Truman Prevatt

Truman Prevatt

Lives in United States Florida, United States
Works as a Mathematical Physicist
Has a website at
Joined on Dec 24, 2001
About me:

PhD in Mathematics


Total: 39, showing: 1 – 20
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I just turned 3/4 of a century old today. Ever since I can remember that have been Leica haters - mostly those that lusted for a Leica but could not afford one. There are also Porsche and Ferrari haters out there because most people can't afford one. Does that mean that a Porsche and Ferrari are not great cars - absolutely not. But the jealously of the is amazing to see. But obviously I am not surprised. I am sorry just because one can't afford a Leica does not mean it does not mean it is a bad camera just as if one cannot afford a Porsche does not mean it is a bad car.

But the haters will be haters - peeing all over a camera most likely never having only owning one or using one.

Link | Posted on May 3, 2022 at 23:13 UTC as 40th comment | 8 replies
In reply to:

noegd: Very tempted by the Studio Max with 32 GPU cores (because the option isn’t too costly). Wondering about 64GB RAM. I don’t need that much but on the other hand I tend to keep my machines for a long time and my current MP6,1 already has 32GB of RAM. It needs to feel as an upgrade ;-)
Will probably pull the trigger unless tests uncover something problematic.

I picked up the M1 MBP 13 inch when it came out. I was a bit concerned about the 16 GB memory on the device. I called an old friend who is a professor of computer science at University of Maryland and had a discussion. The common memory architecture solved the dead time required to transfer data to and from a discrete GPU. He reminded me of the days we had to use shared memory to optimize speed. The shared memory is basically shared memory that works.

With the new higher speed "flash memory" in the SDD's there is much less penalty in using virtual memory. The MacOS ranges virtual memory quite well. With that in mind - I configured my MBP to 2TB SDD and have been extremely happy with the performance. It blows the socks off my wife's high end i9 Intel iMac with 32 GB memory. No complaints at all with my MBP 13 inch M1 either plugged into an external monitor at home or on the road.

Link | Posted on Mar 16, 2022 at 15:24 UTC
On article Landscape Composition - Part 3: Negative space (86 comments in total)

Interesting take. However, imposing symmetry often makes for a boring composition. Often "broken symmetry" provides a more compelling composition if it is effectively used. Take a look at Ansel Adam's Western landscapes. Adams often used "dead" space to drive the eye, for example Monolith, The Face of Half Dome. Then there is "Moonrise" where in the final printing in 1975 the top 2/3's of the print is "dead space" with the moon in the middle - to emphasize the spotlighted grave stones. My criticism of this "rule" is it imposes a symmetry that is often just not found in nature. In fact it was a trade mark of Adam's land scape to use broken symmetry along with the creative use of "dead space" to capture the imitation of the viewer. But to quote W. Eugene Smith, "I didn't write the rules, so why did I follow them." However, that said often "rules" are a good starting point for determining how breaking them will generate tension and make a compelling image.

Link | Posted on Feb 9, 2022 at 14:57 UTC as 7th comment | 1 reply
In reply to:

Truman Prevatt: There is no device sitting on an open network that is completely secure from hacks. Now days devices need to have security implemented in dedicated H/W which makes it more secure to intrusion and hacking, e.g., the Apple T2 chip, the Microsoft Pluton processor. The WD My Cloud is an old design and at some point they had to discontinue it. But make no mistake any device on the Internet is a target.

Backdoor's. Every device on an open network has a backdoor. H/W devices will provide additional level of security that the system S/W providing the cybersecurity. That's why Apple has been using dedicated security chips for quite awhile and why Microsoft is using one now - particularly in their gaming system. Just google "Playstation Hacks" to see the risk of being on an open network. Security features etched in silicon provide such features as secure boot and dedicated AES and key generation that are much more difficult to circumvent through an OS Hack. The H/W based AES provides for rapid encryption and decryption of files so using disk encryption does not slow down the operations. It is better than S/W based security. But nothing is forever secure from a dedicated adversary with the desire and resources.

