Making the subject pop.

I have referred to the need to blur backgrounds in pictures made with short focal length lenses often. As cameras get smaller, focal lengths shorten. The 35mm FFE lens in the iPhone 4S, for example, has a focal length of but 4.3mm, meaning just about everything is always sharp. At a given aperture, depth of field is solely a function of focal length, having nothing to do with sensor size.

To put this in perspective, the 50mm FFE lens on a full frame 35mm camera or DSLR become 150mm on a 4″ x 5″ sheet film monster, 80mm on a 6×6 medium format Hasselblad, 25mm on an MFT body and just 6 mm on the typical cell phone with its microscopic sensor. Compared to a 6mm, the depth of field of a 150mm lens is miniscule – everything is in focus with the former, little is with the latter. So selective focus on small cameras, absent help from software, is not going to happen ‘in camera’, yet.

If a picture is worth a thousand words an instructional video is an order of magnitude more efficient, so I have made a brief video explaining how to confer background blur using Photoshop CS5, which you can see by clicking the image below. While I start and end the process in Lightroom3, that’s not a required part of the workflow. Use whatever database you like for storage.

And remember, the only people who will know you used this technique will be those you tell in advance.

Click to view the 8 minute video.

One day this technology will be built into software in cameras. The user will be able to restrict the zone of sharpness to the main subject. Cameras already have face recognition. Selective focus is a rational extension of this thinking. Meanwhile, PS CS5 does just fine.