My father shoots Canon, and has gotten sort of frustrated with the ADHD problem of the autofocus. Using two different lenses (70-200/2.8, 100-400) and two different bodies (350D, 500D), he's noticed that the AF is easily distracted by foreground clutter, and will also inexplicably refuse to confirm an AF lock (and thus shoot) in some situations you'd think are easy, like a bird on the end of a twig with a background distant enough to be a blur. Have you experienced anything like this? (This is in single-shot center-point AF mode.)
I have a 40D that I also mostly use in center-point AF mode. I mostly use a Tamron superzoom on it which at full telephoto is f/6.3, slightly out of Canon's autofocus spec (f/5.6). If the focus is way off to start with (like say you're focused up close and now you want to focus on that little bird 20 meters out) then the camera won't even know what you're pointing at (and you won't either if you're looking through the viewfinder). The circles of confusion from that stuff in the foreground probably overlap the bird entirely (maybe not at the aperture you're exposing at, but phase AF always works at the len's maximum aperture size). In that circumstance you'd need to get the focus reasonably close to the desired distance before it can lock on through the foreground clutter, either by letting it hunt or by locking on to something else at roughly the same distance without other stuff in the way.
In low-light situations (where I would be using 1/10 second or longer exposures at ISO 3200 without the flash AF assist) it starts to get very picky about what it will focus on, and at that point, if appropriate, I'll tell it to use all AF points again (this significantly improves sensitivity).
I also have a 50mm f/1.4 lens for it. One time while backpacking I decided to shoot a time lapse movie of the stars. I was able to reliably autofocus it on Venus before switching it to manual mode and turning on the timer remote.
I have also hooked it up to a Celestron C5 telescope, which is f/10, far beyond the f/5.6 spec. While the Celestron is manual focus only, I'm hacking some electronics gutted from a used 50mm f/1.8 onto it to make it autofocus. I'm not done yet, but I can easily coax a focus confirmation light out of it with modest indoor lighting.
It's the only SLR I've ever owned so I can't compare it to anything else. I hope what I've written helps.
I would be surprised if the scientists said "it's 4-6 times stronger at the same thickness" and the reporter did the math to get to 2-3 times stronger at half the thickness.
I would also be surprised if the reporter knew that strength increases with the square of thickness; i.e. doubling a material's thickness results in a quadrupling of strength.
You aren't "in the United States" yet, and you do not have your constitutional rights until you are.
Ahh, but you do. He's a citizen. Why? Because he was born here (Jus soli) or naturalized. What protections do Citizens have against the government? Let's start with the Fourteenth Amendment:
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
The jurisdiction clause is not a loophole; if you're not in the jurisdiction of the United States, they can't touch you (legally anyway - this is not a discussion about extraordinary rendition, military action, etc.)
If you can build and operate ten 100 megawatt solar plants for the cost of building, operating and decommissioning one 1 gigawatt nuke plant (and insuring it for liability, and dealing with its waste), why not go with solar?
Because we still have no practical, general-purpose way of storing energy on those scales. Since we have to generate exactly as much electricity as is being used, this in turn means that we've built the grid to run off of base load plants (those which produce the same power output all the time, such as nuclear) and peak load plants (which can adjust to minute-by-minute output requirements but often use more expensive fuel such as natural gas). The grid can use solar/wind/etc all you want but since nature, not man, controls the output to those, they need to be backed up by traditional peaking plants (exactly how much backup you need depends on how much downtime you can accept).
Solar thermal power can partially work around the problem by keeping a large vat of fluid (usually molten salt) very hot and using that capacity to spin turbines through the night. I think the technique is very promising.
"A new antivirus update installed by my administrators. All the computers crash and burn. Now, should we have tested that? Take the number of tests, A, multiplied by the time it takes to do each test, B, multiplied by the tester's salary, C. A times B times C equals X. If X is more than the cost of the downtime, we don't test."
The motors are 99 cents in a surplus bin. The batteries I already have lying around. The flywheels can be anything dense that I can balance properly. It can all mount to the camera via the tripod threads. Some people have used old hard drives and had good results (slightly better than in-camera IS) - it won't take anything fancy.
Yeah, they just don't currently make any unobstructed offset designs (that would solve the contrast and bokeh issue).
