Before taking photographs of the interior of the St. Mary of the Angels Church in Chicago, I asked the woman in the parish office if it would be possible to turn the lights on inside the church. Lighting the church really enhances the beauty of the interior of the building. In fact, an unlit church is hardly worth photographing.
The woman agreed to light the church, but indicated that she would set the lights using a 15 minute timer. So, I was under time pressure to capture my photos! I decided to take as many of the larger scale images as I could while the lights were on and then concentrate on the closer subjects (e.g., stained glass windows, small sculptures) after the lights went off.
Given the rush, I determined that bracketing seven exposures (at one stop apart) should provide enough dynamic range to capture details in both the highlights (particularly the stained glass windows) as well as the shadows. For added insurance, I dialed in a negative two stop exposure compensation before starting my sequence of shots. I also checked my histogram to ensure that the least exposed picture in the sequence didn't have any "blinkies" (blown highlights).
Once I returned home and processed the images, I was disappointed that I didn't capture as much detail in the stained glass windows as I wanted. Given the extreme dynamic range in the scene, I should have gone with at least 9 exposures and dialed in more negative exposure compensation as well. Although there is some detail in the stained glass, it's not enough in my view:
Later that day, I visited the Bond Chapel on the campus of the University of Chicago. This time I wasn't rushed. And, this time I went with nine exposures in a scene with less dynamic range than the one at St. Mary of the Angels. The result is much richer detail in the stained glass windows with detail also retained in the brightly lit chandeliers:
The lesson for me here is that I'm no longer in the film days...digital exposures are cheap! It doesn't make sense to travel to a location and then not create an acceptable image in order to "save" a few exposures. It's better to bracket extra exposures in the sequence and then delete them during processing than it is to fall short and end up with an inferior photograph. And, just because the LCD screen isn't blinking with blown highlights doesn't mean that the sensor has captured all of the fine detail in the bright areas of the frame.
Fortunately, I learned this lesson in Chicago (close to home) before traveling to San Antonio to photograph the Missions. All of my photographs of the Missions of San Antonio captured enough dynamic range for the viewer to see all of the colors and detail of the stained glass inside the churches.