(This post is from an email conversation with a friend. I thought the content might be useful for others.)

Great to hear from you, and very excited about your new D850!  I know you are going to like it.  But wow, the cost of it plus the housing is pretty rough!  Our introduction and conversation in FL was pretty costly for you!!!  🙂

I bought a manual for the D500 because of the pretty dramatic changes / improvements in the AF system.  I had never done that before, either!  I bought mine from Thom Hogan.  His book on the D850 just came out.  And he just published his online review of the D850 yesterday.

You had emailed a couple of weeks ago while I was in Hawaii.  Sorry I’m such a slow responder.

I’m not sure what Brad might have meant about two different grips for the D850.  There’s only one Nikon grip.  Maybe he meant you needed to order two different part numbers to use the grip with the D5 battery?

Here’s what you need for sure:  (Note I am using “x” as a generic placeholder below.  E.g., the EN-EL15x represents two varieties, the EN-EL15 and the new EN-EL15a.)

MB-D18 – That’s the grip, and it comes with two different battery holders, one for the default D8xx/D5xx battery (EN-EL15x), and another for 8 AA batteries.

Neither of those give you any additional speed.

If you want 9fps versus the default 7fps, you have to use the battery that is used in the D4/D5, the EN-EL18x.  The EN-EL18 has less capacity, and the EN-EL18a and EN-EL18b are essentially identical.  All of them raise the top frame rate to 9fps.  To use any of the EN-EL18x batteries in the MB-D18 grip, you have to purchase a little item called the BL-5 Battery Door for around $30.

BTW, even though the D800/D810, D500, and D850 take three different grips, all of the battery holders work fine in all three of the grips.  (A nice thing for me since I have all three.)

Starting with the D800, Nikon really jacked up the price of the grip / battery / charger.  It’s basically $1k to get the additional speed / capacity / controls.  Ridiculous!  But it’s still worth it to me.  I saved some money by purchasing a 3P charger by DST.  It looks and functions perfectly like the Nikon MH-26.