Choosing Micro Four Thirds

Dan Zafra is well-known in the night sky shooter community, and with good reason. His pictures are always technically and artistically excellent. And he's very willing to share his knowledge. For me, the most useful thing he does is his annually-updated Milky Way Photography calendar, which shows you the best dates to photograph the Milky Way for your latitude. Yes, it's possible to shoot the Milky Way at other times (for me, in December), but especially for the Galactic Core, his calendar is what you should follow.

Dan’s Capture The Atlas website also includes his take on the best camera for Milky Way Photography. His most recommended models are all full-frame cameras. Because of their larger pixel sizes and advanced image processors, these will provide the lowest noise and best resolution at higher ISOs.

Semi-Technical Explanation - Noise Effects on Sensor Pixels

A larger pixel will capture more light than a smaller one. That translates into more signal output for the larger pixel before you have to amplify it and any noise that comes with it. And because of quantum mechanical effects, a larger pixel shows less thermal noise, a major noise source in CMOS sensors.

OK, what does this really mean? Thermal noise happens because electrons move in random fashion in a sensor. When you heat up that sensor (higher temperature T), electrons get more agitated and move around more, making more noise. In a smaller pixel, there's more resistance R to this motion, so there's still more noise from those pesky electrons as they bounce around. Thermal noise is proportional to √(T*R). Beyond a certain point, we can't do much about temperature inside a relatively small camera on a warm summer night. But the lower resistance of larger pixels means less noise.

The other significant noise source in a pixel is dark current noise. It comes from electrons spontaneously and randomly jumping out of their orbital position in sensor silicon. (You’d think they’d be happy with a comfortable spot, but noooo. Their bad behavior is related to quantum mechanical uncertainty.) There's more of this noise for a longer exposure - you get more false noise signals the longer you read a pixel. But in a well-designed sensor with relatively defect-free silicon, dark current noise is less of a factor. That said, it's a major reason for shooting multiple frames with shorter exposures and stacking them. Shorter exposure shots show less noise stacked together than one long exposure.

1941 Buick and Milky Way, Death Valley

December 3, 2021

What I Use

I used to shoot extensively with two mirrorless full frame systems, Canon's RF-mount stuff (with some older EF-mount lenses) and the L-mount system supported by Leica, Panasonic and Sigma. My cameras of choice were the Canon EOS R5 and Leica SL2. But because a bad back keeps me from carrying much weight (don’t try to carry 117 pound electric pianos by yourself, even when you’re young - hire roadies to help), I switched to much lighter and smaller Micro Four Thirds (u43) equipment a year ago. I primarily use it for night sky shooting and travel. Panasonic and Olympus / OM System both make u43 cameras and lenses, and there are other u43 lens manufacturers. You can use any brand of u43 lens on any u43 camera - they all work together.

I sometimes use gear with Leica's M-mount if there's a particular lens and rendering I want for a shot. My M-camera of choice is Leica's 40.9MP M10-R. That camera and M-mount lenses are not as light as u43, but they're still lighter than any other full frame camera and lenses, all of which have AF making things heavier. M-cameras also give you a choice of a clear-glass window finder with highly accurate rangefinder focusing in daylight, or live view on the rear LCD or through an accessory EVF. M-mount manual focus lenses have advantages. A manual focusing ring with an accurate stop at infinity can be preferable for night sky photography (but check its infinity focus stop for accuracy in daylight first). The only major catches with M-mount gear are it’s manual focus only - and it can be expensive.

How did I end up using Leica? I started shooting pictures with an inherited Leica M3 and lenses in 1969, so I got used to the M-system. That’s my excuse anyway.

The Best Micro Four Thirds Cameras for Milky Way?

Getting back to Dan Zafra's Best Camera for Milky Way Photography, both of his recommended u43 cameras are a few years old, and therefore lack useful features and performance of newer u43 gear. I use two u43 OM System OM-1 cameras for wide-field night sky shooting, usually with Leica DG Summilux 12mm f/1.4, Leica DG Summilux 9mm f/1.7, or Laowa 7.5mm f/2 lenses. The Laowa lens in particular is very inexpensive for its focal length and aperture, but it is manual focus. These are all prime, single focal length lenses. For a variety of reasons (most notably their larger maximum apertures and lighter weight), I prefer primes to zooms for night sky shooting. The OM-1 was released in March 2022.

Dan picked the three year old Olympus OM-D E-M1X as his top u43 recommendation. Like the OM-1, it has Live Composite for star trails, but its sensor lacks BSI (back side illumination (interconnect), metal interconnect on the back of the sensor with unblocked front for light sensing), and stacked construction (the image DRAM memory vertically stacked behind the light sensors for higher readout speed). The OM-D E-M1X also has two image processors that are a couple generations behind the faster single processor in the OM-1. (And just try saying OM-D E-M1X three times in a row very fast.)

The OM-1 Performs Better

The newer image processor in the OM-1 gives faster performance than the two older image processors in the OM-D E-M1X. The speed advantage isn't super important for night sky shooting, but very few of us have cameras dedicated specifically to night sky. When you shoot in daylight, the extra speed means faster AF when you're shooting, say, sequence pictures of aircraft in flight at an airshow. More recent image processors also show improvements in noise reduction, which does have an effect on night sky photography.

