Frames, Cards and confusion. Question!

sharkey

Not really a discussion this, more a plea to end my ignorance/confusion.

I use a D800 set to put RAW on the SD (16GB) and fine small jags on the CF.. In backup mode. So far, so good.

16 GB SD on its own displays 178 frames available.
4GB CF on its own displays 46 frames available. Four sets of cards tried.
File sizes are approx 42mb for RAW and 5mb for jpg.
When both in the camera available frames displayed - 199 frames??? Confusion reigns.
Instruction book states the display will show the count of the card with the lowest number of frames available and shutter release will be disabled when either card runs out of room?? more confusion.

Finished the shoot and 48 frames displayed - get home and SD is full and CF half empty with more frames exposed than appear on the SD. So, I know the cards where formatted before the shoot (habit), I know all the images are from the shoot and I know that about 30 RAW images are missing because I have the jpgs.

So that I do not lose images again when shooting this way. Any ideas what went wrong? How 5mb images on 4GB card only gets 46 frames? If no answers to be had then what card sizes should I use to successfully complete a similar shoot (100 frames) in this format?

At this point I could write a lot more but am so unsure of myself at the moment I think I'll hand over to you.

All comments gratefully received and read seriously.

Regards

Sharkey

ps.. normally I would run two cards SD as first and CF as overflow. So this set up is new to me.