> db.info.find().pretty()
{
        "_id" : ObjectId("569d4118f80e6a994d6b917a"),
        "baseName" : "01150001.JPG",
        "fullPathName" : "Z:/Michaels/100_0115",
        "width" : 2048,
        "height" : 1536,
        "externalOrientation" : 0,
        "colors" : {
                "rgb" : {
                        "center" : {
                                "a0" : {
                                        "i0" : {
                                                "mean" : [
                                                        "113",
                                                        "122",
                                                        "130"
                                                ],
                                                "stdDev" : [
                                                        "50",
                                                        "53",
                                                        "60"
                                                ],
                                                "median" : [
                                                        "0",
                                                        "0",
                                                        "0"
                                                ]
                                        }
                                }
                        }
                },
                "hsv" : {
                        "center" : {
                                "a0" : {
                                        "i0" : {
                                                "mean" : [
                                                        "108",
                                                        "130",
                                                        "133"
                                                ],
                                                "stdDev" : [
                                                        "57",
                                                        "57",
                                                        "50"
                                                ],
                                                "median" : [
                                                        "0",
                                                        "0",
                                                        "0"
                                                ]
                                        }
                                }
                        }
                }
        }
}
{
        "_id" : ObjectId("569d4118f80e6a994d6b917b"),
        "baseName" : "01150002.JPG",
        "fullPathName" : "Z:/Michaels/100_0115",
        "width" : 1536,
        "height" : 2048,
        "externalOrientation" : 1,
        "colors" : {
                "rgb" : {
                        "center" : {
                                "a0" : {
                                        "i0" : {
                                                "mean" : [
                                                        "130",
                                                        "129",
                                                        "126"
                                                ],
                                                "stdDev" : [
                                                        "63",
                                                        "62",
                                                        "64"
                                                ],
                                                "median" : [
                                                        "0",
                                                        "0",
                                                        "0"
                                                ]
                                        }
                                }
                        }
                },
                "luv" : {
                        "center" : {
                                "a0" : {
                                        "i0" : {
                                                "mean" : [
                                                        "129",
                                                        "126",
                                                        "124"
                                                ],
                                                "stdDev" : [
                                                        "73",
                                                        "54",
                                                        "41"
                                                ],
                                                "median" : [
                                                        "122",
                                                        "123",
                                                        "122"
                                                ]
                                        }
                                }
                        }
                }
        }
}
> db.info.find({'colors.rgb.center.a0.i0.stdDev.1':{ $gt: 50, $lt:60 }},{'colors.rgb.center.a0.i0.stdDev':1})
> db.info.find({'colors.rgb.center.a0.i0.stdDev.1':{ $gt: 50, $lt:60 }},{'colors.rgb.center.a0.i0.stdDev':1}).explain()
{
        "queryPlanner" : {
                "plannerVersion" : 1,
                "namespace" : "files.info",
                "indexFilterSet" : false,
                "parsedQuery" : {
                        "$and" : [
                                {
                                        "colors.rgb.center.a0.i0.stdDev.1" : {
                                                "$lt" : 60
                                        }
                                },
                                {
                                        "colors.rgb.center.a0.i0.stdDev.1" : {
                                                "$gt" : 50
                                        }
                                }
                        ]
                },
                "winningPlan" : {
                        "stage" : "PROJECTION",
                        "transformBy" : {
                                "colors.rgb.center.a0.i0.stdDev" : 1
                        },
                        "inputStage" : {
                                "stage" : "COLLSCAN",
                                "filter" : {
                                        "$and" : [
                                                {
                                                        "colors.rgb.center.a0.i0.stdDev.1" : {
                                                                "$lt" : 60
                                                        }
                                                },
                                                {
                                                        "colors.rgb.center.a0.i0.stdDev.1" : {
                                                                "$gt" : 50
                                                        }
                                                }
                                        ]
                                },
                                "direction" : "forward"
                        }
                },
                "rejectedPlans" : [ ]
        },
        "serverInfo" : {
                "host" : "DESKTOP-SN8UEG5",
                "port" : 27017,
                "version" : "3.0.7",
                "gitVersion" : "6ce7cbe8c6b899552dadd907604559806aa2e9bd"
        },
        "ok" : 1
}