Link | Posted on Nov 23, 2021 at 13:38 UTC

There is no device sitting on an open network that is completely secure from hacks. Now days devices need to have security implemented in dedicated H/W which makes it more secure to intrusion and hacking, e.g., the Apple T2 chip, the Microsoft Pluton processor. The WD My Cloud is an old design and at some point they had to discontinue it. But make no mistake any device on the Internet is a target.

Link | Posted on Nov 22, 2021 at 15:01 UTC as 22nd comment | 4 replies
In reply to:

snapshtr: Looks like the same sensor as Fuji's X series. If I wanted the rangefinder experience I would rather get an X-Pro3, with the more sophisticated hybrid viewfinder.

And the Bayer filter is a good thing.

Link | Posted on Sep 28, 2021 at 21:12 UTC

The EU has less than 8% of the world's population - and they still want to call the shots. Amazing - one would think they have not yet realized that the days of European colonization are long over. As electronic components become smaller and smaller, data rates become higher and higher and interfaces have to change to support that. What the EU will band Thunderbolt 5/6, etc. Does the EU want to have a representative on every Intel, Apple, TSMC, Samsung, Google, etc., design teams wagging their finger - telling them you can do that "it says it right here?" "You can't do that because it is no conflict of what a bunch of lawyers and bureaucrats in Brussels say. Incredible. I would expect there will not only be blow back from Apple, but most of the electronics and communications sector. Maybe the EU would like to see the world go back to RS232 - that's a standard.

Link | Posted on Sep 27, 2021 at 21:18 UTC as 15th comment | 10 replies

Some people need to take a chill pill. The new 5 nanometer M2 chip is in production. Apple announced a two year transition, it has been six months! According to most of the Mac Rumor sites - the hold up on the new MBP 16 inch is not the processor but the display.

Link | Posted on Jul 14, 2021 at 22:04 UTC as 21st comment
In reply to:

Class A: This article creates the misleading impression that the M1 chips are performance wonders. They are not, in terms of top performance.

They are very efficient, so the performance/watt figures are great, but they are not the best choice if you want the best possible performance.

The M1 chips are currently a nice technology to be used in light laptops, but if one is talking about Capture One performance outside this context then there are better solutions.

It is unfortunate that Capture One make no statements as to whether the software redesign will also benefit Windows users.

I'd rather have anything that negatively affects productivity fixed first before the image pipeline is further optimised. There are many, many small bugs and missing features in Capture One that would be easy to address, that would make a far bigger difference to time spent using C1 for many photographers than squeezing out a bit more performance out of the image processing.

Actually in the video interview with the lead engineer, he does address the issue that over time the rewrite will improve performance with the X86 processor. However, that wasn't the goal but more efficient code was generated. On the other hand at some point the Microsoft ARM boxes will be significant competition to the X86 boxes running Windows. One of the big improvements came because the rewrite made efficient use of Metal. My 13 inch MBP running C1 under Rosetta 2 was comparable to a little better performance than running on my late 2017 top end MBP 15 inch MBP. But I have heard the fan come on on my M1 box as of yet. My X86 box sounded like a C130 taking off. The testing I've done so far on the native binary (C21) just released - the native version blows away the Rosetta 2 version and my 2017 X86 MBP looks like a piker now and the fans are still roaring. C1 released two videos - one an interview with a beta tester (photographer) and the other a lead engineer.

Link | Posted on May 29, 2021 at 20:08 UTC
In reply to:

24Peter: I've never purchased or owned an Apple product in my life - and I'm well into middle age :-) But the performance of their M1 devices seems downright impressive. Can't say I'll switch from my PC's- but who knows? I do applaud Apple for their innovation - and marketing savvy!

it's not just Apple, Microsoft is transitioning to ARM based processor. The reason is performance vs. power. ARM bases processors are much more power efficient than the Intel architecture. My new MacBook Pro 13 M1 runs C1 faster than my wive's new Intel iMac (mid 2020 vintage) with the top end Intel and 32 GB of RAM. And C1 runs under the Rossetta emulator. C1 will release its M1 native update in May. On my old top end 2017 MBP 15 - extensive photo editing and the fan was roaring sounding like an airplane ready to take off. On the M1 I haven't heard the fan yet. Microsoft has fully transitioned to an ARM processor in its Surface line.

