ilza

Lives in United States United States
Joined on Nov 2, 2008

Comments

Total: 129, showing: 1 – 20
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In reply to:

Leonp: "As final results can sometimes look unpleasant to the human eye" meaning it only works very very bad at the moment?

Sooo, in the future we will not be able to see some people on photo's anymore, if google decides they are an unimportant detail.

@Leonp: (disclaimer: what I read is only this synopsis on DPR): it looks like what program does is it tries to predict the “perceived quality” of the compression. This is the focal point of every lossy compression algo: you cut away info until you reach the required level of “perceived quality''. (Like: “this is not going to be visible anyway; no need to spend bits on it”.)

The typical algos have very naive estimators of perceived quality, which means that for some regions they would save too much data (decreasing available space for other regions!). A good estimator would allow much better worst-case-quality/size ratio.

So I read “can sometimes look unpleasant ” as: this estimator is much better than what is available, but is NOT YET ALWAYS right.

Link | Posted on Aug 25, 2016 at 00:20 UTC
On article Bolt-on 21: Fujifilm WCL-X70 sample images (54 comments in total)
In reply to:

GabrielZ: Everybody's saying the quality is great. But look at the photo above, the one before you click on the 'View our gallery...' Look at the extreme distortion of the house and telephone pole. They're both literally leaning over!

@Xentinus:
You are confused in:
> If you want to fill the frame with the tall buildings,
> you will need to change the direction of the camera.
> So you will need number 2 too.(unless you have a tilt-shift lens).

No, this condition breaks your No.1, not No.2. With F·tan(α) angle-to-position mapping function (in plain words: “no distortion” ;—]) your No.2 is irrelevant. (See
   https://en.wikipedia.org/wiki/Fisheye_lens#Mapping_function
.)

Link | Posted on Jun 20, 2016 at 04:42 UTC
On article Bolt-on 21: Fujifilm WCL-X70 sample images (54 comments in total)
In reply to:

GabrielZ: Everybody's saying the quality is great. But look at the photo above, the one before you click on the 'View our gallery...' Look at the extreme distortion of the house and telephone pole. They're both literally leaning over!

@Xentinus:
> camera needs to be
>   1-parallel to the horizon
>   2-at the at the middle of the building from ground level...

With a rectilinear lens, your “2” is not necessary. (This is the whole idea of the [tilt-]shift lens.)

> so do buildings on the horizon.

In my analysis, I only looked at the closest building — and only at the vertical lines. Assuming that most of them are REALLY vertical, this allows to find the direction of the horizon line. (Horizontal lines of this building have significant perspective distortions — so the front of the building is not parallel to the plane of the sensor. — This, I think, contributes to the general confusion created by this image.)

Link | Posted on Jun 16, 2016 at 17:43 UTC
In reply to:

Rexgig0: My wife has been using a Sun-Sniper sling since shortly after its introduction. She later added another type of attachment point, that allows for tripod mounting, made by a company other than either Sun-Sniper or BR. Perhaps because she lived in Europe for several years, she prefers the version with the metal cable inside the strap; perhaps thieves cutting camera and bag straps is more common in Europe than North America?

Following my wife's lead, I acquired a Sun-Sniper sling system, but I disliked the camera being upside down. It works better (for me) when attached to the tripod foot of a telephoto lens, with the tripod ring rotated so the camera hangs more upright.

I misplaced my Sun-Sniper sling, and substituted a Magpul sling; rather than something inspired by a carbine sling, I now use an authentic carbine sling. (When not using a large tele lens, I prefer using a Peak Design Slide, Think Tank Strap, or Leica strap, depending upon the size/weight of the camera/lens.)

Quoting: ilza: Europe: "22,000 vs USA: 12,000" WRONG! You are comparing a "Continent to an individual country". Your comparison is not apples to apples...

To the contrary, what I said is 100% correct. And comparing continent to a country is in no way meaningless. MOREOVER, this is the comparison (EU vs US) made by the poster I replied to (who, apparently, cannot read, and never was in US).

Link | Posted on Jun 16, 2016 at 07:06 UTC
On article Bolt-on 21: Fujifilm WCL-X70 sample images (54 comments in total)
In reply to:

GabrielZ: Everybody's saying the quality is great. But look at the photo above, the one before you click on the 'View our gallery...' Look at the extreme distortion of the house and telephone pole. They're both literally leaning over!

