The last weekend I did a fast test of the Benro filters in conjunction with the Haida and Lee Big Stopper, and I used the next material to do the shoots:
Este último fin de semana probé los filtros Benro en conjunto con el Haida y el Lee Big Stopper, y para las tomas usé:

• Canon 40D
• Canon EF-S 10-22mm f/3.5-4.5 USM
• Benro Holder (portafiltros Benro)

Some time ago I used to shot with a B+W ND 3.0-1,000X SC round filter with spectacular results until it fall off to the ground... due to this I started to study the best alternative in the 100x100 size, because it allow me to use ND grads without any vignetting.

I have been searching for a square (100x100mm) ND3.0 filter and I found this list:

• Formatt-Hitech Resin ProStop IRND 10 ($162.92)*
• Lee Big Stopper ($187.00)*
• Haida ND3.0 ($115) ebay
  

There are miles of reviews about the Lee Big Stopper and others filters, like the Hitech ND3.0, but now there are a new competitor in the filters sector, Haida, a Chinese company that are making high quality filters using Scott glasses (the same glass used by B+W) with a good price.

In will not to do an extensive or professional review because I'm not an expert in filters.

Test equipment:

• Canon 40D
• Canon EF-S 10-22mm f/3.5-4.5 USM
• Compatible Lee holder
• 3DPideas Lee adapter (see here)
  

I shot in a cloudy/rainy day with some sun rays once in a while, I know it was not the best day to test the filters.
The photos have been posted without any retouch, directly from the Adobe Camera Raw.

In the photos below you can see that the Lee (5950K) is cooler and the Hiada (5000K) is warmer, but not so warmer like the B+W round filter (see here) for my the photo have the perfect temperature with true colors.

In the next ones you can see a 100% crop of the images. I don't know if I'm wrong, but for my the Haida have a better definition.

And to finish an extreme b+w (yes, I love the exploded sky)...

Well, for my is very clear, if you want an excellent glass, buy the Haida filter.

In the next links you can download the raw files if anyone want to analyze the photos.

• Haida
• BigStopper

* Prices in Amazon.com (17/02/2014)