digital cameras are not investments and that if you were a business owning them then you would be writing off a sizeable fraction of the capital cost each year due to this.

From About.com

"Double Declining Balance Depreciation

The double declining balance depreciation method is like the straight-line method on steroids. To use it, accountants first calculate depreciation as if they were using the straight line method. They then figure out the total percentage of the asset that is depreciated the first year and double it. Each subsequent year, that same percentage is multiplied by the remaining balance to be depreciated. At some point, the value will be lower than the straight-line charge, at which point, the double declining method will be scrapped and straight line used for the remainder of the asset’s life (got all that?). An illustration may help.

In our straight-line example, we calculated that a $5,000 computer with a $200 salvage value and an estimated useful life of three years would be depreciated by $1,600 annually. The first year, we have to compare this to the total amount to be depreciated, in this case, $4,800 ($5,000 base - $200 salvage value = $4,800). Dividing $1,600 by $4,800, we discover the straight-line depreciation charge of $1,600 is 33.33% of the total depreciation amount of $4,800. Using this information, we double the 33.33% figure to 66.67%.

In the first year, we would take $4,800 multiplied by .6667 to get a total depreciation charge of approximately $3,200. In the second year, we would take the same percentage (66.67%) and multiply it by the remaining amount to be depreciated. Continuing with the example, we find that $1,600 is the remaining amount to be depreciated at the start of the second year ($4,800 - $3,200 = $1,600). Multiply 1,600 by .6667 to get $1,066. This is the depreciation charge for the second year – or not! Remember that once the depreciation charges dip below the amount that would be charged using the straight-line method, the double declining balance is scrapped and straight line immediately utilized. The straight line method called for charges of $1,600 per year. Obviously, the $1,066 charge is smaller than the $1,600 that would have occurred under straight line. Thus, the deprecation charge for the second year would be $1,600.

For those of you who love algebra, you may find it easier to use this equation:

Double Declining Balance Depreciation Method Formula

Depreciation Base * (2 * 100% / Useful Life of Asset in Years) "

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