Dan's Data letters #98

Publication date: 31 March 2004.
Last modified 03-Dec-2011.

 

When is a D cell not a D cell?

Given your near-fetish interest in batteries, I thought you might find this interesting.

Curtis

Answer:
"Ultracapacitors" like these are interesting (and standard battery sizes for them are a nice development), but they're not battery replacements. Because they're capacitors, their terminal voltage varies directly with their state of charge - you only get the full voltage when the ultracap's full.

Also, they don't actually hold that much juice. Energy stored in a capacitor, in joules, is one-half times the capacitance (in farads) times the square of the voltage. So one of these D-size ultracaps, fully pumped, holds 1/2 * 350 * 2.5^2 joules; 1093.75J.

For comparison, a regular D size alkaline cell under gentle load will be able to deliver something like 18 amp-hours at a nominal 1.5 volts (PDF datasheet here), which is 27 watt-hours. A joule is a watt-second, so we're talking 97200-odd joules. Even allowing for voltage slump over discharge and heavier load, you should get an easy 50 times as much energy out of the D cell.

The ultracap can deliver and accept monstrous currents, though; far in excess of what even fast charge NiCds can handle. Ultracaps thus make great "buffer" energy storage for things like electric vehicles with regenerative braking. They're not suitable for use as a main energy store, though, partly because they just can't store that much energy per kilogram or cubic metre, and partly because of the irregular voltage problem.

 

Fake floppy: Found!

A while back I e-mailed you asking for the name of a floppy drive "emulator", similar to DAEMON Tools for CDs. You recommended FileDisk, and while the program could create virtual drives, it seemed to be more suited to creating large virtual drives than virtual floppy drives.

I recently found a program called VFD (Virtual Floppy Driver) which is much more user friendly, and while it isn't as versatile as FileDisk, it does its job as a floppy drive "emulator" very well.

Eric

Answer:
Cool!

I've now updated the couple of previous columns where floppy fakers were mentioned, to give the impression that I knew about VFD all along.

 

Halide vs transistors, redux

In 1988, I bought my first SLR - a Canon EOS-650 - and was well-pleased with same. My parents have it now. It still works for them wherever in the world they go.

I was sufficiently pleased with the 650 that, when I gave it to my parents, I took their Nikon F401, sold it, and bought an EOS-630. It's been my principal camera for the last 14 years.

But, now that I'm reaching a milestone of my own (40 in May), I've decided that it's time to upgrade to something, well, more this century/millennium. I'm thinking of going digital and thinking of staying with film - weighing my options and all.

Of course I'd want an SLR (digital or not), and Canon seems to make nice ones. My current investment in lenses (I've only two - 50/1.8 and 70 - 210/4, but I want more) and flashes (430EZ) isn't really the motivating factor that keeps me looking at Canon either; they just kinda work the way I expect them to, y'know?

For DSLRs, the EOS-10D looks nice, and for film SLRs, I'm partial to the EOS-3 currently.

What I'd like your input on, however, is digital versus film. Here's the way I see them stacking up:

Pro:

Film: a) All the resolution, all the time.
b) Major advances in image capturing (new kinds of film, etc.) may be enjoyed by simply swapping the film canister in your camera.
c) Unlimited capacity while travelling. Run out of film? No problem. Buy more.

Digital: a) "Instant gratification." That is, see the picture right after you take it, so that:
b) You know whether the picture you took will turn out before you print it.
c) Given suitable archiving techniques, your original image never degrades, and (thus) you can always get exact duplicates of your pictures printed (within tolerances of the printing process, of course).
d) No extra cost to take more pictures. (Give or take batteries, of course.)

Con:

Film: a) You develop a lot of crap along with that one good shot.
b) And it costs money to develop that crap and buy more film.
c) Negative storage is tricky; when done improperly (which is easy to do) negatives degrade over time.
d) The only way to see your pictures is to develop them.

Digital: a) Built-in obsolescence. Taking advantage of improvements in digital imaging technology requires the purchasing of another camera.
b) Limited selection of "films" for the camera. Sure, the camera can fake different film ISOs by cranking up the sensor amplification, but it's still not as varied as what you get with a film camera.
c) Finite capacity. Run out of room on your SD/flash/whatever card? You have to delete pictures or find a way to store them someplace. This can be a bit of a problem while on vacation. Buying another SD/flash/whatever card isn't as easy as buying more film.
d) The capacity/resolution trade-off. Sure, you can fit lots of pictures on an SD card at 1600 by 1200 JPEG, but you can't make very large prints out of them. And, if you do want to, you're screwed because all you have is the 1600 by 1200 image. Shooting in "raw" is one option, but even a 512 MB SD card doesn't hold that many "raw" pictures.

