BorisK1

Lives in United States MI, United States
Works as a Software engineer
Joined on May 7, 2004

Comments

Total: 444, showing: 1 – 20
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On article Hands-on with the Red Hydrogen One (153 comments in total)
In reply to:

HenryEckstein: Maybe I am just old and jaded or so used to ultra high end gear that the Red Hydrogen phone to me is just a MEH! phone.

THIS IS A REAL SMART PHONE:

1) 8192 by 4320 Pixel 64-bit RGBA OLED display (16-bits per colour channel)

2) 120 Hz refresh rate

3) AMD Ryzen-2 Combined CPU/GPU 3.7 GHz 8 cores 16 threads

4) 256 Gigabytes of SYSTEM APPLICATION RAM

5) 4 terabytes of onboard SSD Flash Hard Drive (Removeable)

6) Thin-Film multi-3D-Stacked Lithium Ion Battery 25,000 Mah
24 hours solid video playback runtime and 14 days standby

7) IP-69 FULL multiday Water and Dustp-roof Mil-Spec rating on all-Titanium case
and Solid Sapphire Crystal Screen face with extra G-shock and Multi-Axis
Vibration resistance.

(In the voice of Crocodile Dundee)
You think this is a phone?
(Pulls out a steel-plated, coin-operated rotary payphone, with a good-sized chunk of the gas station siding still attached)
Now, *this* is a PHONE!

Link | Posted on Nov 4, 2018 at 23:27 UTC

Looks very much like Olympus Air A01 circa 2015.

Link | Posted on Nov 1, 2018 at 00:50 UTC as 60th comment | 1 reply
On article Nikon Coolpix P1000 Review (643 comments in total)
In reply to:

KeepCalm: The review stresses that the slow maximum lens speed causes diffraction when the actual aperture is huge given the focal length of the lens whatever the f number says.
I always thought diffraction was the result of a large proportion of the light travelling over the the aperture blade edges in relation to the light travelling through the orifice.
I am extremely interested in the mechanism how the f number or even worst the equivalent f number causes diffraction in what is a massive 67.4 mm aperture.

No big mystery there. If you take a picture of a point, like a star, diffraction smudges it into a disk instead of a point. An airy disk is what they call the smallest possible size of that disk you could get, using a theoretical lens, perfectly focused.

Link | Posted on Oct 31, 2018 at 22:44 UTC
On article Nikon Coolpix P1000 Review (643 comments in total)
In reply to:

KeepCalm: The review stresses that the slow maximum lens speed causes diffraction when the actual aperture is huge given the focal length of the lens whatever the f number says.
I always thought diffraction was the result of a large proportion of the light travelling over the the aperture blade edges in relation to the light travelling through the orifice.
I am extremely interested in the mechanism how the f number or even worst the equivalent f number causes diffraction in what is a massive 67.4 mm aperture.

The 539mm focal length and 67mm aperture, mean airy disk diameter of 10.7microns (0.0107mm):
http://www.calctool.org/CALC/phys/optics/f_NA
If the sensor is 6mm wide, it's 1/560 of the frame width, or 1/420 of height.

Link | Posted on Oct 31, 2018 at 17:54 UTC
In reply to:

Old Cameras: Still can’t get over the stupid faux advance lever, or in this case “thumb rest”. You’d really have to look hard to realize this is a digital camera since it’s trying so hard to masquerade as a film camera.
The app connectivity is a step forward in functionality but otherwise form follows style and it’s just ridiculous.

Hate the modern look. No black blanket, no shelf for the phosphorus, no rubber bulb for the shutter release.

Link | Posted on Oct 29, 2018 at 20:35 UTC
In reply to:

Ergo607: If Ricoh (or Olympus for that matter) would release a rugged 1" sensor and a 28 or 35mm prime they would have my money already...

There's the SeaLife DC2000 - 1" sensor, 31mm equivalent, f/1.8.
Supposedly, you can buy it without the housing as a "spare part" on the manufacturers site.

Link | Posted on Oct 25, 2018 at 15:49 UTC
In reply to:

kobakokh: with this specs price will be under 1000 USD, maybe... Because of Nikon D610 is way way way better camera and cost 1000... Here is just sensor and lens, nothing others...

It's zeiss. The lens alone will be over $1000. And a full frame sensor won't be much less. The body is extra. But they'll throw in a free USB cable.

Link | Posted on Sep 27, 2018 at 23:53 UTC
On article Panasonic DC-LX100 II First Impressions Review (671 comments in total)
In reply to:

jackfrost15: A little more reach and I would have surrendered my LX100 for this one. Even 90mm would have done it. But a thousand bucks for marginal changes is just too much.

The increase in resolution gives just about the reach you ask for: 75×(√(17÷13))=85.76

Link | Posted on Sep 19, 2018 at 01:58 UTC
In reply to:

sh10453: Almost 1 kg for the 50mm???
Doesn't that go against the whole purpose of the mirrorless system, which is the light weight?
But I guess the L lenses couldn't be made lighter.
I have the 50mm f/1.2 L FD, and it's quite heavy compared to other 50mm non-L lenses.

