While a grab shot with an 8X10 view camera may sound like an impossibility, when you read what Adams said about this shot you must concede that it was, in reality, the ultimate grab shot. On page 127 of his classic book The Negative, (Little, Brown & Co. 1981) he writes: "I came across this extraordinary scene when returning to Santa Fe from an excursion to the Chama Valley. The sun was edging a fast moving bank of clouds in the west. I set up the 8X10 camera as fast as I could while visualizing the image. I had to exchange the front and back elements of my Cooke lens, attaching the 23-inch element in front with a glass G filter (#15) behind the shutter. I focused and composed the image rapidly at full aperture, but knew that because of the focus-shift of the single lens component, I had to advance the focus about 3/32 inch when I used f/32. These mechanical processes and the visualization were intuitively accomplished. Then to my dismay I could not find my exposure meter! I remembered that the luminance of the moon at that position was about 250 candles-per-square-foot, placing this luminance on Zone VII, I could calculate that 60 candles-per-square-foot would fall on Zone V. With a film of ASA 64, the exposure would be 1/60 second at f/8, or about one second at f/32, the exposure given".
Earlier in the same book, on the topic of estimating exposure he says; "As I reversed the film holder to make a second negative, I saw that the light had faded from the crosses! I am reminded of Pasteur's comment that 'chance favors the prepared mind.'"
It kind of makes you feel bad about blaming that missed grab shot on a too-slow computer-driven autofocus system. doesn't it?
In Chapter 3 of The Camera, (Little, Brown & Co. 1980) Adams wrote: "I made this photograph using a Hasselblad camera with 250mm Sonnar lens and an orange filter. With the camera secured to a tripod, I waited until the moon rose to a favorable position for a balanced composition. I made several exposures, at intervals of about one minute, and the movement of the moon between exposures gives each a somewhat different aesthetic effect. The moon moves surprisingly fast through the sky, and exposure times must be quite short to secure a sharp image when using a long lens".