Is the Pentax DA* 300mm f4 lens sharp enough for wildlife? - PentaxForums.com
PENTAX DA 300mm F4 ED [IF] SDM Star Lens for K Mount APS-C Size 21760 | eBay
smc Pentax-DA* 300mm F/4 ED [IF] SDM | LENS-DB.COM
Pentax SMC DA* 300mm F4 ED[IF] SDM Review | PCMag
Amazon.com : Pentax HD DA AF 1.4x AW - Adaptador para objetivo fotográfico (Black, smc PENTAX-DA 12-24mmF4ED AL[IF] smc PENTAX-DA 16-50mmF2.8ED AL[IF] SDM) : Electronics