DSPographer

Lives in United States United States
Works as a digital signal processing engineer
Joined on Jan 10, 2005
About me:

Canon 5D mark II camera.

Canon 28-135/3.5-5.6_IS_USM, 24/2.8, 50/1.8II, 100/2.8_USM_macro, 200/2.8L lenses.

Sigma EF-500_DG_Super flash.

Comments

Total: 40, showing: 1 – 20
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In reply to:

Dr_Jon: So presumably the question is whether it consumes more or less than $1080 in electricity in two years ($3400-$2320)? I guess less.

BTW I doo wonder if people buying the machines and running them in their own houses are at risk of getting raided by the Drug Enforcement people, as usually the house in the street with the big heat signature if the one growing drugs...

USA electricity rates range from 9.7 to 29.3 cents per kW-h.
https://www.chooseenergy.com/electricity-rates-by-state/

Link | Posted on Jan 11, 2018 at 21:42 UTC

I'm not sure we will understand the significance of this announcement until an iced-tea company has a chance to evaluate the details of the block-chain algorithm.

Link | Posted on Jan 9, 2018 at 20:00 UTC as 75th comment
In reply to:

mosswings: Very cool, but two comments:

1. Numerical aperture of 0.2: this is roughly equivalent to an f-number of 2.5.
2. Efficiency of 20% - if I understand this right, only 20% of the incident light is transmitted, a light loss of 2.1 stops. Makes sense - this is effectively a thin metal disk with slots at various spacings and widths. It is far less transparent than a glass element - even many glass elements.

There are applications for this technology, but it does not appear to be in low-light capable imaging systems - that is, consumer cameras - at this time.

You can see the supplemental figures for the article without paying. Figure S8 shows the efficiency, 20% is the peak- which is for blue light, for red light the efficiency is around 5%. The efficiency is the net transmission as you guessed, the efficiency is lowered by the crossed polarizers that they needed to remove the background light to maintain decent contrast. The diffraction-only lens shown would therefore not be of much use for ordinary photography.
A different configuration was modeled with the diffractive component correcting the aberrations of an ordinary simple refractive lens. This hybrid approach does apply to photographic lenses, but it isn't a new idea: Nikon and Canon etc already have lenses with diffractive optical components.

Link | Posted on Jan 5, 2018 at 18:16 UTC
On article UPDATED: Sony a7R III is still a star eater (462 comments in total)
In reply to:

Henrik Herranen: Umm, if the graphs are correct, the attenuation at fs/2 (Nyquist) is about 1.5 dB when compared to DC. This should hardly be visible in images. Then again, the image/video community uses the decibel scale incorrectly in so many imaginative ways (starting from the very incorrect definition of PSNR), so for all I know these dB numbers could just as well be potatoes.

(Short rant: if an audio signal's amplitude is halved, the power of the signal is lowered by a factor of 4, or approximately by 6 dB. But if an image RAW sample value is halved, power of the signal is lowered only by a factor of 2, or approximately by 3 dB. But, everywhere in the video industry people are using the dB scale incorrectly, using the incorrect assumption that a ratio of 1:2 is -6 dB, and not -3 dB as it should be. End of rant.)

The processing that Jim is performing shows the existence of filtering, but it doesn't characterize how local that filtering is. Instead of showing week filtering of all red channel pixels, the low measured effect probably just reflects that only a fraction of the pixels are affected. Further investigation is needed to show how strong the "eating" effect is and what the effect looks like.

Link | Posted on Nov 21, 2017 at 19:30 UTC
On article Sony a7R III sample gallery (254 comments in total)
In reply to:

Amnon G: Did you notice the weird texture in the left eye of the model in the 3rd image? Looks very processed.
Also look at the right eye in photo #6.
I have never seen humans with patterns like this.

So this is over processing or we found the way to identify replicants ;-P

Image 55 clearly shows the blue-tinted contact lens over this model's light brown iris. I don't know why colored contact lenses normally use such a crude dot pattern, but they do.

