to focus better

I was reflecting back on the recent wide field photos shot from the porch on the evening of the 20th. I focused manually using the camera's built-in display. Thought I was OK. But on reviewing the photos on the computer later, after I had torn down, I saw that they were off. Despite zooming the display. Little star donuts. I was not happy.

I want to improve the ability to focus the Canon camera lens manually when using it for astrophotography. This single wish creates a few paths to follow.

I'm curious if I might be able to use a focusing mask. The Bahtinov mask I made two years ago for the C8 telescope is fantastic, easy to use, quick. It was somewhat challenging to make but super cheap. Not challenging, just time-consuming. But, I wondered, can a Bahtinov be made for a small camera lens? What obstacles will a small version present? Will it be easier or more awkward to make?

Using a computer with a DSLR is obviously a better route to go. The EOS Utility application I've enjoying using. From the city. From dark skies. The downside, of course, is more set up time. Cables, wires, power. When I was shooting Jupiter in Taurus, I did not want to (could not) mount a big production. I wanted to work quick and fast. But the big benefit is previewing on a large screen. The 40D display is 3 inches. The Dell laptop screen is 14. Compelling. While the built-in display offers a 10x magnification, it still cannot compare to 10x on the laptop. Or shooting a test shot and immediately zooming in even more.

I thought of full width half maximum (FWHM) waveform analyses available in astronomical focusing software. I've seen people using it before. I saw it in action in MaxIm DL at Manuel's. Under test conditions on the 22nd. But not in the field last night. Previously, he's used FocusMax. It has the same capability. I didn't think there was such a feature in the software included by Canon. But were there independent products that I could use? Something that could interface with the EOS Utility or simply work with an image on the screen. Some searching would be required.

I thought again of Backyard EOS. I recalled it had some focusing aids in it. The software is on my wish list. I definitely think it will be a good tool to have. In particular, I'm attracted to the imaging run component. If it has focusing aids too, all the more reason to get it. But, in the meantime, could I achieve good focus with a home-made mask and the included or some general free software?

All that said, the manual focusing was a struggle. I remembered how sensitive the lens was. I thought of the trick I had seen in Lifehacker, rigging up a magnifying glass arm, to dial in small changes. Ah. The lever! One of our fine inventions. I'd need to find a way to improve on this too. Or avoid touching the focus...