Medium format vs. full frame

Started May 10, 2013 | Discussions thread
kb2zuz Veteran Member • Posts: 3,202
Re: Medium format vs. full frame

glacierpete wrote:

I used to shoot a Linhof Technika (6x7), Fuji GSW 690 (6x9) and Mamiya 7II (6x7) in the past. Mostly with Fuji Velvia. Landscapes and architecture.

I am deeply impressed by the Sigma DP2M. The image resolution is incredible. They way it renders texture in architecture shots reminds me to my old Rodenstock lens. The fixed lens in the DP2M outperforms my Leica R Summicron.

It is hard to believe this camera just has an APS sized Foveon/Merill sensor.

IMHO it is not just about sensor size, or megapixels, Besides Sigma (Foveon) Sony and Canon do have multi layer sensor patents. Just another variable in the equitation in the future.

Cameras are just tools for me, and I am deeply impressed with the images quality this camera delivers for $799.

Foveon will be sharper than a typical CFA camera of similar number of photosites (I'm avoiding using the word MP, because Sigma had the definition of MegaPixel changed so that they can claim 46MP when in reality the image is only) 15.3 million pixels. Yes that 15.3 million pixel image will be sharper than a 15.3 million pixel image from a Bayer CFA camera. But in reality it will not provide 3 times as much sharpness. This is due to the fact that we perceive sharpness around luminance which is mostly based on what is in the green channel. So in reality it's going to be more like 2x as good, closer to 30MP. Now you linked to Lyn Evan's comments, and she claims that the lack of an AA filter makes it even sharper. And that is true to some extent, but the 24MP D7100 comes without and AA filter and if you compare it to other cameras using the exact same 24MP sensor with an AA filter, you'll notice there is little improvement.

My biggest grudge with Foveon though is that it's color accuracy is not very true to human vision and some colors can have poor reproduction.

Now I work with a Hasselblad H4D-50MS and it's got a cool trick. It can take a single shot and it will be a bayer filter interpolated 50MP image. And I can take a 4 shot image where it shifts the sensor one pixel between each shot, as a result it gives you a 50 million pixel uninteroplated shot (by Foveon/Sigma's math that's a 150MP image). So I happen to have shot the exact same image on both settings using the same lens, without even moving the camera and can show you how much the CFA softens the image (or how much an uninteroplated sensor would improve things):

The detail is from the red cropped area. Left is single shot (Bayer CFA), right is multishot (uninterpoated)

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