John A Roberts
Well-known member
Hi Tom,
As you indicate, manufacturers/ marketers commonly use:
- W to indicate a wide field of view (or at least a wider FOV than some other model), and
- B to indicate long eye relief suitable for spectacle users (or at least a longer ER than some other model)
But of course there’s no industry minimum standards, and especially for spectacle wearers ER is often critical
e.g. see Roger Vine’s reviews where he typically compares the claimed and effective ER: http://www.scopeviews.co.uk/BinoReviews.htm
In relation to Swarovski’s models, I previously posted a table that lists all of their binocular combinations and includes their use of W and B designations
A couple of qualifiers:
- While 2 of the SL Porro models were designated B, in those instances it only indicated a folded rubber eyecup as opposed to a hard plastic one - hence my use of ‘B’ in the table, and
- N was used to designate either Normal (on the original Porros - as opposed to the standard/ unlettered 6x30 and 7x42 models) or Nitrogen filled (on the original Pocket models)
As can be seen, Swarovski’s use of the W and B designations has no relationship to front-to-rear field flatness
e.g. a flat field of view is:
- an integral part of the Swarovsion concept for the EL SV line (see the 3rd image in post #7); and
- present to a notable degree on some other models such as the current SLC 15x56 WB (see Roger’s review)
And likewise, the W and B designations have no relationship to the image shape at the side of the FOV, in terms of barrel vs global (rolling ball) distortion
In this instance we have the work of Holger Merlitz, which includes a graph at: http://www.holgermerlitz.de/newk/newk.html
- especially interesting is the wide range of values for the SLC models
John
As you indicate, manufacturers/ marketers commonly use:
- W to indicate a wide field of view (or at least a wider FOV than some other model), and
- B to indicate long eye relief suitable for spectacle users (or at least a longer ER than some other model)
But of course there’s no industry minimum standards, and especially for spectacle wearers ER is often critical
e.g. see Roger Vine’s reviews where he typically compares the claimed and effective ER: http://www.scopeviews.co.uk/BinoReviews.htm
In relation to Swarovski’s models, I previously posted a table that lists all of their binocular combinations and includes their use of W and B designations
A couple of qualifiers:
- While 2 of the SL Porro models were designated B, in those instances it only indicated a folded rubber eyecup as opposed to a hard plastic one - hence my use of ‘B’ in the table, and
- N was used to designate either Normal (on the original Porros - as opposed to the standard/ unlettered 6x30 and 7x42 models) or Nitrogen filled (on the original Pocket models)
As can be seen, Swarovski’s use of the W and B designations has no relationship to front-to-rear field flatness
e.g. a flat field of view is:
- an integral part of the Swarovsion concept for the EL SV line (see the 3rd image in post #7); and
- present to a notable degree on some other models such as the current SLC 15x56 WB (see Roger’s review)
And likewise, the W and B designations have no relationship to the image shape at the side of the FOV, in terms of barrel vs global (rolling ball) distortion
In this instance we have the work of Holger Merlitz, which includes a graph at: http://www.holgermerlitz.de/newk/newk.html
- especially interesting is the wide range of values for the SLC models
John
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