Crop Factor, Low Light and Aperture with m4/3 lenses?

Started Jun 15, 2014 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: A picture is worth...
1

Just another Canon shooter wrote:

Anders W wrote:

Just another Canon shooter wrote:

Anders W wrote:

Just another Canon shooter wrote:

Anders W wrote:

Yes it is. I compared ISO 3200 on MFT with ISO 12800 on FF, i.e., a two EV difference.

Wrong. ISO has nothing to do with EV.

Yes it does. Let me explain:

Suppose the MFT user can take a certain photo at 25 mm, f/2.8, 1/100 s, and ISO 3200. To capture the same photo, the FF user needs 50 mm, f/5.6, 1/100 s, and ISO 12800. Do you get it?

Remove the ISO from that, and you (and I) would be right.

Here is the formula for EV (wikipedia):

where

Do you see ISO there?

You already recognized your own mistake here:

http://www.dpreview.com/forums/post/53862916

That was a different thing.

No that was not a different thing. I corrected your mistake before you did. You didn't recognize that I was right (until later) and instead quibbled about my use of the term "EV" when correcting your error.

So why keep quibbling about what EV is? What I meant when I said that the difference between ISO 3200 and ISO 12800 is two EV is that the former requires two EV more exposure. Do you get it?

Nice spin. Do you get it that "requires two EV more exposure" is not the same as "received two EV more exposure"?

Sure. So I didn't say "received two EV more exposure".

Exposure on those charts is all over the place,

Exposure on which charts? The DPR studio scene? The DPR studio scene is shot such that two cameras should receive the same exposure (same amount of light per area unit on the sensor) at the same camera ISO provided that they both pass the ISO test reported in the "noise and noise reduction" section without problem.

switch to daylight, and you cannot make them equal or different by 2 stops.

In the low light as well as daylight studio scene, you can see the results for different exposures by setting the ISO of the different cameras accordingly, just as I did.

It is just a coincidence that the total light was the same in that particular case.

No, it is not a coincidence.

Do you agree that ISO has nothing to do with EV?

It is not the same thing as ISO but related to ISO in exactly the way I explained.

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