Ritz Camera Centers, the nation's largest retail photography chain, filed for Chapter 11 bankruptcy protection on Sunday.

The Beltsville, Md.-based company submitted its filing in federal bankruptcy court in Wilmington, estimating assets and liabilities at between $100 million and $500 million. The list of its top 30 unsecured creditors is led by Nikon Inc. and Canon USA Inc., which are owed a combined $40 million in trade debt.

The company said revenue from its profitable photofinishing business has declined significantly with the shift from film to digital cameras. Ritz has about 800 photo stores in 40 states, including nearly 20 stores in the Denver area.