I’ve written a couple of articles in the past about ideas that I think would be really nice to see camera makers adopt and integrate into their cameras. This time I want to talk about dovetails both as a tripod mounting system and as a way to make a more rigid and potentially weather proof two part camera.
Most experienced photographers are probably familiar with dovetailed mounts with the Arca Swiss derived tripod mounts used by a whole slew of manufacturers; manufacturers like Arca Swiss, Really Right Stuff, Acratech, Markins, and now even a number of the budget Chinese tripod companies like Benro and Induro.
Mechanically dovetails make really solid joints. The angled surfaces draw the to parts together when the joint is tightened which further helps make a tight joint. Plus generally dovetails are somewhat insensitive to needing to be super precise. If the two surfaces aren’t at perfect angles, the force is applied at a point along the surface not across the whole surface, but the joint is still secure.
There are two points here for dove tails, both are related to integrating them into cameras but for two separate objectives.
The Arca Swiss 1.5“ (38 mm) Double Dovetail de facto ”Standard”
There’s a whole heck of a lot of Not Invented Here (NIH) in the camera industry, and as a direct result of that there’s a whole lot of incompatible but similar looking stuff out there. Manfrott’s RC2 quick release system uses a dovetail that looks superficially similar to an Arca Swiss plate but is wider and as a result entirely incompatible. The same can be said for Gitzo’s own proprietary quick release system; looks like an Arca Swiss plate but isn’t — It’s appreciably wider too.
So I want to make a point here. The idea’s I’m advancing in this post don’t depend on the adoption of the 1.5 inch wide Arca Swiss style standard to work, at least not in totality. Manfrottot’s standard or Gitzo’s standard would work just as well. However, there are a number of advantages I see in the ArcaSwiss standard that makes it make more sense.
To start with there’s already a whole heck of a lot of companies that are making heads that use this standard. A non-exhaustive list includes:
- Acra Swiss
- Really Right Stuff
In fact, only Manfrotto and Gitzo don’t use compatible double-dovetailed plates. And even then, Gitzo offers an adapter for their tripod heads that narrows them to be compatible with the Arca Swiss type plates.
Secondly the 1.5 inch width is just about prefect. Most Canon and Nikon SLR bodies which side cable connections have, though some minor miracle of the camera gods, ended up with the ports being less than 1–1/4 inches wide. Really Right Stuff plates for like the 5D mark III, for example, allow full access to the side connections between the rails.
Thirdly, the 1.5 standard isn’t so wide that it’s a big problem on mirrorless cameras either. Again, one only needs to look at some of the images from Really Right Stuff to see that.
Used as a Tripod Mount
Okay with that out of the way, on to the uses.
The obvious first is for mounting to a tripod.
Don’t get me wrong, I really love my Really Right Stuff camera and lens plates. They’re fantastically well made, and are more than strong enough to be effective for their intended uses. But they aren’t completely without some issues.
To start with the L-plates add overall width to the camera.
Sure it’s not a tremendous amount, 5/8 to 3/4 inch or so depending on the plate. And most of the time that’s not exactly something that matters. Except it doesn’t seem like anybody that’s designing camera bags ever considers that photographers might have these L plates on their cameras and allow for them.
Take a bag like ThinkTank Photo’s Airport Accelerator, which I tried out last year before I went to Alaska and found problematic. One of my complaints was that the bag was designed for 2 cameras to be stowed side by side across the top, with my L-plates attached, the combined extra width of the vertical side plate just didn’t fit at all. I could pack 2 cameras, but they couldn’t be packed in the tandem top spaces that ThinkTank shows on their site.
On the other hand, an integral dovetail providing a vertical rail does’t need to be as wide as an external plate. With an external L-plate the rigidity of the mounting solution has to come from the plate itself. However, with an integral dovetail the rigidity comes from the rest of the camera’s frame, and since its integral to the design, it’s all buried in the body itself anyway.
