The blue dot on mamiya tlr lenses is an indicator of the later batch of Mamiya lens. the most common one is the 80mm/2.8 lens, which you can easily find on ebay.

However, many sellers started branding this “blue dot” and selling for a premium of these “blue dots”. Does it really worth a premium?

What do you think?

I did a little bit of research and compiled opinions from a number of mamiya users. Here is what they say.

I’m not entirely sure on the blue dot lenses. I do have a 80/2.8 blue dot lens. It’s nice and sharp and has good resistance to flare. The shutter is very strong compared to my other lenses (including a black, non-blue dot lens).

…. The blue dot may be an indicator of the later model black TLR lenses. It doesn’t necessarily mean they’re better or have a different optical formula. But they’re likely newer than the non blue lenses. So you’re likely looking at a newer, stronger shutter and potentially better coatings. Otherwise, it’s very likely they are the same as the regular black lenses equivalents without the blue dots. – Flickr Pro user

Sometimes the blue dot falls out leaving a recess where it used to go. The blue dot had more to do with marketing than with functional improvement. A more accurate indicator of age is whether the aperture ring has click stops which was phased in during the 1980s. Some blue dot shutters have them and some do not. It is a nice feature. I have several lenses that have the click stops and a recess in the shutter cocking arm for a blue dot but no blue dot. They seem to work fine without it.
The point is that it is far more important to have a lens with good glass and a reliable shutter than a blue dot. – Flicker user

Nothing special about the “blue dot” lenses except that they are just later versions of the black (as opposed to the earlier chrome) versions of the lenses. As far as I know, there is no substantial difference in the mechanical or optical qualities of all the black lens sets. The blue dot on the cocking lever may have some significance to a collector, but no practical difference to the user. I wouldn’t pay a premium for it; but then I buy equipment to use it, not to have it sit on a shelf as a show piece. – Apug Member

Blue-dot doesn’t really mean much. It’s literally just an insert in the shutter mechanics. People believe it signifies something – but I say it’s BS. – Apug subscriber