trungthu

""" Sigma's choice of F1.8 as maximum aperture isn't a coincidence; it means that the lens will offer the same control over depth of field as an F2.8 zoom does on full frame."""
When we use the...

Yes, I see.
Bayer filter use four capture pixels to record color informations.
""" .. This means it has only one photosite per output pixel, so won't offer the same color resolution as Canon's EOS...

"... This means it has only one photosite per output pixel, so won't offer the same color resolution as Canon's EOS C300 professional video camera, which has four capture pixels (a Red, Green,...

I understood. Thank Revenant very much

Because the F-number is the entrance pupil divided by focal length, reducing the focal length without changing the entrance pupil increases the F-number.
I think, it's wrong here.
When reduce the...

It's an interesting news.

With the sensor's dimension = 6.06 x 4.56 mm, and the resolution 4000 x 3000.
I see that 6,06 mm / 4000 pixels = 0.0015 mm/pixel.
And the most importance thing is how can the "Leica lens" SEE THAT...

Why all the lenses at 50mm f/1.8 for full frame from other branches have the prices around 100USD, while Pentax has 50mm f/1.8 for APS-C, with a smaller covering power, and a higher price?
Why?