Adding an Arca Swiss style dovetail to say a 5D mark III would make it around 1/4 inch wider overall instead of the 3/4 the RRS plate adds. Overall that would make it about the same width as a 1DX mark II is.
The other problem with L-plate is especially relevant with battery grips. At least Really Right Stuff’s plates add a lot of smooth metal to the bottom of the battery grip covering up a lot of material that would otherwise be rubber grip. It’s hard for me to deny, that at least for me, without my L-plate on my gripped 5D, the vertical grip is both more comfortable and feels considerably more secure in my hand.
Both of these issue are results of the external plate having to conform to the camera. The bulk of the covered grip area is a result of the need for the plate to be designed not to rotate. To do that RRS designed the plate to wrap around part of the grip. The other factor is that the plate sticks out just over 3/8 inch (10 mm) from the grip so there’s enough material to be rigid when mounted in the L configuration.
About the only case that isn’t dramatically improved by having an integral dovetail is the case of an un-gripped camera’s bottom mounting point. Even then, having the dove tail doesn’t degrade the usability or capabilities of the camera or interfere with the operation of the camera in any way. At worst it could be argued that it makes it a big “uglier” or something, but even that could be taken care of with some cosmetic bottom plate parts that flatten out the bottom.
What about the 1/4–20 socket?
I don’t personally see any reason to get rid of it, in either use case. There’s nothing inherent in including a dovetail on the side or bottom of the camera that precludes also having a 1/4–20 socket.
For Body + Grip Rigidity
What makes a pro camera body a pro camera body?
Aside from all the obvious features, the one stand out is that the vertical shooting grip is integrated in the design of the chassis. What might not be immediately obvious from that is that the entire camera becomes much more rigid when used on a tripod.
Even ignoring the whole vertical position aspect.
Most battery grips are attached to the camera via a single 1/4–20 screw into the camera’s tripod socket. Moreover, this solution is compounded by the fact that virtually every battery grip on the market uses a relatively weak mechanism to secure that screw.
At a minimum it’s just a plastic thumb knob directly mounted to the bolt. However there have been some grips that have taken things towards being a bit more complicated.
For example, many if not all of Canon’s and Nikon’s battery grips use geared drive trains to couple the finger wheel to the bolt. I think the intent was to gain either some speed or torque over a directly driven bolt, the resulting arrangement doesn’t seem to be appreciably stiffer, and they’re certainly not as rigid as a unified grip camera design.
All of these two part battery grips share a similar feature though. The only thing that really attaches the grip to the camera is the single mounting bolt.
On the other hand, if there’s already a dovetail built into the bottom of the camera for use on a tripod, that can also be used by a battery grip to make a very solid attachment.
Remember, one of the properties of a dovetail joint is that as the joint is tightened laterally, the angled surfaces of the dovetail also pull the two parts together tighter as well. This would greatly increase the rigidity of the camera to grip joint. Maybe not to the same limits as missing the entire part out of a single block of magnesium alloy, but way better than a single bolt does now.
Moreover, it addresses some other issues that can occur.
The top center of a battery grip has to be thick enough to accommodate the bolt drive mechanism. With a dovetailed solution the clamping area, where the grip needs to thicker, is along the edges not in the center, where most camera batteries tend to be the highest.
In addition the dovetail can be tightened and set with simple screws driving a movable jaw on the outsides of the grip against the fixed plate on the camera. This is almost certainly less complicated than a geared drive system, and isn’t susceptible to the teeth breaking (which has happened on the BG-E2N grip on my old 40D).
Likewise, since there more than an inch (25mm) of clearance between the dovetail rails and the dovetail doesn’t inherently have to run the full length of the bottom of the camera to be effective — it really only needs to be centered under the lens mount — I don’t see any reason that a dovetailed battery grip would impose any kind of appreciable impediment to power or control for a grip either.
I’d like to think I’ve made a good case for this being a good idea, or at least put up some food for thought anyway. Sadly I lack the illustration chops to put up some 3D models showing my complete through process. In any event, it’s another thought to chew on.