Individuals who use ink cartridges to print out photos taken on their smartphone and wish to produce higher quality snaps may be interested in a new gadget that has gone on sale in the US.

Photojojo has unveiled an SLR mount for iPhones that will allow serious photographers to attach lenses made by Canon or Nikon to their device.

Founder of the firm Amit Gupta explained: "The iPhone 4 takes pretty decent photos and gorgeous video, but its limitation is the lens built into it that can't go wide or give you shallow depth of field."

As well as allowing users to focus on a person or object and blur out the background, the device can offer a better zoom length without compromising the resolution.

Versions of the device will be available for both iPhone 4 and iPhone 3GS models.

It may be of interest to many amateur photographers, as it was recently revealed by Flickr that the iPhone 4 has become the most popular camera for taking photos that are uploaded to the sharing site.