That's the thing about the non-mrcal tools: they don't give you good feedback. The pixel errors do NOT indicate uncertainties. You can trivially prove this to y

That's the thing about the non-mrcal tools: they don't give you good feedback. The pixel errors do NOT indicate uncertainties. You can trivially prove this to yourself: throw away lots of your data and re-solve. The pixel errors then decrease. But we can all agree that throwing away data gives you worse solves, right? mrcal actually gives you real uncertainties, so you can get proper feedback about what you're doing. There's a whole lot to say on this topic. If you're interested, read the docs. The "tour of mrcal" page gives a good overview.