Focus on Stars: A Next-Generation Precision Focusing Tool

Focus on Stars Focusing Tool

THE PROBLEM

One of the greatest frustrations for many night photographers is focusing accurately at infinity for astro-landscape images. Infinity markings on lenses are often inaccurate, autofocus doesn’t work under starlight, and live view can be noisy at high ISOs in low light, making it difficult to confidently focus on stars.

THE SOLUTION

Focus on Stars is a next-generation precision focusing tool. It uses a Bahtinov filter that has been designed by a photographer specifically to be used with the wide-angle lenses that we typically employ for astro-landscape photography.

Focus on Stars is not the first photography-oriented Bahtinov filter, but I believe it is the best one.

The Focus on Stars filter provides a bright and clear diffraction pattern that makes it easy to confirm accurate infinity focus––even with 14mm or 15mm lenses. Simply place the filter in a standard filter holder, choose the brightest star in your scene and magnify the live view image to 100 percent magnification. You’ll see three pairs of bright spots around your target star, and as the image comes into focus, the pair of bright spots in the center will become equidistant between the pairs on either side. If this idea seems a little “fuzzy,” see the image below, as well as this video demonstrating the concept.

This image shows what a sharp star looks like through a Focus on Stars filter.

The Breakdown

WHEN THIS IS NOT THE RIGHT TOOL

As with all Bahtinov-type focusing aids, the Focus on Stars tool works best with normal to moderately wide lenses, because the diffraction pattern appears progressively smaller with ever-wider lenses. It is still useful with lenses as wide as 14mm, but it’s slightly more difficult to see the effect. If you don’t have much difficulty focusing on stars or planets, or you primarily use hyperfocal focusing, then you probably don’t need this device.

WHEN THIS IS THE RIGHT TOOL

If you struggle to get accurate focus at infinity, or don’t have confidence that your images are sharp until it’s too late to do anything about it, you should give Focus on Stars a try. It adds a step to your workflow, but adds a good measure of reassurance that your images will be sharp. It’s easier to spend a few extra minutes while you are out there on location than to go back and hope for the same conditions on another night.


UPCOMING WORKSHOPS FROM NATIONAL PARKS AT NIGHT

Coast HP7R: A Serious Light Painting Tool

HP7R Flashlight

The Problem

While technically you can light paint with any ol’ flashlights off the shelf, they’re not all equal for the task. Most flashlights fail in these regards:

  • Their color temperature is “off”—usually too cool for the white balances we use in night photography, and sometimes just too weird-looking at any white balance.

  • They’re too broad and diffused to be useful for lighting anything that’s not close.

  • They have a hot spot in the center of the beam, which makes it hard to focus the light where you want.

The Solution

The Coast HP7R is a professional-grade solution to many light painting issues.

Its LED-technology color temperature is very close to Daylight, which makes it easy to control how it looks no matter your white balance. Shooting at Daylight white balance? Use it as is. Shooting at a warmer white balance? Use it as-is for a cool effect, or use the optional LF100 filter holder to add a gel to warm it up a bit. (For instructions on the latter technique, see our Flashlight Filtration Guide e-book.)

The beam itself is either broad and diffused or tight and intense, whichever you want—because the flashlight has both high- and low-power modes (300 and 30 lumens, respectively), as well as a brilliant slide-focusing mechanism built into the lens casing. When zoomed out, there’s no hot spot—the illumination is equal from one edge of the beam to the next, which makes it very easy to control how much light you’re adding to elements of your composition.

Moreover, the HP7R is built solid—very solid. It’s impact-resistant and water-resistant, features a nearly unbreakable LED, and has an anti-roll protrusion on the barrel that keeps it from wandering down a slope. While you can insert four AAA alkalines, it comes with its own Zithion-X lithium ion battery that you can recharge without even removing it from the flashlight.

The Breakdown

The Grandstand, Death Valley National Park. Photographed with three Coast HP7R flashlights—one from each side, and one in the middle pointing to the sky. Nikon D5 with an Irix 15mm f/4 lens. 25 seconds, f/2.8, ISO 6400.

When This is not the Right Tool

If you’re looking to light something close to the camera at a high ISO (say, 6400), then the HP7R is just too intense to control well. In those cases, look for something with very dim illumination, such as a panel light that can be dialed way down (e.g., the Luxli Fiddle).

At 7.2 ounces, the HP7R is also slightly hefty for a flashlight—not enough to be a burden in most situations, but this might not be the flashlight you’d want for backpacking. For a similar flashlight in a lighter profile, check out the Coast HP5R.

When This is the Right Tool

The HP7R is perfect for light painting large or far-away subjects, or for when you’re working at lower ISOs (say, 100 to 800). If I’m carrying just one flashlight, this is the one.


UPCOMING WORKSHOPS FROM NATIONAL PARKS AT NIGHT