If a picture's worth a thousand words, then how much is a smiling photo worth? About 40,000 yen ($350), based on Sony's new "smile shutter" cameras.

Using face-detection technology, the 8-megapixel, DSC-T70 and DSC-T200 Cyber-shot cameras won't snap a high-definition picture until a selected subject smiles.

Even with more than a handful of people in a picture, a photographer can designate which face to focus on by touching an LCD panel with a special pen.

• Click here for FOXNews.com's Personal Technology Center.

"Using the smile-recognition shutter function selected by the touch panel, you can pick which of up to eight people is the key smile," said Sony Product Development's Akira Tokuse.

"In a parents and baby shot, you could select the baby."

The so-called "Say Cheese" technology has three setting levels, from a slight grin to a belly laugh.

Japan sales start next week and global shipments this month.

Sony's smile technology joins Japan's Omron Corp, which developed "smile check" software that analyses happiness by facial features like mouth and eye wrinkles or lip separation.