Originally posted by robdrobd Would they become sharper by increasing the f number (smaller aperture?)
The kit lens will be a bit sharper, have a bit more contrast, and a bit less distortion if you stop it down.
'Stops' of exposure double (or halve) the amount of light reaching the sensor.
In the case of the aperture, stops are 1.4, 2, 2.8, 4, 5.6, 8, 11. This makes a bit more sense when you consider what it means. F/2 means the diameter of the opening is the focal length divided by 2. So for a 50mm lens, 25mm.
The kit lens at 24mm and F/4 is 'wide open' - that is as wide as the lens opening can get. 'Stopping down' by one step would be F/5.6. Two steps would be F/8.
In shot one, you were already at 1/15 second, so F/5.6 would have put you at 1/6th, which is pretty slow to handhold at 24mm, but probably doable.
If you take your M 50, take both lens caps off, and while looking thru it, rotate the aperture ring thru the various stops. You will see the aperture blades move and shrink the lens opening. Your kit lens does the same thing at the direction of the camera, it doesn't have the aperture ring for demonstration purposes.