There have been complaints about the shutter lag of the Sony a7RII and the a9. Independent tests have measured their shutter lag, defined as the elapsed time between the depression of the shutter release and the beginning of the opening of the first curtain of the shutter, to be quite low. I wondered if the issue that… [Read More]
Archives for October 2017
Voigtlander 65/2 Apo Lanthar 1:2 LoCA & focus shift
This is the seventh in a series of posts about the Voigtlander 65 mm f/2 Apo-Lanthar macro lens. The series starts here. I’ve been asked about the Voigtlander 65 mm f/2 Apo-Lanthar’s longitudinal chromatic aberration (LoCA) and focus shift at 1:2 reproduction ratio. I made a series of exposures at each whole f-stop from f/2 through… [Read More]
Stacked filter reflections
For the last few posts, we’ve been looking at reflections introduced by adding UV filters to a Zeiss Otus 55 mm f/1.4 lens on a Sony a7RII. We’ve seen that all the tested UV filters cause reflections, that the detailed nature of the reflections (but not their position) changes with the brand of filter, and that the… [Read More]
Filter reflections versus focus distance
Yesterday I posted results of a test for flare from near-axis light sources. I used a Zeiss Otus 55 mm f/1.4 lens on a Sony a7RII. I noticed at the time that the nature of the reflections varied as I focused the lens. Today, I mounted a Hoya Digital HMC UV(C) filter on the Otus, set it up… [Read More]
Flare from 3 UV filters
A few days ago, I posted a flare comparison of a Zeiss Otus 55 mm f/1.4 lens on a Sony a7RII with and without a 3-stop Hoya ND filter. Questions arose about the filter I used. Michael Demeyer said: I would also expect the quality of the filter to matter. For example, the Zeiss filters,… [Read More]