December 20, 2014, 07:35:17 PM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - ecka

Pages: 1 ... 18 19 [20] 21 22 ... 46
286
No. In reality there is nothing that is a 0. Zero is not a thing, zero is just a tool in mathematics.

You are wrong about DOF but I will let others argue about it. But as a mathematician, I strongly object the statement that zero is not a thing, and that there is noting at zero. How many 200-400 lenses do you own?

Quote
Every point has dimensions and it can be represented as an image of at least 1 pixel,

What if you are shooting film?

I don't use superteles.
Film has it's minimum dot size that can be captured.

287
I'm glad that you are enjoying the discussion. It wasn't my intent to offend anyone.
I didn't confirm the nonsense. Shrinking the picture simply makes it's details imperceptible to you. If you can't see a bacteria, it doesn't mean that there are none. In case with a magic shrinking machine, the details are made smaller so you can still see them by shrinking yourself or maybe using a microscope. However, when you shrink the image on your screen or print a thumbnail, you are just losing the information. Just like for a half-blind person all your images can look same "sharp" or same "blurry". In fact, for him, sharp and blur looks the same. CoC is about perception. DoF is not, it is about information, same as photography. Once the light of an optical image hits the sensor, it is gone, all that's left is the information gathered by the electronics. If you shoot a picture that has nothing in focus, it doesn't matter to what resolution you downsize it, no new information will occur (except the false one). You can manipulate the image in any way you want, but in relativity to reality DoF won't change a bit. If photography is just a form of art for you and perception is the only thing that matters, then perhaps you are not even trying to understand what I'm talking about.

Well by your standard, in reality there is nothing really 'in focus'. The focus 'plane' is a hypothetical thing that has zero thickness. Also on the 'true' focus plane every light point has diameter of 0. Anything in front, or behind this zero thickness hypothetical plane is deemed out of focus because they have a CoC > absolute 0.

The sensor sees something in focus not because they are in focus, but simply because the CoC is smaller than sensor's pixel could distinguish. So what you say? That the image the sensor captures is the real world? It is not.

If above assumption is correct, then take an example, if I shoot a photo with a 320x240 pixel FF sensor, what is my DoF? Even my lens gives a blurry mess I would still get a 320x240 photo that is sharp at pixel level. Does this represent the 'reality'?

The thing is, reality is far weirder than you can ever imaging. We are in a photographic forum, so yes, photography is just a form of art for me and perception is the only thing that matters. I learn from my output photos and prints so I can control my equipment to get the result I want.

Then we leave the underlying physical, electricial or philosophical discussions for some one else or somewhere else.


No. In reality there is nothing that is a 0. Zero is not a thing, zero is just a tool in mathematics. Every point has dimensions and it can be represented as an image of at least 1 pixel. When you are viewing ~18mp image on a ~2mp screen, then 1 dot (color) on the screen represents a group of 9 pixels of the image. Sensor does not capture the real world. The projection of an optical image on the sensor is limited by all kinds of information manipulation by the lens (diffraction, aberrations, vignetting, coma, color tint, distortion, flares and CoC). If the 9 combined pixels carry enough information to represent 1 real world dot, then it will be sharp. If not, then it will be blur (or noise). At 1:1 (100%) it is similar, but with much more false color and noise. If you shrank the blur into oblivion and got some kind of real world information, then it only means that you've destroyed all the rest and the whole blurriness carried only this little.

The sensor and electronics "sees" nothing in focus, just color and contrast of the neighboring pixels.320x240 pixel FF sensor cannot mimic human vision. There are artificial eye implants that allow blind people to see the world in just a few hundred pixels and trust me, it's nothing like the real thing. It's a blurry mess and they can only see a letter or a digit in close-up.

288
Prepared to shrink yourself 100 times and tell me that I am mad, LOL! I'm laughing and crying at the same time! ;D :'( ;D :'(

Even you have confirm that shrinking picture increase DoF do have a real world implication, BUT

Shrink a picture 100 times? Yes! Shrink a human 100 times? OMGWTFBBQChickenWings!

In the end, isn't photography all about perception?  ::)

I'm glad that you are enjoying the discussion. It wasn't my intent to offend anyone.
I didn't confirm the nonsense. Shrinking the picture simply makes it's details imperceptible to you. If you can't see a bacteria, it doesn't mean that there are none. In case with a magic shrinking machine, the details are made smaller so you can still see them by shrinking yourself or maybe using a microscope. However, when you shrink the image on your screen or print a thumbnail, you are just losing the information. Just like for a half-blind person all your images can look same "sharp" or same "blurry". In fact, for him, sharp and blur looks the same. CoC is about perception. DoF is not, it is about information, same as photography. Once the light of an optical image hits the sensor, it is gone, all that's left is the information gathered by the electronics. If you shoot a picture that has nothing in focus, it doesn't matter to what resolution you downsize it, no new information will occur (except the false one). You can manipulate the image in any way you want, but in relativity to reality DoF won't change a bit. If photography is just a form of art for you and perception is the only thing that matters, then perhaps you are not even trying to understand what I'm talking about.

