For fun I did the following. The first shot was taken with my Kino Precision f2.8 105mm Macro lens. I set the shutter speed to 1/125 just like the OP had his set to in his setup. Aperture ring set to f4 (this is not an A-type lens so no good information in the EXIF on the files) and ISO set to 200. I wanted to get an image that just showed the item I was taking a picture of to show how pushable images out of my camera, the K-5 II. Here's a JPEG rendition of that image with nothing done besides a resize and JPEG conversion (quality slider set to 9 on the save);
Here's the image after going through Lightroom with the exposure slider set to +5.00, the max it will go, and then the other sliders tweaked for what felt like best results that I could reach in about a minute of playing around. Resize again done in Lightroom along with conversion to JPEG. No denoise work or anything like that to the file, this is just quick slider work in Lightroom on display;
If Adobe allowed for more distance to slide in Lightroom I'm sure I could have used a worse file. ISO is nearly meaningless in the captures *in this example**grain of salt of course*.
YMMV, not sure if the images out of the cameras you are using are as pushable as the ones I get from mine, although I suspect they are not much worse in this regard. The K-5 II and IIs were really good at this sort of trick.