walang_pangalan

Mr. White, the equilibration times are likely going to be on the order of minutes for a low-mass thing like a lens. But that's just me waving my hands: only a direct measurement can say for sure. Convective effects are going to be much more important in practical use. And, yes, it's unlikely the lens will stop working even if it is asked to perform at 130F.

 

As for Mr. Chappell's conversion argument: he forgets that (a) the solar spectrum, even at the surface of the Earth, is dominated by the near-infrared and (b) all common paints, be they white, black, or even pink, are more or less equivalent absorbers there. If we accept his (reasonable) claim the objects in question at far infrared are also about the same, the result stated again follows: you'll observe the same temperature.

Thermodynamic argument (and observed reality for that matter) says that, for an object in thermal equilibrium with its surroundings, emissivity == absorptivity. This means that two objects in radiative contact with some reservoir (aka "the Sun"), they will both come to the <i>same temperature</i>, <b>regardless of their color or other properties</b>.

 

<p>The color will certainly change the equilibrium times, but not the final temperature. For a camera lens or other thin tubes, I would expect these equilibrium times to be rather short, to the point that color has no practical effect. The better argument is that Canon's "white" is just a marketing tactic, otherwise Nikon and everyone else -- who employ engineers of equal merit -- would be using white too.

 

<p>(And I guess it should be noted that things that take a long time to heat up will take a long time to cool down. Generally speaking, it's a good thing if your optics quickly equilibrate, so if any color is to be preferred, choose black.)

<i>but I'm not sure if my hobby is worth the $1,400 it would take to get both the 400D XTi and a really good lens.</i>

 

<p>If you can afford it, spend the money. The worst case is you find photography is not for you; it's a little easier selling good stuff than not-so-good.

 

<p>As for buying an XTi because a Sony is taking soft pictures ... a tripod may be a better idea.

 

<p>And yeah, you can get the 50/1.8 without much harm.

These units have a big-ass DC->DC converter, output voltage is something on the order of 300V:

 

<p>http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00H19m

 

<p>Who knows what the input voltage is, and really, should you care? You'll have a hard time building or buying the electronics to do the same job, at a significant improvement over the price Canon sells it for.

<i>What would you expect from such people?</i>

 

<p>When they said they don't warrant the cleaning, that's all they meant: they won't guarentee the sensor remains dust-free for any period of time. And how the heck could they?

 

<p>I'm absolutely sure that if you can demonstrate their cleaning efforts damaged your camera, they would be quite happy to repair it for free though. Remember Murphy's Law though, and that coincidences happen. (In particular, the chances are good that a low-quality employee would likely have been dimissed before he saw your camera -- but of course, maybe you are the unlucky one, as someone has to be!)

 

<p>In any case, I'd recommend that when you make your case to Canon -- you can gather up some circumstantial evidence from your own image collection, pre and post cleaning -- that you not immediately assume they are out to rip you off. Your chances of a free repair will increase quite a bit, even if your case isn't 100% air-tight.

I'll add to the pile as well: the extenders, even off axis, are hardly immune from eyeshine effects. Generally, if your subject is filling the frame, it's not much of an issue. As you it gets farther away, red-eye/steel-eye/etc rears its ugly head. And unfortunately, because the extender pushes out your range, it's tempting to take the picture that will exhibit the problem! To that extent, it may be better to think of these things as 'power savers', not 'flash extenders'. And while you are at it, is that 500/4 really a telephoto, or just a low-magnification macro lens?

I'm sorry, but the question, and many of the responses, reads like FUD.

 

<p>I use "canned air" to blow the crud off my 1D2 sensor, when needed. The only way -- at least that I have experienced -- to get a blast of 'fluid' from it is to fail to use the can <b>as indicated in its instructions</b>. Typically, this means using it in a non-vertical orientation, or, most especially, <i>shaking it prior to use</i>.

 

<p>And even if you fail to RTFM, if you simply pre-blow a few seconds prior to directing the jet towards the camera, issues with residues are minimized (if not eliminated).

 

<p>Anyways, the risks of this approach are well known and publicized, along with the comparable risks of other sensor cleaning techniques. It is simply inconceivable the original interrogator missed it all in his "reading numerous forums and articles about how to clean [his] DLSR"...

You can get through life pretty good without a left pinky-finger, but if it fell off one day, would you be asking people for an opinion, or just head to the nearest hospital?

