Comparing Olympus 4/3lenses to FX "Full Frame" offerings

Started Jan 25, 2014 | Discussions thread
Great Bustard Forum Pro • Posts: 42,061

Mr.NoFlash wrote:

Great Bustard wrote:

Well, Dave, as you know, f/2 on 4/3 is equivalent to f/4 on FF, where by "equivalent to", I mean the same aperture diameter for the same diagonal AOV, which will result in the same DOF, the same diffraction softening, and the same total amount of light on the sensor for a given shutter speed (thus resulting in the same noise for equally efficient sensors).

With this in mind, you'll find plenty of excellent lenses for FF to suit your needs. Unless, of course, your "need" is to have a lens with marked with an arbitrary number taken out of context. That is, it makes as much sense to say "f/2 on 4/3 is 'faster than' f/4 on FF" as "12mm on 4/3 is 'wider than' 24mm on FF".

In addition, when it comes to resolution, I hope you're aware that the meaningful measure for an MTF-50 test is lw/ph (line widths per picture height). If you happen to read an MTF-50 test that uses lp/mm (line pairs per millimeter on the sensor), then double that value and multiply by the sensor height (13mm for 4/3, 24mm for FF) to get lw/ph, which will normalize the resolution for a FF photo cropped to 4:3.

We both had a discussion 1-2 years ago.

I may have had it one or two more times in between.

You claim that F/2 on 4/3 (m43) IS (in most respect ) F/4 on Fullframe with your shaky unscientific theory, and first you play nice but then you imply "equal also on lowlight performance".
I said on lowlight performance you must
(a) include the fact that on 50 or 25 mm lenses you have antishake on m43 and no antishake on "the big two" FF with the wide to medium prime lenses ( up to approx 50mm ). Because if we are in extreme lowlight situations, we put prime lenses on our cameras.
(b) when we talk about equivalence we should talk about sensor cost, what can a equal expensive APS sensor achieve versus a sensor where the same cost is spread on FF ?
Part b is to some degree excercized by Fuji X who puts a very good sensor into their APS cameras.

Couple of things. First, we're talking about 4/3, not mFT. Secondly, with the exception of UWA lenses, there are any number of FF lenses with IS.

So what you always constantly imply here in the forums is wrong.

In fact, it is correct: f/2 on 4/3 (or mFT) is equivalent to f/4 on FF, where "equivalent to" means the same DOF for a given perspective and framing as well as the same total amount of light on the sensor for a given shutter speed (and thus the same noise for equally efficient sensors).

But all discussions with you will always be completely useless, you will repeat your theory until you die ( now more on the m43 forum than on the oly slr forum, you found a new playground ).

It is useless for those that choose ignorance.

I will not answer to follow-up posts of you.


It is useless.

For some more so than for others.

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