Is there a way how to sample from small area and then apply content aware fill to the much more bigger area? For example - there is an object on a table. The object fills 90% of the image and the table 10% image. Now, I just want to delete the object. But that doesnt work with content aware fill, because the area around it is much smaller. Is there a solution for this?
Well, straight answer: It's bound to fail not only for technical reasons. Any cloning will be obvious beyond anything acceptable. find additional imagery, clone across different images/ using different layers - the old fashioned way.
What if the background is neutral and there is not much of a texture? I just want to know if there is a way how to define the area where would content aware fill sample from. I dont want to sample from the whole image only from the part I choose.
I am not sure that CAF is the right tool if you want to fill a large area sampling from a small area. You might get away with doing it in stages
One trick is copy just those areas you want to sample from, to a new layer, and use CAF on that layer, but without seeing your image, it is difficult to say what the best aproach is going to be.
There is a Russell Brown tutorial on Adobe TV that tells you how to do just what you're asking via masking. Unfortunately I don't have a link but look for a tutorial where he Replaces a curved window in a brick wall.
Yes, you need to mask the non-table area, and select the area you want to sample from: see this video that Noel referred to: http://tv.adobe.com/watch/the-russell-brown-show/masking-magic/