@ManfredGrebler BorisK1: "The Nikon DSLR 1,2/50 AIS (same period than the Leica lens) has only 380 gr"
Right you are, I missed that one!

Link | Posted on Sep 5, 2018 at 19:14 UTC
In reply to:

sh10453: Almost 1 kg for the 50mm???
Doesn't that go against the whole purpose of the mirrorless system, which is the light weight?
But I guess the L lenses couldn't be made lighter.
I have the 50mm f/1.2 L FD, and it's quite heavy compared to other 50mm non-L lenses.

"Aren't those also manual focus though?"
Are you thinking that the 50mm is basically a pound of glass, surrounded by two pounds of an AF motor?

Link | Posted on Sep 5, 2018 at 15:26 UTC
In reply to:

sh10453: Almost 1 kg for the 50mm???
Doesn't that go against the whole purpose of the mirrorless system, which is the light weight?
But I guess the L lenses couldn't be made lighter.
I have the 50mm f/1.2 L FD, and it's quite heavy compared to other 50mm non-L lenses.

"Lenses don't get lighter just because of mirrorless."
Rangefinder lenses were always known for their small size and weight and high optical quality, due to their simpler optical design allowed by the shorter flange distance.
If you have a Leica-like mount, why not build Leica-like lenses?
A Leica 50mm f:1.2 Noctilux weights 470g. Full frame mirrorless.

https://www.l-camera-forum.com/leica-wiki.en/index.php/50mm_f/1.2_Noctilux

Link | Posted on Sep 5, 2018 at 14:34 UTC
On article Panasonic DC-LX100 II First Impressions Review (671 comments in total)
In reply to:

Joseph K Boston: For that price one could buy a GX9+12-60 3.5-5.6, a far superior package (and I'm a LX100 mk I owner).

@CAcreeks "considering the crop video, a waterproof Olympus TG5 might produce higher quality 4K video."
The cropped area within the LX200 sensor that records 4K video, is slightly smaller than a 1" sensor, which is about 4x the area of the TG5 sensor. Besides, Panasonic has an autofocus system that actually works during video.

On the other hand, if you drop the LX100 into the drink, its video output quickly degrades to nothing :)

Link | Posted on Sep 2, 2018 at 17:20 UTC
In reply to:

TsubasaOfficial: You should avoid using the word "distortion". It's just perspective.
Because if you say so, people will mess this word up with the barrel/pincushion distortions.

"Perspective distortion" is not the same thing as "perspective".

"Perspective" is determined by the subject distance at the moment when the image is captured, and doesn't change afterwards.

"Perspective distortion" happens when the image is viewed, and changes with the viewing distance.

Link | Posted on May 29, 2018 at 17:33 UTC
In reply to:

JackM: Whatever.

https://www.dpreview.com/forums/post/61189489

*Perspective* is fixed when the shot is captured, and is determined by the subject distance.

*Compression* and *perspective distortion* change with the viewing distance.

If the image takes up a narrower view within the viewer's field of vision than the FOV that the camera captured, you get wide angle perspective distortion. If the image is viewed at a wider angle than what the camera captured, you get lens compression.

Perspective distortion is caused by the mismatch of the distances that you see in the image: Perspective of the subject gives you one distance, its angular size gives another.

Link | Posted on May 28, 2018 at 15:26 UTC
In reply to:

dan pv: There is no such thing as "perspective distortion" either. The perspective is correct in all cases. But both terms, "perspective distortion" and "perspective compression", refer to how the image created by wide and tele lenses is different of the image expected by our brain. They don't describe real physical phenomenas. The perspective of the image seems, or looks like, distorted or compressed compared with the image our brain expects due to the difference between the lens angle of view and the human eye angle of view. Both terms are equally legitim as they describe sensations and not physical phenomenas. This article is misleading.

> The front and rear focal points of an optical system are cardinal points that exists without any implication or evaluation made by our brain/senses. They can be entirely computed based on the characteristics of the optical system alone and therefore they are part of a "real physical phenomena". The cardinal points can be fully defined and mathematically explained even to a blind person.

The viewing distance that removes perspective distortion, is a physical characteristic of the printed image. I can express it mathematically.

Let me try again.

Suppose, you know an object's dimensions.

If you measure its angular size, it's trivial to calculate the distance to it.

If you measure its perspective (say, nose-width to ears-width ratio), you can also calculate the distance.

If those two distances aren't equal, that means you're looking at a perspective-distorted image of the object.

Link | Posted on May 26, 2018 at 00:31 UTC
In reply to:

dan pv: There is no such thing as "perspective distortion" either. The perspective is correct in all cases. But both terms, "perspective distortion" and "perspective compression", refer to how the image created by wide and tele lenses is different of the image expected by our brain. They don't describe real physical phenomenas. The perspective of the image seems, or looks like, distorted or compressed compared with the image our brain expects due to the difference between the lens angle of view and the human eye angle of view. Both terms are equally legitim as they describe sensations and not physical phenomenas. This article is misleading.

> So far I can see that our only desagrement is about the terms "real physical phenomena" and "sensation".

Let's say, we take a real-life projector, that projects an image onto a wall.

