Cheap China filter vs. Cokin filter

No need to explain much, the pictures say it all! D90 is set to Aperture priority at f/4.5, ISO 200, focal 38mm focus on the word "AXE" with Tamron lens 17-50mm f/2.8.

First off: no filter @1/20sec


Cokin ND8 @ 1/2sec (pretty close to baseline)


China filter ND8 @ 1/4sec


Cokin ND4 @ 1/5sec


China filter ND4 @1/8sec



Cokin GND4 @1/10sec


China filter GND @1/13sec. Pretty good for this filter right ? WRONG, look at top right corner, it's pinky compare to Cokin


Bottom line is: YOU GET WHAT YOU PAY FOR!!! These 3 China filter cost ~ $20 on ebay and worth about $2 or less. Cokin cost $65 for all 3 and worth every penny.