Interesting: I rotated the (low-resolution) image 4.75° clockwise, and most of what looks like the “perspective distortion” in the house is gone. All the vertical lines of the house but one become “practically vertical” on the screen.

So it looks like the top window of the house has a certain defect; this, the slanted horizon, and the low point of view contribute to a “feeling of strong perspective distortion” — while the actual distortion IS present, but is very weak. Do I deceive myself?

Link | Posted on Jun 16, 2016 at 07:00 UTC
On article Bolt-on 21: Fujifilm WCL-X70 sample images (54 comments in total)
In reply to:

GabrielZ: Everybody's saying the quality is great. But look at the photo above, the one before you click on the 'View our gallery...' Look at the extreme distortion of the house and telephone pole. They're both literally leaning over!

There must be practically no perspective distortion in this shot. Look at the horizon — it goes ALMOST through the center of the shot. When horizon goes EXACTLY through the center (axis of the lens is horizontal), there would be NO perspective distortion.

Link | Posted on Jun 14, 2016 at 02:46 UTC
In reply to:

Rexgig0: My wife has been using a Sun-Sniper sling since shortly after its introduction. She later added another type of attachment point, that allows for tripod mounting, made by a company other than either Sun-Sniper or BR. Perhaps because she lived in Europe for several years, she prefers the version with the metal cable inside the strap; perhaps thieves cutting camera and bag straps is more common in Europe than North America?

Following my wife's lead, I acquired a Sun-Sniper sling system, but I disliked the camera being upside down. It works better (for me) when attached to the tripod foot of a telephoto lens, with the tripod ring rotated so the camera hangs more upright.

I misplaced my Sun-Sniper sling, and substituted a Magpul sling; rather than something inspired by a carbine sling, I now use an authentic carbine sling. (When not using a large tele lens, I prefer using a Peak Design Slide, Think Tank Strap, or Leica strap, depending upon the size/weight of the camera/lens.)

Fujica: your reading comprehension is exactly backwards: Europe: 22,000 vs USA: 12,000.

Link | Posted on Jun 13, 2016 at 04:51 UTC
On article Processor designer ARM acquires Apical (29 comments in total)
In reply to:

maljo@inreach.com: Sounds like a good move.
(I've never heard of either of these companies)

@Richard:

Are you sure? What I’ve heard was that Sony‘s α100 was using Apical’s algorithm, but later versions switched to a different algorithm of DRO. But I never checked this…

Link | Posted on May 21, 2016 at 07:58 UTC
On article Benchmark Performance: Nikon D810 review (1984 comments in total)

@Rishi:

I have no clue how you reached the conclusion that D810 gives a dynamic range similar to MF. Looking at YOUR shots:
  http://www.dpreview.com/reviews/image-comparison/fullscreen?attr226_0=nikon_d810&attr226_1=nikon_d800&attr226_2=pentax_645z&attr226_3=canon_eos5dmkiii&normalization=compare&widget=329&x=0.46943794036589725&y=1.0658090200157284
what I see is a MUCH WORSE dynamic range.

Could you explain this, please?

P.S. Of course, I’m discussing the VISIBLE dynamic range; it may be that changing postprocessing options could change this. But this is the fault of EVERY comparison you do on DPR. Using ACR for comparison is bramaged, since it has different (hidden) biases for different cameras/systems. (I would use DCRaw, which has a straightforward/transparent treatment of RAW files.)

Link | Posted on May 15, 2016 at 00:14 UTC as 63rd comment | 1 reply
In reply to:

mrschmo: Can you do depth screening with a Lytro Illium camera for stills?

What good is “the face in focus” if diffraction restricts the total image resolution to 1.5MPix equivalent?

Did you actually USE the system to achieve the effect you describe?

