From Bygdøy, Oslo. The ferry from Nesodden passes on its way back to Aker Brygge.
I have chosen to keep the lighthouse sharp, and the ferry out of focus. I could also have decided to have the ferry in focus and the lighthouse blurred. Or to keep both of them sharp.
Today's subject is about selecting your depth-of-field.
To be able to create an image like this you need to step out of the comfort zone of your Auto setting.
Aperture Priority (Av on my Canon) is the chosen setting here, and experiment with apertures around 2.8 to 4.5.
Use one focus point and focus on the lighthouse. Assuming you are using a tripod, switch to manual focusing to keep it there without having to worry.
You need a reasonably fast shutter speed to freeze the ferry. I'd recommend a minimum of 1/250 second. If it is too dark for that, increase your ISO. If you use Aperture priority, the camera will suggest a shutter speed for you.
In the case you would want both the ferry and the lighthouse sharp, your aperture setting must be set to a higher number, like f/16 or perhaps f/22.
This is a good exercise to be able to understand the concept of depth-of-field.
Now all you have to do is check the ferry time-table so that you can be in the right place at the right time. :-)