What effect would an extension ring have

[Otta]

Hi

Could someone tell me please , what effect would an extension ring have on a 70 - 200 2.8 L is mk2 .

Thanks

 

[dibbly dobbler]

It will reduce the minimum working distance - ie lets you get closer

 

[Otta]

dibble doubler

Thanks for your reply , as soon as I posted this I came across a sticky describing its uses .

Thanks for taking the time to answer .