Link | Posted on Apr 21, 2016 at 02:55 UTC
On article Crossing the Bridge: Canon XC10 Review (258 comments in total)
In reply to:

nathanleebush: You guys were much too delicate with this monstrosity. "Not so good for: photographers who require RAW file support" .. What is this, 2003? How did the A6300, which seemed to fall from the heavens, only score 5 percentage points higher? It's half the price with 10x the features, and a nicer image to boot, for both stills and video! This emerged like a hot turd from the depths of hell, and will soon return whence it came.. Canon really needs to get it together, but they obviously are not aware of the internet, or they would have fixed their broken product development culture by now. It's amazing to watch them blow their massive video lead with disappointment after disappointment.

smh

This is supported by his claim that ISO800 is not good, but ISO100 and ISO200 are acceptable — with (practically) ISO-invariant hardware!

The only sensible approach is, IMO, to ignore ISO setting, and shoot at a particular f-number/angle with a particular headroom…

   [However, keep in mind that I have practically
    zero experience with videography, only with
    photo.]

Ilya

Link | Posted on Apr 9, 2016 at 05:05 UTC
On article Crossing the Bridge: Canon XC10 Review (258 comments in total)
In reply to:

nathanleebush: You guys were much too delicate with this monstrosity. "Not so good for: photographers who require RAW file support" .. What is this, 2003? How did the A6300, which seemed to fall from the heavens, only score 5 percentage points higher? It's half the price with 10x the features, and a nicer image to boot, for both stills and video! This emerged like a hot turd from the depths of hell, and will soon return whence it came.. Canon really needs to get it together, but they obviously are not aware of the internet, or they would have fixed their broken product development culture by now. It's amazing to watch them blow their massive video lead with disappointment after disappointment.

smh

@Richard:

I do not think the tests of News Shooter make a lot of sense. Take the “scientific approach” to rolling shutter: using a variable-speed fan without mentioning WHICH speed was selected!

Anyway, while THIS test is not “very scientific”, it addresses a REAL concern: rolling shutter is not good. The other two complaints (aliasing, and noise-at-midgray-level) just do not make ANY sense at all.

Aliasing: the main mode of usage “for broadcast” (shoot at 4K, postrocess to HD) was not addressed at all — and judging by the provided samples, it would COMPLETELY eliminate anti-aliasing.

Noise-at-midgray: with Bayer sensors of today THIS should depend on the area of the sensor ONLY. AND: the measurements make NO SENSE at all unless one specifies the headroom available for “brighter-than-white”.

So my first idea is that the guy just does not know that different systems need different level of EV-correction to achieve the same headroom…

ToBeContinued…

Link | Posted on Apr 9, 2016 at 05:02 UTC
In reply to:

yslee1: Sad. It's usefulness in stills might have been questionable, but in video it would've been awesome. Do your focus pulling during post, instead of the hectic nature of the live shoot.

Maybe… But remember that what we discuss is “blurring”, and not “making more sharp”. Plenoptical is always going to be NOT LESS BLURRY than the corresponding “ordinary-focal” shot.

So the possible benefits are not
  • to shoot something with AF, then “improve
     sharpness”, but
  • to shoot something with AF, then “blur
     selectively”.

Ilya

Link | Posted on Apr 8, 2016 at 23:11 UTC
In reply to:

yslee1: Sad. It's usefulness in stills might have been questionable, but in video it would've been awesome. Do your focus pulling during post, instead of the hectic nature of the live shoot.

@Rishi:

1st, I remembered wrong: 1.5MPix limit is for 50° field of view, and (corrected!) 1m–∞ refocusing ability.

2nd: I assume a camera which allows 1Dioptry refocusing ability (e.g., captures image with 1.5MPix resolution at 2m, but allows resolution better than 0.75MPix in the range 1m–∞).

3rd: these are THEORETICAL limits (very similar to Heisenberg principle — and actually proven the same way) for synchronous plenoptical capture. With any particular implementation, one gets even worse results.

Ilya

Link | Posted on Apr 8, 2016 at 07:55 UTC
In reply to:

Everlast66: "we were competing in an established industry where the product requirements had been firmly cemented in the minds of consumers"

So its customers' fault for not realising the great potential of your product?
If I understand correctly, they introduced their innovative product, superior to everything else at same price-point, or maybe solving customers' "big focusing problem", and we customers, with our backward cement-brains simply could not grasp their grand idea?

Sorry, Lytro, but this is totally the wrong attitude!
Every decent entrepreneur knows that you can not argue with the market. You have to read it, understand it, and then add something that solves REAL problems better then competitors.

