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Author Topic: Pentax K100d  (Read 24908 times)
aaykay
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« Reply #40 on: June 01, 2006, 08:56:29 AM »
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This is refuted in my post above, #25 in this thread. K.-M. Anti-Shake works fine with DT lenses (and third party "APS-C" lenses) which are designed specifically for the format of the "APS-C" digital sensors, so these sensor-based systems do _not_ need to use a sensor size that imposes a significant crop on the image produces by the lens.
[a href=\"index.php?act=findpost&pid=67013\"][{POST_SNAPBACK}][/a]

A quote from Canon about the new 17-55 F/2.8 IS APS-C lens:

As an EF-S lens, the new zoom is smaller, lighter and handier than a lens of similar specifications could be, but covers the full 24 x 36mm frame.

So, going by the above, there seems to be space for the reduced-frame sensor to move around and still remain within the imaging circle, since the APS-c specific lens, seemingly covers the entire "full-frame".  

Or, did the above mean that the EF-s lens is "smaller, lighter and handier" than a 17-55 f/2.8 designed for a full-frame sensor, since it has a reduced imaging circle that covers the APS-C frame alone ??
« Last Edit: June 01, 2006, 09:27:13 AM by aaykay » Logged
BJL
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« Reply #41 on: June 01, 2006, 09:49:29 AM »
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If I am not completely mistaken (I could very well be), the APS-C lenses do cover the full 24 x 36 frame.
[a href=\"index.php?act=findpost&pid=67093\"][{POST_SNAPBACK}][/a]
You are mistaken, at least for many of the new digital specific lenses from Nikon, Pentax, Konica-Minolta, and third party lens makers. These lenses come with warnings that they cannot used on cameras with formats larger than "APS-C". Since Nikon, Pentax and K.-M. use the same lens mounts as 35mm film cameras, and in some models the same mirror assemblies (unlike Canon EF-S with its shorter back focus requiring a smaller mirror assembly), the only reason can be vignetting due to inadequate image circle size.

One example for which I have read tests is the Nikon 12-24 DX, which when installed on a 35mm format camera and set to 12mm shows substantial vignetting. As it is zoomed in, the image circle grows (that is basically how a zoom works: variable magnification of the image circle produced at mininum focal length) until the vignetting disappears at 19mm and above, so that it then covers the 24x36mm frame.


P. S. Can you direct me to the source of that very surprising claim about the Canon 17-55/2.8 EF-S covering the 24x36mm frame?


P. P. S. it amazes me how much some people can struggle to justify a fear when the evidence is so solidly against it. Is it paranoia, or a desire to put down a product or brand that they do not like?

I assure you, Pentax's new SR system will work with its DA lenses, which are the great majority of lenses that Pentax produces and sells to its DSLR customers. (And to another fearful group: do not worry, the SLR market dominating and fast growing EF-S and DX systems are not in any trouble either!)
« Last Edit: June 01, 2006, 09:51:38 AM by BJL » Logged
aaykay
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« Reply #42 on: June 01, 2006, 10:20:10 AM »
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P. S. Can you direct me to the source of that very surprising claim about the Canon 17-55/2.8 EF-S covering the 24x36mm frame?
[a href=\"index.php?act=findpost&pid=67096\"][{POST_SNAPBACK}][/a]

The Canon 30D whitepaper, contains this quote.  It has information about the 85 1.2II and also the 17-55/2.8 EF-s, in addition to details about the 30D camera.
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aaykay
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« Reply #43 on: June 01, 2006, 10:33:43 AM »
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P. P. S. it amazes me how much some people can struggle to justify a fear when the evidence is so solidly against it. Is it paranoia, or a desire to put down a product or brand that they do not like?
[a href=\"index.php?act=findpost&pid=67096\"][{POST_SNAPBACK}][/a]

There is no "fear".    There is no dislike about the brand either...have owned Pentax film cameras in the past.  

As far as in-camera anti-shake, Herb Keppler (publisher of popphoto), specifically stated that the KM anti-shake WILL NOT work with full-frame, primarily due to the size of imaging circle.  He personally owns a "system" comprising exclusively of KM cameras and lenses...so there is no partisanship there.

He stated that Sony will have to find some other way of introducing anti-shake into the body, that moves away from sensor-shifting, if it has to work with a future full-frame Sony camera.  Again, this is from a KM owner and publisher who can take his pick from among all the cameras in the marketplace and has stuck to his KM system.  

