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f/2 vs f/1.2 Can you tell the difference?

What’s the difference between f/2 and f/1.2? Well, the easiest answer is… “Around $1,500.”

There is something alluring about ultra-wide aperture lenses. From the mythical Leica Noctilux 50mm f/0.95 to the absurd Zeiss 50mm f/0.7 lens used by Kubric to film Barry Lyndon – photographers always seem willing to plunk down top dollar for fast glass.

I know I have.  But why?

Having recently acquired a version 1 Canon 85mm f/1.2L lens, I’ll admit that it can be addicting. f/1.2. No, not 1.4… I mean, most blokes will be shooting at f/1.4 – all the way open – You see, you’re on 1.4 on your camera. Where can you go from there? Nowhere. Exactly! What I do, when I need that extra little push, over the cliff… That’s right. f/1.2  That’s 0.2 wider. (Sorry, Mr. Reiner)

You may ask – why don’t I just use an f/1.4 lens, bump up the ISO just a little tiny bit, or just nudge the exposure up in post? Well – because my lens goes to eleven f/1.2.

Can you even tell the difference between f/1.2 and f/2?

The reality is, that in terms of light gathering and depth-of-field, the differences between f/1.2, f/1.4, and even f/2 lenses aren’t all that spectacular. In the digital age, there are fewer and fewer practical reasons for that last, costly stop.  There’s a lot more to this, but let’s just look at some examples :

Shot taken at f/1.2, 85mm

Same background – but at f/3.5

F/3.5 is generally the widest aperture for variable aperture kit lens zooms or close to the f/4 aperture of many higher-end constant-aperture zooms. Clearly, the  f/1.2 image just beats down the background into sweet, sweet blurbutter – while even at f/3.5, you’re left with a lot of texture and distracting nonsense in the background.

Wide apertures are superb for subject isolation.

But what about f/2 vs f/1.2?

Here’s two images, one taken at f/2 and one at f/1.2… can you tell which is which?

      

 

How about some crops to help you…

Now, sure, there are some hints to the experienced eye – particularly if one sees the original RAW files… but they are pretty damn close. If you want the answer: The second image (bottom) is at f/1.2 and so are the “A” crops.

Hmmmm…. that Canon 85mm f/1.8 lens doesn’t look so shabby an idea now, does it?

The bottom line is pretty simple. Fast lenses are a LOT of fun. They do things that other lenses cannot… but when you’re thinking about your next purchase, don’t let the wine excitement of an ultrawide aperture lens go to your head. While the price differences are sometimes huge – the (smallish) practical differences  may surprise you.

 

-LB

 

 

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About Leica BOSS

I heart grain. I'm also an unapologetic Leicaphile - bringing original content and photography goodness from around the web with gear, photos & tutorials. Pay it forward.

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