How do I test my lens? I need a dummies guide!

[fetching]

Can someone suggest a simple, dummies guide kind thing for me to test the focus/sharpness of a new lens I bought? I got a 17-40 f4 L a few weeks ago and have not been that impressed with the results when shooting. These charts i see here and there confuse me.


and how do i set up the camera and lighting for accurate results?

thanks

[robertwgross]

To test for focus, use the ruler test. That is documented in this forum.

A typical lens will give you a moderately sharp photo at one of the middle apertures. In other words, avoid the wide open end and the closed down end. At the wide open end (e.g. f/1.8), you can get into problems of depth of field. At the closed down end (e.g. f/32), you can get into diffraction problems. So, in general, test around f/8 or f/11.

---Bob Gross---

[fetching]

To test for focus, use the ruler test. That is documented in this forum.

A typical lens will give you a moderately sharp photo at one of the middle apertures. In other words, avoid the wide open end and the closed down end. At the wide open end (e.g. f/1.8), you can get into problems of depth of field. At the closed down end (e.g. f/32), you can get into diffraction problems. So, in general, test around f/8 or f/11.

---Bob Gross---

thanks, so i can search for ruler test and pull up something?

*goes to search*

[Andy_T]

Take a look at this thread, it should give you some helpful hints for starters:

Things to check after you bring your camera home (http://photography-on-the.net/forum/showthread.php?t=58493)

Best regards,
Andy

[chtgrubbs]

Here's a site with plenty of info, including downloadable test charts:
http://www.normankoren.com/Tutorials/MTF5.html

[tim]

http://www.canon-dslr.com/Canon_Jan05/Canon_SLR_Focus_Test.htm

[fetching]

oh my, those test charts make my head hurt.

[CyberDyneSystems]

In Tim's link.. the second test uses three cel phones.. this is similar to the "AA Battery Test" I would recommend. ei picking out solid objects at different distances to focus on as opposed to a ruler.