Link | Posted on Apr 29, 2021 at 18:40 UTC
In reply to:

Photomonkey: The plastic reels were terrible in comparison to Kindermann reels. Well made and very durable stainless steel. Their tanks and lids were much better than the copycats still found on the market.

Of course if you drop them they can bend. But then they can be bent back

Yep the square edges would get stuck in the plastic reels and once that happens, you can have a problem in the dark or in a changing bag. If one is going to use plastic reels, snip off and slightly round the corners and that solves the problem. Plastic reels if not perfectly dry will also cause the film to bind. Stainless reels for 35 mm are much better. For 120 roll film, plastic reels make some sense but not for 35 mm.

Link | Posted on Mar 27, 2021 at 19:46 UTC

The term sling bag is public domain in that it defines a type of bag. They are also not unique to cameras. A sling bag is a term used for a type of handbag that have a long strap that can hang from your shoulder or across the front of your body. They can be found in purse-style designs or backpack designs. PD does not own the term sling or sling bag when it comes to cameras, Lowepro had one first. In the long run if someone doesn't have the budget to buy a PD bag then they have an option. If it pushes down the price of PD bag it is called competition and the consumer benefits. Claiming that PD has the sole right to the name or the sole right to the design when there have been many sling bags on the market for many different uses before PD was even real - is a real stretch. Competition is a good thing. I have a PD 6L sling bag. It's nice but for what it is - it is overpriced.

Link | Posted on Mar 4, 2021 at 21:40 UTC as 62nd comment | 5 replies
In reply to:

Hello123: A reminder that there is nothing more permanent than what is temporary. ~Milton Friedman ....I think.

Wonderful video

Actually it is an old Greek proverb Ουδέν μονιμότερον του προσωρινού
Some attribute it to the Russians instead of the Greeks. Friedman used it to make a point about economics. But it is a lot older than Friedman.

Link | Posted on Feb 16, 2021 at 21:31 UTC
In reply to:

riveredger: I would support this law. As a homeowner, one should have an expectation of privacy on one's property. I get that there are planes and helicopters already, but I don't see them attempting to film what is happening in my backyard.

An incident in FL that happened to acquaintance. There was some friction between two neighbors. One neighbor was somewhat of a crack pot and thought their next door neighbor was doing something she should not be. I knew the next door neighbor was at their house to pick up a saddle to try out. I noticed a tall poll on the other side of their fence and on that a camera pointed directed into the yard. I inquired and was told the neighbor had put up a camera and was spying on them. There were actually two - one focused on the front and one on the back. They also told me that the country sheriff had told them there was nothing that could be done since it was on their property. A private lawyer told them the same thing. I was a bit dismayed but evidently unless they try to peddle films of peeking into bedrooms - there is little that can be done at least in FL.

Link | Posted on Feb 6, 2021 at 16:11 UTC

It's about time. Simulations and reduction of field testing prototypes has propelled process in the aerospace industry where it is very expensive to build prototypes. SpaceX is a classic example of the power of simulations. Never before has a first stage launch vehicle been reused. In fact Lockheed and Boeing said "it could not be done." All the guidance and control was developed through simulations and today SpaceX routinely safely lands the first state (instead of dumping them in the ocean). The process today is sound enough they can even bring them down on land instead on a barge.

The camera industry will benefit from this approach. Most lenses today are designed using three dimension CAD and simulations.

Link | Posted on Sep 29, 2020 at 20:58 UTC as 17th comment
In reply to:

Cmon: It's stupid to do that with the drone and even more stupid to post it or repost it.

But: would it be really any harm to such a fighter jet if they hit the drone? If yes, then any bigger bird would to the same damage. And that would be bad, if that's really so dangerous.

