F0.95 ???

Started 4 months ago | Discussions thread
hjulenissen
Senior MemberPosts: 1,604
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Re: F0.95 ???
In reply to Roland Karlsson, 4 months ago

I remember a discussion about whether this affected either the total amount of light hitting the sensor, the depth-of-field, or both.

I realize that the t-stop accounts for things like lossy glass (that f-stop does not), but what we are talking about here is a geometric "flaw" of the microlens, causing some light angles to be attenuated. Intuitively, this should cause _both_ less total light hitting the sensor, _and_ changes to DOF?

My Canon 7D was the camera tested by DxO that was most affected by this. Is it reasonable to speculate that if you:

1. Push pixel count vs sensor manufacture process (18MP APS-C for 500nm process), thus having relatively poor light-sensitive fraction of sensor area

2. Want to maintain photon efficiency by compensating with micro lenses

3. What has to "give" is sensitivity to off-angle light, thus potential issues with large-aperture and/or compact wide-angle lenses

If I am right, then there is some real-world trade-off between sensel count/density and image quality, only more complex than the "anti-megapixel" crowd have claimed. You must (if I am right) trade high pixel count vs high photon efficiency vs gracing angle light sensitivity for a given process node.

Given the 7D target users, it would seem like a reasonable trade-off (even better if Canon switched to a cutting-edge process...)

What would you get by going to the other extreme? Choosing a moderate sensel count/density, using no or moderate micro lenses? I guess the 5D classic is an example of this, but say that you did this in a modern design (the Sony A7S?). Could each sensel be essentially "isotropic" (within the angles of practical interest)? Is that a viable approach for a large-sensor, low-light-capable/large aperture, wide-ish angle, highly compact camera (e.g. Sony RX-1)?

-h

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