XA45 Gain vs ISO

[Paulmiller]

I know this is a topic that’s been discussed here, but I never found an answer to my question. 

I have a Canon XR45 camcorder. When in manual mode, I can adjust the gain.  If I remember correctly the settings go from zero to what ever. My light meter says set the ISO to 200.  How does a 200 ISO relate to the gain numbers in the camcorder?

Thanks. 

[rs-eos · Accepted solution]

"Gain" and "ISO" are synonymous in that they describe how signals will be amplified.  Unfotunately, from what I found over the years with camcorders, there's no easy method of determining what ISO value that 0db, 6db, etc. would map to.

I think what I ended up doing once (which was really just out of curiosity) was to set my 5D IV to the same aperture and shutter speed as my camcorder at the time, and then try to match the exposure as best I could to determine what the potential ISO value would be.

One thing I really enjoyed when I had an EOS C70 was that it used ISO values.

What always confused me about gain, is that having an electronics background, it was always "a 3db gain is double the power".  So never got used to that 6dB gain on camcorders meant 1 stop.  So on a camcorder I had many years ago, it had a gain range of 0db to 24db.  I was excited since I thought it had a range of 8 stops! But alas, its range was only 4 stops.