4 votes
Accepted

Why does viewing the sun through a telescope burn your eyes?

Assuming your eye is part of the optic system with the telescope, and assuming the exit pupil of the telescope's eyepiece isn't larger than your eye's iris (that is, your eye doesn't contribute as a ...
scottbb's user avatar
  • 32.7k
4 votes

Brightness of a full frame lens mounted on aps-c vs mounting an identical native aps-c lens

The brightness of the image formed by a lens is the same regardless of the size of the sensor behind it, assuming the image circle fully covers the sensor. An APS-C sensor behind a full frame lens is ...
spunky_h0rn's user avatar
3 votes

Is this Normal?, Nikon 24mm pc-e shift knob wobble

That is not normal. None of the knobs on my 24mm PC-E pull out or wobble like that, and they are not meant to.
Steven Kersting's user avatar
3 votes

Why does viewing the sun through a telescope burn your eyes?

There is no significant difference between looking at the sun with the naked eye and taking a picture of it with a digital camera. There are only two variables that control the exposure, the duration ...
Steven Kersting's user avatar
1 vote
Accepted

Calculating FOV for mismatched lens/sensor size

According to the sensor spec, it has 1920 * 1080 square pixels of 2.9µm size, giving a physical sensor size of 5.568mm * 3.132mm, a 16:9 aspect ratio a diagonal size of 6.388mm Plausibility check: ...
Ralf Kleberhoff's user avatar
1 vote

Brightness of a full frame lens mounted on aps-c vs mounting an identical native aps-c lens

The full frame sensor will not be brighter under the same exposure conditions (Same light in scene, same focal length and f-number, same exposure time, etc.). It will collect more light, but it will ...
Michael C's user avatar
  • 175k
1 vote
Accepted

Brightness of a full frame lens mounted on aps-c vs mounting an identical native aps-c lens

A larger image circle is more light, but that additional light only exists in the areas not recorded by the crop sensor. Essentially, the APS lens is just cropping the image circle before the sensor ...
Steven Kersting's user avatar
1 vote

Why does viewing the sun through a telescope burn your eyes?

Light from a distant object like a star arrives at the telescope as a bundle of parallel rays. The front lens (objective lens) captures these rays. As they traverse the objective lens they are ...
Alan Marcus's user avatar
  • 39.2k
1 vote

Why does viewing the sun through a telescope burn your eyes?

I find xkcd‘s take on this very telling, it starts by asking a different question: How hot can you make something using optics? The answer is: You can‘t make something hotter using optics than the ...
Grimaldi's user avatar
  • 473

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