18-55 ro aslan pishnehad nemikonam..chon mishe goft arzoon tarin va bi keifiat tarin lenze canone....D90 ro ham ke nemitooni ba 50D moghayese koni...D300 ro ba 50D moghayese mikonan...dar morede lenz ham bayad bebini karet chie ta lenz tahie koni...mamoolan lenz haie mese 28-300 lenzhaye kondi hastan va diafragmeshoon balast...bayad havaset be sorate lenz bashe...vaghty az 28 miri roo 300 ta bekhay focus koni momkene soojhe bepare az dastet...