Low Light Performance: The bright T1.5 transmission (equivalent to approx. f/1.4) lets in abundant light and creates beautiful, cinematic bokeh. Low Light Performance: The bright T1.5 transmission (equivalent to approx. f/1.4) lets in abundant light and creates beautiful, cinematic bokeh. Low Light Performance: The bright T1.5 transmission (equivalent to approx. f/1.4) lets in abundant light and creates beautiful, cinematic bokeh.