He recently made a trip to Japan and met with Canon's chairman and other members of Canon management and also a bunch of other industry insiders, including from Sony, Pentax, KM etc., in Japan, before writing the above article.

Maybe you have some special insight into something that he missed !  Always happens.....
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BJL
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« Reply #44 on: June 01, 2006, 12:27:11 PM »
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As far as in-camera anti-shake, Herb Keppler (publisher of popphoto), specifically stated that the KM anti-shake WILL NOT work with full-frame, primarily due to the size of imaging circle.
[{POST_SNAPBACK}][/a]
And why should I believe Herbert Keppler, if he offers no facts, given the fact that KM AS _does_ work with DT lenses designed only for the coverage needs of the smaller "APS-C" format.
Does Keppler quote any evidence, such as how much sensor movement is needed, which would tell us how much larger the image circle needs to be than the sensor diagonal?
Does he mention that telephoto lenses, and zoom lenses at focal length longer than their minimum, naturally produce image circles larger than the format for which they are designed, building in the slack needed for sensor based SR?
How about some reasoning that takes account of facts like this?

And I ask again, why should anyone fear that Pentax is launching this new SR system that does not work with it DA lenses, which are eight of the fourteen lenses that Pentax promotes for use with its DSLRs as the following site?
[a href=\"http://www.pentaxslr.com/lenses]http://www.pentaxslr.com/lenses[/url]
That would leave it working only with the six FA and D FA prime lenses on that list, of focal lengths no longer than 100mm.

Again, such a claim of gross stupidity by Pentax takes some strong evidence to be worth considering, and instead all I hear is "you cannot completely prove that it is not true".

P. S. I wonder why Keppler worries about what Sony would have to do to make AS work in 35mm format, given that there is no evidence at al that Sony has any interest in making a 35mm format DSLR. But of course I can not prove that such a return to 35mm format is not going to happen, so feel free to worry abut this scenario if you wish. I suggest reading "Waiting for Godot" or Kafka's "The Castle" while awaiting "The Return of the King".
« Last Edit: June 01, 2006, 12:47:47 PM by BJL » Logged
BJL
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« Reply #45 on: June 01, 2006, 12:42:08 PM »
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The Canon 30D whitepaper, contains this quote. It has information about the 85 1.2II and also the 17-55/2.8 EF-s, in addition to details about the 30D camera.
[a href=\"index.php?act=findpost&pid=67099\"][{POST_SNAPBACK}][/a]
And it does indeed say that: very interesting. But
1) Other shorter image circle lenses do in general have smaller than 35mm sized image circles, as the 12-24 DX example shows. Maybe the difference is that the EF-S (and Olympus) approach is different from the Nikon, Konica-Minolta and Pentax approaches to shorter focal lengths: Canon reduces the back-focus distance so that shorter focal lengths can be achieved without more extreme retro-focus designs, whereas  Nikon, Konica-Minolta and Pentax use designs that keep their longer 35mm format back-focus distance, so as to be compatible with the 35mm format lens mounts and mirror boxes used in some of their DSLR's.
2) we are getting of the topic of whether SR will work with DA lenses: if DA lenses do indeed have image circles big enough for 24x36mm frame, the problem would be solved!

Anyway, I just realized the biggest fallacy in this worry: at any telephoto focal length, or with any zoom lens zoomed in significantly from its shortest focal length, the image circle is "oversized", except perhaps in some primes that have internal anti-flare baffles that fit tightly to the frame size of the format. Pentax does not yet have any telephoto primes in DA format, so clearly has the opportunity to design the anti-flare baffles of future DA telephotos to work with SR.
« Last Edit: June 01, 2006, 12:49:14 PM by BJL » Logged
MrIconoclast
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« Reply #46 on: June 03, 2006, 01:43:14 AM »
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What's the big deal about so called full-frame??

Full frame is just a holdover from the 35mm days.

The Nikon D2x and D200 has shown that the smaller digital chips can produce excellent results with today's technology.  Add to that the advantage of smaller and lighter lenses, and I am not sure the full-frame is really an advantage, except from a marketing point of view.  

As the chip technology advances further, people are not going to be willing to trade the convenience of smaller, lighter gear for the now obsolete 35mm size frame.

