When posing characters, 3D programs like Poser and Daz3D help out a lot by introducing joint limits. It’s a complicated way to say that your model’s wrist can’t spin all the way around, or their fingers can’t bend in weird angles.
But the problem is, that they kinda can.
You see, when you bend your own fingers, they come up to a specific point.
But when you push them via an external force, you can bend them a lot farther.
You can check with your own fingers. Artists need to observe the world around them, and from my few drawing classes back in school, I remember that hands were some of the most difficult things to draw, requiring many practice sketches to master.
In Daz Studio it’s very easy to break the limits of the joint, you just go to the bend settings (Gear icon) that you want to manipulate and uncheck ‘Use Limits.’
This allows you to bend the finger to a more believable angle. I suggest you use reference pictures or just pose your own fingers the way you want them to see how they behave. Our fingers are springy and can bend quite a bit more when pressure is applied to them, whereas other joints like knees and elbows have a hard limit, causing damage if they get pushed any further.
These are small details but if you want to take 3D posing to a professional level, these are the kind of details that make your model more believable. Even if someone doesn’t consciously notice the error, they’ll know how fingers are supposed to work and they’ll feel that the picture is wrong somehow.
Even if they can’t put their finger on it.