The Abnormal lens
Rogerio Salgado-Martins shares with us his thoughts on the 50mm lens, that benchmark standard to which all others are compared and asks us, why is it so?

The abnormal lens

I’ll just jump the historical part of how the 50mm lens got to be the standard of what would be considered to be normal lens. Just go to Wikipedia and they cover it up very nicely.

Since I want to propose a different approach to the subject and also discuss why we’ve stuck so long with the narrow 50mm as our normal lens, I’ll go straight to the point.

Since I began, like most, I shot with a SLR, soon to buy myself a DSLR. With that kind of camera, I saw through the viewfinder the image reflected by a pentaprism adjusted to show me as true-to-real world dimensional images as long as I had a 50mm lens attached to its body.

If you checked the Wikipedia definition, it mentions that the concept of normal lens implies reproduction of a field of view (FOV) the looks natural to the human eye. That not entirely correct. The normal lens is the one that offers the most natural perspective, in the sense of no distortions, like those caused by wide-angles and teles. If we were talking about FOV, certainly the FOV of the 50mm would not be, by far, be “natural”. Soon we’ll approach that.

Back to my path (D)SLR and the 50mm: I used this combo for almost four years. But I always felt that what I saw was too narrow. I kelp using it because I liked the fact the once I lifted the camera up to my eye, the viewfinder would show me exactly the proportional view of what my eyes were seeing without the camera. I tried wider lenses with my reflex cameras, but the shock I felt of the image pulling me back, forcing me to readjust, didn’t seem right. Like Bresson said – although I wasn’t aware of the saying by then – I wanted the camera to be an extension of my eye.

Why is that? Because the prism was calibrated to consider as normal a 50mm lens. The normal look would only be achieved through that lens. And hence the Wikipedia misleading definition. If only FOV were taken into account, we’d use ultra-wide angles that reach 92º to get close to what we see normally with our eyes.

The 50mm lens offers an angle of view of 47º. That’s practically 45º. Considering our eye is able to reach 92º reach, or something like that, side to side, that pretty narrow. Can’t we go wider without losing the natural feel?

Yes we do.

What has to be considered to establish the idea of “normality” is the diagonal of the film or camera sensor. Each format has its “normal”, it all depends on the size of the diagonal. In the case of 35mm, that is a 43mm diagonal. Hence – a 43mm lens would be the normal lens. 50mm? Pretty far, don’t you think?

So, I guess is only fair to say: 50mm is tele. Just plain, simple, tele.


The great Oskar made this call of making a tele the normal lens and since forever (D)SLRs are calibrating their prisms around it, when it should be the closest round number available, the obvious choice: 40mm. Some companies use the 40mm. Voigtländer has some nice ones. I have a 40mm equivalent, probably one the best lens I’ve owned, the Panasonic Lumix 20mm f/1.7 for micro 4/3. People call the 40mm the “perfect normal”, not without a reason. It offers in a full-frame camera 57º of FOV, ten more than the 50mm. It is the perfect natural view with 10º more of FOV. So much for a bad call made a hundred years ago.

Why not, then, together with the natural perspective, we do consider the FOV as a criteria when electing the normal lens? There’s no way to reach both ends. But we can get as close as we can to both. With the 50mm, in terms of FOV, we go as far as we can get at both ends. That’s just unbelievably wrong. Comparing to the perfect normal, the 50mm has distortion of +10mm long and 10º less of FOV.

It all changed to me when I made the move to a rangefinder camera. Suddenly – now aware of Bresson’s quote – I realized how narrow a 50mm lens looks through a 0.72x magnified viewfinder. It’s not at all natural. It’s a tele. What I want to propose – my whole point of this piece – is that, if a stretch was made to make the 50mm normal, why not consider the 35mm lens the new normal? At least in a rangefinder camera with a 0.72x viewfinder it is.

The 35mm lens offers 63º of FOV. That’s 16 more degrees of FOV will get than with a 50mm. Comparing with the diagonal, the 35mm stretches only 1mm more than the 50mm – 5mm if you take in to account the 40mm, the so called perfect normal lens. So, in terms of distortion, they’re in the same boat. The difference is that with the 35mm you’ll get 16º more FOV. Unless you’re really into bokeh, I don’t see how there’s no obvious advantage in this shift of paradigm: we get the same, or better, approach to a natural perspective than the 50mm would offer, considering their relation to the diagonal; and we’ll be a lot closer to the FOV of the human eye. Isn’t that what a normal lens is supposed to be?

It’s hard to imagine companies readjusting their DSLR prisms. The simple awareness of this, though, could be considered a beginning –  to the fact that, unfortunately, we’re stuck to an arbitrary, misleading and limiting parameter. In the end of the day, we have to settle to the calibration companies set their prisms and finders. Even with rangefinders. The main difference is that with reflex cameras, since you see through the lens, your adjusting is painful and uncomfortable, while with rangefinders that doesn’t happen.

Lastly: I think the best lens is that one you feel better using. I don’t defend the 35mm or think it is the “right one”; actually, I personally prefer wider lenses. So, please, if you love and use the nifty-fifty, don’t take it personally. This is purely a technical debate that has the objective to encourage discussion in our community.

I hope you’ve coped with me this far. Thank you for reading!

Rogerio Salgado-Martins


Thanks for sharing this with us Rogerio. Some interesting points there. I would really like to hear what others think of this and what your perspectives are. I personally prefer to shoot 35mm on a Rangefinder, but for an SLR 50mm.