Recent content by Drakkith

We would see such a star as being, say, 1 billion years into its lifetime, whereas an observer that's closer to the star would see it as being older. A protostar that we observe from very far away might have already passed all the way through its main sequence and become a white dwarf for an...

If you just need an extinction-level event to kill off humanity on the planet, you have many options. Especially in sci-fi. Meteor strike, nuclear war, bioweapons, severe climate change, advanced technology gone wrong, orbital change of the Earth (extra-solar body interaction is a potential...

That is literally the opposite of what I asked. This thread is going nowhere. Thread locked.

@quantum philosopher It's not clear what you're wanting. We can give you a precise mathematical definition of position, if that's what you're after. But you seem to have some sort of philosophical idea that's floating around too. Can you clarify what kind of answer you'd like?

No. While there is some uncertainty in any measurement, this doesn't change the meaning of 'location' or 'position' of an object. Yes, for macroscopic objects this is true. A soccer ball doesn't transport itself fifty yards towards the goal if everyone stops looking at it. For relatively...

@DaveC426913 Here's the thing. I can find at least a few sources supporting what I've been saying. I can also find a few sources, including my Modern Optical Engineering book, that don't define Depth of Field to have anything to do with how the image is displayed, merely stating that depth of...

Thread locked for moderation.

Yes it has. The blur size of every point in the image has been increased by several times its original size in the blown up image. The fact that you can still make out the tape measure is irrelevant.

Okay. I'm not going to debate what is right or wrong if you hold various objects in front of your face. Yes, it is counterintuitive, isn't it? If you believe the definition of depth of field used here is wrong, then please provide a reference supporting your position.

Of course it's a sensible outcome. A badly misaligned camera lens can produce photos that never look sharp unless you shrink down the image to where it is very small. If you viewed a picture from this camera at normal size on your monitor you would say that the entire image is out of focus. If...

Those are essentially the same thing. Besides, at least half or more of the descriptions or definitions I can find of depth of field says something similar to: the size of the area in your image where objects appear acceptably sharp.

Blow up the photograph to a poster that's 20 feet wide and 40 feet tall and viewed from 1 foot away. Now none of the field appears to be in focus.

There is no paradox. 'Genius' physicists and engineers are not bad at the math that they need to use. They may or may not be winning the Fields medal, or making major publications in mathematical journals, but that doesn't mean that they are bad at math.

Ooh. I had no idea the mean free path for air at sea level was so short!

Our cat, Nala.