"But at low ISO nothing can beat this camera." - CEO SIGMA

Started 6 months ago | Discussions thread
gaussian blur
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Re: At low or high ISO, there are quite a few.
In reply to Basalite, 6 months ago

Basalite wrote:

This is a nice enough shot, but any 24MP camera has a good bit more detail at 6000X4000. The bar has been raised considerably over the last year or so. Your jpg is 4704 × 3136 pixels, which is by definition lower resolution. Digital is as cut and dried as it gets. Want more than 6000X4000? You'll need a 36MP or higher camera.

There are two forms of "resolution" used in digital photography. The first one simply defines the size of the image (pixel dimensions) recorded by a particular sensor, which is inexplicably the only one you mentioned.

Pixel count defines the absolute maximum a sensor can resolve. It is not possible to resolve beyond it. Period.

Sigma artificially inflates the pixel count to confuse the user into thinking the cameras are more capable than they really are.

The most important "resolution" is how much *actual detail* a sensor can discern and record within those pixel dimensions. Since current Foveon sensors record all three colors at each pixel, at least at low ISOs, and since they do not use a blur filter, they record far more detail than an equivalent, and beyond, megapixel sensor.

By skipping what you call the 'blur filter' (a pejorative name for an anti-alias filter), you get alias artifacts, which gives the illusion of more detail than there really is. It's false detail that was not in the original subject.

The consensus by those who know such things is that it takes a doubling, or so, of Bayer pixel dimensions to match an equivalent level of Foveon pixel dimensions. In other words a 30MP, or so, Bayer sensor of high quality that does not use a blur filter. This shouldn't be surprising since much of the image data with a Bayer sensor is simply interpolated. Most of those sensors also use a blur filter, something the Foveon does not need or use.

Only the Foveon fanbois make those ludicrous claims, and it's actuall Foveon that has more interpolated data. Contrary to Sigma's claims, it doesn't sample RGB, but rather three overlapping spectra, from which RGB is derived (i.e., interpolated). That's why the software and cameras are so slow and why there are often metamerism issues.

So, no, there is no 24MP camera, APS or 35mm sized sensor, than can record as much detail as the Foveon sensor at around 15MP. It's very easy to test and see. I suggest you look into that.

Nonsense. What you're seeing are alias artifacts and heavy sharpening. You're not seeing details that was actually in the subject.

There is as well a lot of grainy noise, some of which has to be down to oversharpening.

You must be used to the typically soft, low resolution images you see with Bayer sensors that have their resolution ruined by excessive noise reduction and a blur filter. Perhaps you are even a jpg shooter.

Anyone who gets soft, low resolution images is doing something wrong.

Furthermore, since Foveon is inherently more noisy than Bayer, it's Foveon that has the excessive noise reduction.

Lastly, an anti-alias filter is required to avoid alias artifacts. Some people might like that look but it's certainly not 'higher resolution.'

It looks more like ISO 1600 on an APSC camera. In any event, it is not what I would call a relaxed presentation of fine detail.

Good luck getting such detail with a Bayer sensor camera that is not the D800e or medium format.

No luck needed, since it's very easy to do.

There are maybe 18 or 20 "perceptual" MP worth of apparent "sharpness" owing to the high degree of microcontrast, which is standing in for actual resolution.

That's ridiculous. I suggest you go learn how the Foveon sensor works.

It's basically correct.

I can certainly understand the appeal of a fairly high res camera in such a compact package, but how limited do we really want to be for ISO, lens selection and overall camera performance?

Maybe you are young and inexperienced if you can't appreciate the fact that most film photography was done at the low ISOs the Sigmas excel at.

If all you have are insults, you have nothing.

Lens selections? One could buy all three cameras and have world class leading primes in three small bodies. You never heard of photographers using prime lenses? They are the kind of people that actually understand what resolution means.

Three lenses is more limiting than hundreds of lenses from several different manufacturers. Simple math.

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