 

You can be pretty sure that the part that fell out does something useful, if only because Canon wouldn't have added it to the camera otherwise. So get thee to a phone and call Canon technical support, or just take a trip to a Canon repair place. You'll feel a lot better in the end.

<i>In the case where it involves something that's actually useful like shutter actuations, then this seeking of knowledge is even more useful.</i>

 

<p>Most people buying a used 1D of some kind or another, are well advised to simply assume that the shutter or other things will break the next day and be prepared to pay for it. Even used, these cameras are not inexpensive items, and a shutter replacement is fairly insignificant in the grand scheme of things.

 

<p>So I join Mr. Murray in wondering why everyone spends so much time obsessing over minor details like this. Simple intellectual curiosity is all well and good, but given it's a solved problem, why not be curious about things that are more important and truly unknown? For example, a good deal of the so-called "maker-note" information in the EXIF data.

Mr. Matteoli, I have a 580EX I and II and both work fine with DCB batteries and adapters, so I can't imagine why the CP-E3 would be any different. However, if you plug the CP-E3 into the 580EX II and it explodes like a hand grenade, well, like the signs in the parking lots say, "The management is not responsible for any damage."

 

As for selling a 580EX "I" to get the "II" version: probably a waste of time and money. I flipped my fairly old 550EX for a 580 II simply because the 580's appear to do a better on the NiMH batteries. The differences between a 580 I and II are somewhat better build, more flexible head, and cosmetic.

<i>I think the info about Lexar cards not working in Canon is seriously out of date and the problem or problems were resolved a long time ago.</i>

 

<p>Yes. Like everyone's mother says, a little reading comprehension goes a long way.

 

<p>I use only SanDisk Extreme III cards. Quite a collection now, from 512MB to 8GB, in nice even binary steps. I get the impression that the larger cards are somewhat slower than the smaller (<= 2GB) though. If this effect is real -- no exact timing data collected -- it's more likely because of Canon's use of very small cluster sizes on the 4GB and larger devices. But when the tin-foil hat slips off a bit, one begins to wonder about the bastards at SanDisk making the III's a bit slower of late to kick-start sales of the IV's...

Your question "<i>how do I replicate certain films?</i>" begs a counter-question: <i>"why would you want to do such a thing?"</i>

 

<p>But the easiest way to get that "film look" is probably to add some noise to your images.

 

<p>http://www.clarkvision.com/imagedetail/film.vs.digital.summary1.html

 

<p>So try shooting at a higher ISO? Other aspects - in particular, saturation and contrast - can be dialed on your camera, as per the user manual. Or just collect raw data and mangle it to taste on your own. Either way, you won't find exact matches, since the responses of film are not the same as a filtered photo-diode. (This is a good thing too. While we aren't at the stage of a full-frame imaging spectrometer yet, the removal of the film substrate from the processing chain connects you closer to the firmament of reality re: photography: the photons themselves.)

<i>But most people are going to start with the camera and figure out the rest later, and right now Canon is losing sales because of that.</i>

 

<p>Actually, if photo.net is any indication, it looks like most people go to the nearest camera store and say "I want a DSLR by the manufacturer that has the largest market share!"

 

<p>Or, almost equivalently, they buy whatever the salesdroid behind the counter was told to push that day. The small number of people who think about long term consequences have already figured out that it's better if they buy their Canon equipment online at B&H, Adorama, et al.

Mike Dodd: <i>I want to go out and rephotograph these locations many of which I first photographed 10 or 20 years ago to show changes in these habitats (I am an ecologist). There is absolutely no way I could remember where the exact location is to go back to and at the time I took the picture I had no idea that I would want to go back there, so I only recorded the nearest village or name of the approximate area.</i>

 

<p>An unfortunate lack of data collection. But you will probably do better than you think. Consider this:

 

<p>http://www.amazon.com/Footsteps-John-Wesley-Powell-Comparative/dp/1555660258

 

<p>I have that book. And I doubt that John Wesley Powell, or even Shoemaker/Stephens had a GPS receiver.

 

<p>Ben Frey: <i>I don't understand why so many people here are arguing against a demonstrably good idea.</i>

 

<p>The application you have in mind needs more accurate positions -- particularly in the vertical -- than commonly available units provide. You also need accurate estimates of camera orientation as well, which GPS does not provide at all. Are there any ~$100 INS systems available in form-factors you can cram into a camera?

Mass issues are a needless distraction as you'll get stronger, buy a tripod, whatever. Buy the most powerful flash you can afford. My guess is that if you can afford a 5D and the 24-105/4L, you'll have no trouble at all acquiring a 580EX II.

