Question for Great Bustard

Started 10 months ago | Discussions thread
Carol T Contributing Member • Posts: 708
Re: Answer from Great Bustard:

Great Bustard wrote:

kiwi2 wrote:

In the previous thread that has seemed to have run foul of the administrator, you said..

"He was wrong to say that, too. What he should have said is, "At f/16 FF equivalent and 1/500 to freeze the action, the amount of light projected on the sensor will result in a noisy photo".

I did, indeed, say that.

Surely the lens physically doesn't become f/16 just because someone has decided they want to compare "equivalence" with some other format size?

I also had a post in that thread where I replied directly to you, with the title, "Equal to / is vs Equivalent to", and that post went something like this.

The lens on the FZ200 is a 4.5-108 / 2.8, which is written right on the lens. It is not a 25-600 / 16 and it most certainly is not a 25-600 / 2.8. However, the lens is *equivalent to*, as opposed to "equal to", a 25-600 / 16 on FF, where "equivalent to" means the same [diagonal] angle of view and the same aperture diameter.

We all understand that the equivalent focal length gives the same [diagonal] angle of view, which results in the same [diagonal] framing if the photo is taken from the same position.

However, the significance of the equivalent relative aperture, which gives the same aperture diameter for the same [diagonal] angle of view, is not understood by many. The significance of the equivalent relative aperture is that it results in the same DOF for the same position and [diagonal] framing, and *also* results in the same total amount of light projected on the sensor for the same scene and exposure time. This, in turn, results in the same noise if the sensors record the same proportion of that light and add in the same amount of electronic noise.

These points are discussed in more detail here.

So, the fact that you now call me out and "ask":

If I decide I want to compare "equivalence" of the FZ200 to APS-C, then does the lens suddenly become f/10.5?

Or if I decide I want to compare "equivalence" against medium format, then does it suddenly become a f/22 lens?

I would insert that its 108mm focal length and 38mm aperture means it's f/2.8. That does not change no matter what we compare equivalence against?

It will still expose at 1/500 sec f/2.8.

Yes? No?

when those questions were answered in detail in reply directly to you in the deleted thread, what does that tell you? More than that, it was not only me who spelled it out to you, but Richard Butler and others as well, in multiple replies to you. Yet, lock in step with all the anti-Equivalence crowd, you *actively ignore* what is explained to you. I hope this thread isn't deleted, too -- I prefer to link and quote than type it all out again when the same denials come from the same people over and over and over and over...

Maybe you could get it made a sticky over on the m4/3 forum, lol.

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