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

Started Mar 6, 2014 | Discussions thread
viking79 Forum Pro • Posts: 14,147
Re: Resize the A7/r to 16 MP to see how it compares...

LTZ470 wrote:

viking79 wrote:

LTZ470 wrote:

viking79 wrote:

Resize the A7/r to 16 MP or preferably the m4/3 to 24 or 36 MP.


Yes, one can resize any photo, but why? I was wanting the A7r to make some printable landscape shots to hang...

Yes, and you can see how much more detail the A7R shows at the same image area. Pixel level detail is unimportant, what matters is how much detail the image contains for a field of view or crop you are doing.

Notice how once I enlarged the m4/3 image to 36 MP, the 100% crops are now the same magnification? Before you were zooming in more on the A7r sensor than you were on the m4/3 sensor so the magnifications were off if you are looking at 100% so you aren't comparing the same thing.

Untrue, I used Paintbrush and cropped at 100%...sorry but thats 100% crops for each photo, nothing untruthful about that...100% is 100% correct?

Resizing defeats the whole purpose of owning a specific camera...

No, pixel peeping at 100% view level without knowing what you are looking at does.

I know what I am looking at a PRO glass vs mediocre glass...

I think I will just use the 24mm f/2 and LA-EA4 which I detest, but is phenomenal glass in front of the A7r...

I am not saying the 24-70mm is a great lens, but when compared on fair grounds to the Olympus 12-40mm it is fairly comparable.

Exactly what I did I utilized 100% crops from the same program...fair is fair...100% is 100%...no resizing hogwash or blowing things up or resizing down...

So do you have a different program i can crop at 100% to show different results?...


Here is what I mean. Also, I don't mean to sound harsh at all in any of my messages.

If you take a 24-70mm lens and compare it to a 12-40mm lens, you are starting on unequal ground with different focal lengths.

So you use an m4/3 sensor with the 12-40mm lens, and you now get the same field of view as the A7R with 24-70mm lens. So we have different lens focal lengths and sensor sizes, but they have equivalent field of view.

When you go out shooting you select a focal length based on field of view not focal length. Say you use 70mm on the A7r, you naturally would select 35mm on the m4/3 camera.

When you take these photos, you are capturing the same size of framing, but with one camera you are capturing the same area with 36 MP and the other with 16 MP. So the A7R has captured the same size of scene with 36 MP and the olympus with 16 MP. If you crop at a 100%, lets just say 1 MP, you have enlarged the Olympus image 16 times, but you enlarged the A7R image 36 times, this is not comparing apples to apples.

So what you have to do is first resize one of the images to match the other (since we are talking same field of view here), you could also down size the A7R image to 16 MP, since we wanted to see which is capturing more detail for the same scene we up-sized the m4/3 image. We can see that for the same framing the A7R is capturing more detail (as expected, it is 36 MP), so even though the lens looks a little bad at pixel level, it is still capturing more detail than the sharper appearing 12-40mm f/2.8 at the same field of view.

For Olympus to benefit from a crop advantage, you have to use the same focal length lens, but then you have a tighter field of view. This is a different use case not being discussed here. As soon as you start comparing a 12-40mm f/2.8 lens to a 24-70mm f/4 lens on full frame we are talking equivalent fields of view and not telephoto applications where the extra crop might be useful. If you put the same 24-70mm lens on each camera, then sure, the OM would capture more detail, but at a tighter field of view.


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