Tom Fanelle checking the light
My good buddy Tom Fanelle brought his miniS4 set to Maryland and we spent 3 hours composing a number of setups that would stress the lenses and exploit any flaws that may exist. We tested for chromatic aberration, distortion, flaring, breathing, bokeh, skin tones, and overall image. Since the miniS4s are T2.8 and the Xenars are ~T2, we never opened up more than T2.8 to keep the test consistent. We shot on the Red Scarlet-X at 4K, 23.98fps, ISO 800, Red gamma 3, with a 6:1 compression. For most tests we exposed the scene at middle grey using my Sekonic 758-cine meter, for the low light scene we exposed the subject 2 stops below. Please note that many of the scenes involved natural ambient light and for this reason there may be subtle differences in lighting between lens changes. At the bottom of this blog is a video putting all of these tests into motion, be sure to watch this as well. R3D and JPEG stills from the test are available to download below.
R3D/JPEGs Link: https://dl.dropboxusercontent.com/u/61506902/LensTestStills.zip
This first setup tested distortion on the 18mm lenses. Pay close attention to the vertical pillars especially near the edges of frame.
click on any photo to enlarge
Looking again at the same scene lets look at the aberration that shows up from this overblown windows being shot wide open.
Note the aberration that appears along the window frames. The miniS4 renders magenta-purple while the Xenars have a greener tint. When stopped down to T4 the aberration becomes less prevalant. Now lets look at another area of the scene where aberration rears its ugly head.
And below are the same crops stopped down to T4.
This next set of crops is from another scene shot on the Cooke 100mm and Schneider 95mm at T2.8 focusing near infinity. Note the aberration that appears on the light post and trees.
Lastly for the CA test is a low light scene exposed 2 stops under. The tungsten light fixtures provide another point of comparison.
The way a lens flares is very much part of that its character. We conducted two tests, one in direct sun light and another using a lower powered LED Maglight. The Cooke renders an octagonal flare because of it's 8 aperture blades while the Xenar has 18 blades and produces a more circular flare. *1.5 IRND & Circ Pola used
Continuing along the talk of aperture blades, let's now look at the bokeh produced in defocused areas of a scene. This setup involved the 75mm lenses at T2.8 at a distance of about 6' to the tree. *Note that there is a slight difference in the brightness of the scene because a door in the background was slightly ajar during the Cooke shot.
Our skin tone test was shot on the extreme telephoto ends of each set, the Cooke 100mm and Schneider 95mm at T2.8. This test is a good example of how skin is rendered, sharpness wide open, another example of bokeh. *1.5 IRND & Circ Pola used
Lastly we conducted a test to compare breathing on both the 25mm and 75mm lenses. While the breathing on the Cookes were minimal, it is still visible; however breathing on the Xenars are nearly zero. Below are couple stills from this test but see the embedded video to watch this test in motion.
All of the above test can be seen in motion in the following video. Have a look and leave your thoughts in the comment box.
As a Xenar owner I'm hesitant to make any statements claiming a victor in this test because I'm a bit bias, so I will leave that up to you the reader to make the decision. And honestly I don't see this as a test to prove one is better than another, but to show everyone that the Xenars do hold their own against a set as established as the Cooke miniS4/i. (Shameless plug) If you are interested in using either of these lens sets, both are available for rent at our website www.BrumarFilms.com Thanks for reading.