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

Started 4 months ago | Discussions thread
Anders W
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Re: Crop Factor, Low Light and Aperture with m4/3 lenses? Part 2
In reply to Just another Canon shooter, 4 months ago

Just another Canon shooter wrote:

Anders W wrote:

My point is that the "enlargement theory" proposed in the OP of this thread is wrong. Whatever advantages the larger format has, that's not the way it gains them.

Using wrong arguments to disprove a wrong theory does not make you right.

I used the right argument to disprove the wrong theory and prove another one correct.

None of the posters here which are still active says that it is a simple matter of more enlargement.

May I remind you that you entered an exchange between me and posters who made claims based on enlargement that there were good reasons for me to question. Whether these posters are still active in the thread or not is secondary but at least one of them (the OP) has continued to post on that topic as you can see here (and subsequent posts in that subthread):

http://www.dpreview.com/forums/post/53901715

Rather, the simple truth is that it is easier, regardless of sensor size, to make an f/2.8 normal lens that performs well wide open than to make an f/1.4 normal lens that performs similarly well wide open. The aberrations you have to correct for decent performance are simply smaller at f/2.8 than at f/1.4 and that's it.

Right.

Good.

The lowly Canon 50/1.4 at f/4 beats the Panasonic 25/1.4 at f/2 by a comfortable margin (PZ) both in the center and at the borders,

Did you see the big sign on PZ's home page saying that their results are not comparable across sensors/platforms?

That is what you actually get in reality.

With the 25/1.4, yes. That's why I prefer the 20/1.7 (and the 1.7 to 2.0 range over 1.4).

Panasonic 25/1.4 on E-M5 (16 MP)

1.4 690/590

Canon 50/1.4 on 5D2 (21 MP)

2.8 920/690

See? The 25/1.4 is well behind. BTW, the figures are per picture height. Per diameter, you have to add 8% to the FF format.

As I said, I don't find much need for the shallow DoF that comes with a 50/1.4 wide open on FF and the lens is big and heavy.

And yet, you cannot tell just by looking at a few pictures which DOF is enough for you.

Of course I can.

Do you find the DOF below too shallow (sorry for the boring photo)?

Yes.

I'd much rather have the FL control (more lenses in my bag rather than in a drawer back home) that I get with MFT.

One good way to get FL control is to have a capable zoom (with less lenses in the bag). The m43 system has no meaningful answer to the FF f/4 zooms.

For my needs, the 12-40/2.8 is a meaningful answer. When I need the FF equivalent of f/4 or (or a bit wider) for subject isolation by background blur, I would usually use my 45/1.8 and/or 75/1.8. I prefer that to carrying a 70-200/4 FF zoom.

EDIT: DXOmark contradicts your claim that the 20/1.4 is sharper than the Canon 50/1.4 (as PZ does), by far, but you knew that, right?

As to PZ, I already notified you here

http://www.dpreview.com/forums/post/53900103

of the fact that you have apparently overlooked the big sign about non-comparability across platforms posted on their home page. As to DxO, things are pretty complicated as you have already recognized in your exchange with knickerhawk. If you have more to say about the matter, I suggest we continue the exchange there, i.e., here:

http://www.dpreview.com/forums/post/53921414

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