Exchange Sony A7R IV with GFX 50S?

Started 2 months ago | Questions thread
Erik Kaffehr
Erik Kaffehr Veteran Member • Posts: 3,509
Re: That's not what DPReview concluded...

Velocity of Sound wrote:

If you read their "best landscape camera " showdown, the A7RIV is their top pick. The GFX 50S is listed in addition for consideration (listed third, behind the Canon EOS 5DS R, although I don't know that they ordered the list by strength of recommendation). The GFX 100 isn't listed. However, they had this to say:

If you look solely at the camera body, it's hard to justify the GFX 50S over its high-res full-frame peers because, while light, fast and capable by medium format standards, the image quality isn't significantly better than the smaller, lighter, faster and often cheaper rivals. However, the GF lenses make it easier to get full benefit from its 50MP, meaning it regularly delivers to its full capability.

Hi,

Resolutionswise, the A7rIV is pretty similar to the GFX 50S/R. The GFX 50 models have a special microlens design that yields a smaller than normal pixel aperture that enhances sharpness at the cost of increased aliasing.

Both cameras can make good use of a lot of different lenses.

I guess there's some discrepancy there with another series of articles that they wrote some months back, in which they concluded that larger sensors are superior. The conclusion is also a bit wishy-washy: they say image quality isn't significantly better, but that GF lenses regularly deliver "full capability." If that implies that Sony lenses aren't getting the full capability then it would seem to state that image quality is better.

It is obvious that larger size has an advantage. But the 44x33 mm sensor is just 1.68 times the area of the the 24x36 mm sensor. Going from APS-C is 2.25X, a much larger step. The 1.68X size is equivalent to 2/3EV advantage.

Now, if you look at the Sony lens line up, you have f/1.4 lenses from 24 mm to 85 mm and you can also use Canon or Sigma mount lenses. Fujifilm has only one f/2 lens and that is the GF 110/2.

So, to some extents, the larger apertures more than compensate the 2/3 EV advantage of the GFX 50 with regard to photon collection ability. (*)

Another factor is that the Sony models have in body image stabilisation, which is a quite obvious advantage unless you have IS in the lenses or use tripod, which many landscape photographers do.

Another question is how sharp the lenses are. It seems that the GF lenses are very sharp, although I would say that little is known about sample variation.

So, I think that DPR's evaluation may have some merit, like all mankind, DPR editors are fallible.

In many ways, I think that the GFX 100 is the really right stuff.

Best regards

Erik

(*) Technically speaking, it depends. A larger sensor is always beneficial when exposed fully to the right at base ISO.

But, when higher ISO is used , there is usually some reason for it like, like shutter speed, need of DoF. a 24x36 mm system has a 2/3 stop advantage in DoF over a 33x44 system. So, if say f/8 is needed for DoF on 44x33, 24x36 mm will deliver the same DoF at f/6.2.

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Erik Kaffehr
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