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VBLondon
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Posts: 790

Re: Why is FX so 'optimal' a format?

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stevenj2 wrote:

That is, if a true native DX system with proportionally smaller flange distance, opening, lenses of course, and so the mechanical works, too, would have meant similar angles of view, DOF, even bokeh, achievable on DX equivalent to FX. So then I believe and propose native DX could have been just as 'optimal' as FX!

There is a native DX analogy - the Fuji X system.

They have some nice small f2 primes, but these are equivalent to an f3 in FX.

They have f1.4 primes, equivalent to f2.1 in FX.

Yeah, someone analyze the shapes and layout of lens elements of a 'comparable' DX 50 1.8 vs FX 50 1.8. Is the FX version mathematically or physically more elegant?

The Fuji 35mm f1.4 is equivalent to an FX 52.5mm f2.1, so let's compare it to the 50mm 1.8G Nikkor. They are almost identical in size and weight. The Nikkor is a bit faster, just under 1/2 a stop. The Fuji is $600, the Nikkor under $300.

Only Olympus went there in it's own way - DSLR 4/3 was changed to mirrorless 4/3 (same size sensor), had to change to new lens line.

Good example. 4/3 tried to compensate with unusually 'fast' zooms - the f2 series. For example, the 35-100 f2 4/3 zoom was equivalent to the Nikon FX 70-200 f4. Except it weighed exactly twice as much and was somewhat bigger and much more expensive. Not optimal in my book.

And so, in the broad terms, I concur, FX is 'optimal' format as you propose.

It depends!

A lot comes down to how you think about equivalence. A smaller format gives you smaller lighter lenses if you are willing to compromise on equivalent aperture. As soon as you start trying to get the fastest lenses in small formats, they get big and expensive and slower than FX equivalents.

The Panasonic 200 f2.8 in m43rds is a good example. I read a thread in that forum where someone had complained about the $3000 price tag of this not terribly exotic telephoto.

If you compare only FL equivalents, you think this is great value compared to a $10,000 FX 400mm f2.8.

If you compare FL and Aperture equivalents, you might wonder why a Panasonic 200mm 2.8 costs $3000 and a Canon 400mm f5.6 costs $1200 (weighs the same as the Panasonic), or that a Canon 200mm f2.8 costs $750 and weighs much less.