Digital holography captures holograms by charge-coupled device or complementary metal-oxide semiconductor cameras, which have a spatial resolution still not reaching that of silver-halide holofilms. Thus, due to the sampling theorem, the angle between the reference and object wave is limited. Only fields coming from small objects, objects far away, or optically reduced fields can be recorded. Here we investigate optical reduction by a system of lenses, and show that a system of two concave lenses results in a drastic reduction of the object-target distance, while the effect of using more lenses is insignificant. Experimental results obtained with Fresnel and lensless Fourier-transform geometry are presented, and implications on holographic interferometric metrology as well as on holographic 3-D television are given.