Why Make a Soft Focus Lens Filter?
Why would you do this instead of using photo editing software for the same effect? There are a few reasons.
1. Know what you're shooting: With digital photography, everyone pretty much expects to see photos instantly. If you're taking your sister's senior picture, she doesn't want to hear you say "don't worry, I'll mess with the pictures on my computer and erase the blemishes." It's also good for you to know exactly what you are shooting, and not just hope it looks right after some digital editing.
2. Maintain your integrity: Digital photography experts know if a photo has been edited. That's why the experienced photographers at major newspapers never get away with cheating. You'll never edit a clear image to look exactly the same as an image that was originally shot in soft focus.
3. Save money: Finally, free photo editing software certainly won't fool anyone. It's not versatile or detailed enough. To do the job properly, you'll need Adobe Photoshop or another good photo editing program. Those cost a lot more than a pair of pantyhose or a roll of plastic wrap.
Finally, if you want the costumes and backgrounds from the glamour photo studios, you're on your own.