Minimum handheld shutter speed (reciprocal rule) and the longest star-point expo
Minimum handheld shutter speed (reciprocal rule) and the longest star-point exposure by the 500 rule and the NPF rule.
Answeringour last check, 2026-10-21
1 of 1checks answered this week
306 msmedian answer time
$0.02listed price per call
$0.02price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://photo-calc.x402tookit.com/shutter-rule
| Category | Image and media |
|---|---|
| Provider host | photo-calc.x402tookit.com |
| Networks | eip155:137, eip155:42161, eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp |
| Payment schemes | exact |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-21 | valid payment request | 402 | $0.02 | 306 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"aperture": 2.8,
"focalMm": 24,
"pixelPitchUm": 4.3,
"sensor": "full-frame"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"aperture": {
"description": "f-number (for the NPF star rule)",
"type": "number"
},
"declinationDeg": {
"description": "Declination of the stars, 0 at the celestial equator (default 0)",
"type": "number"
},
"focalMm": {
"description": "Actual focal length in mm",
"type": "number"
},
"pixelPitchUm": {
"description": "Sensor pixel pitch in micrometres (for the NPF rule)",
"type": "number"
},
"sensor": {
"description": "full-frame (default), aps-c, micro-four-thirds etc.",
"type": "string"
},
"stabilisationStops": {
"description": "Lens or body image stabilisation in stops (default 0)",
"type": "number"
}
},
"required": [
"focalMm"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"asOf": {
"type": [
"null",
"string"
]
},
"cropFactor": {
"type": [
"null",
"number"
]
},
"degraded": {
"type": [
"boolean",
"null"
]
},
"disclaimer": {
"type": [
"null",
"string"
]
},
"equivalentFocalMm": {
"type": [
"null",
"number"
]
},
"focalMm": {
"type": [
"null",
"number"
]
},
"handheldMinShutter": {
"type": [
"null",
"string"
]
},
"handheldMinShutterS": {
"type": [
"null",
"number"
]
},
"handheldWithStabilisation": {
"type": [
"null",
"string"
]
},
"handheldWithStabilisationS": {
"type": [
"null",
"number"
]
},
"notChecked": {
"items": {
"type": "string"
},
"type": [
"array",
"null"
]
},
"npfAtDeclinationS": {
"type": [
"null",
"number"
]
},
"npfS": {
"type": [
"null",
"number"
]
},
"reasons": {
"items": {
"type": "string"
},
"type": [
"array",
"null"
]
},
"sensor": {
"type": [
"null",
"string"
]
},
"source": {
"type": [
"null",
"string"
]
},
"starRule400S": {
"type": [
"null",
"number"
]
},
"starRule500FullFrameS": {
"type": [
"null",
"number"
]
},
"starRule500S": {
"type": [
"null",
"number"
]
},
"summary": {
"type": [
"null",
"string"
]
},
"verdict": {
"type": [
"null",
"string"
]
}
},
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}