Link | Posted on Oct 26, 2017 at 19:43 UTC
On article Sony FE 100mm F2.8 STF gallery and first impressions (318 comments in total)
In reply to:

sh10453: I like this lens. I'm not a fan of bokeh circles. Nice subject isolation.
Thanks Rishi.

Since all the control over the amount of apodization occurs in the first stop, I think a valid criticism is that this lens should have allowed finer aperture increments than 1/3 stop. [Edit] Wait, can you actually do this by simply manually adjusting the aperture in "clickless" mode?

Link | Posted on May 11, 2017 at 13:51 UTC
On article Sony FE 100mm F2.8 STF gallery and first impressions (318 comments in total)
In reply to:

sh10453: I like this lens. I'm not a fan of bokeh circles. Nice subject isolation.
Thanks Rishi.

I agree that stopping down more than a stop is not what this lens is intended for. However, I see stopping down by 1/3 stop (as shown in the article yielding a less strong apodization effect) as a valid option: still different from a traditional lens but not as buttery-smooth as wide open. This seems more flexible to me than a lens which only has the equivalent effect of this lens stopped down by 1/3 stop. If Rishi instead always wants fully hard edged bokeh balls of a lens with no apodization at all, then he doesn't represent the photographers this less is targeted to: those that want the option in some situations to have smoother bokeh.

Link | Posted on May 11, 2017 at 13:37 UTC

Some more technical details:
http://image-sensors-world.blogspot.com/2017/02/sony-presents-3-layer-stacked-sensor.html

Link | Posted on Feb 7, 2017 at 21:48 UTC as 18th comment
In reply to:

jhinkey: And I hope the woman sues him in civil court if she hasn't already . . .

Maybe that's why the maximum fine is low: the expectation is that the victim will get a more appropriate amount in a civil suite.

Link | Posted on Jan 18, 2017 at 22:34 UTC
On article Leica announces M10 with new sensor, slimmer design (114 comments in total)
In reply to:

NAwlins Contrarian: Today a sensor of at least 36 MP without an anti-alias filter would seem like a minimum starting point, given how Leica and its fans seem to really like its sharp lenses. I don't see where the M10 does or does not have an anti-alias filter. Although 24 MP is fine for most uses, the Sony A7R II and Nikon D810 have shown that there is very little or no penalty in noise or dynamic range to upping the pixel count.

The need to accommodate the wide range of angles of light that the rangefinder style lenses present to the sensor may be one reason the pixel count is not higher.

Link | Posted on Jan 18, 2017 at 21:27 UTC

On an off-topic note: Shouldn't state legislatures realize that the fines versus jail time options are now ridiculously unbalanced? The maximum fine of $5000 is less than the price of many better drones, almost a year in prison seems pretty extreme in comparison.
Ex. according to the cinema 5D review the DJI Inspire-2 premium plus needed SSDs will cost about $8000 for the kit. Getting conked on the head lens-first by that system at either maximum speed or at free-fall from height would probably cause damage that would make a $5000 fine seem meaningless.

Link | Posted on Jan 18, 2017 at 20:59 UTC as 18th comment | 2 replies
In reply to:

Thomas Traub: flying drones should be forbidden because it is much more dangerous than most of the people recognize!
I fly an RC-controlled airplane (more of them) and I know that there could be some tricky situations that are not easy to handle. The big difference is that an airplane can be managed if something is wrong, f.e. the engine stops or one rudder goes bad - you have other ones.
If a drone has has a technical problem only with one of the engines or with wind or so on it comes down like a stone. And don't belive that it is easy to fly a drone only because 95 % of the work is done by an electronic-automatism that has a self-correction via GPS.
I know that some of us don't want to hear this or want to face the risk becaus it seems to be so easy to make pictures from above....

If something went wrong, it comes down like a stone - from 300 m above - 2 kg or more ......