I'd applaud every innovator, even if they fail, but take the lesson out of that failure. But Lytro don't seem to be willing to admit their mistakes and are not showing they learned their lesson, despite its worth of $50 million of investors' money.

@Rishi:

> Why hold up today's product as representative
> of the potential the technology holds?

This technology holds NO potential. A simple calculation shows that the whole idea is a snake oil. One cannot get more resolution that with a hyper-focal shot by the usual camera. (Read: very blurry, about 1.5MPix max for typical examples of usage.)

YES, there is A benefit comparing to a hyperfocal shot: one can make this blurry image yet-more-blurry away from a particular “focused surface”. But THIS benefit is not what the advertisement were promising.

Link | Posted on Apr 6, 2016 at 06:11 UTC
In reply to:

yslee1: Sad. It's usefulness in stills might have been questionable, but in video it would've been awesome. Do your focus pulling during post, instead of the hectic nature of the live shoot.

Depends on the range of the distance you want to be able to focus-pull to. With a reasonable range (IIRC, 2m–∞) the theoretical max of resolution is about 1.5Mpix (with std focal length). Not enough for video applications.

If one restricts this range of distances (say, to 2m–2.5m), then one can reach the resolution needed even for 4K video. I’m not in a position to judge if such tiny freedom in focus post-pulling is worth the troubles.

Link | Posted on Apr 6, 2016 at 06:02 UTC
In reply to:

greenlens: Yes, LoCA is there but no onion rings so far.

@Rishi:

I have doubts about LEDs as “bokeh subjects”: too large. For my testing, I reflected LED from a ball bearing. With LED about 10 ball’s diameters away, the reflection is really dot-like.

Link | Posted on Apr 4, 2016 at 02:31 UTC

Could you please fix your reference to read noise of 1e⁻?

You forgot to read http://sensorgen.info/Calculations.html. Summarizing:

The quoted numbers are obtained by fitting a certain formula to the measured data. The formula assumes a simple model of the sensor readout. This simple model works remarkably well for most of the sensors — but it does not work AT ALL for sensors “changing the layout” depending on the ISO setting.

The A7S (ii?) sensor uses a trick (capacity change or somesuch) somewhere about ISO6400 (do not remember the details; see the Jim Kasson’s detailed investigation). As a result, the numbers you refer to are entirely a red herring.

AFAIK, the best sensors have the best read noise close to 2e⁻. (SOME of the numbers on sensorgen which are below 2e⁻ contradict my [much more advanced than curve-fitting] research. So I assume their approach is flawed in this regard too. For example, AFAICS, they do not take into account the quantization of the noise by ADC.)

Link | Posted on Mar 29, 2016 at 00:11 UTC as 31st comment

I’m completely confused by this interview… Correct me if my reading is wrong: He says:
  • Cinematographers react quickly to changes in tech;
  • Until the last year, he thought that film has better DR;
  • AFAIK, in Super 35mm film vs FF digital, w.r.t. DR, digital
    wins for 8–10 years already (at least for photo cameras).
How to combine these? Are cinema camera so far behind?

I see that Alexa is about 6 years old — and it looks it can easily match the performance of photo cameras… How to understand all this?

Link | Posted on Mar 18, 2016 at 10:18 UTC as 17th comment
On article CP+ 2016: Things we found that had been cut in half (135 comments in total)
In reply to:

Onur Otlu: "..and features a new XA (extreme aspherical) element which has been rendered even more aspherical in this lens by being cut in half."

This was my favourite of them all - along with "ugly bokeh".

Thanks for the humor, and Rishi was right - you've *got* to keep this going!

1-element lens is very easy to design — at least if you have a material with VERY high refraction index not depending on wavelength.

The best lens is going to be very thin, going along the sphere. Radius = focal length, center is in the center of image.

This design has f-number up to f/0.5, no spherical aberration, and no coma — but it has very strong astigmatism: the tangential/saggital curvature of field are: flat vs focal length.

From this description, it is very easy to calculate the ellipses of confusion. So this design may be good for supertelephoto only…

Link | Posted on Mar 1, 2016 at 01:04 UTC
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