In many production circles, the prevailing wisdom among camera operators (and others) is that cameras that come with a single fixed lens force them to compromise their craft in some way. A bit of informal testing has shown that such a lens, in certain applications, outperformed other higher end lenses costing more than the entire camera and lens package.
Dan Grimes, manager of instructional production and engineering at the University of Nevada Las Vegas, recently did his own lab test using a Sony PMW-EX3 camcorder with a 1/2in imager and a series of Fujinon lenses. His findings might surprise some.
Grimes oversees the television production department housed within the Hank Greenspun School of Journalism and Media Studies at UNLV, which produces a wide variety of programs related to the school. The department also creates shows that appear on the local cable TV operator (Cox Cable) that are branded as “VegasPBS Rewind.”
“I often hear the discussion about lens performance and price relative to imager format and wanted to put the equipment to the test,” he said. “There are also questions as to whether the lenses that come with these inexpensive (approximately $8000) cameras could resolve to match their imagers.”
The camera and lenses he used were as follows:
· A Sony VCL-614B2X camcorder package (made up of a Fujinon 14x5.8mm lens that is manufactured for and comes with the camera)
· A Fujinon HS18x5.5BERM lens
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· A Fujinon HSs18x5.5BRM lens
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· A Fujinon XS13x3.3BRM lens
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·According to Grimes, “All lenses exhibited enough resolution for 1920 x 1080, easily showing more than 1000 lines per picture height (contrast not considered) both minimum and maximum focal length. However, the lens that came with the camera seemed to be absent of a myriad of aberrations found in the other three lenses, each costing more than the entire camera and lens package.”
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·Among his findings:
· Both HS series lenses could not be focused for both the center and outside areas with the f-stop fully opened (f1.4). Optimum and consistent resolution was found at f4 to f5.6.
· Both HS series lenses suffered from lateral chromatic aberrations on the outsides when not perfectly focused. Usually, one side would have blue shifted to one side and the other red.
· Both HS series lenses would breathe when focused (focal length varied when focusing).
· The HS18x5.5BERM without the extender engaged had slightly better resolution than the HSs lens.
· The HS18x5.5BERM exhibited all the typical problems with the multiplier in, yet still maintained decent resolution.
· The XS series lens exhibited all the HS issues.
· The XS series lens exhibited strong barrel aberration at wider angles.
· The VCL lens did not have strong monochromatic aberrations (squares staid square) except at the minimum focal length (slight barrel distortion).
· The VCL lens did have lower contrast and lower resolution when at smaller apertures (f16 and higher). Optimum resolution was at f2.8 to f4.
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·His conclusions: “All lenses were well matched for the 1/2in imager, in general resolution and contrast,” he said.
“What I found was that the cheaper lens that came with the camera performed as well as the more expensive lenses. Clearly, this lens was optimized for this camera either optically and/or electronically.”
However, Grimes was quick to point out that there is still good reason to purchase and use the more expensive Fujinon lenses, because they provide additional focal length range, available accessories and filters, and the ability to use studio controls.
“But I wouldn't encourage purchasing the more expensive lenses for image quality,” he said. “I guess what I am really getting at is don't discount the included lens because of its price.”
Editor's note: Fujinon responds to comments in the above article:
Dear Editor:
After reading the article titled “Single, Fixed Lenses Get a Bad Rap,” in the August 16th issue of “Beyond the Headlines,” we at FUJIFILM Optical Devices U.S.A. believe a timely and clarifying response is in order. The article describes “informal” lab testing done by Dan Grimes, manager of instructional production and engineering at the University of Nevada Las Vegas, using a Sony PMW-EX3 camcorder with a 1/2in imager and a series of Fujinon lenses.
Grimes states: “All lenses were well matched for the ½-inch imager, in general resolution and contrast. What I found was that the cheaper lens that came with the camera performed as well as the more expensive lenses. Clearly, this lens was optimized for this camera either optically and/or electronically.” Yes, there are differences between the Fujinon OEM lenses that are delivered with the camera package and the optionally available lenses. But first, no details are given of the test conditions, which leaves open many, unknown variables.
To clarify, the Sony PMW-EX3 camera that Grimes used has the ALAC (automatic lens aberration compensation) circuit for correcting lens aberrations. The only lenses that are designed to be corrected by this camera are the packaged 14x (Fujinon model number XS14x5.8 and the optional wide angle XS8x4, which was not tested.) The XS13x3.3BRM lens that was tested, as well as the HS18x5.5BERM and HSs18x5.5BRM - also tested, were not designed for ALAC correction on this camera. These lenses will work with ALAC on other Sony camera models in the near future. The differences in aberrations between the lenses are directly attributable to the ALAC-compatible lens circuit.
The article states that the HS and HSs lenses appear to have deficiencies at the extreme ends of their respective ranges. The HS and HSs lenses are wider, longer, and have shorter MOD than the packaged 14x. And it must be noted that they are being tested at focal lengths beyond the range of the packaged 14x lens.
The article asserts that the contrast is better on the HS lenses. This is due to the HS series’ coatings and internal barrel construction. The XS13x3.3BRM was noted to exhibit barrel aberration at wider angles. This lens is a wide angle; hence, greater distortion at the wide side is typical when compared to a normal focal length lens.
There are many factors that go into the cost of a lens. Construction differences are a major factor in pricing. The materials used in the HS and HSs series of lenses are designed for years of rugged use in the ENG news market. The motors are much faster and more precise. The gearing is designed for minimal backlash.
The servos in the HS and HSs lenses are digital and include a host of digital user features. These lenses take full advantage of all of the digital, high-end rear controls, as well as integration with pan & tilt and robotics. The HS and HSs digital servos have Fujinon's exclusive FIND (Focused Intelligent Network Diagnosis) system. This self diagnostic system provides immediate analysis of the lens electronics.
Signed,
Thom Calabro
Director of Marketing and Product Development
FUJIFILM Optical Devices U.S.A
