Forum Übersicht - dyxum: Lens talk area : Is there something wrong with my 50/1.7?

Author: Pete Ganzel
Subject: Is there something wrong with my 50/1.7?
Posted: 09 May 2007 at 07:50

Hi Eldonito:


Looks to me more like misfocus than a general sharpness issue.

If you focused by just setting on the infinity symbol there is more than enough error wide open to result in an unsharp image. It is very difficult to focus these fast lenses accurately enough when used wide open. Autofocus may or may not give you better results than manual focusing.


Both lenses (f/1.7 and f/1.4) are certainly useable wide open (as are most brands prime normal lenses). I don't think that even the 10mp alpha can resolve what these lenses can do wide open (I don't have one yet /smile.gif" style="vertical-align:middle" emoid="" border="0" alt="smile.gif" />


http://www.pbase.com/pganzel/image/73969383.jpg



I would try a test with manual focus and an eyepiece magnifier to verify that you are really getting sharp focus before rejecting the lens. Also make sure the eyepiece diopter is adjusted for your vision.


Your object almost looks to me like a mite or some other critter. I've found little spiders inside lenses occasionally. As mentioned previously, not likely a serious problem as far as sharpness goes. The front cell of this lens is really easy to remove and your foreign object could be dislodged quickly.



Pete




Edited by Pete Ganzel - Today at 07:51


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