AND FLYING OVER HUMANS OR IN A CITY IS AN A B S O L U T E N O G O ! ! ! ! !
And it is forbidden near everywhere ....

I worded it poorly. I didn't mean another example of FAA enforcement, but another example of a drone operator being charged.
I did provide a quote from the fly for fun section as well.
The FAA does mention that you can follow club safety rules if you are a member of a national hobby club. It looks like the FAA would require this to fly a hobby UAV over 55 pounds.

Link | Posted on Jan 17, 2017 at 23:48 UTC
In reply to:

Lensmate: If people cover their hands up, won't they just switch to retinal scanning? Eyes are usually the sharpest section in most photographs of people. [excluding nudity]

Retinal scanning is almost never used, it is just confused with iris scans which are what are really used.
The iris texture is only visible using infrared for people with pigmented (ex. brown/black) irises. Near-IR can be blocked with quality sunglasses, but normal sunglasses won't work.

Link | Posted on Jan 17, 2017 at 22:07 UTC
In reply to:

Thomas Traub: flying drones should be forbidden because it is much more dangerous than most of the people recognize!
I fly an RC-controlled airplane (more of them) and I know that there could be some tricky situations that are not easy to handle. The big difference is that an airplane can be managed if something is wrong, f.e. the engine stops or one rudder goes bad - you have other ones.
If a drone has has a technical problem only with one of the engines or with wind or so on it comes down like a stone. And don't belive that it is easy to fly a drone only because 95 % of the work is done by an electronic-automatism that has a self-correction via GPS.
I know that some of us don't want to hear this or want to face the risk becaus it seems to be so easy to make pictures from above....

If something went wrong, it comes down like a stone - from 300 m above - 2 kg or more ......

AND FLYING OVER HUMANS OR IN A CITY IS AN A B S O L U T E N O G O ! ! ! ! !
And it is forbidden near everywhere ....

Another example: A drone operator convicted of reckless endangerment:
https://news.seattle.gov/2017/01/13/city-attorneys-office-prevails-in-drone-case/

Link | Posted on Jan 17, 2017 at 21:57 UTC
In reply to:

Thomas Traub: flying drones should be forbidden because it is much more dangerous than most of the people recognize!
I fly an RC-controlled airplane (more of them) and I know that there could be some tricky situations that are not easy to handle. The big difference is that an airplane can be managed if something is wrong, f.e. the engine stops or one rudder goes bad - you have other ones.
If a drone has has a technical problem only with one of the engines or with wind or so on it comes down like a stone. And don't belive that it is easy to fly a drone only because 95 % of the work is done by an electronic-automatism that has a self-correction via GPS.
I know that some of us don't want to hear this or want to face the risk becaus it seems to be so easy to make pictures from above....

If something went wrong, it comes down like a stone - from 300 m above - 2 kg or more ......

AND FLYING OVER HUMANS OR IN A CITY IS AN A B S O L U T E N O G O ! ! ! ! !
And it is forbidden near everywhere ....

Sometimes the FAA directly enforces its rules. They just settled a lawsuit against SkyPan for flying over New York and Chicago for $200,000. This is reduced from the initial proposed amount of $1,900,000.
http://arstechnica.com/tech-policy/2017/01/faa-and-aerial-photography-firm-settle-drone-dispute-for-200000/
According to the article, the FAA says breaking its rules is illegal:
""Flying unmanned aircraft in violation of the Federal Aviation Regulations is illegal and can be dangerous," FAA Administrator Michael Huerta said"

Link | Posted on Jan 17, 2017 at 21:22 UTC
In reply to:

Thomas Traub: flying drones should be forbidden because it is much more dangerous than most of the people recognize!
I fly an RC-controlled airplane (more of them) and I know that there could be some tricky situations that are not easy to handle. The big difference is that an airplane can be managed if something is wrong, f.e. the engine stops or one rudder goes bad - you have other ones.
If a drone has has a technical problem only with one of the engines or with wind or so on it comes down like a stone. And don't belive that it is easy to fly a drone only because 95 % of the work is done by an electronic-automatism that has a self-correction via GPS.
I know that some of us don't want to hear this or want to face the risk becaus it seems to be so easy to make pictures from above....

