[HELP] Sigma PD Merrill Foveon modification - Chinese speaking member help needed

Started 8 months ago | Questions thread
docmaas
Veteran MemberPosts: 4,792
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Re: English-4880/4680 yuan
In reply to carrrlangas, 8 months ago

I'm sorry if it sounded factual. My intent was to raise it as a question. In reading the English rendition of the Chinese it seemed to be saying that but the translation is awkward. Ironically I could probably decipher it if spoken but I only speak Chinese not read it.

I wonder if my impressions were correct though since sony nex camera resolution issues have been worse with short register wide angles than with longer register retroflex lenses from slrs.

There are two different ways problems arise concerning register and sensor. In a short register lens like the leica or contax g the problem can occur because of how obtuse the angles are when they impinge on the sensor. The shallower the angle the more difficult it is for the light to fall fully on the pixels at the extreme outside edges of the sensor. This is the problem with some short register wideangle lenses on some of the sony nex cameras. Wide angle retroflex design slr lenses work better because the angles to the edges of the sensor are more acute and the more acute the angle the more light can get into the pixel well over the lips of the pixel wall.

The other factor is how deeply inside the camera body the sensor lies and how wide the opening to the sensor is. The deeper and narrower it is the more of a tunnel effect there is and that results in light obstruction as well. If there is a tunnel problem then short register lenses might outperform the longer register lenses as they may get more light past the walls of the tunnel created by the body of the camera in relation to the sensor location.

I believe the lens itself creates the tunnel into the sensor in the dp cameras so how wide the lens is in the body is going to determine the characteristics of the tunnel effect.  Here is a picture of the converted camera with exposure pumped up to show the sensor well.

You can see the walls are pretty vertical compared to the walls in a nex camera.  Not sure which lenses will work the best.  Wide angle lenses are probably going to be the most problematic.

Mike

carrrlangas wrote:

DOCMAAS: "It appears that large focal plane distance lenses will only perform marginally in the corners while those designed to be closer to the film plane like konica, leica, contax g etc may be a better match for the dpm cameras."

Hmmm, I didn´t got to understanding this. Bummer, my point in all this is to use my Pentax K mount DA limited lenses, they have a register distance arround 40mm

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