The OM-1's viewfinder EVF has over twice the resolution of the OM-D E-M1X, and its LCD has 1.6x the resolution of the OM-D E-M1X's LCD panel. Both cameras' EVFs have reasonably lag-free 120Hz refresh rates, but the OM-1's 5.68MP EVF resolution can almost make you forget you're looking through an electronic viewfinder.

Finally, the OM-D E-M1X weighs 2.19 pounds vs the OM-1's 1.3 pounds, both with batteries installed. That’s more than the full frame Leica SL2, a heavy mirrorless camera. Some night sky locations can be in pretty remote places, and a major reason I bought into u43 was reduce the weight I had to carry. OM-1 battery life is rated at 520 shots vs the OM-D E-M1X's CIPA-rated 870. That's not surprising given you can put two previous-generation batteries in the OM-D E-M1X.

But the OM-1 has a USB C port for external charging and power. That makes it possible to connect a large USB battery pack to it for much longer run times. That's very useful when you're doing a Live Composite star trail shot over a few hours. And when you don't need those longer run times, you can leave the larger battery at home to minimize weight.

The OM-1 also has a streamlined menu system, making it much easier to find things than in the menus on the older Olympus cameras.

Panasonic Lumix G9 - Second Fiddle?

I have a Panasonic Lumix G9, purchased before the OM-1 was available. That's Dan's second pick for u43 cameras. It's good enough for night sky pictures, and enables the aperture rings found on some Lumix Leica DG lenses. (Those rings do nothing with Lumix Leica DG lenses mounted on Olympus / OM System cameras.)

But the OM-1 gives me lower noise at high ISO, plus Live Composite for effortless star trails. And its Starry Sky AF actually works for star focus. No other camera has an AF mode that does that. I can't always use it - sometimes I'm shooting important foreground along with the night sky, and have to focus for depth of field. But one more overall advantage of u43 is wider depth of field for the same angle of view. A u43 9mm lens has the same angle of view as a full-frame 18mm lens, but more depth of field, since it's half the focal length. That's what allows me to more easily get pictures like this one of the Milky Way at Chaco Canyon's Pueblo Bonito ruin.

Pueblo Bonito Wall and Milky Way, Chaco Canyon

September 18, 2022

The Other New u43 Camera - Panasonic Lumix GH6

Panasonic's Lumix GH6 arrived around the same time as the OM-1. The GH6 uses a 25MP sensor of unknown construction. Yes, you get 25% more pixels. But the camera is heavy at 1.8 pounds with battery. And that battery gives you just 360 shots before you have to recharge it. With its built-in (and non-removable) cooling fan for continuous running, it's aimed at video shooters. For these reasons, it was never a contender with me for night sky shooting.

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This winter's knee and ankle sprains have healed enough that I can once again plan night photography trips. It's been fun composing music for the first time in over 20 years with great new tools, but I'm eager to get outside and shoot again.

Notes

Some of the noise theory that appears here comes from my 25 years' experience as an analog and mixed signal integrated circuit designer. That's what I did when I wasn't playing keyboards onstage or shooting photographs.

More Information

Mark Bohrer (October 9, 2022), 11th Century Ruins - 21st Century Light. Retrieved from https://www.markbohrerphoto.com/blog/21st-century-light-painting-in-11th-century-ruins

Richard Butler, Jordan Drake (August 4, 2022), Panasonic Lumix DC-GH6 review. Retrieved from https://www.dpreview.com/reviews/panasonic-lumix-dc-gh6-review

Roger N. Clark (nd), Pixel Size, ISO and Noise in Digital Cameras. Retrieved from https://clarkvision.com/articles/pixel.size.and.iso/

DPReview (February 10, 2022), Sensor readout speed of A7iv. Retrieved from https://www.dpreview.com/forums/post/65915599

DPReview (August 4, 2022), Panasonic Lumix DC-GH6 review. Retrieved from https://www.dpreview.com/reviews/panasonic-lumix-dc-gh6-review

Dyxum.com forum (January 13, 2018), Is sensor noise really that important? Retrieved from https://www.dyxum.com/dforum/is-sensor-noise-really-that-important_topic130569.html

Keith H. Lundberg (nd), Noise Sources in Bulk CMOS. Retrieved from https://www.mit.edu/~klund/papers/UNP_noise.pdf

Ben G. Streetman and Sanjay Bannerjee (2000), Solid State Electronic Devices. Fifth Edition. Prentice Hall, Upper Saddle River, New Jersey.

This is the latest edition of what was (and may still be) the textbook for the University of Illinois’ undergraduate device physics course.

University of Washington (nd), Shot and Thermal Noise. Retrieved from https://faculty.washington.edu/seattle/gis129/575%20copy/noise-pdf/harvard-noise-lab.pdf

Dan Zafra (nd), Best Camera For Milky Way Photography In 2023. Retrieved from https://capturetheatlas.com/best-camera-milky-way-photography/