← The evidence ledger
Evidence row 2201251
Observed , by sync.x402_bazaar/1.
- Kind
- listing
- About
- source_record x402_bazaar:https://photo-calc.x402tookit.com/exposure-value
- Recorded
- Previous row
- None: the first of its kind about this subject
- Body SHA-256
- 8355f57a31d20f308350953f4784201aa0d69b91a7d82ab9ee205d2269e7bcaf
- Leaf
- 0xae0544ead397005220ca865a244b00bc9e54ea95f92234e6a84f3cacf2f0a2e7
What was observed
{
"endpoints": [
[
"x402",
"https://photo-calc.x402tookit.com/exposure-value"
]
],
"name": "Photography Calculators",
"owner_address": "0xb531320805c5bed1d46aeadcf4f008fdf172dbda",
"raw": {
"accepts": [
{
"amount": "20000",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"maxTimeoutSeconds": 300,
"network": "eip155:8453",
"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"scheme": "exact"
},
{
"amount": "20000",
"asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
"extra": {
"feePayer": "D6ZhtNQ5nT9ZnTHUbqXZsTx5MH2rPFiBBggX4hY1WePM",
"transactionVersions": [
0
]
},
"maxTimeoutSeconds": 300,
"network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
"payTo": "DUPiupXtuox38dcGoXUKer5mAydCzmaHjrbQ66qeEm8s",
"scheme": "exact"
},
{
"amount": "20000",
"asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
"extra": {
"name": "USD Coin",
"version": "2"
},
"maxTimeoutSeconds": 300,
"network": "eip155:137",
"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"scheme": "exact"
},
{
"amount": "20000",
"asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
"extra": {
"name": "USD Coin",
"version": "2"
},
"maxTimeoutSeconds": 300,
"network": "eip155:42161",
"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"scheme": "exact"
}
],
"description": "Exposure value (EV) from aperture, shutter speed and ISO, the light level it suits, and equivalent aperture and shutter pairs.",
"extensions": {
"bazaar": {
"info": {
"input": {
"method": "GET",
"queryParams": {
"aperture": 8,
"iso": 100,
"shutter": "1/125"
},
"type": "http"
},
"output": {
"example": {
"aperture": 8,
"asOf": "2026-10-11T08:40:14.777Z",
"degraded": false,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"equivalentPairsAtSameIso": [
{
"aperture": 1,
"exactShutterS": 0.000125,
"nearestStandardShutter": "1/8000 s"
},
{
"aperture": 1.4,
"exactShutterS": 0.000245,
"nearestStandardShutter": "1/4000 s"
}
],
"ev100": 12.9658,
"evAtIso": 12.9658,
"iso": 100,
"notChecked": [
"metering of your actual scene (this is the maths of a chosen setting, not a meter reading)",
"reciprocity failure for very long exposures on film",
"…1 more"
],
"reasons": [
"EV = log2(N squared / t), referenced to ISO 100; each ISO doubling subtracts 1 stop.",
"Equivalent exposures keep the same light: close the aperture one stop and double the shutter time."
],
"shutterS": 0.008,
"source": "computed locally",
"suitsLight": "overcast",
"summary": "f/8 at 1/125 s and ISO 100: EV 12.97 at ISO 100 (suits overcast); EV at the chosen ISO 12.97.",
"verdict": "COMPUTED"
},
"type": "json"
}
},
"schema": {
"$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, e.g. 8",
"type": "number"
},
"iso": {
"description": "ISO (default 100)",
"type": "number"
},
"shutter": {
"description": "Shutter time such as 1/125 or 0.5",
"type": "string"
}
},
"required": [
"aperture",
"shutter"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"aperture": {
"type": [
"null",
"number"
]
},
"asOf": {
"type": [
"null",
"string"
]
},
"degraded": {
"type": [
"boolean",
"null"
]
},
"disclaimer": {
"type": [
"null",
"string"
]
},
"equivalentPairsAtSameIso": {
"items": {
"properties": {
"aperture": {
"type": [
"null",
"number"
]
},
"exactShutterS": {
"type": [
"null",
"number"
]
},
"nearestStandardShutter": {
"type": [
"null",
"string"
]
}
},
"type": "object"
},
"type": [
"array",
"null"
]
},
"ev100": {
"type": [
"null",
"number"
]
},
"evAtIso": {
"type": [
"null",
"number"
]
},
"iso": {
"type": [
"null",
"number"
]
},
"notChecked": {
"items": {
"type": "string"
},
"type": [
"array",
"null"
]
},
"reasons": {
"items": {
"type": "string"
},
"type": [
"array",
"null"
]
},
"shutterS": {
"type": [
"null",
"number"
]
},
"source": {
"type": [
"null",
"string"
]
},
"suitsLight": {
"type": [
"null",
"string"
]
},
"summary": {
"type": [
"null",
"string"
]
},
"verdict": {
"type": [
"null",
"string"
]
}
},
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
}
},
"lastUpdated": "2026-11-02T04:07:20.272Z",
"quality": {
"l30DaysTotalCalls": 2,
"l30DaysUniquePayers": 1,
"lastCalledAt": "2026-11-02T04:07:20.077Z"
},
"resource": "https://photo-calc.x402tookit.com/exposure-value",
"serviceName": "Photography Calculators",
"tags": [
"photography",
"exposure",
"ev",
"calculator"
],
"type": "http",
"x402Version": 2
},
"source": "x402_bazaar",
"summary": "Exposure value (EV) from aperture, shutter speed and ISO, the light level it suits, and equivalent aperture and shutter pairs."
