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View Full Version : New 50mm f/1.4 Focus Test - Measurebaters Welcome!

scottbergerphoto
21st of February 2004 (Sat), 18:21
I fear I'm becoming one of those, you know, dreaded Measurebaters! I was a little unhappy with the reults of the last focus test I posted of the Canon 50mm f/1.4 particularly at f/1.4 and f/2.0 even though the results were in line with its MTF tests at Photodo.com. I repeated the test, but made some changes to avoid the issues of DOF, 3D target, and inadequate lighting. I was alot happier with the results at f/1.4 and f/2 on this test.
I beg your indulgence, observations and constructive comments.
The test results are located at:
http://www.pbase.com/scottbergerphoto/revised_50mm_focus_test

Scott
Tom W
21st of February 2004 (Sat), 18:52
Looks good!! Soft at 1.4, but soft is better than "not-available". :)

From f/2.0 on up, it looks very good.
Sendide
22nd of February 2004 (Sun), 00:26
hiw about the shutter speed? couldn't it improove the "1.4" pic?
just wondering..
dpanicc1
22nd of February 2004 (Sun), 04:19
Looks like what I'd expect.
scottbergerphoto
22nd of February 2004 (Sun), 09:32
hiw about the shutter speed? couldn't it improove the "1.4" pic?
just wondering..
No. The shutter speed was 1/60 second on a tripod with mirror lock up. The result at f/1.4 is about what you would expect for the lens's MTF value at f/1.4. You can get some interesting information and MTF test results at www.photodo.com. It's important to realize that the ability of a lens to transmit what passes through it unaltered varies with the f/stop and the quality of then lens. At f/1.4 almost the entire surface of the lens is being used to create the picture. It's easy for a lens to be sharp in the center at small apertures >f/8. It's much more expensive to make a lense accurate to the periphery. That's why L glass is so expensive. The picture at f/2 appears acceptably sharp and by 2.8 very sharp. Many inexpensive lenses will not get sharp till f/5.6-f/8.

The first test I did on this lens, http://www.pbase.com/scottbergerphoto/50mm_f_14__focus_test , I think was a fairly good demonstration of the relationship between f stop and DOF. I think this test is a fairly good demonstration of lens performance (MTF) and f stop.
Scott