[Brightcolours]

[quote name='Sylvain' timestamp='1331463843' post='16548']

Well, well







BC, a real question -no trick here.

Would you say that granted a similar ISO sensitivity calibration, the sensor quality difference doesn't show in a linear fashion but only as you get high in the sensitivy range? I mean, ISO 100-400 on a FT sensor being (for example) almost indistinguishably close to an APS-C, only as you go higher, the gap would enlarge exponentially? (maybe not signal wise, but visibly?) If so, wouldn't the actual larger aperture of that 35-100 f/2 be an actual advantage? Only above that "close to APS-C" ISO range, would that wider aperture only compensate for the sensor shortcomings.



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Hello fanboy. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' /> <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/laugh.gif' class='bbc_emoticon' alt=':lol:' />



Interesting how I was talking merely about the lenses, and somehow you manage to start talking about ISO sensitivities. Not sure how that works, but oh well.



But I will play your game. What exactly about ISO sensitivity? What does it have to do with f2 exactly? I really am not sure what your point is.

If you point is that f2 will somehow allow you to use a lower ISO setting...



What does that mean? Like a famous lens designer pointed out.. the aperture is only for DOF control, not exposure control (Peter Krabe, head of Leica's optics design team).

You control exposure by varying the exposure time. And if that gives you too long exposures for whatever purpose, you up the ISO setting.



So now I am puzzled what actually is it you want to argue. That you have no ability to vary ISO settings? And since you have no ability to vary ISO settings, f2 somehow becomes a plus over the same aperture, which just happens to be named f4, because the focal length is different?



Is your point that ISO 100 of a typical MFT camera is vastly superior over ISO 400 of a typical FF camera, and that therefore f2 somehow becomes a plus over the same aperture, which just happens to be called f4, because the focal length is different with an equivalent FF lens?



I really am puzzled what you want to argue. In reality, the f2 will only ever become a plus over the f4 on FF, if the f2 lens can be used at ISO settings lower than available on FF.

So, suppose the FF camera has a lowest ISO setting of 100. If the MFT camera will offer a native ISO setting of ISO 50, it will all of a sudden have a 1 stop advantage (or be comparable to f2.8 on FF). If the MFT camera will have a native ISO setting of ISO 25, it will have a 2 stop advantage (or be comparable to f2 on FF).

Of course, then the DOF settings are not comparable. It then is only about trying still to capture any image in very odd circumstances. I can not think right now of situations that would make sense of using f2 at ISO 25... My imagination apparently is too limited this sunday to think of such a situation. ISO 25 makes sense in the same way an ND filter makes sense. But f2 at those circumstances??



About my cell phone generation market remark, read it in its context. A context which was about that for instance FF 135 format users would never consider an f8-f11 28-300mm superzoom. And the cellphone generation will not blink an eye there. The comparison of lenses given is an example of that. My remark then was aimed at the small aperture lenses of MFT, not the options and abilities of the camera bodies.