"Optical viewfinders" on mirrorelss cameras

[Tiago C]

Dot sights. I've never used one but they seem to make a lot of sense for long lens photography.

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Some advantages:

• The subject always appears to be in focus as you look through dot sights. If the camera/lens struggles to focus you have a better chance of keeping the subject on target, especially considering that small DOF. This video from Alpha Dhooters shows great examples of getting the subject back in the frame:
• The wide angle of view enabled by dot sights makes it much easier to recenter the subject if it leaves the frame momentarily
• The wide angle of view increases the chance of finding other subjects in the area and of antecipating critical action moments (e.g. bird hitting the water)
• They doesn't suffer from lag nor from low resolution
• They are very affordable

Some disadvantages:

• The sights don't allow exposure preview
• It's not possible to be totally sure which subject is in focus. For BIF I think this might not be a significant problem
• Current solutions don't allow see the camera settings as you look through
• Current solutions attach to the hot shoe, which is not very tight and consequently bumps will affect calibration
• Current solutions don't allow to preview the size of the frame on the sight

Design ideas:

I'm not sure why there isn't a camera (apart from the Olympus SP-100) with an integrated dot sight to assist in BIF and action photography.
An integrated solution could perhaps have a little screen to display the camera setting, wouldn't have calibration problems (caused by hot shoe interface), and could show a preview of the frame at different focal lengths (a few 3:2 rectangles).

Here are two more videos showing various dot sights (the sights look like a trend in China!):

What are your thoughts?

 

[Steve W]

People have been kicking this one around for quite a few years. Opinion is divided on whether it’s a benefit or a hinderance. Dot finders are common in Astro and in shooting. As for shooting things like BIF I’m not sure I’d like to be holding a 500 or 600 mm lens out in front of me.
They may have a place on lighter outfits. Nikon originally released the df-m1 dot sight for the P1000 which has a massive zoom range (3000 mm equivalent). Olympus also has the dot sight EE-1 which is similar. As they are both hot / cold shoe mounted they have found use on DSLR’s and ML. For me, I don’t think it’s right. I like my eye to a viewfinder, camera held well and stable instead of holding a screen in front of my face like a point & shoot or a phone.

 

[Tiago C]

People have been kicking this one around for quite a few years. Opinion is divided on whether it’s a benefit or a hinderance. Dot finders are common in Astro and in shooting. As for shooting things like BIF I’m not sure I’d like to be holding a 500 or 600 mm lens out in front of me.
They may have a place on lighter outfits. Nikon originally released the df-m1 dot sight for the P1000 which has a massive zoom range (3000 mm equivalent). Olympus also has the dot sight EE-1 which is similar. As they are both hot / cold shoe mounted they have found use on DSLR’s and ML. For me, I don’t think it’s right. I like my eye to a viewfinder, camera held well and stable instead of holding a screen in front of my face like a point & shoot or a phone.

That's a good point about the weight but would it be an issue on a tripod/monopod?
The advantage of a typical viewfinder as you say is having a resting point but cameras could be designed with a resting point that doesn't cover the eye.