How to plot log

I'm trying to plot this function and my plot should look like the second picture ( for a= 110, b=2,c=2., d=7) but mine doesn't can you please tell me what im doing wrong? this function gives Log ( CSF) but plot is for CSf vs F

function func = qcsf(a,b,c)
f=1:5;
x= log(f)-log(b)  ;
y= c*(log(2)/2) ;
csf= log(a)-log2(x/y).^2 ;
qcsf= power(10,csf);
figure
plot(f,csf);

Answer 1

[Rafael Hernandez-Walls]

change

plot

for

semilogy

Answer 2

[Jas M]

i did but y axis values are completely different..