Am 26.10.2014 16:12, schrieb Thomas de Groot:
> On 26-10-2014 14:19, clipka wrote:
>> Am 26.10.2014 10:22, schrieb Thomas de Groot:
>>> On 26-10-2014 9:54, Stephen wrote:
>>>> On 26/10/2014 08:13, Thomas de Groot wrote:
>>>>> But, it is the reason why on goggles, the baseline /is/ extended.
>>>>> Consider also those military stereoscopic viewers. From my own
>>>>> experience with stereoscopic viewers used for aerial photographs,
>>>>> extending the baseline makes objects appear like billboards.
>>>>
>>>> Would that not be more of the "telescopic" effect of the lens's used?
>>>>
>>> Hmm... I am not sure how much the lens influences the effect indeed. My
>>> guts tell me it is the baseline mostly, but then who would rely on his
>>> guts? :-)
>>
>> Actually it is a combination of the telescopic effect of the lens -
>> which enlarges the viewed objects in the horizontal and vertical - and
>> the /absence/ of (sufficient) baseline extension - which would emphasize
>> the depth cues accordingly.
>>
>> For instance, in 20x binoculars I think you'd ideally need a baseline of
>> around 12m; obviously this would make such devices very impractical to
>> carry around, so that's not done.
>>
> ....but which is achieved for instance with aerial photographs used for
> cartographic photogrammetry, with baselines of hundreds of metres.

... and probably also far more than 20x zoom, right?

A billboard effect in objects is an indicator that the baseline is still 
a compromise.

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