The Mob over at Gulf Camera attempt to answer the question: Which lenses will cover “Open Gate” on the ARRI Alexa XT camera?
From Gulf Camera…
Super 35 film has an image circle of 28.5mm and the Alexa 16:9 is a little smaller at 27.8mm. Using the “Open Gate” mode on the Alexa XT camera requires an image circle of 33.5mm for complete lens coverage. Many of the lenses in use today will not completely cover this larger sensor size. What lenses will work with Open Gate? I decided to take a look using the Gulf Camera inventory of lenses to find out what will work – and what will not. Some very popular lenses are missing from this project. . . if you have a favorite lens you would like me to add to the list – by all means get one to me and I’ll add it to the test.
Alexa “Open Gate” produces an image with a 1.55:1 aspect ratio. Apart from visual effects photography the 1.55:1 aspect ratio is too ‘square’ for most modern production. An aspect ratio of 1.78:1 (16X9) is most often seen in television production and 1.85:1, 2:1 or 2.4:1 are commonly used in feature film production. I have selected 1.85:1 as my Open Gate “cropped” aspect ratio as it is very close to 16X9 for television and also is used frequently in feature film.
Gulf Camera take a look at some of the commonly used zoom and prime lenses used on an ARRI Alexa XT in Open Gate mode.
Here is a Zoom lens tested.
Optimo 17-80 at 17mm on Alexa XT Open Gate
Optimo 17-80 at 17mm on Alexa XT Open Gate 1:85 crop
Here is a Prime lens tested.
Zeiss CP2 21mm on alexa XT Open Gate
Zeiss CP2 21mm on alexa XT Open Gate with 1.85 crop
There are a stack more tests on the ARRI Alexa XT camera with open gate with more lenses that you need to see at Gulf Camera.
They have even left space for further testing with more lenses on the ARRI Alexa XT camera to be done in the future.