Extender and Lense

[TxFirefighter4305]

Can I double stack two 1x extenders and a 50mm to make a 150mm lense?

 

[TxFirefighter4305]

Or just one extender and my 28-90?

 

[thebeginning]

a 1x teleconverter will do nothing. a 2x teleconverter doubles the focal length, and a 3x tele triples the focal length. unfortunately, you lose quality with most 2x teleconverters and above (but not 1.4x teleconverters usually). stacking them is an easy way to lose sharpness and clarity in your pictures and increase CA. i wouldnt suggest it.