T1.4 and T2

[Deniz Zagra]

Why do lens companies make 2 different lens lines which apparently have the same characteristics with the exception of higher speed. Arri Master and Ultra primes, Cooke S4 and S5, Leitz Summicron-C and  Summilux-C, Panavision Primos and Panaspeeds…

Wouldn’t it be easier to have just one state-of-the-art lens line. Is there a significant difference in sharpness, contrast, or resolution? I heard that standard speed lenses (T2 or T1.9) have more corrected bokeh which adds to the sharpness whereas the high speed versions (T1.3 or T1.4) have uncorrected “Christmas ornament” bokeh which reduces sharpness no matter how much the lens is stopped down. Is this it?

[Aapo Lettinen]

contrast, price and lens size will differ between the two options. On paid cinematography shoots it is pretty rare to shoot wide open so the weirder wide open bokeh of a 1.2 / 1.3 / 1.4 lens would rarely matter that much. But the size and price difference and the often better contrast in backlit situations can make the 2.0+ lens a better overall choice for a project.

Normally one would stop down at least 1.5 stops if it is possible, no matter what kind of lens is used. If wanting a wide open effect or there is not enough light, then one might choose to shoot wide open. But shooting wide open is always a compromise no matter how high quality your lens is, so normally it is only done if absolutely necessary. And if shooting with anamorphics the image often breaks down to some extent if shooting at too wide aperture so one needs to be even more careful and really know how the lenses behave before making decisions.

When video capable dslr's came out it was the norm to shoot wide open with them to exxagerate the shallow dof effect but nowadays it is common to just "shoot by the standards" so stopping down any lens a little bit is the normal approach and when stopped down the other differences between different speed lenses are often pretty minimal but the contrast may differ signifiantly because the faster lens has lots more unused glass surface when stopped down and thus more chance for the light to play all kind of tricks