Take the depreciation. Reduces your taxes currently. Entirely legal and ethical. I think you can make an argument for either 5 year classification (items with an expected life between 4-10 years, including most computers and similar equipment) or 7 year property.
Of course, if you subsequently sell the equipment, even for less than your original purchase price, you may have a reportable gain for income tax. Because the depreciation has lowered your basis in the items. In a grossly simplified example, let's assume your $1,000 lens is depreciated in equal amounts over 5 years. You will therefore get a $200 deduction in each year and reduce your taxes. However, if you then sell the lens after year 5 for $800, you will have to report a gain of $800, since your basis will now be zero for the completely depreciated asset. To cacawcacaw's point above, I assume there is a reason your accountant is suggesting this (vs expensing the asset all at once - which is an option for certain businesses). Press your accountant for a clear answer.
Still a good move - always take the deduction today for potential reportable income tomorrow.