One thing for sure, other than no timelapse feature, Sony really got it right with the newly released A7RIII.  With dual card slots, a bigger, longer lasting battery, improved autofocus and touchscreen, just to name a few, the Sony A7RIII is not at the professional level for mirrorless cameras.  Sony has really stepped up their game by adding many new lenses, taking the photography world by storm.  With great lenses such as the Sony G-Master 85mm 1.4 and others, professional, high quality photography is at your fingertips.

A digital camera is no good without power so the very first thing you should have are spare batteries.  This camera takes the Sony NP-FZ100 rechargeable battery.  I make sure to have at least 3 batteries for camera.  One is in the camera being used, one on charge and one charged and ready to go.  By the time you use up one battery, you could have several batteries charged.

Now, in order to charge all of those batteries, I recommend a second charger.  You may want one for travel and one for home/studio or just always have 2 on hand to charge 2 batteries at once for those very busy days.  If you are burning up batteries that quick, however, I recommend more batteries!!  The Sony BC-QZ1 is the standard charger that comes with your A7RIII.

One more thing of importance, now that you have dual card slots would be SD cards.  You really don't need super-fast cards for this camera and I find that the SanDisk Extreme Pro 64GB SDXC UHS-I memory cards work great.  I just don't like filling up large 128GB card.  I like to use no bigger than 64GB SD cards so I lose risking less if something were to go wrong, of course.

If you do video work, or just want to protect your investment.  It is a great idea to buy a cage for your Sony A7RIII.  I have the full camera cage made by SmallRig and it fits perfectly, offering lots of 1/4"-20 holes for attachments and handles.

If you are like me, I love to do timelapse videos.  A a former Nikon Professional I enjoyed the settings that came with all of my Nikon camera bodies for timelapse.  This is one thing where I think Sony continues to drop the ball and have certainly heard our complaints.  Sony always wanted us to pay for an app which I find ridiculous, and with the Sony A9 and the A7RIII, this is no longer an option.  But alas, there is still a way to handle this with the use of a very reasonably priced intervalometer for around $24 through Amazon.

For traveling I absolutely love my Sirui ET-2204 Tripod.  It is lightweight, has an arca-swiss ballhead and folds up to fit in my small carry-on luggage.  It is a very solid tripod and I highly recommend it.

That is pretty much it for now.  I will be adding more recommendations for this camera in the near future.  Stay tuned and