Looking back some 3 to 4 years, I was a devoted user of Lee Filters although they were far from perfect. I didn’t think the quality was great and I can point to examples of colour shifts in my work. When I moved to Micro 43 I found the Lee 100mm filters were too large so I switched to using Hi-Tech 85mm filters and then more recently the Hi-Tech 67mm.
I was very pleased with the Hi-Tech filters and they were also much better value than the Lee equivalent. That was at least until I purchased the Sony RX10. When I use the 85mm Hi-Tech filters with this camera (the 67mm filters vignette badly) I find the sky takes on a purple tint. I can correct this in Lightroom using the grad tool but it’s annoying. What’s interesting is that this isn’t a noticeable problem when I use the filters with the Olympus EM5.
Now enter the GM1 and I found a similar problem was now occurring with the 67mm Hi-Tech filters. It’s not as strong an effect as the 85mm filters on the Sony but I can still notice it. Again, the effect isn’t noticeable when using the filters with the Olympus EM5.
It was this small but very frustrating tint that has taken me back to the Lee filters. I decided to bite the bullet and invest in the Lee Seven 5 filters, and I’m so pleased that I have. These filters and holders are very well made indeed. Best of all there is no discernible colour shift on any of the cameras I use. What really hit home for me was when I used the 0.9 Grad for this image and found the effect to be perfectly natural. If there was going to be a colour shift it would be with this filter but the results are excellent.
If you are thinking of investing in the Lee Seven 5, my view is that the expense is well worth it.
The Lightweight Photographer 
Old post but I have a question about the use of ND grad filters on MFT cameras.
Is the graduation on the Lee seven 5 ND grad filters identical to the graduation on the 150x100mm ND grad filters or is there a difference due to the targeted system (MFT vs FF camera)?
In other words, is the difference only about the size of the filters or is there more to it.
Thanks.
I just compared the two using a 0.6 hard grad and I would say the Seven 5 does have a harder/sharper transition.
I have a similar question regarding the Lee 100mm system vs. the Seven5 system. Most of my glass is for Canon with 77mm mount, but I also just purchased a OMD EM-5 MkII with 12-40/2.8 (62mm mount) for longer hikes. Is it possible to use the Lee 100mm system on both Canon and Olympus? I only ask because Lee filters are a bit of an investment. If I can get away with one set, that would be great, but if there are genuine differences between the two, it would be good to know before building up my filter kit. Thanks!
Hi Bill, yes its very easy to use the Lee 100mm system with the 12-40 lens. The only thing that I find is the 100mm filters are a little on the large size. You just need a 62mm filter ring for the lee adapter. The alternative if you want to try it out on a budget is to use a 62mm-77mm stepper ring. You can then use your 77mm filter ring on the 62mm lens. You can buy the stepper rings from Amazon for a fraction of the price of a filter ring.