I'm planning to get a Celestron C5 and use that as my next lens. I'm hoping to also get a cheapo prime lens (Probably a used Canon 50mm f/1.8, since they seem to break so easily) and use its guts to work the C5's focus knob. I'm hoping to add some cheap gyroscopic stabilization (motors and flywheels), and as for the bokeh issue, I'm hoping to mostly point it at things with fairly regular backgrounds already. There is one ugly, but easy solution to the bokeh problem: I can put some card stock over the front with a circular hole between the secondary mirror and one edge - that will convert it to a very, very slow (f/30) "unobstructed" lens. Hope the subject stays still.
I'm pretty sure there is a way to make those things, smaller, less sensitive to dust and cheaper.
One approach would be to use mirror lenses, like a reflecting telescope. Most such telescopes these days have a central obstruction for the secondary mirror, which reduces contrast and has unappealing donut-shaped bokeh. However, there are a couple interesting offset-mirror scopes that avoid this problem, such as the Scheifspeigler and Yolo designs. While most are designed to be very slow (f/10 or longer), they can apparently be made as fast as f/5.5. Add in a motorized aperture, autofocus, and image stabilization, and you've got a (very weird looking) telephoto lens.
The only downside is that stereo phono jacks have more noise than separate RCA jacks, since the L and R signals are not isolated from each other in the cable and can have crosstalk.
It gets worse - most installations put the L and R speaker outputs in the same room!
For some reason, submitter is assuming that its somehow easy to cram all of the necessary technology into a package the size of your Shift key and still have room for a battery.
Yes, if only there was evidence that it was possible to produce such a tiny device so cheaply.
LEDs are highly directional, thus they make a better replacement for a spotlight than for a standard bulb (diffusers waste power, lowering efficiency)
LEDs are a (nearly) point light source that happens to be integrated into a plastic lens. This lens can be made in a number of different shapes - the ones with the familiar raised-sphere top work as a convex lens to focus the light into a relatively narrow beamwidth, but if you put the diode at the center of that sphere, you get an even radiation pattern instead.
At least your parents could afford duct tape for your shoes!
(Seriously - ActiveX was first released in '96, about the time that ~1GB hard drives and 133MHz Pentiums were typical, and took a few years to catch on. By then your screamer DX2 box would have been several generations out of date. If you were smart, you never would have put Windows95 on it.)
Back when it was introduced, ActiveX had no legitimate competitors.
Yes it did; the native Win32 app. IMHO most of the ActiveX-reliant applications of that day would have been better off written that way anyway. It would have been more portable because it never would have tied them to any particular browser version, and it would have been more usable, too.
It doesn't seem like a great idea to me. There are a lot of different ECC algorithms and implementations. It seems to me that it would be better to let the hard drive manufacturer select one that closely matches the expected signal and noise characteristics of a particular disk drive rather than some generic algorithm in the filesystem.
First, I suspect that disk drive manufacturers are more keen on selecting an ECC implementation that matches their drive's marketing requirements.
Second, at work, I currently have a RAID1 whose backups have corrupt checksums nearly exactly half the time. As best I can tell, for whatever reason, there's a few sectors where different data got written to the two disks in the mirror. Without filesystem-level ECC, there is no guaranteed way to tell which disk has good data - if I tell the RAID controller to do a verify, I have a 50% chance of wiping out the good data (and if I don't do a verify, LSI tech support tells me to take a hike). End-to-end checksumming is the only answer here - it's not just happening to me.
The energy savings with this scheme is due to the fact efficiency of chillers is lowest when asked to produce coldest output.
In practice this depends entirely on the design of the chiller - specifically the choice of working fluid and the choice of pressures. The refrigerator in your kitchen is happy to efficiently exhaust heat from freezing air to sweltering air. Heat pumps' theoretical limits of efficiency are the same as heat engines in reverse. The carnot efficiency of an engine with a 290K cold side and a 300K hot side is 3.33% - the carnot efficiency of an engine with a 280K cold side and a 300K hot side is 6.66% - exactly double, meaning exactly half the 280K/300K gas is used (or, with a chiller, produced). This means that with a given amount of energy and a theoretical-efficiency chiller, I can move the same amount of heat with either colder air or more air - it doesn't matter which.
If any one power circuit is lost, nothing really bad happens.
If by circuit you mean phase, then you never lose just one phase. Cutting one wire of a three-phase system leaves only one circuit, not two - two-thirds of your load circuits will not have power.
I've seen the loss-of-neutral failure exactly once - an electrician was doing work on what he thought was a separate circuit, and disconnected the neutral to a live circuit (there might have been more to it than that, but that's what he confessed to doing). End result was 208V into a 120V UPS which promptly fried.
