There are other techniques also, like measurement of turbidity of spore suspension and total plate count method (as said by Oadi Manty), but, haemocytometer gives most accurate count of fungal spore/conidia in a suspension.
The measurement of sporulation produced by fungi at any circumstances, with different types of fungi or different size of spores are more reliable and accurate results if we work it by hemocytometer. But if we have uniform type of spores (after filtration), we can measure the sporulation using OD with a standard curve. Also the absorption should consist only spores and should be taken immediately after adding the sample into cuvettes to minimize spores deposition. Unfortunately, this method will be useful for approximate estimation of sporulation.