In general, complicated lens designs such as zoom lenses will have the biggest difference between f stops and T stops regarding exposure accuracy. F-stops are the theoretical amount of light transmitted by the lens t-stops, the actual amount. And I would expect the same for lenses marked in f stops. And, the spec for my Ziess lenses for iris accuracy was + or - 1/3 stop for each mark on the iris ring. The T stop markings were only truly accurate with the lens wide open. So the exposure "advantage" of T1.4 was not nearly so much as I expected.Ģ. Yes, there was less depth of focus, but no more shadow detail could be recorded. Shadow detail did not improve between T2.0 and 1.4 due to increased flare. f-stop makes high-quality camera bags, backpacks, and packs that keep your camera, photography and cine gear safe on any adventure. Way back, when I used to own lenses, I took my set to Panavision and had them measured for MTF and transmission at different apertures and I learned a couple things:ġ.
And most likely, though I'd really need to google this, an overall correction for the lens design. F/stops are measuring the light that hits the lens and t/stops are measuring the light that comes out the back of the lens. That said, I don't believe T stops are measured for each individual lens and diaphragm setting. In practice, f/stops cannot necessarily have a direct relationship, have like a perfect relationship with the exposure. Thus, the T stops are more accurate for measuring exposure. T stops take into account loss of light transmission through the lens, while f stops are a simple mathematical calculation from the focal length of the lens and the diameter of the iris.
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