Originally Posted by Pinewood
Beneath that rather ugly exterior, the Canon 10x42 L IS,beats a Porro prism binocular heart, so it has true stereopsis. The Canon may be considered a true Alpha Porro.
Happy bird watching,
While the Canons are now all poro prisms and have most of the benefits that that optical design bestows, their set up isn't the same as for a "normal" poro which has a much wider objective spacing than IPD (eyepiece spacing).
My Nikon 8x32 SE has an objective spacing of 132mm and a my IPD is 69mm, so quite a significant difference and this gives an appreciable 3D effect: like having you eyes set 132mm apart.
I have just measured my 10x42L and the objective spacing, which is fixed, is 69mm and my IPD is also 69mm. This suggests to me that there is no more 3D effect than a roof which will have a similar straight through view. Most people will have an IPD within a few mm of mine, so even if it is different it will not make any discernible difference to the negligible 3D effect.
Having said that it doesn't diminish from the fact that the Canon 10x42L is a brilliant binocular.
PS Kimmo sorry for saying what you have already said but I missed your post #11.