289
DoF does not rely solely on optics, so badgerpiper's  statement is false. DoF relies on apparent aperture (optics) and subject magnification (optics, reproduction size and viewing distance).

If you look at same sized prints, as common sense dictates you must, the crop camera capture is enlarged more, so the CoC is smaller, so the DoF is less.

Why doesn't everybody who is inclined to post read the links I have provided? It is all in there. Depending on how you make your comparison, and you have to clearly state the way you want to compare the captures, a smaller sensor can be shown to have more DoF than a ff camera, the same DoF, or as in this instance, less DoF than that ff camera.

You cannot separate DoF from subject magnification and viewing distance at the output size.

Finally, someone who knows what I was talking about! I am not crazy,hahaha!

When you enlarge a picture, CoC gets bigger, DoF gets shallower. Don't believe me? Take a mild shallow DoF photo and down scale it to thumbnail image, see, suddenly everything is in focus! Magical isn't it?  :P


Note when you crop a photo, you essentially zooming in and stopping down. On the other post we had a very detailed discussion about what this does to the background blur, in short, when you zoom in and stop down, close background blurs less, distant background blurs more, and life is complicated!

http://www.canonrumors.com/forum/index.php?topic=15904.0

That's completely insane :D.
Imagine that you have a magical shrinking machine. You print the photo say 30x20, you shrink it 100 times and it looks super sharp to you. Now you shrink yourself 100 times too and see that the picture didn't change. The problem is that your printer and monitor do not have an infinite number of pixels to show you that, and even if they did, then your eyes wouldn't see it, because they would be too small. Different print sizes that include the destructive reduction of resolution dots isn't doing any magic, you are shrinking the image, but the dots stay the same size. CoC is about the perception, not about magical information transformation. There's no such thing as magic. I say - you're both mad.

290
Wow...this became a way bigger discussion than i intented it to be. :o

So if i got everything right it is like that:

Same focal length + same aperture + same distance to subject on different formats =  different FoV but with same same DoF. And that makes total sense to me because the lens projects the same image as before but on a smaller area to capture it.

And same focal length + same aperture + same object framing (which means bigger distance to subject on smaller formats) = bigger DoF on small formats because the focal distance is further away and smaller DoF on bigger formats because the focal distance is closer to MFD.

I hope my english is good enouh so everybody undertood what i meant...  :-[

Greetings from Germany,
Knut Skywalker

Yes, you've got it right.

No, that is not correct.

"Same focal length + same aperture + same distance to subject on different formats =  different FoV but with same same DoF."

That scenario, assuming you are comparing same sized reproductions (print or screen), results in less DoF from the crop camera because it is has a smaller CoC. Think of it like this, you have to enlarge the crop cameras image 2.5 times more (by area) than the ff one, bigger reproduction ratio = less dof. Don't forget any detail of the crop camera image is reproduced bigger than the same detail from the ff image on a same sized print (or screen).

IF, using your above scenario, you compared two prints from the different sensors where the details of the subject were the same size, so the crop camera print would be 40% the size of the ff print, then the dof would be identical.

You cannot remove reproduction size from the DoF calculation, DoF calculators assume a base standard, often an 8"x10" print viewed at 12", if you compare two same sized prints from different sized sensors then the smaller sensor has been enlarged more.

This is all covered and explained in my first reply, the second post, on page one. "If pictures are taken from the same distance using the same f-number, same focal length, and the final images are the same size, the smaller format has less DOF."

Quite correct. Canon itself uses a COC 0.035mm in DOF calculations for FF. On APS-C the image must be enlarged more to produce a 7x5 inch print, which means a smaller COC is needed and hence for APS-C, Canon uses a COC of 0.019mm in its calculations.

So, in your reality, if you print the same picture in two different sizes, the bigger one will have less DoF? :D
Good lord... I'm wasting my time here  ???
Same logic - there is a magical print size which makes your P&S images look like they were shot using a FF camera? :D

Yes that is the reality I live in, unbeknown to you it is also the reality you live in, ignorance is bliss, you are wasting everybody's time here.....

Reproduction size and viewing distances are fundamental to DoF calculations, you cannot work out DoF figures without knowing how big your print will be and the viewing distance, as I keep saying, DoF calculators often work to the standard of an 8"x10" print viewed at 12".

Read about CoC, you know that "technical mumbo-jumbo" "you can ignore", well it turns out you can't ignore it if you want to understand the answer to the OP's question.

