I’ve been obsessing over large format photography for the past year. Not because I shoot it professionally, but because understanding why it’s hard makes me a better photographer across everything else I shoot. And recently, while trying to wrap my head around why so many large format portrait attempts end up slightly soft even when the photographer swears they nailed the focus, I came across a technique that genuinely stopped me mid-coffee-sip.

In this Joel Grimes tutorial, he breaks down what he calls the dual focusing technique, a method he developed after shooting thousands of large format portraits over a decade without a single out-of-focus image. That’s not a typo. A decade. Zero misses. Here’s the video:

If that doesn’t render for you:

The Core Problem With Standard Large Format Focusing

To appreciate the fix, you need to understand the problem. With a view camera, you focus by looking at the ground glass at the back of the camera, usually under a dark cloth, with the lens wide open. Once you’ve got your focus dialed in, you close the lens down to your shooting aperture, cock the shutter, and then slide out the ground glass to insert your film holder.

Here’s where everything can fall apart. That sequence, closing the lens, cocking the shutter, physically swapping the ground glass for the film holder, introduces vibration and movement. Even a fraction of a millimeter of shift at the camera can translate to a noticeably soft image, especially when you’re shooting at a focal length where the depth of field is razor thin. The camera doesn’t move dramatically. It just moves enough.

Most photographers compensate by stopping down aggressively to buy themselves more depth of field margin. But if you’re doing commercial portrait work and you need that beautiful shallow-focus look, stopping down isn’t a creative option. It’s a concession.

What the Dual Focusing Technique Actually Does

Joel’s solution is elegant in its simplicity. Instead of relying solely on the ground glass to confirm focus before making the switch, he introduces a second focusing reference point, a separate focusing aid that physically corresponds to the plane of focus the camera is locked to.

The idea is this: before you remove the ground glass and insert the film holder, you use a secondary tool to mark or confirm the exact plane where focus is sharp. This gives you a repeatable, physical reference that doesn’t depend on the ground glass being in the camera at the moment of exposure. If anything shifts during the film holder swap, you have a way to verify and correct your focus before you actually fire the shutter.

This matters most for portraits because your subject’s eyes are the target. A millimeter of drift at the film plane can push the eyes just enough out of focus to ruin an otherwise perfect frame, and you won’t know it until you’re looking at the developed film.

Walking Through the Technique Step by Step

Here’s how to apply what Joel demonstrates:

  1. Set up and focus normally on the ground glass. Use a loupe, get the eyes sharp, and take your time. This step doesn’t change.

  2. While the ground glass is still in place, bring in your secondary focusing aid. Joel uses a device that can be positioned to physically match the focal plane you’ve established. The key is that this second reference sits at the exact same distance from the lens as the ground glass’s emulsion plane.

  3. Lock in your settings. Close the lens to your shooting aperture. Cock the shutter. Do not touch the focus rail or the bellows after this point.

  4. Remove the ground glass and insert the film holder. This is the vulnerable moment. Move carefully but don’t be paralyzed; the point of the dual reference is that you don’t have to be perfect, you just have to be consistent.

  5. Use your secondary focusing aid to verify the plane of focus is still intact. If there’s been any drift, you’ll see it here. Correct before you shoot.

  6. Fire the shutter. With confidence, because you’ve verified focus twice.

The secondary focusing tool is what makes this repeatable at a professional level. Joel built his methodology around this over years of commercial portrait work, and the results speak for themselves.

Where I’d Adapt This for My Own Work

I don’t shoot 4x5 on client jobs. My bread-and-butter is digital, and I’ve spent enough time at Sunday morning photo walks with a mirrorless camera to know that most of my focus anxiety is just workflow anxiety. But the underlying principle here, verifying focus with a secondary reference rather than trusting a single point of confirmation, translates everywhere.

When I’m shooting tethered and I want to confirm critical focus before a big sequence, I don’t just trust the camera’s AF confirmation. I zoom into the tethered image on the laptop, check the eyes at 100%, and then keep shooting. That’s a form of dual verification. Different tools, same logic.

Where I think this technique has its limits is speed. If you’re shooting a subject who can’t hold absolutely still, the time it takes to run through this sequence becomes a liability. Joel is clearly working in a controlled portrait studio environment with cooperative subjects. Bring this workflow to an active kid or an unpredictable location shoot and you’ll need to adapt.

The Takeaway

The dual focusing technique works because it removes trust from the equation and replaces it with verification. You’re not hoping the focus held through the film holder swap, you’re confirming it.

Watch the full tutorial to see Joel’s actual setup and tools in action, because some of this really does need to be seen to be understood: youtube.com/watch?v=k0KlYXDtzOo.