0° | 3.3° |
Multiply by the 4.60× crop factor for the full-frame equivalent field of view.
Milky Way exposure: NPF and 500 rule
| Focal length | NPF @ f/1.8 | NPF @ f/2.8 | Strict NPF @ f/2.8 | 500 rule |
|---|---|---|---|---|
| 8 mm | 16.9 s | 21.2 s | 11.6 s | 13.6 s |
| 10 mm | 13.5 s | 17.0 s | 9.3 s | 10.9 s |
| 12 mm | 11.2 s | 14.2 s | 7.7 s | 9.1 s |
| 14 mm | 9.6 s | 12.1 s | 6.7 s | 7.8 s |
| 16 mm | 8.4 s | 10.6 s | 5.8 s | 6.8 s |
NPF = (35 × f-number + 30 × pixel pitch) ÷ focal length, with a pixel pitch of 2.4 µm (typical for this format — exact resolution not in our database). The strict version (Michaud's detailed NPF for the galactic core) gives pin-point stars at 100% view; the 500 rule is a loose rule of thumb that shows trailing on modern sensors.
Hyperfocal distance chart
| Focal length | f/2.8 | f/5.6 | f/8 | f/11 | f/16 |
|---|---|---|---|---|---|
| 10 mm | 5.5 m | 2.8 m | 1.9 m | 1.4 m | 1.0 m |
| 14 mm | 11 m | 5.4 m | 3.8 m | 2.8 m | 1.9 m |
| 16 mm | 14 m | 7.0 m | 4.9 m | 3.6 m | 2.5 m |
Focus at the hyperfocal distance and everything from half that distance to infinity is acceptably sharp (circle of confusion 0.0065 mm). Use the hyperfocal calculator for other settings.
Compatible lenses (1 in our database)
| Lens | Focal length | Max aperture | Mount |
|---|---|---|---|
| Pentax 01 Standard Prime 8.5mm f/1.9 AL [IF] | 8 mm | f/1.9 | Pentax Q |
Native and adapter-free compatible lenses from the Lensfun database. Third-party and adapted lenses may also work.
How to check the Pentax Q7 shutter count
Pentax and Ricoh DSLRs store the count in MakerNotes; ExifTool decodes it with `exiftool -ShutterCount image.dng`.
ExifTool tag: ShutterCount. Always test an original, unedited file straight from the card.
Where to buy
Compare new and used prices at these retailers:
B&H PhotoAmazonKEH (used)MPB (used)