This is the first result of my new Lee nd-grad filters. I have never used grads before, so I'm still learning and I was a little surprised that I found it quite hard to see how it graduates on the lcd-screen on my A6300. Need to get used to it, I think.

This shot was taken with a A6300 and a Batis 25 with a 2 stop hard grad filter.

 

Can anyone give me some advise on how to lighten up the barn a bit?

 

I'd use an editing software like PS or GIMP, create two layers of the same image, correct the brightness of the barn in the background image and then apply a soft eraser

tool to the top layer with your current image in the area of the barn... 

 

 

Can anyone give me some advise on how to lighten up the barn a bit?

 

You could also use the brush tool with very soft feathering in Lightroom to lighten up the barn a bit.

Thanks for the advice, will try this soon and post the result here.

I tried it with both methods, can't seem to get the brush tool method working now. I must be doing something wrong, so I should research the brush tool function on youtube I think

The correction is quick and quite rough, a little more refinement alongside the edges and a little less extreme brightening it up should do the trick better.