<p>Interesting thread, and so is the avalanche of elaborated posts!<br /> Sandy, neg diagonal of 24x36 is 43mm or thereabouts, so a 50 feels a little longish, for many. To tell the truth, most old nominal 50mm Summicrons are even a wee bit tighter, at 51.9mm (Read 52mm).</p>
<p>So, basically, a 35mm lens gives you a perfectly natural view with a little bit of crop margin to put lines straight...</p>
<p>Industrial standards of a "standard" lens were much more accurate in most other formats than 135, like 75mm in square MF. A 40mm in 24x36 might be the perfect all-around-one-lens option, if there is such.<br /> Hope that helped! Cheers, Knut</p>