lib/PHPExif/Exif.php
public function getExposureMilliseconds()
    {
        if (!isset($this->data[self::EXPOSURE])) {
            return false;
        }

        if (is_numeric($this->data[self::EXPOSURE])) {
            return $this->data[self::EXPOSURE] + 0;
        }

        $exposureParts = explode('/', $this->data[self::EXPOSURE]);

        return (int) reset($exposureParts) / (int) end($exposureParts);
    }
public function getExposureMilliseconds()
    {
        if (!isset($this->data[self::EXPOSURE])) {
            return false;
        }

        if (is_numeric($this->data[self::EXPOSURE])) {
            return $this->data[self::EXPOSURE] + 0;
        }

        $exposureParts = explode('/', $this->data[self::EXPOSURE]);

        return (int) reset($exposureParts) / (int) end($exposureParts);
    }
Returns the Exposure

@return float|boolean