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Dorian Gray
Veteran Member
 
Join Date: May 2005
Location: Paris, France
 
2011-01-11, 20:18

Quote:
Originally Posted by Matsu View Post
f/2.8 ISO 400 on APSC+0.67x reducer (net f/2 speed)
A quibble only, but you mean a 0.71x reducer, i.e. 1/(square root of 2). Edit: or more likely, you do mean 0.67x, but the f/2 speed is rounded. Fine.

Quote:
Originally Posted by Matsu View Post
What does the dynamic range of a good 4/3rds sensor look like at ISO 200 vs a full frame sensor at 800?
They'd be equal if the sensors were equally sophisticated, but at the moment most full-frame sensors, although not cutting-edge, are still far better than the 12-megapixel Four Thirds sensor.

Quote:
Originally Posted by Matsu View Post
Of course you reserve the option to shoot the FF at lower ISO as well.
Yeah: this is where the argument runs aground, I fear. And physics say we'll never overcome this either. Mid-tone grey at ISO 100 on an imaginary Four Thirds sensor with 100% quantum efficiency would still be noisier than mid-tone grey recorded by today's relatively inefficient full-frame sensors at ISO 100. No amount of new technology can change this: incoming light is just too noisy! The only way for Four Thirds to catch full-frame is by allowing much longer exposures, i.e. offering ISO 25, which can only be achieved by deeper electron wells; and since capacitance is closely related to area this is a hard ask (the old digital cameras with very low ISOs didn't have deeper wells, but rather less efficient micro-lenses — or none at all). Worse, any improvements to small sensors might be applied equally to larger ones.

Quote:
Originally Posted by Matsu View Post
It would be really interesting to see some f/2.8 standard zoom designs reformulated into f/2 APSC designs. With an extra stop of brightness, and 50% greater spatial resolution
41%, since gaining a stop would imply a 0.71x reducer. (And of course it would be a bit lower than 41% because of imperfect optics.) Edit: I should leave rounded figures alone!

Quote:
Originally Posted by Matsu View Post
After a fashion it makes sense to sell high-level, expensive APSC lenses and relatively cheaper APSC bodies. Lenses I will keep for a long time. Bodies I will recycle every 2-4 years... I don't believe that the price differential between APSC and 35mm should be so great, but maybe it is, and maybe that's where the manufacturers want to keep it?
The idea of reducers, etc., is interesting, but it sounds a lot like Four Thirds, which failed because the cost of APS-C sensors plummeted, and even full-frame sensors were put into $3k cameras. Full-frame sensors admittedly have things against them from a manufacturing point of view, which makes them disproportionally expensive and forever doomed to be one step behind the cutting-edge of sensor developments. But this is more than made up for by their real performance advantage at base ISO, which cannot be regained by clever optics on an APS-C sensor, and by the strong emotional attachment to "full frame" — note my use of this loaded term throughout this post, for example!

Last edited by Dorian Gray : 2011-01-11 at 20:33.
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