{"id":8197,"date":"2013-03-21T07:00:39","date_gmt":"2013-03-21T14:00:39","guid":{"rendered":"http:\/\/wkoopmans.ca\/notebook\/?p=8197"},"modified":"2013-03-21T07:03:40","modified_gmt":"2013-03-21T14:03:40","slug":"pentax-q-40mm-homebrew-telephoto","status":"publish","type":"post","link":"http:\/\/wkoopmans.ca\/notebook\/?p=8197","title":{"rendered":"Pentax Q 40mm homebrew telephoto"},"content":{"rendered":"

\"Wallace_Koopmans_40mmQ-9119\"<\/a><\/span><\/span><\/span><\/span><\/span><\/p>\n

I chose this lens from my parts bin\u00a0because it was a complete package including a helical focus\u00a0system, unfortunately\u00a0I don’t know what camera it came off but it appears to be a 40mm f2.8. That 40mm\u00a0when converted to a full frame equivelent is\u00a0220mm.\u00a0 Once I figured out the distance it needed to be placed from the sensor I mounted it on the end of a piece\u00a0of ABS\u00a0tubing which also attached to a modified Q to C-mount adapter I had purchased on the internet.\u00a0 Initial testing was done with no aperture, it was wide open.\u00a0 The resulting images were soft and lacked contrast as you can see with these following images.\n\t\t