i bought a bower 14mm f/2.8 wide angle lens for a used pentax d200 i have. i paid $350 at b&h. except for the permanent atatched petal lens hood it seems to be all metal construction. it is massive and rather large about the size of a short telephoto or fast macro.

today i did a search on b&h and it wasnt listed. i guess it’s discontinued.

i haz ben very disappointed in this lens. hard to focus, queer distortion, soft at f/2.8. a wide angle lens of such short focal length is supposed to have great depth of field when stopped down and get sharper. this did nothing.

i decided to see if i could adjust it. i lifted up the rubber focus ring grip. the only thing securing the distance scale to focusing barrel was/is/will be cellophane tape! i kid you not.

under the cellophane tape are 3 split rings secured with a screw each. i peeled off the tape and removed the screws and rings. there is a slot under one ring and i can adjust an internal lens element.

i set the camera on a tripod 2 feet away from a target, a box with small letters on it, and started fooling around.

roughly i estimated the distance scale up against the focusing ring and moved it to 5 feet and checked focus. i did this by taking a bunch of photos and then using the camera’s magnifying feature to examine the photo.

the ring is now accurate for 1.5 feet, 2 feet and 5 feet. anything below that and past that isnt even close.

what ever i did to the internal element has eliminated the “queer distortion”.
i haz ben to the city to snap photos. no matter how careful i line up the camera i always get curvature on the left side of photo. sure, wide angle lenses have distortion. it’s supposed to be rectilinear. the distortion of perspective, line meeting at infinity.

poorly corrected lens can have pin cushion,barrel and other distortions. my example had as severe curve distortion on left side.

it’s gone! it also seems to focus much sharper now wide open. stopping down to f/4 puts it near perfect. and…further stopping down to f/5.6 and f/8 increase the depth of field to a fantastic amount.

i am happy with this lens. for $350 it rivals brand name models. i would even say i have a collector’s item.

but who does that? partial disassembly and fooling around to see what happens? not many i’ll warrant. i noticed 3 other set screws further up the focusing ring. maybe i could have tweaked it more.

i want to do some astronomy pix to see if it got better.

i bought this k mount model because it has the AE chip in it for full Av,TV and even in camera manual adjustment. the lens reports f stops and focal length to exif comments. if it is no longer available i guess i’m lucky.



Leave a comment

No comments yet.

Comments RSS TrackBack Identifier URI

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s