What I understand as "perspective distortion" in photography is similar to that image being "in focus".

It's true that we have a "sensation" of the image being fuzzy, and without this sensation, there's nothing inherently "wrong" with an out-of-focus image.

And yes, it could be measured without the brain (there are projectors with autofocus).

If you consider that image being "in focus" as not "real", then the perspective distortion is not "real" either.

Link | Posted on May 25, 2018 at 22:16 UTC
In reply to:

dan pv: There is no such thing as "perspective distortion" either. The perspective is correct in all cases. But both terms, "perspective distortion" and "perspective compression", refer to how the image created by wide and tele lenses is different of the image expected by our brain. They don't describe real physical phenomenas. The perspective of the image seems, or looks like, distorted or compressed compared with the image our brain expects due to the difference between the lens angle of view and the human eye angle of view. Both terms are equally legitim as they describe sensations and not physical phenomenas. This article is misleading.

> The term "Perspective distortion" means 2 completely different things in Photography and Perspective Geometry.

Agreed.

> In Perspective Geometry "Perspective Distortion" is called the difference between the central projection on a flat plan (as is the Perspective in Photography) and and the image created by the eye (=central projection on a curved plan). Because of this differences between the 2 types of central projection a photography will never perfectly resample an image seen by the eye.

> There is no such thing as the "Perspective distortion" with the meaning it has in Photography.

Yes, in photography, "Perspective distortion" means something very different, and I can't find a good definition.

This type of perspective distortion is not a property of the image.

What *is* a property of the image, is a specific *viewing distance*, from which it looks undistorted.

In photography, perspective distortion is the property of the image's angular size, as seen by the viewer.

Link | Posted on May 25, 2018 at 21:48 UTC
In reply to:

dan pv: There is no such thing as "perspective distortion" either. The perspective is correct in all cases. But both terms, "perspective distortion" and "perspective compression", refer to how the image created by wide and tele lenses is different of the image expected by our brain. They don't describe real physical phenomenas. The perspective of the image seems, or looks like, distorted or compressed compared with the image our brain expects due to the difference between the lens angle of view and the human eye angle of view. Both terms are equally legitim as they describe sensations and not physical phenomenas. This article is misleading.

> If you make 2 photos of a person from a tripod without moving the camera or the person with a tele and then with a wide the perspective won't change. That's a fact.

Up to this point, we're in complete agreement.

> The tele image will be a crop of the wide one. The measurements of the head of the person in bot images will be identical. That means NO REAL DISTORTION induced by changing the FOV (=the lens). This is a well known fact in Perspective.

Agreed here, too. But it's not about changing the captured FOV.

We print the image, and start changing the *viewing distance*. This changes the *angular size* of the image for the viewer.

When the image's angular size matches the camera's FOV, the viewer's view exactly matches the view of the subject *as seen at the subject distance*.

At other viewing distances, what the viewer sees, does not correspond to *any* subject distance.

It's distorted, because you *can't* see a subject like this. Perspective doesn't match the angular size.

Link | Posted on May 25, 2018 at 20:06 UTC
In reply to:

dan pv: There is no such thing as "perspective distortion" either. The perspective is correct in all cases. But both terms, "perspective distortion" and "perspective compression", refer to how the image created by wide and tele lenses is different of the image expected by our brain. They don't describe real physical phenomenas. The perspective of the image seems, or looks like, distorted or compressed compared with the image our brain expects due to the difference between the lens angle of view and the human eye angle of view. Both terms are equally legitim as they describe sensations and not physical phenomenas. This article is misleading.

Perhaps you're thinking that I'm measuring whether or not the human will get the feeling of distortion, rather than some physical quality of the image?

Here's another way to show that there *is* real distortion.

Let's say you measured the width of my nose (nose_width), the distance between my ears (ears_width), and the distance from my nose to my ears (face_depth).

Then, you take a head shot, print it, and view it.

If you measure the ear-to-ear angle you see *within the image*, you can calculate the apparent distance to the ears:
ears_apparent = ears_width / (2 * tan(ears_angle / 2)).

If you measure the nose-width angle, you can calculate the apparent distance to the nose in the same way:
nose_apparent = ears_width / (2 * tan(ears_angle / 2)).

Now, (ears_apparent - nose_apparent) should be equal to face_depth.

But that only happens if the image's angular size within the viewer's FOV is equal to the captured FOV.

Otherwise, they won't be equal. So the image really is distorted.

Link | Posted on May 25, 2018 at 15:09 UTC
In reply to:

photophile: OK. Interesting video and thank you for taking the time to illustrate - but seriously ? FEET??? What is that? How many feet in a gallon?

He actually asked about "FEET". Which, according to a Google search, stands for "Fellowship of European Evangelical Theologians". The volume of an average human body is 18.41 gallons. Google says that there are about 600 million evangelicals in the world. Assuming 1% of them to be theologians, we get 110,460,000 gallons total.

Which works out to about 0.000,000,009 FEET per gallon.

Is this better?

Link | Posted on May 25, 2018 at 14:26 UTC
Total: 444, showing: 1 – 20
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