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What Is The Fastest Lens Possible? How ‘Fast’ Should We Go Before It Makes No Practical Sense?

By Kishore Sawh on November 18th 2014


This may sound churlish, but it boggles my sensibility when I see photographers obsessed with aperture values, F-Stops. I would go far as you say that half of the gear lust I encounter has to do with some lens’ ability to defocus a background to the point of utter obscurity, and gather light so well it can see through clothes, and time.

[REWIND: F-Stops & T-Stops? Which One Matters To You & Why]

For those budding photographers who are just getting started and beginning to see the correlation between aperture and a specific image result, and are learning to recreate the images they have admired, this is to be expected. This group is consumed with the desire and need to experiment, and while it’s like world ambition running at full speed before the talent can walk, it’s understandable. But the obsession extends beyond the beginners, and it’s concerning. A more blurred background does not a better picture make. Having an insanely faster lens today is also becoming less a concern with the rate of development of new sensors.


I often get asked about lenses to choose and most of the time, the questions revolve around what aperture to look for, and then digresses into just how fast a lens can get. In this video, Matt Granger addresses the topic of speed and theoretical F-stops. Just how fast a lens is it possible to make? Going over how aperture is measured and f-stops are arrived at, to the impracticality of having lenses past a certain ‘speed,’ Granger does a decent job touching on the key points.


If you’re interested in learning more about F-stops and T-Stops and what they really mean to you, check out this article I wrote a few weeks back which should cover most of what you’ll want to understand. Also be sure to see more from Granger on his site and YouTube.

Source: YouTube

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A photographer and writer based in Miami, he can often be found at dog parks, and airports in London and Toronto. He is also a tremendous fan of flossing and the happiest guy around when the company’s good.

Q&A Discussions

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  1. Rich Zimmermann

    Being a rock’n’roll photographer, a 70-300mm f 1.8 would be awesome. With VR of course for my Nikons.

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    • adam sanford

      I wouldn’t hold your breath, unless Sigma really offers that f/2 zoom we’ve heard rumors of.

      If you’re a rock *concert* photog, I think you’re stuck with the choice of a “slow” f/2.8 zoom or two bodies with decent f/1.4 (standard FL) or f/2 (short tele FL) primes for the foreseeable future. I see so many concert photogs in the pit at rock concerts packing 24 f/1.4, 50 f/1.2 and 135 f/2 lenses for that reason.

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  2. Peter Nord

    Don’t we all want a 50 the size of a dinner plate?

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  3. norman tesch

    i seen an article where the people using a cropped sensor camera really arent getting the joy of say a f2 but with the crop you also get cropped stops in that lens. so for full frame cameras we get f2 and cropped get f2x 1.6…that isent advertised to often. how many people would buy cropped sensor if they knew that?

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    • adam sanford

      Norman, we hear that often. The isolation of the subject ‘pops’ less on APS-C vs. FF at the same aperture, this is true.

      But not everyone is using huge apertures just for small DOF. An large aperture lens lets in more light to allow for quicker shutters in tough environments, and *that* isn’t affected by crop factor. Folks trying to capture very dark scenes handheld where IS won’t save them — scenes where you have a moving subject in poor light and (for various reasons) you can’t use a flash — absolutely love large aperture glass. Photojournalists and especially concert photographers fit into that category.

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  4. adam sanford

    Or, put another way, some folks want microscopic camera bodies to shoot in absolute darkness without noise.

    The pursuit of such unreasonable expectations hurts our backs and wrists from lugging massive and unbalanced rigs around, it hurts our eyes from all the post-processing we do to chase the noise and it hurts our bank accounts from pushing the limits of what sensors and optics can do.

    Call me old-fashioned, but that doesn’t sound like that much fun to me.

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    • Holger Foysi

      You don’t have to buy and carry those lenses. So where is the problem?
      I, personally, like large aperture lenses.

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    • adam sanford

      Holger, there is nothing wrong with it at all. Large aperture glass is really fun to use and takes unique shots.

      I’m just agreeing with the author’s point about enthusiasts (of late) seem to obsess about large apertures. More and more, I hear questionable comments like “I almost always shoot this thing wide open because **why else would you buy an f/1.4 lens?**” and I just shake my head.

      It’s like a creamy large aperture shot is the only ‘photography catnip’ some folks want to chase after — which I’m fine with — but it’s the disdain and lack of understanding why anyone would want to shoot anything else that I just don’t appreciate.

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    • Holger Foysi

      I like the option of being able to use it wide open and, most of the time, get higher resolution already at earlier apertures when stopping down.

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    • adam sanford

      Agree. f/4 is the new f/8 on modern glass, it seems.

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  5. Brandon Dewey

    Great article and video

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  6. adam sanford

    With pickle jar sized f/1.4 primes as big as f/2.8 zooms, we are approaching the limits of what our hands can comfortably carry around all day. That’s why no one has made a 24-70 / F2 zoom for FF cameras — it would likely look/feel like a 70-200 f/2.8! (Sigma might be crazy enough to do it, though — there have been rumors)

    But IS is *far* more lightweight to implement. So one might imagine that the lenses of our near to mid-term future are far far far more likely to have the *same* max apertures we use today but with more sophisticated IS systems that buy us 4, 5, 6 stops of shake reduction. It’s not what small DOF obsessives want, but it’s what they’ll get for the most part.

    But fear not, f/0.9 people: there will always be third parties making a huge lead pipe you can bolt on to a deck of cards sized mirrorless body to shrink your DOF or attempt to shoot in complete darkness. :-P

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    • Adrian Jones

      Stressing is is such a great point because ultimately its about how much light you can get to the sensor. A lot of time people obsess over low apertures because they of the added light but if you can lower the shutter speed you get more light. People also think their out of focus areas are going to better because they have a low aperture lens and this is false. I’ve seen some disgusting bokeh come out of low aperture voigtlanders, some even consider the sigma art 50mm 1.4 to have less than pleasing bokeh. It seems the glass and treatments have more of an effect then Fstop. But more importantly how what the heck do you expect to get into focuse with a DOF of .01mm?

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