Originally posted by ManuH For the public used to 3x, 5x and even 10x (Panasonic TZ5, Canon SX100...) on a compact body, how to sell a camera with a prime lens or a very limited zoom range?
For my argument, I will first have to prepare some facts. By "mFT, FT, mPK, PK" I mean the micro4/3, 4/3, Pentax APS-C and Pentax FF K mount specifications. Here we go:
Image Circle Diameter ICD (mm / crop-factor):
mFT: 21.63 mm / 2.00
FT: 21.63 mm / 2.00
mPK: 28.12 mm (K20D) / 1.54
PK: 43.27 mm / 1.00
Mount Hole Diameter (mm / %ICD):
mFT: ~42 / 194%
FT: ~48 / 222%
mPK: 47 / 167%
PK: 47 / 109%
(original M42 was 97%. So even ~100% isn't or wasn't ambitious and originally only introduced for f/1.2 lenses. The early "digital" requirement for larger mounts was lifted due to advances in micro lens technology.)
Flange Back distance (mm / %ICD):
mFT: ~19.3 mm / 89%
FT: ~38.67 mm / 179%
mPK: 45.46 mm / 162 %
PK: 45.46 mm / 105%
(limited by mirror box to >56%. So even a figure ~100% isn't or wasn't ambitious)
Now my argument:
Both, FT and mPK are ill-defined standards with way too large measures for the given image circle. mFT actually only brings these measures back to normal as we already had for PK. Therefore, going full frame will do the same trick for Pentax.
(ok, the mFT mount hole is still huge -- but a lens isn't forced to be equally large and Olympus got their own legacy problem with FT lenses here
).
This does also mean that a FF lens can be scaled down 1:2 to get a lens with equal relative resolution (ignoring diffraction, of course), field of view and aperture in F-stops.
One such example is the Sigma 28-300mm F3.5~6.3 DG Macro (Full Frame). It is 74 x 86 mm (diameter x length) and 490 g.
A corresponding 10x mFT zoom would then scale to these properties:
Olympus 14-150mm F3.5~6.3 10x Macro (mFT). It is 37 x 43 mm (diameter x length) and 80 g.
I ignored here a 44 mm flange diameter and rounded the x 1/8 weight-factor up to allow for materials not exactly made thinner by 1/2.
Originally posted by ogl There is also the problem with dust for camera without mirror, but with interchangeable lenses. Don't forget that such small camera won't has Shake Reduction system like E-420 has not.
Any size camera can have shake reduction. Even P&S do. E.g., the Pentax SR subsystem is relatively small and very thin.
Originally posted by take Got one Oly buddy demonstrate when compact body meet ZD ED14-35mm F2.0 SWD. This is how it will look:
Argument not valid. Cf. above. FT wide angle lenses had to be unneccessarily large because of their 179% flange back distance.