A7r 24-70 at 70mm vs EM1 12-40 at 40mm (80mm EFL)

Started Mar 6, 2014 | Discussions thread
OP LTZ470 Forum Pro • Posts: 11,926
Re: Resize the A7/r to 16 MP to see how it compares...

GaryW wrote:

LTZ470 wrote:

Camley wrote:


If I understand what you have done (and I am not sure that I do!), it isn't a fair comparison at all.

What matters is that you compare images from the same size print. ...

So 100% may be 100% but you must normalize the print size.

To achieve a 100% crop of ANY photo you have to open with a program that opens them at 100% then you can make a 100% crop from that photo by cropping/cutting out any portion/area then Save As, this will give you 100% Crop of the photo...

But 100% crop of more MP gives you more magnification, as if you were printing to a larger size on the wall. Why would you print, say, 20x30 for the A7r and examine details next to a 10x15 print, for example?

If you're comparing at 100% from both cameras, that's just flawed and misleading, but does favor the smaller mp sensor.

If you want to take M43 out of the discussion, consider Nex-5/6 vs. Nex-7. A lot of people used 100% crops to "prove" how bad the noise level was with the Nex-7. And yet, when resized to the same resolution, it wasn't all that different (certainly, less so). Meanwhile, the Nex-7 shows more detail. But you have to set up the test to have the same framing, and then resize as necessary to compare. Anything else and you're actually not equivalent.


Anything else that does not do this is not a fair comparison at all...I.E. resizing...or making one photo crop 150% with the other being 100%...

Not fair to use two different magnifications, which is what you're doing with 100% crops.

Folks will try and make you believe anything,

Some of us have been doing these kinds of tests for years. You believe what you want, and we will explain that it's wrong.

but 100% is 100%, NO ONE can change that..

Different magnifications! NO ONE can change that... without resizing.

.not even the forum experts, even though they would love to sell us the "used car with the great tires'...

This isn't the first time where people have fooled themselves.

Do the test correctly, and if the Sony is worse, then it's worse. It's known to not be great at 24mm. But at least match the resolution.....

Both photos should be sharp and have decent IQ at 100% regardless of format...the corners and sides of the A7r 24-70 do not so you would have to resize down to the 16Mp size and/or crop off the smeared/mushy portions...

So if I make a crop of the A7r shot with 1280 X 900 and a crop of the EM1 shot 1280 x 900 this will show the difference?

I'll take a few shots with 24mm f/2 and 100% Crop and then we'll see the difference 100% crop or not...

BUT at 100% crop they should both look sharp and have decent details in my book...period...

Gary thanks for the help and comments...

Packing up the 24-70 to go back, got it for the 24mm, and it's just not good enough for the price...nice lens though! Size is not too bad either...--

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