}What the leaf hashes
{"body":"8355f57a31d20f308350953f4784201aa0d69b91a7d82ab9ee205d2269e7bcaf","id":2201251,"kind":"listing","method":"sync.x402_bazaar/1","observed_us":1793646803052409,"prev":null,"subject":"x402_bazaar:https://photo-calc.x402tookit.com/exposure-value","subject_kind":"source_record"}Proof
Fold these into the leaf in order, hashing each sorted pair with keccak256, to reach the root of (444186 rows).
- 0xae055cf329dc8840d5dc3ee61847d09ea3d2e72206de8e7d2afbab1ba1923f86
- 0xafb7afa02c477844760b6facf29c364bb0a8c73617cf65ae23eb015af1206f3d
- 0x52c06f88f89cf73941ad1eb3b819d05cc514ebb91796f3e8320cb831bc50722e
- 0x08457e6ab986954ffcb2826a056b176dc6d852b5234b9c4a606dc65324c985a6
- 0xe7f849e59f3c71db168cad8e92a372bfe4f657b013e234fae0195f29ee00ec17
- 0x4e1365c5e8d18f6a80cf986e5fdd73da98f824a5994c89943ddf18e4ff2170c9
- 0x2d1db0647fc6dc113381fd7d6440f214209ea6b6442a70719cc0906440988c5a
- 0x741d170afd0cebf378e9d643d0a2f01f3f7b943b4d9d60a9849dc88cf8306c38
- 0xb74cc98b3df4a6d77b911968be2fc86e4754c1755fbb566f87b0511e3207cda1
- 0x54cd33a6d8a7a6dda2952d1d8e3cc48f31493ce76bf83838993036f0cc00b82d
- 0x60e6510b4216df3c62e82dc5349d949fa747b708c8c536c898f4b7d5c2fea27c
- 0x4b689db5a9e6139b1b496c240f18ec19fa5b0f0bc49dacaed806958889560cc9
- 0x30482ffd581ea067af14f15cf3c17e7dcb174f749e858ecded170a1f5f75cc59
- 0x27deeb1ef1692b4773e73c16b6d8d0cdf4251fe2660821e5336f57539770fd2f
- 0x793184605629cd36ba80a07cbe115ca35e8923297bf024260c6f5c06b255f638
- 0x2922573a524a0694086782ac45fa3083d3fc3f6a2a479b2105e1e2f06b2916f7
- 0x07ad80c0c234ecea379a2f4450dfd0804db049dbc62abe77af6306049ca6b6c2
- 0x98cbbf2c68ab4c0b4db782aeb88bea1f30b02178cf8b5d3d24a931d19492ea6d
- 0x252cce55f1a3d5391c16f82d7f62494429a5f69b03486d4cfcfb7b2c96d6c884
- Day root
- 0x78fecaabbe319e56f5c4b80fc02e2052e198ad24781da8832a475ff65f2002d1
- Chained
- 0xdc35957db5d1371ca382b9152878ffece28ec7c5cb4f98fd71ddb367f8b999b2
- Published
- On Arc Testnet, block 70432815: 0x56b814612eb2e3e544153df3e91e1f7199106d1e430c7d8c6b653feeb9ebe9af