Have you ever wanted to be a little more precise with focus when using a view camera? Where exactly should we set the focus and what aperture should we use to ensure a full depth of field with everything sharp from near to far? Raise your hand if you’ve ever used the method “just focus on something and stop down to f32.” It’s ok, I’m guilty of taking that approach myself. It works more often than we’d like to admit. But wouldn’t it be nice to know with 100% certainty that you nailed the focus and used the correct aperture? We shoot these huge sheets of film for the sake of maximum sharpness so let’s do it right!
“Twilight Boles” - Colorado, October 2020. Velvia 50 4x5, 300mm lens - 2 minutes at f32, no filters. There’s a lot of depth going on in an image like this and movements won’t help at all. Where should we focus in these situations?
There’s really only one way to dial in the focus with more precision: use a millimeter scale on your camera. Unlike smaller film formats where focus is built into the lens and a nifty scale is provided, the bellows facilitate the movement for focus on view cameras. Since there are so many variables with large format lenses, nearly all camera manufacturers have omitted any sort of scale for focus - aside from monorail cameras and a few rare field models. A while back I decided I didn’t want to guess focus and depth of field anymore so I created some focus scales that I’m going to share here. What I’m going to show you in this article is how to add these focus scales to your camera and how to use them.
Make the Focus Scales
Here’s what you’ll need to add these scales to your camera (aside from the camera itself!):
Access to a typical office-jet or whatever printer.
1 sheet of half-page shipping label paper. Avery 5126 shipping labels or equivalent.
A razor blade/exacto knife and a straight edge, or a small paper trimmer if you have one.
Some normal transparent tape (Scotch, etc).
First off, download the file below. I have it in PDF or PNG, whichever you prefer. The only reason I didn’t embed it in the website is so your browser won’t do any resizing. Print this image onto a sheet of label paper without making any adjustments to the scale. The buttons below will open in a new tab, you can print from that tab or you can right-click to download the files and print from your preferred software.
Next, find a suitable flat area on the bed or focus rail of your camera, near the point where the rail extends when focusing. At the top of this page you can see where I attached the scale on my Chamonix, in the following images I will show where I attached it on an Intrepid mk4 camera. Some cameras have more of a flat bed and that might be a better place to put it. Choose a suitable length for the scale and cut it out of the label paper using a razor blade and a straight edge - I used a small paper trimmer that I own. Cut out both the left and right side scales if you’d like one on each side. Cut out the reference chart if you want to stick that on the camera somewhere.
Carefully peel back a small amount of the label backing and start working the sticky scale onto the camera, use a razor blade to separate the backing if you need to. These labels stick pretty well to most surfaces, though a smooth surface would be ideal. Continue peeling more of the backing while working the label on the camera as straight as possible. After it’s on there, put a piece of clear tape over the scale to weather seal and trim any excess tape with the razor. This scale has been on my Chamonix through rough weather for well over a year, it can always be replaced if needed.
Great! Now you have a focus scale on your camera. What does this do for us? Next I’m going to show you the focus spread method of focusing. Here’s the really cool thing: it works with every single lens! Wide or long, it doesn’t matter - the focus spread method works no matter what. It’s also ridiculously simple to use.
We all know tilt can help manipulate the plane of focus, but what I’m trying to help you with today is those types of scenes where tilt or swing can’t be used. Think of a forest scene, or any landscape with a tall object running vertically through the frame. For these scenes we need to use hyperfocal focus, where we focus somewhere in between near and far and stop down to achieve a full depth of field. The focus spread method will allow us to focus in exactly the right spot and choose the correct aperture.
