A retailer told me some months ago that Manfrotto of all people were calling for a standard and it would be the Swiss Acra type. Looks like it's happening as for instance Ebay listings mention it more and more.
Trouble is what is the standard? The wiki mention a width of 38mm but where? I have one where the plate measures 43.5mm across the widest part of the dovetail and around 39.3 across the shortest. The top plate on it is 53.6mm wide in that direction.
The weird thing looking around at them is that it may be more sensible to use them with the clamping knob sticking out of the back and some have spirit levels that would be hidden under the camera. On others it might finish up under the lens. A few have them on the sides so are always "visible".The one I have is clearly intended to be used with the clamping knob under the camera. A weight saving measure as it's only 35mms across the plate in the other direction. The minimum opening for the clamp with the plate out is 38mm at it's narrowest point. I'd guess that really is the Acra standard.
A really serious topic of conversation. What is the correct standard size and just which way round should they be used.
If various companies make a "standard" to various sizes they carry on supplying all of the quick release plates to go with their holders. Actually the way the clamp is secured in the holder there isn't all that much scope for size variation in the plates without what could be a serious loss of strength and rigidity.
John
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