billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

Says the guy who doesn't want extra weight on his camera, and besides, I can see the bird through my viewfinder when I bring the camera up to my eye. I do not need confirmation that I can see it, I CAN see it. Why would I need a sight to see what I can already see.
Besides that, I use, what is called, (Tracking expandable spot large) on my Sony a9, once I see the bird without having to put a colored dot on the bird, the camera puts it's on own spot on it and tracks it for me, does it in the camera, do not need a manual sighting tool, I have an automatic one in the camera. It is called an advanced focusing system. You should try it.
Besides, my keep rate is almost 100%. Bottom line is, if you don't need a sight, why buy one Dik?
Below Dik, is a shot taken without a sight, just the camera.

Dik

Try one, and you will buy it. It's only $140 or so. The Olympus Dot Sight weighs near nothing compared to the camera and lens, and eliminates losing the bird in the viewfinder.

Almost 100% keep rate for BIF? What do the ten frames on either side of that shot look like, keeper rate wise.

Geegee Loc: Peterborough, Ont.

Yes, I own a red dot sight which I use with my 150-600 G2 Tamron on my D500. It is excellent for BIF and the distance from camera to subject is a non-issue.

One of the problems is that the shoe of the sight will not be snug enough in the camera's hotshoe and it can swing from side to side. I make a habit of always inserting the sight fully and rotating it fully clockwise when mounting it on the camera. If the sight is 'sighted in' this way and you always install it this way it need not be recalibrated every time you install it.

The second problem is that you cannot tighten the knurled nut enough with your fingers and you will inevitably bump the sight and it will move. I solved this problem by drilling two radial holes in the nut from one outer edge through the center and out to the opposite outer edge. This gives me four holes which allows a lever to be inserted in a hole so the nut can be tightened enough for the sight to stay put. I use an allen key as a lever because it will not bend. A thin plastic washer under the knurled nut will keep it from marking the rails of the hotshoe of the camera.

Sight it in with the camera on a tripod so that the dot is in the center of the viewfinder. When you are using it just remember that if you center the dot on the bird it will appear in the center of the picture regardless of the focal length. An advantage of the red dot sight is that you can use it with both eyes open so you have a large field of view to see the bird coming. It takes a bit of practice to be comfortable with both eyes open. You will have to anticipate where the bird will be so that you can zoom you lens for that distance. I use back button focus for continuous focus and set the camera for a small cluster of focus points around the center. Another advantage of the red dot sight is you can use it as a sighting scope for a long focal length lens to locate a bird in a tree when your camera is on a tripod. This rig is usually on a gimbal head on my monopod but it will work just as effectively on a tripod or hand held. (The battery lasts a long time but remember to switch it off when you are finished.)

Geegee Loc: Peterborough, Ont.

You are indeed fortunate to be able to see a bird in flight through your viewfinder when using a long telephoto lens but most of us are not that fortunate. Also most of us do not have a Sony a9 camera. The red dot sight may not be for you but it certainly is for the rest of us.

1grumpybear

You can not beat it for sports. You have both eye open with almost a complete field of view. Both eyes are focused on the subject with the red dot on your point of interest. What makes it great for me is if something else catches your attention that you would not see in the view finder you can immediately swing your camera to it and fire away. So for birds in flight I think it would be great because you can see what else is developing. Yes I do have to adjust the red dot to the focus point each time I use it but it takes less than a couple minutes.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

With the Nikon, I use E lenses, they keep exposures exact at 10 and even 14 fps. Focus is dead on.
With the Sony, like I said, with the Tracking Expand Flexible Spot Large, at 20 fps. all are sharp as a tack. Why do you ask? Are you not getting this.

Fotoartist Loc: Detroit, Michigan

I began using a red dot sight about 3 years ago for birds and it really helped me. Now, I guess I have a more trained eye and i don't rely on it. So, even in the long run it fulfilled it's purpose.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

It is not only with the Sony a9, I also can do the same with Nikon's GROUP AUTO focus system.
I photograph in Florida's wetlands with a group of 50 dedicated photographers, I guess we are all indeed fortunate to be able to see a bird in flight in our viewfinders. I guess because we have ALWAYS looked through the viewfinder to find a bird. And for the rest of us, we do not need a red dot to find a bird, thank you very much for your concern, but for the 99.9% of photographers who do not use a dot, they seem to be able to get along without it also.

Verryl

What am I missing in the "follow the bird in flight?" Doesn't the red dot need a nearby background to reflect off of to adjust the aim onto the flying bird? If one could put the red dot directly on the bird instantly, why would you need it?

Verryl

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

Cookie223 Loc: New Jersey

I have a number of red dot sights on a number on my firearms, but never tried it on a camera. I don’t know if this would work, but it should be cheaper. Get a hot shoe cover, then find a cheap fiber optic sight for a shotgun. Use double adhesive tape to mount it on the HS cover, see if that works for you. Orange is the easiest
to see, followed by green. If you like the result, you can trim it, and secure it with a more solid glue. If you don’t, you can use it on a shotgun. Overall cost around $20.
Good luck

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

If one could put the red dot directly on the bird instantly, why would you need it?

tlmly

Based on personal experience, I would strongly advise using a “tube” style red dot sight rather than an “open” style. My first experiment was with the open style. It worked well against a darker background but following a bird against a bright sky did not. The red dot was barely visible against the sky. Switching to the tub style made a huge difference with dot visibility in all light conditions. Perhaps I did not get a good enough open style sight and there might be some that are more visible against a bright background, but I would try to test it first. For clarification about the two styles to which I referred see:

https://sightmark.com/blog/index.php/2019/01/17/open-or-tube-reflex-sights-which-type-of-red-dot-sight-should-i-buy/

rmalarz Loc: Tempe, Arizona

I am basing my posit on the fact that light, most of the time, travels in a straight line from subject to the camera. Additionally, the sight is not in line with the axis of the lens.
--Bob

johngault007 Loc: Florida Panhandle

If you are replying thinking I was asking a sarcastic question, I wasn't.

After reading most of the discussion I learned something that I didn't know before. Well, until you came into the discussion and provided nothing except snarky comments.


Cheers