Hi Gary
Sigma FP
New model well worth considering.
Leica L mount
Good Ha/red response out of the box
full frame 24MPx sensor
incredibly low noise sensor
takes cheap E3 connection intervalometers
body weighs just 422g with battery
<$2000
Optional removable electronic viewfinder
Picture of Horsehead and Flame Nebula by Thierry Ligault
3-hours (360x30s) with the Takahashi FSQ-106 (F/5) and Sigma fp refiltered by Eos4Astro
https://www.facebook.com/photo/?fbid...00020990035369
Comments & noise measurements by Thierry about this camera
https://www.facebook.com/thierry.legault.5
In terms of Megapixels and print sizes, comparing the native pixel size to print resolution is a quaint notion that is about 15 years out of date. High quality low noise raw digital images have been being upsampled to higher than native print resolutions for more than 15 years. In 2006, I was given a 1000x15000 pixel image of a scuba diver drilling a core sample in a 4 metre porites coral. The image file I was given was scanned off a slide some years earlier, the slide was no longer available for rescan. The scan was good quality.
Using software and techniques available in 2008 (better techniques and software are available now) the image ended up as a 60x90cm poster print in our building foyer. I was using a 2003 version of Photoshop. That is an extreme example and it took a lot of careful work. Certainly, today, 200% upscaling is really pretty standard. You just have to learn how to do it without creating artefacts or buy software that does it for you. Without special upscale software, when you print a large image, you can set the file at 200DPI. So a 24MPx sensor, 4000 x 6000 pixel can print 20x30 inches at 200DPI. The reason is that a big print should naturally be viewed from a greater distance and doesn't need the 300-360 DPI print resolution. 200DPI viewed from 500mm away is not resolvable by the human eye. A 20x30inch print should be viewed from at least that distance if not further.
You will get a better large print from a clean low noise well-upscaled 24MPx sensor than you will from a noisier high MPx crowded smaller sensor printed at native resolution.
Joe