I just learned about the perspective function in zbrush. however when i turn it on the model is distorted so much. feels like a 30mm lens when it says it is around 70. front view looks totally different from the front view of the orthografic view. shouldn’t they look the same on side and front?
Next to the Draw>Persp button there is a slider to adjust the focal length. Simply set it to a value that feels right for you.
thx aurick. actually my main question is that, should I be sculpting in perspective view? should I turn on perspective view only when sculpting at something like 45 degree angle, and then turn it off when I am sculpting just the front and side views?
Sculpting in perspective and orthographic modes have their advantages and disadvantages.
For the most part in my opinion you should primarily sculpt with perspective on.
Orthographic has no perspective at all, and thus is incorrect. Everything in the world has some perspective no matter how close you are or how big the object is. So if you sculpt your model in orthographic and then look at in a game engine or in max or maya or any other app it is going to look completely different because all of those apps have perspective. it is very hard to nail down realistic and correct proportions while in orthographic.
So to answer your question, no a model should not look the same from the front or the side with perspective turned on; because perspective adds perspective and orthographic has none.
The only time that i turn off perspective is to check and manipulate the overall silhouette and form of my model. This is a lot easier to do while in orthographic mode.
Thanks so much for the quick reply. Makes a lot of sense now. So in terms of reflecting what a human eye can see what would be the recommended value? I’m asking this because I heard that some artists like to sculpt in around 80-88, i can see some difference when changing to these values from the zbrush default 70. Is 70 the standard setting? I’m sorry if Im asking such beginner questions.
When i first started using zb 3.0 i didn’t like 70 setting either. I even wrote a script that automatically set it to 80 every time i hit “p”. But now I am used to it and it doesn’t really bother me and I use 70 all the time. It really just depends on what feels good to you like aurick said.
Yes 70 is the zb default setting.
Thanks so much for clarifying things for me. I really appreciate the quick replies. Did not quite expect it because it is 6:00am where I am living. Heheh maybe I should be posting around this time more often 
Cheers, and hope to see some more new posts from you.
is there any info on the different perspective focal lengths in zbrush and how close they are to Max/Maya/etc defaults?