Help with Vivitar lens (follow up to previous post)
Tested out the lenses given to me by my father (the 100-500mm zoom and 19mm prime). I toke them to the country side, shot some landscapes with the wide angle and wetland birds with the tele. Noticed some problems with the wide angle. Need input to figure out what was wrong (sorry, I'll try get samples scanned asap):
For pictures taken (~6 samples, distant landscapes taken @ F8) with the wide angle, the right most 1/6 of each photo, appear to suffer from severe softness (regardless of object's distance from camera). Sharpness elsewhere was fine and glass looks clean. I am not sure what caused these problems and it looks like my only option is to get Vivitar to examine and fix it. Please help, any inputs are welcomed.
As for the tele, it worked like a dream. I now have the gear to help me start shooting wildlife.
#2. "RE: Help with Vivitar lens (follow up to previous post)" | In response to Reply # 1JM Registered since 01st Mar 2007Sun 24-Mar-02 11:02 PM
Actually I see the potential that the mount, which Vivitar would change depending on the manf. lens ios to be used on, is not truely parallel to the film plane. This would cuase the plane of focus to pull away from the film plane somewhere, in your case the softness.
It may be a simple repair but you might check the screws around the mount to see if the are all tight. The shoot a few shots of a newspaper that is perfectly parallel to the film plane using a good slow film or slide film. Analyze the result for your softness as this is a good way to judge resolution.
It is not common for a round lens that is spun during focusing to retain the softness on one side if it is a glass aberation.
#3. "RE: Help with Vivitar lens (follow up to previous post)" | In response to Reply # 2Tue 26-Mar-02 12:56 AM
Dear Jeff and Yslee,
Thanks for your input. I examined the lens briefly this morning before heading to work. I did notice something peculiar: the holder of the last element at the back seemed somewhat whobbly. Which means the element might not be parallel to film plane. Will find time to look at it closer tonight. Thanks again, this gives me better hope of fixing it!
#4. "RE: Help with Vivitar lens (follow up to previous post)" | In response to Reply # 3Sat 06-Apr-02 12:16 PM
An update: I tightened up the screws on the Vivitar and gave it another try today. Results were mixed. I have one picture with the softness (landscape shot again). All others (mixed with 1-2 landscapes) were OK. I am taking it back to Vivitar for a check up.
Thanks for your help.