Tulips with Higher Aspirations

A pleasing effect, indeed.

I say it looks rather dark. Is there option to adjust the exposure value when this pinhole effect is used?

This is what I like about this feature. The original is lighter. My photos on Ipernity always come out a little darker. The settings are automatic and most of my filters come out well exposed. Here is another flower to compare, using the same pinhole filter. www.ipernity.com/doc/821673/33818727

It is much about matter of taste of course ;-)

On many of my cameras there is also a similar feature called something like "pinhole", "vintage" or "vignetting". The reason why I usually don't like them is the way how they try to imitate some sort of a "mechanical vignetting". Anyway, the thing I find problematic or even ugly is how "white/bright" objects become gray close to edges. The way I like to work with vignetting myself is an added "soft light" blend. But these pinhole effects also have their place, like seen on that other picture of yours.