Reading resolution charts comparing MFT lenses to FX lenses

Started Mar 29, 2013 | Questions thread
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Anders W Forum Pro • Posts: 21,465
Re: Speaking of Flat Earth believers ...

John King wrote:

John King wrote:

Great Bustard wrote:

John King wrote:

Perhaps Andy had more pressing things to do than arguing the toss with you and your fellow travellers, many of whom were involved in that thread, all singing from the same hymn book ...

Seems to me that he answered succinctly and precisely all the thousands of posts you and your fellow travellers have made asserting the contrary, both before and since. Not the slightest need for him to state it again, or in a different form.

If you and said fellow travellers cannot understand that clear message, that's your problem ...

Equally, I am not interested in debating this with you either. May as well try to reason with a religious fundamentalist. The zeal with which you pursue your personal re-writing of the history and usage of photographic terms places you in this position, no one else ...

..."trying to reason with a religious fundamentalist", how would you characterize the nature of the author of the quotes POST here?

Flat earthist ... ?

But, to get things back on track, in case you change your mind, let me repeat my question (this time without the typo):

For a given scene, does f/2.8 1/100 ISO 400 on mFT (4/3) have the same exposure as f/5.6 1/100 ISO 1600 on FF?  A "yes" or "no" will do nicely.

If "yes", then I'm afraid I don't see what point you are making.  If "no", what is the significance of the exposures being different?

As always, answers are voluntary, not compulsory.  Either way, enjoy your day. 

If you prefer, trying to argue that the Earth isn't flat with a devout flat-Earthist ...
Take your pick ...

May you enjoy yours as well.

It being late here, and at the end of a long week, I misunderstood your question - I answered about the author of the referred post, not the author of the "quotes" that the author of that post has almost certainly misquoted, or quoted out of context.

Your convoluted modus operandi has this effect all the time - it appears to be directed towards adding confusion rather than clarity to every thread in which you participate. It flows through to the convolutions of your "equivalence theory" and whatever ramifications it might have for photography. I suspect the latter is limited, as Andy W stated here:

"If you decide that you want to go with something rather different, based upon depth of field and photon noise, then you can make a perfectly good argument that F2 on Four Thirds is equivalent to F2.5 on APS-C and F4 on full frame. This is an alternative framework for comparison that offers a useful different insight, but it's just that - an alternative that uses a different convention. It's just not one we've chosen to adopt (especially when writing brief specification comparison tables)."

This follows his previous paragraph that:

"However, everything comes down to what you want the word 'aperture' and F-numbers to mean, which is why both sides of the debate are so vehement that they're correct. If you're talking in terms of metering and exposure, F2 is F2 is F2, regardless of format. And that's the context we use when listing specs, because that's what manufacturers use and the vast majority of photographers understand."

Maybe you should do a course on clear "thinking and writing, rather than the one you are currently doing - "How to win friends and influence people" ...

Good night ...

I worked out for myself what is now referred to as the principles of equivalence back in 2007, when I was first about to buy a digital (as opposed to film) camera. I did so for the same reason, I think, that Joe (Great Bustard) did. I thought I needed them for the purpose of comparing the performance of different systems (sensor sizes) and choosing intelligently between them based on my own wants/needs. I also thought I needed them in order to translate my practical photographic experience (largely based on 35 mm film) to other formats.

Luckily, in the end, the whole thing turned out to be pretty simple at least in terms of general principles rather than technical nitty-gritty.

1. With respect to exposure, an f-stop is an f-stop no matter what sensor size we are talking about.

2. With respect to light accumulation (and thus photon noise), DoF, and diffraction, however, f-stops have to be divided by the square root of the sensor area in order to be equivalent. For example, if x is the f-stop on FF and y the equivalent f-stop on MFT, then

y = x / 2

since the FF sensor area is approximately four times the sensor area of MFT, and the square root of four is two. For example, if x is 8 then y is 4 so that f/8 on FF is equivalent to f/4 on MFT.

There is obviously no need to choose between points one and two above. On the contrary, that would be downright foolish. They are not alternative points of view but complementary ones. You need to understand and make use of both.

I have by now read a very large number of posts by Joe on this subject since I have often taken part in threads where we both discuss these things with people who haven't yet understood them properly. In so doing, I have very rarely encountered instances where he fails to be clear, and if he makes a mistake, he is as a rule very quick to admit it as soon as it is pointed out.

While Joe and I do not agree about everything as readily as we do with regard to the above, I always enjoy debating with him precisely because he makes an effort to be clear and has a great sense of intelletual honesty. To accuse him of being generally unclear in his thinking and writing, let alone deliberately unclear, is about as unfair an accusation as I can think of.

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