Anybody using MFT bodies for astrophotography?

Started Oct 8, 2016 | Discussions thread
Astrotripper Senior Member • Posts: 4,484
Re: Anybody using MFT bodies for astrophotography?
17

Legacy lenses are not a good idea for astro. I've got a bunch of them, I even did some astro with them, but a cheap Olympus 45/1.8 completely demolishes any legacy glass I ever used for those purposes. Astrophotography really requires high class optics, and legacy lenses are very rarely it.

Here's my astro album on flickr . Look at descriptions for details on how the photo was taken.

You basically have few options for astrophotography:

Wide angle astro landscapes

This is where all you need is a camera, a lens (and a tripod) and some nice scenery under dark sky. And this is where a smaller sensor of Micro 4/3 puts you at a significant disadvantage to a 35mm format DSLR. There's nothing in MFT that could rival something like a Nikon D810 with a Sigma 20/1.4. There are however lenses that close some of that sensor gap, like Panasonic 1.4/12. But that costs a lot. If you choose to shoot with fish-eyes, MFT pretty much matches FF, since there's Olympus 1.8/8. But judging from what you wrote, this is not what you want to pursue.

Deep space wide field astrophotography

"Wide" in this context means something like this . You use focal lengths ranging from standard to telephoto (lets say 25mm to 150 mm). But to really get anywhere with those, you need a tracking mount. And here's where smaller Micro 4/3 cameras have an advantage. You can freely use any of the mobile star trackers and you should be able to get long enough exposures to do some serious imaging. And you don't need a sherpa or a 4x4 to get your equipment to a dark spot, you can just walk there with a backpack. There are enough good and affordable lenses to make this work. Go to Lenstip and check out their reviews, especially the section on coma.

This is basically a mobile version of "serious" astrophotography. So of course, we are talking image stacking here, a number one tool in any astrophotographer's toolbox.

The moon

You can shoot the Moon with any telephoto lens, the longer it is, the better. Here's what 300mm gets you (I'm pretty sure this one is a 1:1 crop). Here's what a cheap 1300mm MAK telescope gets you. And here's what a lot of post-processing can get you (750 newtonian with a 2x Barlow lens and a lot of time spent stacking and stitching). An affordable telescope on a cheap tracking mount will be enough to take amazing photos of the Moon (and Sun , with a proper filter). You can even manage without tracking, but that's inconvenient.

Deep space astrophotography with a telescope

A dedicated astrograph and an advanced tracking mount are very, very expensive. But you can manage with something much cheaper. Some telescopes are better than others. APO refractors are popular for AP, but usually limited in focal length (and can get pricey). Newtonian telescopes are a cheap way to get pretty large apertures (and focal lengths). But probably the bulk of the cost will be a tracking mount.

Now, this is where a smaller sensor has it's advantages. Both refractors and reflectors suffer from off axis optical aberrations. For refractors, that's field curvature and for reflectors, it's coma. So unless you use corrective optics (which can be as expensive as the scope itself, if not more), a large sensor just goes to waste, as only the image in the center will be of satisfying quality. With my SkyWatcher 150/750, I still got noticeable coma in the corners and edges of the frame (but managed to capture supernova with it, although that is a heavy crop). Plus, a smaller body means less flex and less issues with balancing the whole setup. Definitely a plus when dealing with cheaper telescopes.

And if you ever witnessed any equivalence argument, you probably heard about total light gathering and how poor 4/3 is at it. Well, with astrophotography, you simply gather more material for stacking and you can make up for a smaller sensor that way. Basically, light gathering is determined by how much time you have on your hands

However, sensor performance becomes very important as well. And not all sensors are created equal. Old 12mp sensors were all but useless for astro, with horrible pattern noise and all around shi**t performance at long exposures. New 16mp sensors are much better. However, the ones made by Panasonic suffer from much higher levels of dark current noise. You do remove that with dark frame subtraction when stacking, but it's still a pain. Because of this, your GX7 is the worst choice for AP as far as MFT goes. It was actually a reason I went with Olympus and not Panasonic. Doesn't mean you won't be able to get good results (I even got decent ones from E-PL1, as horrible as it was), but that's not the best MFT can do. And with new generation of sensors, I'm sure the gap will be even bigger.

To sum it up, you can do astrophotography with MFT just fine. The limiting factors will not be the camera, but your telescope, mount, access to dark skies and your post-processing skills. And weather, of course.

 Astrotripper's gear list:Astrotripper's gear list
Sigma DP2 Merrill Olympus PEN E-PL1 Olympus OM-D E-M10 Panasonic Lumix DMC-GM5 Olympus E-M1 II +17 more
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