Aperture - A Brief Rundown
Let’s talk about aperture for a minute. There’s a bit of a myth that diffraction doesn’t affect large format images since the film is so big. This simply isn’t true; while we do have huge sheets of film to mask sharpness issues, the lenses still do lose sharpness when we stop down too much. There’s also a myth that diffraction has to do only with the size of the aperture opening, meaning that it’s acceptable to use f64 on a 300mm lens but not a 90mm lens. Again, not entirely true - the longer 300mm focal length allows light to scatter more before hitting the film and will still suffer from diffraction at f64. The upshot of all this is that diffraction has more to do with the f-number and film size than anything else. (This concept has been shortened greatly for the sake of our sanity - feel free to dive into the topic more on your own if you’d like)
In some ways large format lenses don’t quite behave the same as smaller formats. The center of the lens is often sharpest rather close to wide open, say around f11. However at that aperture the corners are typically quite soft with significant light falloff. For most LF lenses, f22 is generally regarded as the ideal aperture where sharpness is rather even from center to edge and the lens has its full image circle. At f32 diffraction has certainly started, but it’s minimal and often required to give us more depth of field. Unless absolutely necessary, f45 and beyond should be avoided. This is true for 8x10 as well as 4x5, but remember that with 8x10 film you have more film size to “mask” sharpness issues and less enlargement is required to make the final print. The longer focal lengths of 8x10 can also mean that you have no other choice than to stop down beyond f45.
Using Focus Spread
So here’s what we want to know when using focus spread: when can we get away with using the ideal aperture of f22, and when do we need to stop down more? The focus spread is simply how many millimeters the focus rail moves between the furthest and nearest objects in your composition. Using the scale and a loupe to focus, you find the furthest object in your scene and record the reading on the scale. Then crank out the focus rail until the closest object is sharp with the loupe and record this mm reading. The difference between these two readings is the focus spread. To get everything in focus, simply place the focus exactly halfway between those two readings and stop the lens down according to the chart below:
On this chart you will see a number for “acceptable aperture” and “optimal aperture.” The reason I’ve included both is because conditions aren’t always optimal. There might be some wind that requires using a shorter exposure time and larger aperture, or twilight might be fading fast and you don’t want to run too far into film reciprocity. It’s also ok to use the “acceptable” setting when working with extreme close-up subjects. If it’s a nice calm day, aim for the optimal aperture. If wind or subject motion is a concern, feel free to open up the aperture by a stop to try to freeze the motion. It’s better to have a slightly reduced depth of field to increase your chance of freezing motion.
If you want another way to remember these numbers, think of this: The acceptable aperture is roughly 7 times the focus spread in mm. The optimal aperture is roughly 10 times the focus spread, meaning that a 3mm focus spread requires an aperture of f32.
Let’s look at a practical example in the field. The image above is a situation where tilt doesn’t help since the yucca pokes up above the horizon. Using a loupe I focused on the mountains and the focus scale read 12mm. I then focused on the yucca which gave me a reading of 15mm. It can be very hard to focus on white sand on a ground glass so I chose the yucca as my close object. This is a focus spread of 3mm, meaning that f32 will ensure total sharpness from near to far. All I have to do is set the focus right between 12 and 15mm, at 13.5mm and stop down to f32.
It’s that easy! No matter what lens I have on the camera this method works. What you’ll find in practice is that wide lenses often have a very small focus spread for most landscapes and that longer lenses result in a larger spread - especially in the forest. If you find the spread is beyond 10mm it might be wise to try rethinking the scene. Consider if movements can help at all or try composing differently. It’s really best to avoid shooting at f64 if possible.
“Danvers Sunset Rainbow” - Central Montana - May 2020. Portra 160 4x5, 210mm lens - 1 second at f22, no filters.
Using these scales has opened my eyes to how often I can get away with shooting at f22. In the past I often thought that my long-ish 210mm lens would require f32 nearly all the time, but it’s always nice to know that the sharper f22 aperture is possible. It was particularly useful in the image above, where the wind was really whipping and I wanted a shorter exposure time while still maintaining a complete depth of field. With a touch of tilt, the focus spread was only 2mm between the nearest grass and furthest mountains. Just a short exposure at f22 was all I needed!
Remember that the numbers on the scale are arbitrary. It doesn’t matter which hole on the base of your camera that the front standard is screwed into or which lens you’re using. All we’re looking for is the difference in millimeters between near and far and the point in between those two readings. A reading of 63mm and 66mm is still a 3mm focus spread, just like readings of 12mm and 15mm.
These scales can also be helpful if you do any close-up work and need to calculate bellows compensation. The focus spread method also works well with scenes where tilt can be used. Both of those topics are rather broad and need a blog post of their own, some more material is on the way soon! Did these scales work for you and your particular camera? If so, tag me in a photo on Instagram @alexburkephoto
This blog post is meant to go with my new ebook “Large Format Film Photography.” Consider purchasing this book to take your large format photography to the next level while also supporting me to create more educational content like this!