When I first started taking shots like this one – items of discarded or washed-up stuff on the beaches near our home town in the UK – I shot them in a slightly different way. Specifically, I tended to shoot them with a relatively large aperture (f/4 or f/5.6) to throw the background out of focus. The problem with doing that though, especially when you're shooting this close to a foreground item, is that the depth of field becomes very shallow. This is great for the background, but not so great for capturing detail in the foreground item you're shooting.
Lately I've been using a slightly different approach: shooting with a smaller aperture to capture the detail in the foreground object, but then blurring the background to simulate a shallower depth of field using Bokeh (Alien Skin's lens simulation plugin). The benefit of this approach is twofold. First, the foreground element is sharper, both in terms of front-to-back and intrinsic detail (most lenses performs better at f/8 or f/11 than they do at f/4 and f/5.6). Second, it's relatively straightforward to add as much blur to the background as it needs. In the case of this image the processing was even easier as I used Gaussian Blur for the background rather than Bokeh – I just duplicated the layer, blurred it, then blended it with the lower layer using a mask.
The net result is that the final image looks like it was shot using a large aperture – the item is cleanly separated from the background – but there's a lot more foreground detail. In other words then it's a technique that allows you to get the shot you want rather than one that compromises foreground detail with respect to background blur (or vice versa).
On a different note ...
As I mentioned when I posted my last entry, I've switched to using Disqus for comments rather than Movable Type. Judging from your responses to my last image it all seems to be working well, but if you do spot any problems please let me know.
10.55am on 15/9/11|
Canon 5D Mark II
EF 24-70mm f/2.8L USM