While computers all have power supplies that'll take 208V no problem, there's lots of things that don't, and I suspect if this failure mode was as common in non-industrial settings (with few large motors) as you make it out to be, there'd be a steady stream of dead equipment (and dead 277V fluorescent light ballasts) to show for it - especially considering your scenario could happen with residential split-phase 240V power too. I do agree that having some design headroom is a good idea, though.
Google and Facebook would meticulously ignore both (unless by "central" you mean "powers the whole datacenter"). That's the whole point of designing your software to withstand some of your servers going offline at any time.
Slashdot Mirror
I have a 40D that I also mostly use in center-point AF mode. I mostly use a Tamron superzoom on it which at full telephoto is f/6.3, slightly out of Canon's autofocus spec (f/5.6). If the focus is way off to start with (like say you're focused up close and now you want to focus on that little bird 20 meters out) then the camera won't even know what you're pointing at (and you won't either if you're looking through the viewfinder). The circles of confusion from that stuff in the foreground probably overlap the bird entirely (maybe not at the aperture you're exposing at, but phase AF always works at the len's maximum aperture size). In that circumstance you'd need to get the focus reasonably close to the desired distance before it can lock on through the foreground clutter, either by letting it hunt or by locking on to something else at roughly the same distance without other stuff in the way.
In low-light situations (where I would be using 1/10 second or longer exposures at ISO 3200 without the flash AF assist) it starts to get very picky about what it will focus on, and at that point, if appropriate, I'll tell it to use all AF points again (this significantly improves sensitivity).
I also have a 50mm f/1.4 lens for it. One time while backpacking I decided to shoot a time lapse movie of the stars. I was able to reliably autofocus it on Venus before switching it to manual mode and turning on the timer remote.
I have also hooked it up to a Celestron C5 telescope, which is f/10, far beyond the f/5.6 spec. While the Celestron is manual focus only, I'm hacking some electronics gutted from a used 50mm f/1.8 onto it to make it autofocus. I'm not done yet, but I can easily coax a focus confirmation light out of it with modest indoor lighting.
It's the only SLR I've ever owned so I can't compare it to anything else. I hope what I've written helps.
Light Amplification by Stimulated Emission of Radiation.
Your preference really depends on whether you're buying GB or I/Os per second.
I would also be surprised if the reporter knew that strength increases with the square of thickness; i.e. doubling a material's thickness results in a quadrupling of strength.
Ahh, but you do. He's a citizen. Why? Because he was born here (Jus soli) or naturalized. What protections do Citizens have against the government? Let's start with the Fourteenth Amendment:
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
The jurisdiction clause is not a loophole; if you're not in the jurisdiction of the United States, they can't touch you (legally anyway - this is not a discussion about extraordinary rendition, military action, etc.)
Because we still have no practical, general-purpose way of storing energy on those scales. Since we have to generate exactly as much electricity as is being used, this in turn means that we've built the grid to run off of base load plants (those which produce the same power output all the time, such as nuclear) and peak load plants (which can adjust to minute-by-minute output requirements but often use more expensive fuel such as natural gas). The grid can use solar/wind/etc all you want but since nature, not man, controls the output to those, they need to be backed up by traditional peaking plants (exactly how much backup you need depends on how much downtime you can accept).
Solar thermal power can partially work around the problem by keeping a large vat of fluid (usually molten salt) very hot and using that capacity to spin turbines through the night. I think the technique is very promising.
That puts the testing quality roughly somewhere between most video games and Windows.
You can nearly eliminate the voltage drop with MOSFETs.
"A new antivirus update installed by my administrators. All the computers crash and burn. Now, should we have tested that? Take the number of tests, A, multiplied by the time it takes to do each test, B, multiplied by the tester's salary, C. A times B times C equals X. If X is more than the cost of the downtime, we don't test."
"Is there a lot of this kind of downtime?"
"You wouldn't believe."
"Which company do you work for again?"
"A major one."
The motors are 99 cents in a surplus bin. The batteries I already have lying around. The flywheels can be anything dense that I can balance properly. It can all mount to the camera via the tripod threads. Some people have used old hard drives and had good results (slightly better than in-camera IS) - it won't take anything fancy.
Yeah, they just don't currently make any unobstructed offset designs (that would solve the contrast and bokeh issue).
