Three Quick Questions vs The Enjoyment of Photography

Started Jan 2, 2013 | Discussions thread
OP Great Bustard Forum Pro • Posts: 38,968
Re: Three Quick Questions vs The Enjoyment of Photography

acahaya wrote:

grumpyolderman wrote:

Ironically, Equivalence works against larger formats, as the noise advantage for larger sensor systems disappears for Equivalent photos.

GB, enlighten me here, same scene, same metering, FF show less noise (maybe not if the sensor is 7 years old) in real pictures, why is this then? Assuming same number of pixels per sensor, the larger pixels will get more light per pixel at same exposure settings, making it easier for the sensor to generate a final picture with less noise, I would say latest sensors compared FF still has about a 2 f-stop advantage in noise alone, and some in DR

You have to adjust the ISO on FF to make equivalence work thus loosing the advantage regarding noise and DR (provided that the sensors have the same efficiency).

But it's not the higher ISO that reduces the noise advantage (if anything, it helps maintain it) -- it's the fact that the same total amount of light (Total Light = Exposure x Effective Sensor Area) falls on the sensors for all systems for Equivalent photos.

The problem with the whole equivalence theory is that many people, especially non-native speakers like me often have problems to understand the difference between equal and equivalent (= is not the same as ~).

Absolutely -- "equilvalent" does not mean "equal":

The second problem is related to the fact that people always think of exposure in terms of aperture and speed only and forget the ISO.

ISO is not an element of exposure -- it is an element of processing.  For a given scene, f/2.8 1/100 ISO 200 and f/2.8 1/100 ISO 800 have the same exposure -- the ISO 800 photo is simply processed to be 8x (3 stops) brighter.

The way GB explains the equivalence theory leads some people to believe that they have to increase the ISO on mFT for equivalent results.

Just the opposite.  The usual manner in which to get Equivalent photos between mFT and FF is to use 2x the focal length on FF, 2x the f-ratio, the same shutter speed, and 4x the ISO.

That is the reason i asked to add examples in the other thread.

All those misunderstandings cause a lot of confusion, don't ask me how often i've been told that my FT and mFT lenses are actually only half as fast as they claim to be and therefore much too expensive and if combined with the fact that FF has also an additional 2 stop advantage, you have to be a fool to use mFT at all

A 12-35 / 2.8 is equivalent to (not "equal to") a 24-70 / 5.6 on FF.  That means that it has the same DOF and projects the same total amount of light on the sensor.  However, as you note, "equivalent" does not mean "equal", and there's more to a lens than the DOF range it offers and the amount of light it projects on the sensor (although, you have to admit, those are two pretty important features of a lens).

We can debate the merits of the Panasonic 12-35 / 2.8 on an EM5 vs the Tamron 24-70 / 2.8 VC on a D600, of course, and Equivalence certainly makes no claim about which is "superior" to the other -- each system has advantages over the other.

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