I was looking for a field in EXIF data which could distinguish whether or not a pop-up flash was used as opposed to an attached flash. I didn’t see a field in Lightroom or Windows Explorer that indisputably gave me the answer I was looking for. Ideally I would get a guide number or something distinguishable. In my troubleshooting, I opened the Image Data Converter application provided by Sony and I found a couple of EXIF fields I didn’t know were there, and maybe an explanation as to why the A900 files are larger. I also found a minor difference in the camera setups and I need to investigate whether or not I need to retest.
Here is a merger of screenshots from the Image Data Converter tool.
Take a look at the “File type” field. The A99 and A77 say “ARW 2.3 (compressed) format” and the A900 says “ARW 2.1 (non-compressed) format”. Seems pretty conclusive to me. The A99 and A77 RAW files were nearly identical in size, where the A900 files were 50% larger. I also noticed the DRO was set to Auto on the A99 and A77 and to Advanced Auto on the A900. If I retest, I probably need to turn this off to be fair. I also had CA and shading compensation set to Auto on the A99 and A77 and to be completely fair I probably need to turn those off as well.