The lens computer can only "see" the extender directly connected to it, so if you change "realized" to "reported" you have it right. Of course, if you put two converters on, the optics are f/8 regardless of order or what the lens computer thinks.

In the EOS system, the lens senses the existence of the extender, not the body. And because the lens can't "see" past the first extender, when the body asks the lens who it is and what kind of properties it has, the lens can only report the effect of the 1.4x, even if the 2.0 is mounted as well.

<i>I need to actually pick up the lens or the customs charges could be brutal.</i>

 

<p>Nah. If you avoid UPS and its brokerage scam, you'll only pay the usual GST/PST when ordering stuff from the USA. Do note that if you go into Buffalo itself you'll pay New York sales tax at the counter, and then be hit with the taxes at the border coming back. Unless, of course, you are thinking of <i>smuggling</i> the item across the border, but I guess thats a subject best left undiscussed at a family oriented website like photo.net ...

Mark U challenges readers re: <i>patents</i>

 

<p>A quick check on the net:

 

<p>http://www.camerapedia.org/wiki/Minolta

 

<p>Says that the 127 million was for an autofocus issue, not a flash issue. Unless the two were in some way the same, and the multitude of writers at Wikipedia have whisper-gamed the content into incomprehensibility.

 

<p>Many hits (both on and off photo.net) are saying the Nikon D system is under patent, but irritatingly, no patent numbers are forthcoming. Does anyone know them?

 

<p>The off-the-film flash stuff was indeed introduced in 1976 by Olympus:

 

<p>http://en.wikipedia.org/wiki/History_of_the_single-lens_reflex_camera

 

<p>But 31 years later, it must be in the public domain at this point. So, one would imagine, would most of patents of this kind.

 

<p>Personally, I find it highly strange that using distance information in a flash photography system could be patented at all. It would like like patenting the use of a wheel for a wagon. But the workings of a government agency are never intended to be sensible, let alone predictable.

I see a few hot pixels, but nothing a dark frame can't fix.

Air is air: magnification increases by extension/focal length.

<i>If you are using a lens hood, at a wedding no less, why would you have crap on the lens in the first place?</i>

 

<p>I'll run the risk of the wrath of the forum administrators and repeat myself from an earlier submission today: "shit happens".

 

<p>And my 500/4 lasted two years wearing a "lens hood" 100% of the time, but it needed a good scraping in the end as well. Fortunately, it has a nice, large, flat surface. I guess if one's lenses never leave a studio..

<i>Why would you shoot with anything in front of your beautiful and expensive glass?</i>

 

<p>Because cleaning the crap off a flat, removable, filter is a hell of a lot easier than cleaning the crap off the non-removable, curved, lens?

 

<p><i>My tests show no difference.</i>

 

<p>In some situations the difference is observable. Simple demonstration: take a cheap filter and an expensive filter and use them as mirrors. Reflect the Sun, and notice how the cheap filter has a much brighter reflection than the expensive one.

 

<p>But of course, if you can't observe a difference, then why bother?

 

<p>I use Hoya Super HMC's, though I'm having a hard time finding the 82mm PRO1 "slim" version locally.

J. Harrington wrote, referring to a Canon 10D: <i>I can't understand why you'd want to sell yours.</i>

 

<p>There are many reasons to want a better camera than a 10D. The biggest one is that the 10D is <i>extremely slooowwww</i> compared to even the 20D. Night and day.

"W*mart" makes inexpensive prints, but for that lack of money you get:

 

0. An abominable user-interface. Anyone who hates fiddling with images on their computer will not find it any easier or pleasant interacting with those kiosks.

 

1. Lack of flexibility. You can ask for 4x6's or 8x10's. No 8x12 (or at least I can't find one that does it). And if you start asking for crops, see item (0), above.

 

2. Even after careful de-dusting prior to showing up at the kiosk, a fair fraction of your prints will come with dust spots at random locations and sizes anyways. Murphy's Law dictates where the dust will end up.

 

More than likely, after about the 10th print you'll start looking at the printer selections from Epson or Canon (those kiosks are in fact no more than a Windoze computer with a lower-end printer attached). And then maybe even come to the conclusion I have: I vastly prefer looking at the images on a display. Make a 1920x1080 crop and a good many images look fantastic on a Sony Bravia in the living room. Not my living room though, nor my Bravia ;-(