Suggestion for buying a GND filter

This is a great thread idea, and I too look forward to reading the advice and rationale!

 

I'll assume it's your first time using these? And for digital?

I'd get the cheapest "good" brand and perform the basics of the process - doing as much hands-on as possible and associated post-production. Filters often-times imply use of so many additional pieces in the equation making the final product. And those costs can easily add up VERY quickly! Do ya need a tripod, holders and adapters, square (or rectangular) - and those questions you posed above.

I've a Lee Big Stopper filter and a couple Grads I got on-sale which included the holder and adapter for the lens I was using at the time - fine brand and use of the equipment is pretty easy enough. But I also got it on a significant saving from usual pricing - this brand is expensive - and recent prices look even more so now. With that said - I've no regrets getting these - top quality. But I also don't use them that often - so the cost does not sting (versus had I paid full-price).

I'm sorry this response does not really contain anything substantive - but just from experience I'd watch tutorials from notable landscape photographers posted on this forum, adopt what appeals to your interests and application, get one of the above and try it - but really work with it and even try to take a local workshop (if available in your area).

There's a little blurb here which hits on many points -
https://community.usa.canon.com/t5/Camera-Accessories/Lee-filters-vs-other-brands/m-p/243332

His response is good but I didn't see any mention of color cast per se -
You can see here if interested -
http://www.timparkin.net/2009/07/grad-filters-singh-ray-vs-lee-what-colour-cast/#comment