Hello, I stumbled across an easy way to achieve critical focus on a tethered 4x5 view camera. I am a studio photographer that uses a Leaf Valeo 17wi( must be tethered to a computer to work) on a sinar p with a Phase sliding back and Live View dongle.
I had to do a job that required large reasonably high quality photos of diamond rings. I wound up using Helicon Focus to combine in focus slices of a ring. I tried a 'blind' focus - in the ground glass I focused on the very top of the ring, made an exposure and determined the top of the ring was in focus - at this point, with the focus knob, I racked the back standard with the DB on it down a little bit, it barely moved, a smidgen, a touch, took another exposure and by the third exposure the shoulder of the ring was now sharp, 8 to 12 exposures the whole ring was done. It assembled very well, the shots were good.
Soon afterward, in my normal workflow I decided to try this trick/solution. You know how it is - yesterday everything was in focus, today you can't focus at all, everything looks soft, yet it the same camera, lens, lights and set. You refocus and refocus - sometime it works, sometimes it doesn't.
I shoot 8.5x11 pages of jewelry to reproduce a 8.5x11 - 100% on the page. The jewelry is set up on a 12" high box and the camera/DB is about 7' off the floor and parallel to the floor, it is very difficult to focus this arrangement. I now do a rough ground glass focus, first - then take an exposure and check the highest ring on the page in my 100% window in LC11 software. I might decide that the top of the ring is sharp but I am not happy with the bottom of the ring and the background it's on. I simple rack the back standard down a touch, take another exposure and big surprise(the first time) it's all in focus. I then check the top and bottom of the page with the 100% window to make sure the whole page is good. Sometimes I might have rather large/high bangles and I can easily check if they can make focus, moving the DB up or down slightly to fine tune the focus, might increase the f-stop a half a stop if they don't make focus, take another exposure and check the 100% window, move it around to check the whole page. No more climbing a ladder multiple times, opening the lens, sliding the back across. I find this trick/solution to be easy, and very accurate and lots faster than repeated ground glass focusing.
I use this technique on almost all my photos. Don't use Live View much at all. One GG focus and the rest is this 'blind' focus adjustment that works terrific, Sure there are times that I rack the back standard/DB in the wrong direction and see in the 100% window that the type on the bottle is softer that the first exposure, I just make two small adjustments in the other direction and bang on focus. Even if I do this focus trick 4 to 6 times it is easy.
Since the sinar p is a 'self locking' focusing camera, this technique works well, on a locking camera this might not work at all. Could work on a Hasselblad or any Alpa, Cambo Wide Ds type camera that has a focusing ring. Could be used outside with a newer Phase or Leaf back as long as you can see your focus point at 100% on your lcd - that might be very difficult in bright sunlight.
Good Luck,
Brian Woolf
