XF56 f1.2 released and specs

Started 6 months ago | Discussions thread
Krich13
Regular MemberPosts: 381
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Re: XF56 f1.2 released and specs
In reply to malcolml1, 6 months ago

malcolml1 wrote:

Krich13 wrote:

malcolml1 wrote:

Yes, I follow your argument apart from one step which actually represents my original question:

>

For semiconductor sensors what matters is the total number of photons per photosite, pretty much regardless of the site area. Make two sensors: say an APS-S and FF ones both of say 16 megapixels. Expose them using the same scene for the same duration using 56/1.2 and 85/1.8 lenses respectively. Each photosite will receive the same NUMBER of photons (the number per unit area is 2.25 times larger in the first case, but the area itself is smaller by the same factor).

I agree with the area and scaling factor part, but my original question was whether it is true that the 56/1.2 will deliver the same number of photons per unit area on the APS sensor as the 85/1.8 lens on a FF sensor.

No, it will receive 2.25 times more photons PER UNIT AREA.

Totally agree that the 56/1/2 will deliver more photons per unit area than the 85/1.8 - and this is my question - if this is the case, how is the 56/1.2 equivalent to the 85/1.8 in terms of the light delivered per unit area - your statement above says they are:

"Make two sensors: say an APS-S and FF ones both of say 16 megapixels. Expose them using the same scene for the same duration using 56/1.2 and 85/1.8 lenses respectively. Each photosite will receive the same NUMBER of photons (the number per.."

Seems to be a contradiction.....

Where is the contradiction? Each photosite of the full frame sensor would have 2.25 times larger area (the same number (not density) of megapixels), number of photons _per_unit_area_ 2.25 times smaller, the TOTAL NUMBER of photons is the same. What is so difficult?

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