So there you have it. I see an upside and a downside to both, of course, and I'm seeking input from someone who lives in the digital world about advantages/disadvantages I may have missed (for either format).

I suppose a large factor in my decision will be a consideration of what I actually do with my camera, which is to take it on my trips to other places with me, and take the occasional picture locally too (mostly of my cats). I don't do (much) Web stuff, and besides, what with Photo CD and all, transferring images to PCs isn't much of an issue, really.

So what do you think?

Patrick

Answer:
Regarding resolution, yes, film has higher resolution capacity than a six megapixel digital sensor, but "all the resolution" is bounded by how much detail there is in the scene, and what your shutter speed/camera steadiness/lens quality combination will allow you to capture. I rabbited on about this in my old D60 review, and will ramble further in a moment.

Regarding swapping in different film - yes, you can just swap in hyper-fast B/W or IR or slide film in seconds, which is nice. But don't expect anything new; there are no very different kinds of film coming out these days, or indeed much in the way of refinement happening - Kodak's much-advertised "High Definition" film is apparently just their old Royal Gold 400 with a new name, for instance. Some "classic" films are even being withdrawn from the market owing to lack of interest.

Regarding running out of "digital film" while travelling - yes, it can happen, but it's not that hard to buy digital storage on the road these days. You just need some more paraphernalia. Get a memory-card-to-CD-R device and you're set, since CD-Rs are now very easy to find (like, in supermarkets).

And, heck, it's pretty easy to buy more memory cards in most civilised nations, though that's not a very economical solution.

Digital's instant feedback is, of course, its biggest advantage. This also mitigates the storage problem, since you can delete dud images and get the space back.

Yes, digital cameras become obsolete faster than film ones (well, unless you're a Film Is Dead fanatic who holds that all film cameras are obsolete already), but if a digital camera does what you want to do, nobody's going to shoot you for hanging onto it well after it's become obsolete. People are still using EOS-D2000s for professional photography, and those are FIVE WHOLE YEARS OLD now!

Capacity-versus-resolution isn't too big a deal for many digital shooters these days, with 512Mb and bigger memory cards becoming quite affordable, and the abovementioned archiving gadgets. RAW format does indeed eat up the space, but it's questionable how necessary it is for casual shooters.

Also, how much resolution you need for a given print size depends on viewing distance and viewer expectations. The abovementioned D2000 (a.k.a. the Kodak DCS520) only has 1728 x 1152 resolution, but shots from it (and similar-or-smaller-pixel-size crops from shots by more recent DSLRs) have frequently run as double page spreads in glossy magazines. Grungy? Sure. So's an ISO 400 film shot that's been pushed to ISO 1600; that kind of thing runs in magazines all the time, too.

At normal poster-viewing distance, a full-A3-sheet print from a 1600 by 1200 image will generally look very good. If it doesn't, resolution is unlikely to be the culprit.

If you're going for close inspection, 300 dots per inch is the generally accepted "perfect" print density for inspection at 30cm by people with 20/20 vision. 150dpi for 60cm, 75dpi for 120cm, et cetera.

If you're aiming for 300dpi (assuming, of course, that the source file is sharp enough that you're not wasting your time), then obviously a 1600 by 1200 image can only be printed at 5.3 by 4 inches.

In the real world, though, 200dpi commonly passes muster perfectly well.

Resolution is nice to have, but you shouldn't get hung up about it.

If the purchase price of an EOS-10D isn't a problem for you, then I think you'll be very happy with it. You may well find yourself upgrading to a better DSLR in a few years, but there's a good chance you'd find yourself buying that same camera even if you pick a film camera today.

Note: People who, like you, currently have a massive collection of two lenses, but unlike you don't feel constrained by them, probably don't actually want any kind of DSLR. They should get an integrated-lens camera (digital or film) instead.

Point-and-shoot integrated-lens cameras are smaller and lighter than SLRs, digital ones are never going to get dust on their sensor, and the better ones are right up there with DSLRs for image quality. Actually, the worse ones can be right up there too, given the lousy lenses that many SLR owners put on their cameras.