These planes are flying at about 300 meters per second. They make a pretty good wave and there air is funneled into the air intake of the engine. That much speed needs lots of air. A drone or bird can take out an engine. Flying at 300 feet above the deck - most likely a lost engine would crash the plane - in an urban area. Even if the pilot punched out a 300 feet, he might not have survived. Most likely he would have tried to steer the plane to a safer location to crash - riding it down.

US Airways flight 1549 was brought down in the Hudson river because of birds in the engine. If not for the fact the pilot was experience and could land crash land it in the water - a hundred people or so would have died. Yes this was a big deal. It was illegal and most likely reposting it would fall under accessory after the fact. This was a big deal and it could have turned very bad very fast.

I say throw the book at all involved.

Link | Posted on May 18, 2020 at 21:08 UTC
In reply to:

JavaJones: Well, at least Autel actually *makes* something. I was expecting this to be yet another patent troll case.

Actually that doesn't matter. Take it from someone that has 23 patents with two different companies, patents cost money. Patents are protection of a companies investment in research to protect the IP developed as a result of this investment. A patient undergoes a large amount of peer review. First by the company's lawyers, next by their patent law firm they hire to shepard the patent through the process and finally by the patent examiner. It matters little if the company developed he patent to build themselves, license or sell. It is their property and the patent is the legal process to protect their investment.

Link | Posted on May 17, 2020 at 21:11 UTC

Global economic meltdown. Over 20 million newly unemployed in the US alone and it's not even close to being over. The projected unemployment rate in the us when the numbers come out at the end of the month - 16 to 20 percent. The US is not along. JPMorgan and Goldman are projecting a 30 to 40 percent contraction of the world economy. These conditions have not been seen since the Great Depression - no not Great Recession of 2008 but the Great Depression of the 1930's. And we don't even have a vaccine and many are preparing for the second wave. If 1919 is any indication the second wave will be much worse than the first. Disposable income is shrinking and camera sales were tanking starting years before Covid-19. Camera companies will do their best to survive. But camera sales are not going up anytime soon because when one has a choice of eating or paying the rent or mortgage and buying a new camera - buying a new camera will lose out.

Link | Posted on Apr 26, 2020 at 22:21 UTC as 44th comment | 31 replies
In reply to:

Kjeld Olesen: What is this doing here? Where is the D in DPReview? This article is 20 years late! Forget film!

Well has film seems to be making a comeback one has to remember that the D in DPR is Amazon. Film making a comeback more opportunities for Amazon. Personally if I am going to do a serious landscape - it will be on sheet film with my 4x5. A 4x5 negative simply prints itself.

Link | Posted on Apr 17, 2020 at 20:51 UTC
On article Ins and outs of ISO: where ISO gets complex (153 comments in total)
In reply to:

TheGrammarFairy: Nice work and I want to make sure I understand: you're saying the camera adds different levels of analog amplification depending on the ISO? That seems to to be at odds with the idea that a raw file is unprocessed sensor data.

Also, those tone curves you talk about, is that what some people call "digital gain" or something else entirely?

In any digital system, be it imagery or RF the role of amplification is to keep the signal range within the input range of the ADC. A system is designed so that the dynamic range of the sensor is less than the range of the ADC so the ADC is not the limiting factor. So amplification is not bad and is required. However, an amplifier is an active device and it adds noise to the output signal. The higher the amplification - the more noise. So there is a trade off. In the RF world - digital receivers have been the mainstay since the 1980's. So the RF world is pretty far ahead of the digital imaging world as CMOS chips with onboard amplification and ADC hare relatively new. At the end of the day the human eye has about 20 stops of dynamic range. Comparing that to digital cameras - a 14 bit ADC gives you about 11to 12 at best for a lot of technical reasons. The amplification strategy will deterring how efficient the ADC range is used.

Link | Posted on Apr 16, 2020 at 23:19 UTC
Total: 39, showing: 1 – 20
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