Size comparison of FE 4/2470 on A7 vs Olympus 12-40 f2.8 on GX7

Started Feb 6, 2014 | Discussions thread
blue_skies Forum Pro • Posts: 11,638
Re: @Cole ...

LTZ470 wrote:

blue_skies wrote:

cosmonaut wrote:

Well considering the a7 has a sensor twice as big

four times as big

and a Zeiss on it I would consider it an amazing piece of technology. Not to mention the difference in DXO marks. Heck my iPhone scores a 76 in DXO....

Four times as big without native glass and slow shutter and slow AF and no stabilization = limited camera

great for portraits and landscapes and studio only = limited

Cole, you keep showing these images, but they are not that impressive at all.

You basically have the longest lens with the m43, big deal. That is not the same as highest IQ - let me explain.

The Nex-7, with LE18200 is just as sharp, if not sharper - it gets 24Mp as well, and this is an OSS stabilized lens.

Even the Nex is almost double the sensor size of the m43, and it would be more than comparable.

You removed the f-stop from the exif (why), but the Oly lens info reads Lumix G Vario 100-300/f4.0-5.6, so at 300mm you are at f/5.6 on the Oly.

This would compare to 600mm f/11.2 on the FF. Yet you shoot the FF with a 300mm f/5.6.

So I assume that you have a harder time nailing focus (DOF limited) and you have to crop heavily to get the images to match.

The FF measures 828x1200, the Oly measures 984x1200. Are they both crops, to make them look similar?

If I consider the Nex-7, it has 24Mp with a 1.5x crop ratio, and the A7r with 36Mp at 1.0x crop ratio.

The Oly has a 2x crop ratio, with 16Mp.

So, I can shoot the Oly with 16Mp at 2x crop, or a 300mm lens becomes 600mm at 16Mp.

The Nex-7 has 1.5x crop, the LE18200 becomes 300mm effectively, and I would use 2x zoom to reach 600mm. I would have 12Mp then.

The A7r has 1x crop, and the FE70200 needs a 3x zoom to reach 600mm, and also has 12Mp then.


In your case, you use a 300mm lens, but loose OSS, but you only need a 2x zoom, so you'd get 16Mp again.

All that I see so far, is that the Oly has a 300mm long and slow zoom which has longest reach.

However, the delta is not that significant as you try to show in your pictures.

If you can't get non-OSS results with the A7r, it is not a fair comparison, you shoot the A7 at ISO800 and the Oly at ISO320, stabilized. Why not up the ISO on the A7r to 1600? It will make up for OSS for sure, and noise levels will be comparable.


If you are like Danny, who uses 500mm and 800mm long telelenses, then the math changes. The m43 gives him 1000mm and 1600mm FF equiv, but only on 16Mp. The Nex-7, with the same lenses, would give him 750mm and 1200mm FF equiv, but on 24Mp. If you do the math, you'll find out that the number of pixels on a subject, provided that they fit in the frame, are almost the same (same pixel pitch).

The A7r has the pitch of the Nex-6, so you'd loose detail against the m43/Nex-7 combo


I don't see any of the cameras limited by your shots - perhaps you limit yourself by a specific shooting style? The LA-EA4 with 300mm is a challenging setup, unless you use a tripod. Even then, you'd have to shoot at higher ISO and faster shutter to match the images, which will make it a bit easier.

Consider this thread:

It clearly shows that the m43 sensor is high ISO limited, and has to blow out the highlights to even 'compete' against the larger sensor camera. I would argue that the m43 camera is severely limited - as I can stop down a larger sensor camera, but I cannot open up the m43 camera past f/1.0, now can I? Heck, even f/1.0 is a bit crazy.

As to the fast/slow AF, before AF we used zone-focus, trap-focus, burst-focus, and I add in tracking-focus, etc. There are so many ways to shoot with a camera other than "point & shoot" and hope for the best.

A lot of the m43 arguments seems to be just that: "the camera makes me the best photographer I can be, I love my gear", whereas I see a photographers as one "who can get the most out of his gear". In this context, the m43 and larger sensor cameras are quite different - larger sensors are far less limited than smaller sensors cameras.

As Eric pointed out: a small (P&S) camera is great for many applications, but it is a 'one-trick-pony', as you can only shoot at low ISO and deep DOF. The m43 is not that far removed from that, in context of a larger sensor camera.

So which camera is most limited? Hint: not the larger sensor camera.

And I know - we'll get the limited lenses story again. Same as when Nex started out. But the argument against Nex cameras has pretty much subsided, as there are good lenses out now. The same will happen to the FE lenses - so far the two primes are next to the best ever reviewed in their class - something to ponder about.

Even the Stylus one did better than the A7r and Sigma 70-300 with a Teleconverter added...

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