In this paper the effects of scattering noise on input images for holographic storage in photorefractive lithium niobate crystals have been investigated in detail by means of measurements of loss of signal to noise ratio (LSNR). A variety of lithium niobate crystal samples with different dopants, different doping concentrations, different annealing after growth, and used for different recording geometries are studied. More attention has been paid to the characteristics of scattering noise resulting from object beams. The experimental results show that the effect of scattering noise in oxidized crystals is less significant than that in reduced or as grown crystals. Comparing with transmission and 90° recording geometries, reflection geometry is less subject to the effect of scattering noise.