[Klaus]

[quote name='larsrc' timestamp='1285139967' post='3081']

My guess is that the Foveon technology cannot deliver data fast enough, possibly due to heat issues.



I am amused at how quickly the world has changed from "who wants video in a still camera" to "who would buy a still camera without video". This camera is for those who want a lot of detail - this is in my opinion roughly equivalent to a 30MP Bayer camera. Who else gives you that in an APS-C size body? If it delivers speed and good handling, it would be a wonderful thing for wildlife photographers looking for light gear.



-Lars

[/quote]



I'm wondering how the Foveon chip (the "bottom" photodiodes of the three layers) behaves with ultra-wides.

[popo]

[quote name='Pinhole' timestamp='1285126104' post='3077']

Unless I missed something, it doesn't shoot video. It seems a bit odd, considering it's more or less standard these days. I wonder what the target audience is?



I'm curious to know what the sensor can deliver, but I'd want some features that the Sigma doesn't offer. Maybe they really should license the sensors, because I get the impression it is hampered by their package.

[/quote]

I'd argue that Sigma are not going after the mass market like CaNikon and co. They can afford to target more specific groups with unique features, such as the sensor. I don't see lack of video as a barrier to a specialist product like this. I guess it'll be tough still, as it may be limiting for those buying into a new single system. If you already have a system, you don't want to duplicate your lens collection...



If the price can be kept low enough body only, then it might yet be economic to get as a 2nd system for specific applications. Then again, judging by the price of the SD15, this seems unlikely to happen. As such it'll be a premium price tool for those who really need it.

[boren]

Lack if video is not such a terrible omission, but with 30MP-equiv resolution LV can very useful for ultra-accurate MF.

[popo]

[quote name='larsrc' timestamp='1285139967' post='3081']

This camera is for those who want a lot of detail - this is in my opinion roughly equivalent to a 30MP Bayer camera.

[/quote]



Putting aside the considerations of physical sensor size, I'd have to say this sensor has the potential to exceed the detail of current FF bodies. Where the lens is up to the job of course... but I'd think 30MP bayer equivalence is a bit conservative. Given the smallest colour unit in a bayer cell is only 1/4 the area, it could be 60MP equivalence in best case.

[wim]

[quote name='popo' timestamp='1285155734' post='3088']

Putting aside the considerations of physical sensor size, I'd have to say this sensor has the potential to exceed the detail of current FF bodies. Where the lens is up to the job of course... but I'd think 30MP bayer equivalence is a bit conservative. Given the smallest colour unit in a bayer cell is only 1/4 the area, it could be 60MP equivalence in best case.

[/quote]

Well, I don't agree. Previous Foveon sensors had an (optimistic) advantage of about 30% to 40 % when deFoveonised, i.e., Foveon MP divided by 3. That would put it roughly in the 20MP ball park compared to Bayer sensors (46MP / 3 * 1.3), or up there approximately with the 18 MP Canon sensor.



We'll have to wait for the first test results, however, to see how it really performs.



Kind regards, Wim

[Brightcolours]

[quote name='wim' timestamp='1285160794' post='3091']

Well, I don't agree. Previous Foveon sensors had an (optimistic) advantage of about 30% to 40 % when deFoveonised, i.e., Foveon MP divided by 3. That would put it roughly in the 20MP ball park compared to Bayer sensors (46MP / 3 * 1.3), or up there approximately with the 18 MP Canon sensor.



We'll have to wait for the first test results, however, to see how it really performs.



Kind regards, Wim

[/quote]

Also remember that that advantage was a bit of a fake advantage, only there because of the lack of AA-filter (which is not connected to the type of sensor).



Still, it looks to be a nice camera from Sigma, finally.

[popo]

[quote name='wim' timestamp='1285160794' post='3091']

Well, I don't agree. Previous Foveon sensors had an (optimistic) advantage of about 30% to 40 % when deFoveonised, i.e., Foveon MP divided by 3. That would put it roughly in the 20MP ball park compared to Bayer sensors (46MP / 3 * 1.3), or up there approximately with the 18 MP Canon sensor.



We'll have to wait for the first test results, however, to see how it really performs.



Kind regards, Wim

[/quote]

Let's take a simple best-case for foveon. Say you're shooting a highly detailed blue subject. Only 1/4 of the sites on a bayer sensors can detect blue*, whereas a whole layer of sensors on the foveon will. The 18MP Canon sensor only has about 4.5M blue detectors, compared to around 15M in the new Sigma.



*assuming perfect colour filters, I know that isn't the real case.



Green might in theory show the least difference, but the AA filter almost certainly means you would never get the expected improvement from the increased number of green sites.



The diffraction impact will also kick in earlier on the foveon... that might limit the apparent sharpness at what were previously considered "good" apertures. Even f/5.6 is probably in the diffraction softening zone on this Sigma.

[Guest]

[quote name='larsrc' timestamp='1285139967' post='3081']

My guess is that the Foveon technology cannot deliver data fast enough, possibly due to heat issues.



I am amused at how quickly the world has changed from "who wants video in a still camera" to "who would buy a still camera without video". This camera is for those who want a lot of detail - this is in my opinion roughly equivalent to a 30MP Bayer camera. Who else gives you that in an APS-C size body? If it delivers speed and good handling, it would be a wonderful thing for wildlife photographers looking for light gear.



-Lars

[/quote]

Well, I wasn't saying I'd want video, but if it is a purely photographic tool (which is fine), there should be some other features. I haven't used a Sigma, though I'm interested in the sensor technology, particularly in terms of dynamic range.



Are these cameras limited to Sigma lenses too? That might be a limiting factor for high definition images.

[mst]

[quote name='Pinhole' timestamp='1285180923' post='3101']

Are these cameras limited to Sigma lenses too? That might be a limiting factor for high definition images.

[/quote]



Yes, SD cameras are only available with Sigma's own SA mount.



-- Markus

[wim]

[quote name='popo' timestamp='1285173651' post='3096']

Let's take a simple best-case for foveon. Say you're shooting a highly detailed blue subject. Only 1/4 of the sites on a bayer sensors can detect blue*, whereas a whole layer of sensors on the foveon will. The 18MP Canon sensor only has about 4.5M blue detectors, compared to around 15M in the new Sigma.



*assuming perfect colour filters, I know that isn't the real case.



Green might in theory show the least difference, but the AA filter almost certainly means you would never get the expected improvement from the increased number of green sites.



The diffraction impact will also kick in earlier on the foveon... that might limit the apparent sharpness at what were previously considered "good" apertures. Even f/5.6 is probably in the diffraction softening zone on this Sigma.

[/quote]

My note was based on previous Foveon sensors and comparisons of test shots. The thing is that the Foveon actually still only has 1/3 of the number of actual sensels or pixels indicated by Sigma, just that they can read the full spectrum. And this gives them a slight edge over Bayer sensors, as I mentioned, in the past anyway, of about 30 % to 40 % over their actual number of sensels, but certainly nothing like 3X that.



Regarding diffraction and sensors: I won't go into this, except maybe for a thread specifically dealing with that. Let me just note here that we never talked about diffraction limits with film and halide grains, so why should we all of a sudden with sensors. In my book it is a total non-issue, except for engineers specialized in this subject <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.



Kind regards, Wim