My birthday is 15th May (although I'm sure that you'd already got it marked in your calendar) and in 2012 I was given this Amazon Kindle 4 for my birthday.

Once I had registered the device online, it opened a personalised letter from Jeff Bezos which started: "Dear David, Kindle is a revolutionary reading device, and we're excited that you have joined the millions of people around the world who read on Kindle".

As I've studied interaction design, I was interested to see that the letter also said: "Our top design objective was for Kindle to disappear in your hands - to get out of your way - so you can enjoy your reading". It's not every day that designers tell us what they were trying to achieve and then ask us to email them with feedback.

To light the Kindle in the photograph, I just used an ordinary desk lamp, leant the Kindle on an old camera film box and placed it on top of my closed laptop computer.

I donated this photograph to the ADay.org project which asked people to photograph their daily life on 15 May 2012.

Depth of field is "the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image". One way to control the depth of field is to use the camera's aperture-priority mode (it's often shown as "A" or "Av" on the mode dial). The aperture is the hole that affects the amount of light that is allowed through the camera lens to the digital sensor or film.

The aperture-priority mode allows the photographer to change the aperture whilst the camera finds a shutter speed that will produce a photograph that is correctly exposed.

Use large apertures for smaller depth of field

A large aperture will let more light through the lens than a small aperture and produce a smaller depth of field. The larger the aperture, the lower the f-number e.g. f/4.

A larger aperture can be useful when you want to concentrate the viewer's attention on a specific subject by making the background blurred and out of focus such as in nature or macro photography.

In my photograph of Scrabble letters, the first photograph uses a large aperture (f/5.6) and could have been shot without a tripod as the shutter speed was 1/250 seconds.

Use small apertures for greater depth of field

A small aperture will let less light through the lens than a large aperture and produce a greater depth of field. The smaller the aperture, the higher the f-number e.g. f/22.

A larger aperture can be useful when you want to allow the viewer to enjoy detail throughout the photograph such as in landscape photography where you may want both the foreground and background to be in focus.

In my photograph of Scrabble letters, the last photograph uses a small aperture (f/36) and needed a tripod as the shutter speed was 1/6 seconds.

Tunbridge Wells has a number of ghost signs and this one is near the junction of Albion Road with St James' Road. The sign says: "Piano (?) H. Hardcastle For secondhand pianos, organs, exchanges & all renovations. All estimates free."

Wikipedia says that stratocumulus undulatus clouds are "often seen at either the front or tail end of worse weather, so may indicate storms to come, in the form of thunderheads or gusty winds". And not long after I took this photograph in Tunbridge Wells, it started to rain.

Cameras shouldn't be taken outside in the rain but a little light rain didn't stop me taking my camera into the garden at Ightham Mote near Sevenoaks. The main problem was that water would get on to the front of the lens but it was easily removed with a lens cloth.

If a ghost sign is a  faded painted commerical sign then this sign for the Ritz Cinema in Tunbridge Wells is a ghost sign on a ghost building because the derelict building will eventually be knocked down. Photographs of the interior from 2009 can be compared with how the cinema used to look when it was opened in 1934.

My first photography workshop is being advertised at Ightham Mote near Sevenoaks in Kent. The poster says: "Photography Workshop. Sunday 29 April. 11am–4pm. Bring your camera for a chance to pick up some practical tips on photography from David Salmon."

Staff at Ightham Mote created the poster and they have used two of the photographs that I took at Ightham Mote in May 2011.

Details of all three of my photography workshops (29 April 2012, 8 July 2012 and 21 October 2012) are available on the National Trust web site.

This photograph is of the old Pizza Hut restaurant in Mount Pleasant, Tunbridge Wells. It's been derelict along with other shops and the ABC Cinema for more than ten years. However residents who like Pizza Hut pizzas shouldn't have to wait too long before a new site opens in St John's Road.

I took this photograph at about 11pm just outside the village of Down Thomas in Dorset. Although the sky looked black, a 30-second exposure meant that the camera was able to detect some of the light pollution from nearby Plymouth. This has added a golden glow in the sky above the end of the lane.

The Westerham Suite at Elvey Farm near Pluckley was too big to fit into one photograph even with my wide-angle 10-24mm lens. Elvey Farm was visited by a ghost-hunting journalist from the Telegraph in 2008 and recommended by Time Out Kent and Sussex in 2011.