Sometimes it’s just not possible to get everything sharp at once.
You may feel like you don’t know how to focus, but the reality is when you’re zoomed in tight on a subject, there might never be enough depth to get everything sharp, even at the lens’s minimum aperture.
The answer is to shoot a series of images with the focus set slightly further away each time, and then use a technique called ‘focus stacking’ to merge the separate photos into a finished picture that’s sharp from front to back.
This can be amazingly effective, and in this example you can’t see the joins! You can quite easily carry out focus stacking in Photoshop.
In Photoshop CS4 or CS5, combine all your separate shots as layers in a single image (make sure you get them in the right order before you start).
Now you can use the Edit menu to auto-align and then merge the layers. Note that Photoshop will automatically combine the sharpest areas from each image in the final result.
Focus stacking software
The alternative is to use a dedicated focus stacking program such as Helicon Focus 4.2 Lite. You shoot your sequence, load the images you’ve taken, hit the Render button and let the software do the rest. It costs £19 ($30) for a one-year licence.