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Archive 2013 · Lens size: sensor size, registration distance, aperture
  
 
jcolwell
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p.3 #1 · p.3 #1 · Lens size: sensor size, registration distance, aperture


carstenw wrote:
To me this kind of thinking makes no sense. "Fast" is about light and exposure, getting the shot when there isn't much light. An f/2 lens on MFT is still an f/2 lens...


+1



Sep 25, 2013 at 08:31 PM
freaklikeme
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p.3 #2 · p.3 #2 · Lens size: sensor size, registration distance, aperture


Steve Spencer wrote:
No the point is that with a larger sensor (or really any sensor) you can both have small lenses if you want and you can have shallower depth of field if you want, but they won't be the same lenses. Shallow depth of field lenses for any system are going to be large. For a FF system you could have a set of small lenses and a set of large wide aperture lenses that will be a lot larger. But this could be true at least to a considerable extent even for m4/3rds. You could build a set of
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Actually, Cosina is producing a line of f/0.95 lenses for M4/3 (17, 25, and 43mm so far) that aren't that overwhelming in size or price, given their specifications. They are fully manual, so I'm sure that saved some on size and cost. I doubt a company with Cosina's history in the industry would bother with the line if they didn't see a market for it.

I don't disagree with your supposition that lenses can be made slow and small (though I think wide angles wider than 35mm or so will prove problematic in the size department for the E-mount), and I think small and relatively slow will be how Sony launches the line. It'll be interesting to see if Sony can create a price-to-performance value proposition with those lenses that makes people want to buy them.



Sep 25, 2013 at 09:16 PM
Mescalamba
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p.3 #3 · p.3 #3 · Lens size: sensor size, registration distance, aperture


You can use Metabones SpeedBooster on m4/3s to gain a bit of light too and get effective focal length like on APS-C. If you must have fast lens.. It defies why m4/3 exist, but why not.. its better than not use some lens.

Tho Olympus used same thing when they made f2 zooms if I remember correctly.



Sep 25, 2013 at 09:28 PM
Steve Spencer
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p.3 #4 · p.3 #4 · Lens size: sensor size, registration distance, aperture


freaklikeme wrote:
Actually, Cosina is producing a line of f/0.95 lenses for M4/3 (17, 25, and 43mm so far) that aren't that overwhelming in size or price, given their specifications. They are fully manual, so I'm sure that saved some on size and cost. I doubt a company with Cosina's history in the industry would bother with the line if they didn't see a market for it.

I don't disagree with your supposition that lenses can be made slow and small (though I think wide angles wider than 35mm or so will prove problematic in the size department for the E-mount), and I
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I did know that Cosina/Voigtlander made these lenses and while they aren't huge, they aren't small either. For example the 17 f/0.95 is 540g, 63.4mm in diameter and 80mm long. That is a lens that is about the same size or perhaps a little larger than a typical 35mm f/2 or f/1.8 lens on full frame which has similar imaging capabilities. The same could be said about the 25 f/0.95 which weighs 410g, is 58.4 mm in diameter and 70mm long again the same size or a bit larger than a typical 50 f/1.8 or f/2, and the 42.5 f/0.95 which weighs 571g, is 64.3mm in diameter, and 74.6mm long again about the same size as an 85 f/1.8 or f/2. These lenses show the general pattern I was noting: when equating lenses for imaging capabilities they end up being about the same size.

I also think even the wide angles will be pretty small if they make them f/4. A 21mm f/4 for FF can be quite small and even an 18mm f/4 doesn't have to be that big and if someone makes a 10.5mm f/2 for micro four thirds or a 9mm f/2 I doubt it would be smaller. Similarly a 14mm f/2.5 for APS-C or 12mm f/2.5 would end up being the same size too. It seems to me that similar imaging capabilities regardless of the format results in similar lens sizes, and that seems to be true whether making very fast lenses for a small format (like the Cosina/Voigtlander lenses for m 4/3rds) and comparing them to moderately fast lenses on FF, or making slow lenses on FF and comparing them to moderately fast lenses on a smaller format.



Sep 25, 2013 at 09:47 PM
douglasf13
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p.3 #5 · p.3 #5 · Lens size: sensor size, registration distance, aperture


carstenw wrote:
To me this kind of thinking makes no sense. "Fast" is about light and exposure, getting the shot when there isn't much light. An f/2 lens on MFT is still an f/2 lens.

On FF f/4 gives the same depth of field, but it isn't a "speed" thing, it is an equivalence thing. Anyway, let's not open this can of worms again.



An f3.5 lens would be considered "fast" on 6x7, but not on a 1" sensor. It's all relative to sensor size.

Outside of the DOF differences, a lens at f1.8 on a D7000 at ISO 100 would be equivalent to shooting f2.8 on the D800 at a little over ISO 200. Of course, if you're not comparing similar sensor tech, that comparison may slide a bit one way or another, but it's a decent guide, and I'd imagine that the FF NEX will have similar sensor tech to the aps-c NEX cameras.

The question to me is, outside of the issues some have with X-trans, would someone rather have the 23/1.4 lens for Fuji on an X camera, or the rumored 35/2.8 lens for the FF NEX?? You're gonna have a little more equivalent speed with the Fuji f1.4 lens, but the f2.8 FF NEX lens is quite a bit more compact. It may hinge on the price of the FF NEX and lenses. Hmmm....



Sep 25, 2013 at 10:49 PM
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