The high end Minolta Dimages, the excellent Sony DSC-F828, the Canon PowerShot Pro1, and the top-end Fuji FinePixes are all excellent cameras. If you're not going to buy a suite of lenses to go with a DSLR, there's very little reason to bother with one. Lots of pro photographers tote a point-and-shoot or two around with their heavier digital artillery, and not just as emergency cameras.

 

I guess I must be a subjectivist

I just thought the following two quotes were particularly relevant to your ramblings on file sharing. I still cannot fathom how one attempts to discuss such an issue as copyright as if it were merely a socio-political issue, completely disconnected from fundamental principles. If you wish me to explain this connection fully I shall be glad to, but I will not bother unless you express an interest in discussing it.

"The right to life is the source of all rights and the right to property is their only implementation. Without property rights, no other rights are possible. Since man has to sustain his life by his own effort, the man who has no right to the product of his effort has no means to sustain his life. The man who produces while others dispose of his product, is a slave."

- Ayn Rand, "The Virtue of Selfishness"

"What the patent and copyright laws acknowledge is the paramount role of mental effort in the production of material values; these laws protect the mind’s contribution in its purest form: the origination of an idea. The subject of patents and copyrights is intellectual property."

"An idea as such cannot be protected until it has been given a material form. An invention has to be embodied in a physical model before it can be patented; a story has to be written or printed. But what the patent or copyright protects is not the physical object as such, but the idea which it embodies. By forbidding an unauthorized reproduction of the object, the law declares, in effect, that the physical labor of copying is not the source of the object’s value, that that value is created by the originator of the idea and may not be used without his consent; thus the law establishes the property right of a mind to that which it has brought into existence."

- Ayn Rand, "Capitalism: The Unknown Ideal"

David

Answer:
I hesitate to get in discussions with Objectivists, since in my experience they seldom go anywhere interesting. I guess I just attract mail from the weirder ones.

This was the start of just such an exchange; David ended up patiently explaining to me that in his opinion there should be no consumer protection laws (pretty standard Objectivist fare, at least for those who haven't done any deeper analysis of the philosophy). He gave me the impression that in the USA he lives in, there apparently aren't any consumer protection laws - that he'd noticed, anyway. He now tells me I misunderstood him. Whatever.

Anyway, this first message of his raised a couple of points I've seen mentioned elsewhere, so I think it's worth reprinting my reply.

It should be noted that the vast majority of commercial music is no longer owned by the people who "originated the idea". It's owned by a corporation, usually as the result of commercial and legal manipulations which most people of good conscience do not think are fair.

It should also be noted that those lucky musicians (and other artists, including a small but growing cadre of writers) who do retain their copyrights are, overwhelmingly, reporting very good results from giving away some or all of their work - not putting it into the public domain, but making it available for free download. That's not the way to make $50,000,000 a year, but not many artists have big enough heads that they think they're actually worth that much. Cory Doctorow seems to be doing just fine selling books that anyone can download for free.

Thanks to corporate ownership of artistic works, they're often used without the consent of the originator of the idea, as in the numerous hilarious cases of pop songs with socialist/anarchist/whatever lyrics, which generally express the opinions of the performers, being sold by one megacorp to another megacorp for (edited...) use as ad jingles.

Sometimes the band members are fine with this (sometimes not all of them are - Jello Biafra has said many times that his already poor relationship with the rest of the Dead Kennedys wasn't improved by their desire to sell "Holiday in Cambodia" for use in a Levi's ad...), but in the usual case when the band has no say whatsoever about what gets done with their music, it doesn't matter whether they consent or not.

If you want to take the hard-core position that they signed their rights away so the problem is theirs [as, unsurprisingly, David did], then OK, but given the well-known devious practices of record companies which leave "successful" bands with a share of the profits that's close to, or less than, nothing, I think this view doesn't line up well with the quotes you provided.

If, on the other hand, you think it's a good idea for copyright to be made non-transferable, I'm with you. Good luck getting that law passed, because the media portion of "America's Most Persecuted Minority" [which is what Ayn called big business in "Capitalism: The Unknown Ideal"...!] really, really likes things the way they are.

(And then, of course, there's the growing but not yet conclusive evidence that music trading is doing the record companies as much harm as VCRs did the movie industry.)

If you want to ask me a question, feel free - but please read this and this first.

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