Here's three grips - one which we sell, one which we don't sell, and one which no-one even makes...yet.
Grip One - The
Nikon MB-D16 is the dedicated grip for the Nikon D750. In case that makes you scratch your heads, there is also an
MB-D17 for the Nikon D500 and an
MB-D12 for the Nikon D800, D810, D810A and D800E. Nikon have made a lot of these add-on packs for their high-end enthusiast and pro camera. They're all about the same idea - just get the right number.
The grip is big, but not too heavy. it has controls for vertical shooting, space for a second EN-EL15 rechargeable batterie, and can also take an accessory tray to use up standard AA cells. For the nervous types one of these trays is good insurance against forgeting to charge your batteries overnight. Instead, you can forget to buy AA batteries - your camera still won't run but for a different reason...
I can attest to the convenience and utility of Nikon grips if you are doing a lot of wedding or portrait work. The easier position for your right hand means that you can shoot longer and with better control than arching your wrist over for hours. Definitely a must-buy if you're working.
Grip Two - the internet iShoot casting. This fits onto a Fujifilm X-100 body - and you can get similar castings for other brands. It's an eBay purchase made just on speculation.
There's no leatherette covering to the grip handle and it is not as secure a grab for me as the dedicated Fujifilm. I find my fingers still curl over the top of it rather than securely enfolding it, but at least it is a sort of a grip.
Where it succeeds is the incorporation of Arca-Swiss rails on the bottom and the left side. The bottom one is self explanatory, but the side one is very useful for studio stand mounting on a three-way head - you needn't tilt the head 90º to go for a magazine orientation. It means that if you need both horizontal and vertical versions you can just slide the camera out of the A-S block and slide it in on the other rail. Saves a great deal of time and imaginative language. If the camera was dedicated to the studio I would unbolt the grip portion and chuck it away.
I also make use of that side rail to mount an old Metz flash on an A-S quick release plate for a big old flash/handle setup. If you use an external battery pack and a Metz hammerhead you can get extremely quick recycling time.
The downside of the casting is the weight - it is more than the others - and the slippery nature of the finish.
Grip Three - The Left-Handed Olympus Flabbergaster.
I wonder if Japan has the same percentage of left-handed people as the rest of the world...apparently about 10-12%. If it does, do they find using cameras designed for right-handed people a pain?
Of course they can adapt...they have to when they are shooting matchlock muskets at each other or they would get flash burns all the time. And some are ambidextrous anyway. But wouldn't it be nice to make a digital camera just for the lefties and soak up ALL of their business? The population of Japan is 127, 000, 000 people so 10% is 1, 270, 000 and if you sold a camera and an accessory to half of them you could buy an awful lot of saki and octopus balls...
Righto. Most cameras are right handed - except for ancient Alpas and Exaktas - and most cannot be mechanically or electronically adapted to operate left-handed. But the ones that have a firing control in the base of the camera - one that takes a switch command from an accessory grip - like the Olympus OM-D E-M5 series...
Well, you just design a lefthanded grip that screws into the bottom of the camera, ring up the advertising department, and start making room in the basement for the sacks of money. It is a no-brainer when you are just providing an electric signal with a switch.
C'mon Olympus. Make us proud.
