Davethehiker wrote:
Thanks for this link. I just placed my order. It's a little more expensive but worth it to keep it simple. I'll be mounting this on my Sony A77II with my 300mm f/2.8 and maybe my 1.4 TC.
I have a BSA 30mm Red Dot Scope (was $28 on Amazon) and an Xtend-a-Sight mounting bracket (was $31 on eBay). Works well, but it's a tad bulky. To adjust, I need to remove the adjustment caps and use a screwdriver.
I got the Olympus EE-1 Dot Sight when it came out ($129), and while it is more expensive it is much easier to use. It is lighter and more compact, and much easier to adjust using the wheels. Plastic mount means it won't scratch up my hot shoe.
Once aligned, the dot will line up with the central focus point on your camera. The dot sight has a wide FOV that is not magnified so it blends into the full FOV of your eyes.
A dot sight has three advantages. First, it makes it easy to get your camera on target. This is really good if you are shooting with a super-telephoto fixed lens (you can't zoom in/out to adjust FOV). But I find it convenient even with a zoom, because it takes time to zoom out and back in. If you want to be quick, a dot sight works well.
Second, it makes it easier to track a moving subject because it won't move out of your field of view. But you are tracking a non-magnified subject, so there is less certainty about what you are shooting.
Finally, if shooting in burst mode you don't lose sight of the subject while the camera is exposing. This is particularly important in mirrorless format because of the extended blackout during exposure. At high rates, you can barely follow a subject because it is just flashing at you in the viewfinder. But you get a similar advantage with a DSLR.
Because the hot shoe has slack, you need to align the dot sight when you mount it on the camera. Alignment is easy if using a tripod; just focus the camera on a distant object and then adjust the dot sight to line up on the same object. If hand carrying, you need to rest the camera on something that will act like a tripod. Once aligned, you can then hand hold; at least until you accidentally knock it out of alignment. But it's easy to check; just aim at a distant object and take a picture; if the object lines up on playback you are good to go.