Whenever possible, for maximum quality, pictures should be made at base ISO which means with very high quality high speed lenses and preferably in diffused light.
To illustrate this, shooting at base ISO 200 on my Pen-F inside the engine shed that houses the broad gauge engine Iron Duke, I wanted to capture this lovely trolley load of antique luggage with maximum iQ in beautifully directional light. For this I used my 17mm f1.2 Pro lens for its light gathering power and high end optical quality. As the Four Thirds Organisation truly says, "The camera begins and ends with the lens.”
Above is Iron Duke itself in similar lighting conditions and taken once more at base ISO on the 17mm f1.2 for optimum iQ. I love the tone, texture and detail plus the way it goes from sharp from the left to the middle of the image and then progressively fades out to unsharp the further to right you go, reflecting the depth of field at f1.2.
More luggage this time using dark light to make the subject stand out against its background and add a bit of melodrama to the image and also add a sense of mystery plus a sense of connection with the main subject to the door at the rear of the shed.
Yes and finally a selfie of me with the Lady of Legend 😊. You can see my reflection as I am taking this picture of new 2019 build No 2999 steam locomotive in the guise of a Great Western Railway's "Saint" class design, all the originals having been scrapped in 1953.
Other images in the same set may be found here.