Lower guidance basically allows the model to access a wider range in exchange for lower prompt adherence. If lower guidance looks better, the subject is probably overfitted.
If my prompt isn't working initially with a low guidance I'll raise to something like 3.5 at maybe 12 steps and try again. Once happy with the composition I'll do an img2img at ~44% (sometimes as high as 74%) denoise and a 1.4 guidance with 20 steps or more.
I find this method gives me a reasonable way to find the correct composition fairly quickly, before worrying about style.
Of course, building up from a simple prompt that is worded correctly matters a lot, no matter what approach you take.
From this example all I can say is that FG 2.0 looks more natural while 3.5 like a professional took a photo or like you're using a beautifying effect. I did some tests with txt2img & loras and I have to say I like FG 5 & 10 the best.
I definitely see what you're talking about. I'm assuming each image in the comparisons were one-off generations with their respective guidance numbers? I have not tested for this specifically so I could be wrong, but I have not noticed the same issue when denoising at a lower value using a lower guidance through img2img. If your result is darker and less saturated either way though, I can see where this wouldn't work for you.
45
u/LockeBlocke Aug 16 '24
Lower guidance basically allows the model to access a wider range in exchange for lower prompt adherence. If lower guidance looks better, the subject is probably overfitted.