  Recently introduced, spaceplates achieve the propagation of light for a
distance greater than their thickness. In this way, they compress optical
space, reducing the required distance between optical elements in an imaging
system. Here we introduce a spaceplate based on conventional optics in a 4-$f$
arrangement, mimicking the transfer function of free-space in a thinner system
- we term this device a three-lens spaceplate. It is broadband,
polarization-independent, and can be used for meter-scale space compression. We
experimentally measure compression ratios up to 15.6, replacing up to 4.4
meters of free-space, three orders of magnitude greater than current optical
spaceplates. We demonstrate that three-lens spaceplates reduce the length of a
full-color imaging system, albeit with reductions in resolution and contrast.
We present theoretical limits on the numerical aperture and the compression
ratio. Our design presents a simple, accessible, cost-effective method for
optically compressing large amounts of space.