If something went wrong, it comes down like a stone - from 300 m above - 2 kg or more ......

AND FLYING OVER HUMANS OR IN A CITY IS AN A B S O L U T E N O G O ! ! ! ! !
And it is forbidden near everywhere ....

Note: part-107 rules are for "fly-for-work" drone operation, but fly for fun safety rules are similar. An excerpt from the "fly-For-Fun" FAA page states:
"Never fly over groups of people"
https://www.faa.gov/uas/getting_started/fly_for_fun/

Link | Posted on Jan 17, 2017 at 20:50 UTC
In reply to:

jhinkey: This kind of thing needs to be nipped in the bud as it will get out of control quickly with the meteoric rise in drones. Well legislated rules and strict tough enforcement for violations are a must.

Last year someone (not sure if they eventually caught them) crashed a drone into the wheel on the waterfront in Seattle - lucky no one on the ground got hurt when it fell.

Correction Inspire-1 max level still air speed is 22 m/s = 49 MPH.

Link | Posted on Jan 17, 2017 at 16:59 UTC
In reply to:

Thomas Traub: flying drones should be forbidden because it is much more dangerous than most of the people recognize!
I fly an RC-controlled airplane (more of them) and I know that there could be some tricky situations that are not easy to handle. The big difference is that an airplane can be managed if something is wrong, f.e. the engine stops or one rudder goes bad - you have other ones.
If a drone has has a technical problem only with one of the engines or with wind or so on it comes down like a stone. And don't belive that it is easy to fly a drone only because 95 % of the work is done by an electronic-automatism that has a self-correction via GPS.
I know that some of us don't want to hear this or want to face the risk becaus it seems to be so easy to make pictures from above....

If something went wrong, it comes down like a stone - from 300 m above - 2 kg or more ......

AND FLYING OVER HUMANS OR IN A CITY IS AN A B S O L U T E N O G O ! ! ! ! !
And it is forbidden near everywhere ....

True, and you would most likely be charged under a state statute: but I think the local police & prosecutor would be likely to cite the FAA rule when charging you with something like reckless endangerment.

Link | Posted on Jan 17, 2017 at 16:51 UTC
In reply to:

junk1: Is this any more reckless than people playing baseball in a neighborhood? Ever get hit by a baseball in the head? Or imagine what a baseball could do to a window or siding. Would we charge the person with reckless endangerment? I'd rather have a drone hit me than a baseball "line drive".

Baseball 0.149 Kg vs 2.948 Inspire-1 drone
Speed: Baseball 37.1 m/s standard line drive, 53.6 m/s Max Major league home run, Inspire-1 drone 22 m/s max in still air.
Baseball kinetic energy: 100 J standard drive up to 214 J max speed.
Inspire-1 kinetic energy: 713 J at maximum level flight speed.
Baseball helmets are designed to withstand 100 J.

Link | Posted on Jan 17, 2017 at 16:36 UTC
In reply to:

jhinkey: This kind of thing needs to be nipped in the bud as it will get out of control quickly with the meteoric rise in drones. Well legislated rules and strict tough enforcement for violations are a must.

Last year someone (not sure if they eventually caught them) crashed a drone into the wheel on the waterfront in Seattle - lucky no one on the ground got hurt when it fell.

Inspire 1: About 6.5 lbs with a 22 MPH top speed. Not exactly as dangerous as an out of control car. Still, its illegal to operate over other people which basically bans operation over cities.

Link | Posted on Jan 17, 2017 at 16:18 UTC
Total: 40, showing: 1 – 20
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