Rejoice !!! Yet another equivalency thread :D Locked

Started Jan 31, 2014 | Discussions thread
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Jay Ell Regular Member • Posts: 256
Re: Rejoice !!! Yet another equivalency thread :D

goblin wrote:

Jay Ell wrote:

Thank you so much Jay !!!

That's almost more than what I wanted to know

I knew that the "standard" lens is generally accepted to be the diagonal of the sensor / film area, and that for FF 50mm is not quite standard, but close to standard, but I have completely omited that 55 or 57 would be a better "Bang for the buck".

So what would be a "standard" (in the means of - easiest and least expensive to build for a given result, not in terms of diagonal of the sensor)

Maybe better word than "standard" in this case would be "easiest" or "cheapest" to make?

And in the sense of diagonal of the sensor (or about that) word "normal" is usually used, not "standard", though I imagine both are easy to understand.

focal length in 4/3 ? Is there a formula or dependency or (should I use this word :D) equivalency to calculate that ?

If the lens is slow, you can make slightly wider cheaply than if it's fast. If it's fast, then I would guess based in flange focal distance and image circle size that mayby about 40mm lenses are in the least expensive to make, give or take a bit. I'm not really qualified to make a better guess.

I am saying "4/3", as I want to keep the constraint of the comparison with "Standard" "classic" lenses, which happen to be mostly old FF products. Removing the mirror indeed changes a lot of things, so let's make it difficult.

Or does the problem you mention above (flange distance and whatnot) completely change things in the specific case of 4/3 completely change all the requirements, making it impossible to compare ?

The 4/3 is a bit special that it has rather large flange focal distance (ie. the lens sits far from the sensor) in spite of the rather small sensor. If a FF DSLR had the 38.67 mm flange of 4/3, the fast 50mm normal lenses would be even cheaper than they're with the approximately 45mm flange they have now and there might be several 43 or 45 mm "normals" available.

The 38.67 mm allow 4/3 lenses of the cheapest/easiest kind to be somewhat shorter than the traditional 50mm, but unfortunately nowhere near to make them in the "normal lens" neighbourhood (ie. 25mm or so).

Micro 4/3 of course does not suffer from this drawback.

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