Transparency and zooming

I have rendered some transparent objects using alpha blending, and I have zoomed the transparent objects by changing fov (also tried camera src point change) and I get a color change near the top and bottom edges of the object when I zoom to close. Can anyone tell me why this is happening? Is there any work around for this.
Thanking You,

this may be due to 2 things i think !
1st, your z buffer isn’t initializd correctly
2nd, are you using texturing ? if yes, maybe correct the lod.

I am initializing the Zbuffer properly to 32bit and also setting the DEPTH_TEST accordingly. It was displaying properly
when the objects are rotated, but it gives
color change only when i zoom in only, that too when too close the objects.