Crop Factor, Low Light and Aperture with m4/3 lenses? Part 2

Started 9 months ago | Discussions thread
Veteran MemberPosts: 3,734
Re: Here is how it actually works
In reply to Truthiness, 9 months ago

Truthiness wrote:

knickerhawk wrote:

Truthiness wrote:

Anders W wrote:

Truthiness wrote:

knickerhawk wrote:

We're talking about cropped sensors, not cropped images.

It does not matter how you crop the image!

If you need to stretch a 1cm image to 100cm output size, the aberrations of the lens will be more visible than if you stretch a 2cm image to 100cm output size. This is obvious so it is a bit odd how someone gets the motivation to argue it.

Apparently, you overlooked some of the earlier replies in the thread, for example this one:

Apparently you didn't bother to read what I wrote and have wrote before in this thread.

In other words, for two lenses with identical designs but scaled in all relevant dimensions so as to create image circles of different size (e.g., a 50/1.8 for FF scaled downwards so as to make a 25/1.8 for MFT)

You're now talking about apples and oranges.

The point made was the more you need to enlarge an image, the more the aberrations will show, thus the lower the resolution will be.

This of course only applies to the same lens only and that's been the thing I've made an argument about.

What you are now doing is that you're changing the lens. That is beside the point I was making, as the point was about how small sensor stresses the lens more than a larger one. The same lens, not a different one.

I'm not reallly that interested how lens X performs compared to lens Y regardles of how the lens Y is designed (perfectly scaled from X of whatever) as it is not the point and is often not relevant as scaling a lens perfectly doesn't necessarily achieve what one thinks it does, in practise, as the manufacturing tolerance issues etc. come to play.

And round and round we go...

By the way, your reference to small sensors "stressing" lenses suggests a new name for the focal reducer that Brian Caldwell is developing. Instead of calling it the Metabones "Speedbooster" perhaps he should call it the Metabones "Stress Reducer."

So when you don't have an argument you go to ad hominem. Please grow up.

Please apply your "stress" and "stretched" analysis to the lens used in this camera.   Is it the ultimate "unstressed" lens because the "sensor" (film) is so large or is it the ultimate stressed lens because the image required to be projected is so "stretched"?  Maybe it's somehow both?  Or maybe we'd just be better off not trying to think of it in these terms in the first place.

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