The CoC is not about DoF. When there are 3 parts in the image - sharp (DoF), blur (OOF) and "not sure", the CoC is about the "not sure" part.

Don't try to bend the spoon, that's impossible, because there is no spoon.

291
Wow...this became a way bigger discussion than i intented it to be. :o

So if i got everything right it is like that:

Same focal length + same aperture + same distance to subject on different formats =  different FoV but with same same DoF. And that makes total sense to me because the lens projects the same image as before but on a smaller area to capture it.

And same focal length + same aperture + same object framing (which means bigger distance to subject on smaller formats) = bigger DoF on small formats because the focal distance is further away and smaller DoF on bigger formats because the focal distance is closer to MFD.

I hope my english is good enouh so everybody undertood what i meant...  :-[

Greetings from Germany,
Knut Skywalker

Yes, you've got it right.

No, that is not correct.

"Same focal length + same aperture + same distance to subject on different formats =  different FoV but with same same DoF."

That scenario, assuming you are comparing same sized reproductions (print or screen), results in less DoF from the crop camera because it is has a smaller CoC. Think of it like this, you have to enlarge the crop cameras image 2.5 times more (by area) than the ff one, bigger reproduction ratio = less dof. Don't forget any detail of the crop camera image is reproduced bigger than the same detail from the ff image on a same sized print (or screen).

IF, using your above scenario, you compared two prints from the different sensors where the details of the subject were the same size, so the crop camera print would be 40% the size of the ff print, then the dof would be identical.

You cannot remove reproduction size from the DoF calculation, DoF calculators assume a base standard, often an 8"x10" print viewed at 12", if you compare two same sized prints from different sized sensors then the smaller sensor has been enlarged more.

This is all covered and explained in my first reply, the second post, on page one. "If pictures are taken from the same distance using the same f-number, same focal length, and the final images are the same size, the smaller format has less DOF."

Quite correct. Canon itself uses a COC 0.035mm in DOF calculations for FF. On APS-C the image must be enlarged more to produce a 7x5 inch print, which means a smaller COC is needed and hence for APS-C, Canon uses a COC of 0.019mm in its calculations.

So, in your reality, if you print the same picture in two different sizes, the bigger one will have less DoF? :D
Good lord... I'm wasting my time here  ???
Same logic - there is a magical print size which makes your P&S images look like they were shot using a FF camera? :D ... and the next one is even better?

292
Wow...this became a way bigger discussion than i intented it to be. :o

So if i got everything right it is like that:

Same focal length + same aperture + same distance to subject on different formats =  different FoV but with same same DoF. And that makes total sense to me because the lens projects the same image as before but on a smaller area to capture it.

And same focal length + same aperture + same object framing (which means bigger distance to subject on smaller formats) = bigger DoF on small formats because the focal distance is further away and smaller DoF on bigger formats because the focal distance is closer to MFD.

I hope my english is good enouh so everybody undertood what i meant...  :-[

Greetings from Germany,
Knut Skywalker

Yes, you've got it right.

293
When comparing different formats using the same lens and aperture at equivalent distance (same FoV) -

That's just not possible. It is not possible to have same lens (assume prime) mounted on different sensor format and still achieve same FoV. Physics doesn't work like that.

If by 'same FoV' you mean same subject framing, then background would have different magnification. That's my point, different perspective can't be compared.

Yes, same FoV means same angle and, of course, the perspective in some cases will be different.

Quote
Also from your above post, you seem to indicate that under all circumstances FF will always have equal or shallower DoF, I and a lot others couldn't agree on that.

That is correct and the whole lot of others is misinformed.

294
Don't get me wrong, there are many brilliant photographers, but in most cases I'm inspired by some of their works and not by their philosophies or personalities. Sometimes even a bad photographer gets lucky and shoots an insanely, unbelievably, stunnishing photo (?perfect). So, for me, this question cannot be answered.
I'm mostly influenced by the online photographic communities and I'm happy being a part of it.

Ok, if I may couch the question differently..

'Has the work of any photographer influenced you? or do you particularly admire the work of any photographer?'

No, not really. For me it's like fishing. Once you get experienced enough, you'll see that there is no magic in it and "the luck" is for amateurs. What is left is the artistic creativity, but I'm more into design than art (like Spielberg vs Art Documentary :) ).

295
Lenses / Re: What lens delivers the strongest background blur?
« on: July 16, 2013, 07:34:20 AM »
I'd like to share a photo shot by a pal on another forum:

He used 200mm f2 to do this shot: tell me if any shorter lens can ever achieve this effect:

hint: subject distance: 17.6m



35 1.4? pfff, not even close

Well, my vote is for 200/1.8 (first page). What I meant with 35/1.4 is that 500/4 is very impractical for what we are discussing here.

