Large format cameras are easily the most technical of their kind, but they reward the photographer with extra capabilities and stunning resolution. This video takes another look at some of those capabilities.
Coming to you from Ben Horne, this video is an additional look at the mechanics of a large format camera. In his previous video, he discussed rear tilt, which allows a photographer to enlarge or shrink foreground and background elements. In this video, he's talking about front tilt, which allows the photographer to change the angle the focal plane makes with respect to the film plane. This is a more well-known movement, as it's the same thing a tilt-shift lens does. The benefit of tilting the focal plane is the increased depth of field achieved without changing the aperture, which allows one to maintain a certain shutter speed and aperture combination or avoid using ultra-narrow apertures that could introduce noticeable diffraction. For example, in the waterfall photo, he likely wanted a certain shutter speed for the water blur and chose an aperture for the amount of available light and film speed, then used front tilt to increase his depth of field. As an aside, if you want a laugh at how truly big large format is, notice how when Horne mentioned his 150mm lens, he said that it's his wide angle lens.
Great article Front and Rear tilt and swings made the plane of the lens and the plane of the film equal. This mechanically corrected converging lines, like when the edges of a building looking up appear to be leaning in towards the center of the building.
Hey Alex! Thanks for sharing this. Ben is a great guy.
So... about that "increased depth of field"...
Tilting the front standard alters the angle of the focal plane. It does not increase the depth of field at all. Not even a little bit. Depth of field is affected by aperture, focus distance and film size.
You'll notice in the video, he talks about tilting down to alter the focal plane. Doing this tilts the focal plane in relation to the film.
When talking about the image of the salt flats, he mentions that there were no clouds in the sky. This is an important point, because if there were clouds in the sky, they would have been very soft since the focal plane no longer covers the entire vertical area of the image.
In the photo of the falls, his main goal was to get the entire pine tree in focus as well as the falls. So he talks about being very deliberate with his tilt to place the top of the focal plane near the top of the tree and stop down to get the falls in focus.
When tilting (altering the angle of the focal plane), stopping down the aperture will increase the depth of field only along that focal plane. It does not affect depth of field in relation to the film/lens plane.
Speaking of stopping down and diffraction. Diffraction varies according to several factors like lens construction and film/sensor size. Ben shoots 8x10. At that size, diffraction is almost a non-issue, especially compared to the narrow depth of field. We don't use front tilt to avoid stopping down. We use it out of necessity when shooting landscapes where we want a foreground and background element in focus, not to avoid diffraction. Stopping down won't do a thing to get an entire scene like that in focus. You'll notice, most of his images were shot at f/64.
If anyone is interested in learning more about the technical aspects of tilting and altering focal plane, my best suggestion would be a book by Harold M. Merklinger called "Focusing the View Camera : A Scientific Way to Focus the View Camera and Estimate Depth of Field"
If you don't want to buy a book, the geometric rule at play here is called the Scheimpflug principle. There are many published papers available discussing the Scheimpflug principle and it's effects.
Although, if you are considering getting into large format photography, just buy the book!
Yes, of course you’re right regarding dof. I used the term (perhaps loosely by technical standards) to refer to the range of in-focus elements in the final image as opposed to the depth of the focal plane. Thanks for the insight on the process!
Now let's use your reach to get Sony on board for a 5x7 digital sensor! Can I get an amen!?