> Think about the differences in your experience with propane and wood fired fireplaces. Our eyes and brains are very, very good at working at vastly different

> Think about the differences in your experience with propane and wood fired fireplaces. Our eyes and brains are very, very good at working at vastly different lighting conditions and presenting the results similarly. That's why they noted that one should use a camera to compare because our eyes are lying to us. (Seriously: Try to guess proper exposure needed for a photo just with your eyes. Even with experience it's hard and you're likely to be off by one or two EV (i.e. a factor or two or four in brightness!)). However, if you have EXIF info you can probably still compare brightness of flames across photos, as an image's brightness only depends on the actual scene brightness, ISO, aperture and exposure time. And the latter three are merely factors.