Quote
Contrary to popular belief, in order to get most background blur (isolation), you shoot head/shoulder with wide angle (35), half body with medium (50/85) and full body with telephoto (>200), not the other way around.

Wide for full body, tele for close up just gives you flat and boring snap shots.

Yes, I agree :).


296
Lenses / Re: What lens delivers the strongest background blur?
« on: July 16, 2013, 06:44:13 AM »
Just let me guess...
200/1.8? :)

200mm f/1.8 would score a value of 3.1 which means 5th place ( behind 500 f4 but better than 300 f2.8 ).

Good luck with that. The error of this comparison is in the "given magnification".
In reality, for background blur, I'd pick 35/1.4 over 500/4 any day of the week :)

P.S. You forgot 1200/5.6 ;).

297
Yes, you can put a 100mm lens on a P&S (try Pentax Q or Nikon 1) and you are still wrong. I always measure DoF in relativity to reality, not "bokeh balls". :)

Due to different standards, I still call this comparison apples to oranges.

Result: When talking about format affecting DoF, always compare same angle of view, or effective focal length, since comparing different angle of view doesn't make sense.

We are still in disagreement but that's okay.

These are small apples vs big apples of the same taste :)

When comparing different formats using the same lens at the same distance and aperture (different FoV) - DoF is the same.
When comparing different formats using different but equivalent lenses and apertures at the same distance (like APSC+50/1.8 vs FF+80/2.8, same FoV) - DoF is the same.
Cropping the image doesn't change the DoF.

When comparing different formats using the same lens and aperture at equivalent distance (same FoV) - FF DoF is thinner.
When comparing different formats using different but equivalent lenses at the same distance and aperture (like APSC+85/2 vs FF+135/2, same FoV) - FF DoF is thinner.


298
Q2. If you shoot a photo A, then crop the border out leaving a smaller photo B, magnify it back to original size, then in relativity to reality DoF A = DoF B, but in relativity to dimensions of the photograph DoF A < DoF B, because you are not getting closer, you are magnifying it as well as the DoF.

No need to cross my text just because you don't agree with me. Photo is always relative to dimensions of the output, there is no relative to 'reality' to speak of, otherwise your are just muddying the water. When you are comparing two photographs, you compare them at the same output size, otherwise the comparison is just wrong.

"Yeah, put those two photo side by side, B has 2 times larger blur circle in the background, but when you make photo B 2 times smaller, the blur will look just the same!" Well, you are essentially manipulating objectivity to make it suit your theory.

I'm just stating facts. Blur circles ≠ DoF.
DoF A is shallower in both cases, except when you are measuring it in blur circles. By your logic: P&S camera has the biggest blur circles (sometimes thei don't fit inside the image :) ), therefore it produces the thinnest DoF when compared with the same focal length lens on a DSLR. This is wrong in all theories, not just mine.

"thinnest DoF when compared with the same focal length" < This, if you can somehow manage to put a 100mm lens on a P&S, it gives you a huge telephoto equivalence, then DoF will also be a lot thinner than when the lens is mounted on a DSLR. Think about it...

Yes, you can put a 100mm lens on a P&S (try Pentax Q or Nikon 1) and you are still wrong. I always measure DoF in relativity to reality, not "bokeh balls". :)

299
Q2. If you shoot a photo A, then crop the border out leaving a smaller photo B, magnify it back to original size, then in relativity to reality DoF A = DoF B, but in relativity to dimensions of the photograph DoF A < DoF B, because you are not getting closer, you are magnifying it as well as the DoF.

No need to cross my text just because you don't agree with me. Photo is always relative to dimensions of the output, there is no relative to 'reality' to speak of, otherwise your are just muddying the water. When you are comparing two photographs, you compare them at the same output size, otherwise the comparison is just wrong.

"Yeah, put those two photo side by side, B has 2 times larger blur circle in the background, but when you make photo B 2 times smaller, the blur will look just the same!" Well, you are essentially manipulating objectivity to make it suit your theory.

I'm just stating facts. Blur circles ≠ DoF.
DoF A is shallower in both cases, except when you are measuring it in blur circles. By your logic: P&S camera has the biggest blur circles (sometimes they don't fit inside the image :) ), therefore it produces the thinnest DoF when compared with the same focal length lens on a DSLR. This is wrong in all theories, not just mine.

300
Don't get me wrong, there are many brilliant photographers, but in most cases I'm inspired by some of their works and not by their philosophies or personalities. Sometimes even a bad photographer gets lucky and shoots an insanely, unbelievably, stunnishing photo (?perfect). So, for me, this question cannot be answered.
I'm mostly influenced by the online photographic communities and I'm happy being a part of it.

Pages: 1 ... 18 19 [20] 21 22 ... 46