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Old Jun 4, 2006, 3:31 AM   #31
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Angle of view depends on the focal length and the sensor/film size.

What the manufacturers should do is publish clearly the angle of view for every lens they manufacture that will fit on different sized sensors. They need not print it on the lens.

This is what large format manufacturers do.
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Old Jun 4, 2006, 7:13 PM   #32
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Peripatetic, you have a grip on the focal length/AOV issue, and you explained the 28-135 confusion nicely for this guy newest. One statement, though, a few posts back, I am inclined to question.

You say that the current round of FF cameras--5D, 1DsMkII--push the resolution limits of even the Canon "pro" lenses. The 5D has 12MP and the 1DSMkII has 16MP, true. In fact, though, the pixel density of both those cameras is lower than that of the 20D, 30D, and Rebel XT. In fact, a FF sensor would have to have 20MP to equal the density of those three cameras. It would need 30MP to equal the density of the Nikon D2X. And isn't it the pixels per square inch that would challenge a lens' ability to resolve detail?

Finally, a point for "newest". You've come a long way from your one-lens-fits-all wish, but before you start buying lenses helter skelter, I suggest you just shoot with that kit lens for a while. There is no standard "set of lenses" that everyone needs. It depends on what they shoot. For example, 70-300 is the most popular midrange zoom--primarily because it is a relatively inexpensive zoom. However, for photographers who have been shooting for a few years, and who own a 70-300, it is the lens most often left behind when they go shooting. Why? Too long for portraits. Too short for birds. Too long to hand hold. To short for a tripod collar, so it is front heavy on a tripod.

My wife and I shoot a lot. I use the 17-85 and 100-400 with occasional switch to the Sigma 12-24. She uses the 500mm F4L with a Canon 1.4xII or 2xII extender. Obviously, we must shoot different subjects. I would have little use for her 700mm or 1000mm lens/extender combo,and she would be unable to shoot with the "short" lenses I use.

BTW, the lens you were originally looking for is a Nikon. If you haven't bought already, the D200 with the Nikon 18-200mm VR lens is the ultimate walkaround camera. In fact, someone with no lenses getting into DSLRs would do well to look into Nikon before plunking down cash on a Canon with "only" 8.2MP and no all-purpose stabilized zoom lens.
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Old Jun 5, 2006, 3:08 PM   #33
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By giving up the cigs and beer, you might be adding on more years of living, andto enjoy your new toys. Thank the wife on this one!
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Old Jun 5, 2006, 4:37 PM   #34
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wburychka

Quote:
You say that the current round of FF cameras--5D, 1DsMkII--push the resolution limits of even the Canon "pro" lenses. The 5D has 12MP and the 1DSMkII has 16MP, true. In fact, though, the pixel density of both those cameras is lower than that of the 20D, 30D, and Rebel XT. In fact, a FF sensor would have to have 20MP to equal the density of those three cameras. It would need 30MP to equal the density of the Nikon D2X. And isn't it the pixels per square inch that would challenge a lens' ability to resolve detail?
This is hearsay rather than first-hand experience, however the reports are that even the L wideangle lenses, including the primes, don't have the resolution at the edge of the image circle that is required for these full-frame sensors. Hence many pros use lenses like the Zeiss 21mm prime with an adapter.

The centre of the image is fine on the wide-angle L lenses, and there is no problem with the telephoto and normal lenses.

Your point about pixel density is a very telling one, and has led commentators to suggest that greater pixel densities are frankly irrelevant unless Canon does something about their wide-angle lens resolution.

Of course on the crop cameras only the centre of the image is being used, where resolution is much better, and the lenses can thus sustain the demands from the sensor.

The Nikon D2X exhibits similar problems unless you marry it with their top-grade digital lenses, which are very very good.
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Old Jun 6, 2006, 5:51 AM   #35
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I tend to agree with peripatetic since a full-frame will expose the deficiency in the lenses (especially @ the WA) - All one has to do is to check the MTF:





Both the sharpness and contrast drop off quite sharply in areas outside the APS sensor frame for the 16-35L (and this is the better example of other L primes)...

-> Dynamic range and noise are probably the benefits of going full-frame, but in sharpness perhaps the 'digital' lenses are better after all throughout the frame... At least according to the MTF's I've seen! :-)
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Old Jun 6, 2006, 7:41 AM   #36
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Peripatetic and NHL: Then what you are saying is not that FF sensors are a challenge for these lenses, but rather these lenses are just not very good at the edges and corners. In that case, their deficiencies must be equally obvious with film, since a fine grain ISO 50 or 100 film will capture more detail than a 12 or 16 megapixel full frame sensor.

Or am I missing something?
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Old Jun 6, 2006, 8:09 AM   #37
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Quote:
Peripatetic and NHL: Then what you are saying is not that FF sensors are a challenge for these lenses, but rather these lenses are just not very good at the edges and corners. In that case, their deficiencies must be equally obvious with film, since a fine grain ISO 50 or 100 film will capture more detail than a 12 or 16 megapixel full frame sensor.
Well, if you're right that fine grain film really will capture more detail then yes, it must simply be the case that they are equally deficient with film and no-one really noticed until these FF digital cameras came along.

Perhaps that grain obscures the resolution deficiencies of these lenses when used with film.i.e. that it looks like detail but it's just grain/noise. So that the real issueisn't that these sensors have a resolution advantage over film, but rather that their S/N ratio is so much better that they are showing up these lenses where it wasn't possible to see before.

Or perhaps your statement about film is mistaken and the digital sensor have a resolution advantage too. Michael Reichman says you should look up "vortex shedding" to understand why you might be mistaken in this matter.

http://www.luminous-landscape.com/essays/clumps.shtml
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Old Jun 6, 2006, 9:18 AM   #38
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You might get a lot of flame for this...

-> Digital is also binary - Each larger pixel only captures one color (R,G, or B) :-)
Demosaic ???
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Old Jun 6, 2006, 11:00 AM   #39
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Yes, there is a demosaic process and each photosite is only sensitive to one color.

But, you've got up to 16K levels of brightness stored for each photosite, depending on the A/D converter and final format.

According to Michael's article, a grain in film is either on or off. I don't know enough about film to know if that's right or not.

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Old Jun 6, 2006, 11:22 AM   #40
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A 'grain' is analog - you can have as many level as you want (This quantization varies depending on the # of bit from the A/D)
-> Remember you used to be able to "push" by varying the process time... (or temperature)!
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