我不是光学专业的，哪位能帮忙解释一下下面的光路，它是CANON EF600 F4 L
有一个坏的，想改造，请问：
1.前组4片后面有剩余色差吗？
2.第5，6枚镜片的作用除了缩短镜桶长度外，还有别的吗？第6枚后面有剩余色差吗？第6枚镜片的作用？
3.第1枚和第8枚镜片的作用？
谢谢<img src="data/attachment/forum/dvbbs/2005-4/20054272243696371.gif" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'data/attachment/forum/dvbbs/2005-4/20054272243696371.gif\');}" onmousewheel="return imgzoom(this);" alt="" /><img src="data/attachment/forum/dvbbs/2005-4/20054272283729884.gif" border="0" onload="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor=\'hand\'; this.alt=\'Click here to open new window\nCTRL+Mouse wheel to zoom in/out\';}" onclick="if(!this.resized) {return true;} else {window.open(\'data/attachment/forum/dvbbs/2005-4/20054272283729884.gif\');}" onmousewheel="return imgzoom(this);" alt="" />