Lunar Eclipse, which is the slowest shutter speed you can use to keep the moon sharp?

[SnowMiku]

There is a Lunar Eclipse happening in some areas soon. https://www.timeanddate.com/eclipse/lunar/2022-november-8

I've been looking at calculators to work out the slowest shutter speed for my Canon 200mm F2.8L, 1/2 sec shutter speed is what it recommends for my 90D. When I select a Full Frame sensor and less Megapixels it recommends a slower shutter speed of 1 second. This will be on a tripod with no tracker.

I don't understand why APS-C and Full Frame and the amount of Megapixels would make any difference to the slowest shutter speed I can use while keeping the moon sharp if using the same 200mm lens.

For those shooting the eclipse, which is the slowest shutter speed your going to use?

 

[neuroanatomist]

I don't understand why APS-C and Full Frame and the amount of Megapixels would make any difference to the slowest shutter speed I can use while keeping the moon sharp if using the same 200mm lens.

What matters is the size of the pixels, and sensor size and MP count are used to calculate that. The moon is moving, and the more pixels it crosses the more blurry it appears. The idea is to use a shutter speed fast enough so the moon doesn’t move more than 1 pixel.

Same reason focal length matters, the longer the FL the narrower the field of view, and the faster the moon moves across it.

Last time I shot a blood moon, it was a 0.5 s exposure with a 1D X at 1200mm (600/4 II + 2xIII).

 

[stevelee]

I shot a total lunar eclipse with my 6D2 and 400mm lens at f/8 and f/11, ISO 400, bracketing exposures. The shutter speeds for best exposure started at 1/2500 and got down to 1/60 before totality. At that point my camera became unstable on the tripod, so I gave up. I should have tried some shots handheld and bumped the ISO. But back inside, after a bit I realized had nothing to lose by trying my G7X II. Of course the image was small on the sensor, but still I got some shots at totality. f/2.8, 1/8 sec., ISO 3200. I didn't do anything in the Raw conversion to change the color. It cropped down to this:

 

[stevelee]

That was on January 21, 2019, at 12:03 am. If you zoom in a bit, you can see some stars.

 

[SnowMiku]

What matters is the size of the pixels, and sensor size and MP count are used to calculate that. The moon is moving, and the more pixels it crosses the more blurry it appears. The idea is to use a shutter speed fast enough so the moon doesn’t move more than 1 pixel.

Same reason focal length matters, the longer the FL the narrower the field of view, and the faster the moon moves across it.

Last time I shot a blood moon, it was a 0.5 s exposure with a 1D X at 1200mm (600/4 II + 2xIII).

That makes me sense to me now, thanks

On the calculator I'm using it says 1/6 sec slowest shutter speed for your setup but yours is tack sharp at 0.5 sec. Here is the link to the calculator http://xjubier.free.fr/en/site_pages/LunarEclipseExposure.html

This is one of my shots from last year but there was clouds over the moon, 90D - 200mm - F/2.8 - 2sec - ISO 800.