I have some where the old meters, however I have found no point with a digital camera, if I want to capture a picture where there is a problem getting the exposure correct, I bracket it, one 4 stops over, one 2 stops over one correct one 2 stops under and one 4 stops under. I then have two options, either select best, or load them all into Photomatrix and get a HDR version.
With old film the film cost money, so did not want to bracket it, taking 5 at a time on 36 exposure means 7 pictures only. But with 500 and you can delete in camera not worth the effort to use external exposure meter, and to be frank some scenes you just learn, 1/250 second f16 with 100 ASA for the moon for example, no exposure meter will tell you that.
I find fluorescent and LED lighting is a problem, as they often flash, so meter reading is wrong. Also I take all in RAW so either 12 bit (Pentax) or 14 bit (Nikon) not 8 bit Jpeg, if using Jpeg then the bracket needs to be 1 stop not 2, in the main I used just 3 exposures +2 normal and -2 that is enough, using old Pentax lens the camera does not measure the stop down light level, so have to manually set camera so many stops over exposed.
Not set the three variables for years, even when setting aperture and speed, the camera still selects ISO to suit. (ASA = ISO)
Just seen your other post, your camera about same as my Pentax K10D the problem is old CCD sensor, more modern cameras with CMos are far more sensitive. As with mine your max ISO is 3200, with my Nikon looking at more like 64,000 ISO so taking photos at this time of years with Pentax means tripod.
Still a very good camera, but it is now rather old. But your lens is far better than my standard lens, OK I can fit a 400 mm (600 mm in 35 mm equ) but to be frank would have been better with your fixed lens.