Which is clearer, 400ansi lumens or 750 lumens?

According to the actual brightness commonly used in the market, 750ANSI lumens is equivalent to 2200 lumens.

Considering that the solid angle of the whole sphere is 4π, the total luminous flux emitted by 1 candle light is 4π (about 12.56) lumens. The total solid angle of a ball of any size is 4π, so the total luminous flux of candlelight is fixed at 4π, which does not change with the change of distance, so it is wrong to say that the total luminous flux emitted by 1 candlelight is 1 lumen at about 0.28m around it.

Illumination and lux:

Illuminance can be measured directly with an illuminance meter. The unit of illumination is lux, which is a transliteration of English lux and can also be written as lx.

When the light flux of the illuminated object is 1 lumen in the area of 1 square meter, its illuminance is 1 lux. Sometimes, in order to make full use of the light source, a reflective device is often attached to the light source, so that more luminous flux can be obtained in some directions to increase the illumination on the illuminated surface. Such as car headlights, flashlight, photographic lamp, etc.