STD (Provia) vs Velvia

Hi OP,

Well, frankly speaking, there is mild difference but it's not huge. Some parts of the image have barely changed. Because that's the deal with Film Simulations - the effect is much more subtle compared to the kind of options present on Panasonic or Olympus cameras.

The only simulations that produce dramatic change are Classic Chrome and Classic Neg. These can be recognised in a blind test. The rest frankly are not vastly different. See, for example, these images from the wonderful website jmpeltier.com

The difference is obvious (river), but certainly not dramatic

Do you even see any difference? At this small resolution, I can't

I can tell them apart side by side, but given only one, I won't know which simulation it is

So that's that. Velvia sometimes delivers and noticeable punch and sometimes is pretty close to Provia. It varies according to scene and lighting.

If you need extra punch, you'll need to apply in camera tweaks.

That was most likely related to the subject, the lighting and last but not least the overall colors. Velvia can be really punchy, for my taste most of the time too much, so I barely use it. As Kamerakiri already mentioned, there are some film sims which provide a much more visible impact, like Classic Chrome, Classic Neg, Eterna or the fairly new Bleach Bypass.

There is a fairly in-depth article about the simulations over at Imaging Resource:
https://www.imaging-resource.com/news/2020/08/18/fujifilm-film-simulations-definitive-guide

Here is a direct comparison between Classic Chrome and Classic Neg, while the difference in some photos is striking and visible at first glance, on others it's much more subtle:
https://www.jmpeltier.com/classic-chrome-vs-classic-neg/

You might want to give the Fujifilm X-RAW Studio software a shot, you can download it for free directly from Fujifilm. The software needs you camera to be connected and actually uses the camera itself for all the processing, with the software being more or less a more comfortable UI to control you in-camera conversions. This is the most comfortable and easiest way to compare different film simulations on different images.

As usual, depending on the camera, you can further tweak each sim with some additional settings. For example there is a Color-setting which lets you adjust the overall color (de-)saturation of the film sim. Staying with Velvia, set Color to +3 or +4 and the impact of the film sim should be higher right away.