Sigma and Foveon resource (usage tips) and information thread.

Roger J said:
Greetings Ted
If you click on the right arrow and go through each slide it gives you all information.
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Thanks Roger. The small text at upper right did escape my notice, duh!
 
xparUSA said:
Thanks Roger. The small text at upper right did escape my notice, duh!
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No worries It is hard to see. Like everything else I'm grandfathered in at a excellent rate for the top tier of Zenfolio. It never goes up, so I put up with little things.
 
Roger J said:
Greetings to the Sigma transplant people, which I'm one of. As for the Sigma Foveon being ASA 100 I found the early models SD9 SD10 were good from 100 to 400 depending on how you used the camera. Think positive film. As for the later models SD14 through the SDQ-H I used up to 3200 ISO
Here are a few snaps at higher ISO Also SPP works excellent for PP which I hate to do so I try to get it right in the camera. One has to learn SPP and it's Free works excellent with the FP series cameras also.

elitefoto9.zenfolio.com

Elitefoto9

Elite Photography by R. E. Jones I use and prefer Sigma Cameras and Lenses. OR, United States
elitefoto9.zenfolio.com
Enjoy
Roger J.
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Roger J said:
Greetings to the Sigma transplant people, which I'm one of. As for the Sigma Foveon being ASA 100 I found the early models SD9 SD10 were good from 100 to 400 **depending on how you used the camera**.
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A long time ago, I tested an SD10 at 800 ISO varying the shutter time but keeping the exposure constant with the aperture setting. Ambient temp. was about 90F.

0.6 sec, f/2.8:
IMG02843.jpg


25.0 sec, f/22:
IMG02848.jpg


From which I would suggest that "how you use the camera" in high ISO would best be in Shutter Priority with as high a shutter speed as possible ...
 
Roger J said:
Greetings
Here are a few varied ISO shots with different Sigma cameras. The EXIF is in the upper right corner

elitefoto9.zenfolio.com

Sigma Foveon High ASA/ISO

Elitefoto9
elitefoto9.zenfolio.com

Have fun
Roger J.
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It would appear that the series of pictures supports my point: For example, in the third picture, The scene lighting value is about "deep shade" (15EV minus 4EV), the shutter 1/3200 sec, the aperture f2.8 at 1600 ISO. The series appears to favor large apertures thereby leading to high shutter speeds.
 
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GaryLH said:
In the recent Quattro info from Sigma, they have mentioned that the blue layer acts as a luminous layer for the green and red layer as well, it us not clear if that is also the way the Merrill works as well.. But it could explain some of this issues that are sometimes seen when the sensor gets too much light.
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For the record, using the top layer "works" but is technically incorrect. But they had no choice because of the low resolution of the middle layer which is very close to being technically correct.

There has been a debate going in the past, on whether...the true base iso for the foveon is 100 or 200. I have always felt 200 worked better in general.
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I have personally measured the ISO on several of my Sigma cameras and I can confirm that the "base" is close enough to 100.

I used the Standard Output Sensitivity method but Sigma told me long ago that they use REI. Should be close.

People who prefer 200 ISO are simply getting 1EV headroom so as to reduce unwanted blown highlights but that preference does not affect the so-called "base" ISO.
 
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