I'm planning to get a Celestron C5 and use that as my next lens. I'm hoping to also get a cheapo prime lens (Probably a used Canon 50mm f/1.8, since they seem to break so easily) and use its guts to work the C5's focus knob. I'm hoping to add some cheap gyroscopic stabilization (motors and flywheels), and as for the bokeh issue, I'm hoping to mostly point it at things with fairly regular backgrounds already. There is one ugly, but easy solution to the bokeh problem: I can put some card stock over the front with a circular hole between the secondary mirror and one edge - that will convert it to a very, very slow (f/30) "unobstructed" lens. Hope the subject stays still.
Actually I'm not so hot on the whole idea of installation of speakers in rooms. The walls cause horrible multipath.
One approach would be to use mirror lenses, like a reflecting telescope. Most such telescopes these days have a central obstruction for the secondary mirror, which reduces contrast and has unappealing donut-shaped bokeh. However, there are a couple interesting offset-mirror scopes that avoid this problem, such as the Scheifspeigler and Yolo designs. While most are designed to be very slow (f/10 or longer), they can apparently be made as fast as f/5.5. Add in a motorized aperture, autofocus, and image stabilization, and you've got a (very weird looking) telephoto lens.
It gets worse - most installations put the L and R speaker outputs in the same room!
Yes, if only there was evidence that it was possible to produce such a tiny device so cheaply.
LEDs are a (nearly) point light source that happens to be integrated into a plastic lens. This lens can be made in a number of different shapes - the ones with the familiar raised-sphere top work as a convex lens to focus the light into a relatively narrow beamwidth, but if you put the diode at the center of that sphere, you get an even radiation pattern instead.
Just making sure I have this right - an eon is 2.718 hours?
At least your parents could afford duct tape for your shoes!
(Seriously - ActiveX was first released in '96, about the time that ~1GB hard drives and 133MHz Pentiums were typical, and took a few years to catch on. By then your screamer DX2 box would have been several generations out of date. If you were smart, you never would have put Windows95 on it.)
Yes it did; the native Win32 app. IMHO most of the ActiveX-reliant applications of that day would have been better off written that way anyway. It would have been more portable because it never would have tied them to any particular browser version, and it would have been more usable, too.
You left out one other environmental requirement that must be obeyed.
Are you suggesting that DVDs are priced based on their costs, rather than based on what the market for them will bear?
First, I suspect that disk drive manufacturers are more keen on selecting an ECC implementation that matches their drive's marketing requirements.
Second, at work, I currently have a RAID1 whose backups have corrupt checksums nearly exactly half the time. As best I can tell, for whatever reason, there's a few sectors where different data got written to the two disks in the mirror. Without filesystem-level ECC, there is no guaranteed way to tell which disk has good data - if I tell the RAID controller to do a verify, I have a 50% chance of wiping out the good data (and if I don't do a verify, LSI tech support tells me to take a hike). End-to-end checksumming is the only answer here - it's not just happening to me.
In practice this depends entirely on the design of the chiller - specifically the choice of working fluid and the choice of pressures. The refrigerator in your kitchen is happy to efficiently exhaust heat from freezing air to sweltering air. Heat pumps' theoretical limits of efficiency are the same as heat engines in reverse. The carnot efficiency of an engine with a 290K cold side and a 300K hot side is 3.33% - the carnot efficiency of an engine with a 280K cold side and a 300K hot side is 6.66% - exactly double, meaning exactly half the 280K/300K gas is used (or, with a chiller, produced). This means that with a given amount of energy and a theoretical-efficiency chiller, I can move the same amount of heat with either colder air or more air - it doesn't matter which.
If by circuit you mean phase, then you never lose just one phase. Cutting one wire of a three-phase system leaves only one circuit, not two - two-thirds of your load circuits will not have power.
I've seen the loss-of-neutral failure exactly once - an electrician was doing work on what he thought was a separate circuit, and disconnected the neutral to a live circuit (there might have been more to it than that, but that's what he confessed to doing). End result was 208V into a 120V UPS which promptly fried.
While computers all have power supplies that'll take 208V no problem, there's lots of things that don't, and I suspect if this failure mode was as common in non-industrial settings (with few large motors) as you make it out to be, there'd be a steady stream of dead equipment (and dead 277V fluorescent light ballasts) to show for it - especially considering your scenario could happen with residential split-phase 240V power too. I do agree that having some design headroom is a good idea, though.
Google and Facebook would meticulously ignore both (unless by "central" you mean "powers the whole datacenter"). That's the whole point of designing your software to withstand some of your servers going offline at any time.