Napioa - Wind Origins

Napioa - Wind Origins
by octopus                

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Apr
25
asked What is the relationship between field of view and focal length for fisheye?
Apr
25
comment Prevent Lightroom from discarding lens model from EXIF
@inkista Yes, version 2015.5.
Apr
25
asked Prevent Lightroom from discarding lens model from EXIF
Mar
31
comment Sum of pixel values more than incident photons
@faf No, it's built in since version 10.1. What version do you have?
Mar
31
revised dcraw command for 14 bit raw image
added 15 characters in body
Mar
31
answered dcraw command for 14 bit raw image
Mar
31
answered Sum of pixel values more than incident photons
Feb
28
answered What can a fisheye lens be useful for?
Feb
25
accepted What is this lever for on the lens mount? (F-mount, not aperture lever)
Feb
24
comment What is this lever for on the lens mount? (F-mount, not aperture lever)
Here's another photo I found.
Feb
24
asked What is this lever for on the lens mount? (F-mount, not aperture lever)
Feb
12
comment What is the shape of the focal plane?
I understand your question, but it should be noted that you are completely misusing the terms focus point and focal plane. The focal plane is not the plane of objects in sharp focus, as shown in your sketches. You can google for what it actually is, e.g. en.wikipedia.org/wiki/Cardinal_point_(optics)#Focal_planes
Feb
6
comment Does a full frame with a teleconverter perform better than an APS-C without a teleconverter?
But I didn't actually sit down to do the calculations, so I might be wrong. My wave optics classes were a long time ago, I guess I should sit down, brush up on optics and derive the exact result ;-) But not until later today.
Feb
6
comment Does a full frame with a teleconverter perform better than an APS-C without a teleconverter?
@Michael Regarding diffraction: the frequency of light won't be changed by the optics of course. The wavelength will be different inside glass and air. What ultimately matters is the difference in optical path length from various points of the aperture plane to the same point of the projection plane. This led me to the conclusion that it is indeed the apparent size of the aperture (from the perspective of the projection plane, as seen through the TC) that matters.
Feb
6
comment Does a full frame with a teleconverter perform better than an APS-C without a teleconverter?
@Michael I don't see the point of your last comment, does it contradict with anything I said? I am merely trying to help the OP understand the issues involved so he can come to the answer himself without having to "just believe". Let's not make this about who is right, I am not arguing with you, I am chasing the right answer ;-)
Feb
6
comment Does a full frame with a teleconverter perform better than an APS-C without a teleconverter?
@Michael Now it is true that the same opening will correspond to a different "f-number" in the two cases. But that has no significance, does it? It's the physical opening that is the relevant quantity to compare: that's what has to be the same between the two to cases to have the same amount of light and the same depth of field, and that's what has the same maximum value between the two cases. (The maximum f-number will be smaller for the teleconverter case.)
Feb
6
comment Does a full frame with a teleconverter perform better than an APS-C without a teleconverter?
@Michael Thanks for the comments. Regarding noise levels: the point I was making is that for the same opening of the aperture blades the same amount of light (photons) will be "recorded" in both cases if the teleconverter has perfect transmission. Since it doesn't, in fact the FF gets less light in the end, and will have more noise. Regarding diffraction: it happens at the aperture blades (the smallest opening the light passes through). The magnification happens at a later stage along the optical path. Again, there will not be a difference given the same opening of the aperture blades.
Feb
5
comment Does a full frame with a teleconverter perform better than an APS-C without a teleconverter?
You say "in general when the best cameras are coupled with the best lenses the best teleconverters will usually give better image quality of static subjects shot from a tripod mounted camera than shooting without a TC and then cropping away.". But if you think about what a teleconverter actually does, all arguments point in the opposite direction. Please see my answer. If I made a mistake in my reasoning, what is it? Otherwise this is all just anecdotal.
Feb
5
revised Does a full frame with a teleconverter perform better than an APS-C without a teleconverter?
added 361 characters in body
Feb
5
answered Does a full frame with a teleconverter perform better than an APS-C without a teleconverter?