Digital must and will evolve into its own world, and ultimately throw off the last vestiges of film, including 35mm film size.    I am amazed at the number of digital converts who still think that they have to have a 35mm sized sensor.
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Ben Rubinstein
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« Reply #47 on: June 03, 2006, 06:31:32 PM »
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FF is far more than just keeping with that old time size!

If you use it for what it is needed for then you don't need to bother arguing about it, if you don't see the need then you don't need it.
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BJL
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« Reply #48 on: June 05, 2006, 01:28:58 PM »
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FF ... If you use it for what it is needed for then you don't need to bother arguing about it, if you don't see the need then you don't need it.
[a href=\"index.php?act=findpost&pid=67308\"][{POST_SNAPBACK}][/a]
Excellent summary! I sometimes wanted a medium format SLR to get the grain out of my B&W prints, but never needed it enough to bear the burdens of the larger format; but other photographers clearly did need medium format SLRs. Ditto for every step along the digital SLR format range of 13.5x18mm (4/3), 15x22.5mm (EF-S), 15.7x23.7mmm (DX/DA/DT), 18x27mm (1D?), 24x36mm (35mm), 33x44mm, 37x49mm. Different wants and needs lead different photographers to make different choices.

One possible difference from film though: the print resolution differences are now far smaller than the format size differences might suggest, with 35mm format offering only about 15-30% more linear print resolution ("lines per picture height") than some far less expensive 15.7x23.7 format SLR's. (1DsMkII vs D2Xs, 5D vs D200 or Alpha 100).
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Ben Rubinstein
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« Reply #49 on: June 05, 2006, 02:53:29 PM »
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Hey BJL, you know as well as I do that the resolution is not the reason for FF     . FF happens to have more resolution at present but that is not the argument for it by any means otherwise the D2X would have killed the FF argument. "The original 1Ds has less resolution therefore FF is no longer needed." Nope doesn't sound right at all does it?

FF is good for those who want control over shallow DOF, better tonality and DR, better handholding capabilities (I had always thought this from experience and logic but had it confirmed today when reading the Canon Lens Work III which states that handshake is more noticeable with crop cameras due to the extra magnification), larger and usually brighter viewfinders, the ability to use a large selection of lenses as they were intended, etc, etc.

Although I will be buying the pancake trio to go with a pentax body within a year, a 70mm f2.4 lens is just simple not fast enough to be a true portrait lens given that on a crop camera it becomes a 100mm lens. But you don't get the 100mm drawing of the subject not do you get the DOF. What you do get is too much background detail. Just an example of why some people might want FF.
« Last Edit: June 05, 2006, 02:59:00 PM by pom » Logged

BJL
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« Reply #50 on: June 05, 2006, 04:32:27 PM »
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you know as well as I do that the resolution is not the reason for FF ...
FF is good for those who want control over shallow DOF, better tonality and DR, better handholding capabilities
[a href=\"index.php?act=findpost&pid=67468\"][{POST_SNAPBACK}][/a]
That is quite a change of tune about resolution! Am also interested to see that you (quite sensibly) do not talk about the wide angle crop problem of smaller formats anymore.

When the 1Ds and 14/n came out and for a long time after, resolution definitely was one of the two main arguments made by fans of "FF", and the other biggest argument was the loss of wide angle coverage. I do not recall much or any talk about DR in those days.

It is interesting to see how both of those two common arguments have faded away somewhat as the mainstream DSLR formats have closed those gaps considerably, and yet many of the people who used to make those arguments have not changed their conclusions, they have simply moved on to new arguments to support the same claims of FF's great superiority. Consistently supporting a belief or claim despite having to abandon or downplay previous arguments and shift to new ones is a warning sign that the real reasons for the belief or claim are something other than the ones being stated.

Of the new list of FF advantages, I point out that
- the dynamic range/tonality/DR advantage is real (so far) but is mostly or entirely at minimum ISO, where APS-C formats already have plenty of DR for most purposes. As soon as FF needs to use a higher ISO, DR goes down, and an APS-C format can in many cases use a lens of shorter focal length and lower minimum f-stop to get the same shutter speed at lower ISO, balancing out the DR difference in those persistent but often misleading comparisons done at equal ISO speed and equal f-stop.

- On shallow DOF and better hand-holding abilities, again this is true sometimes, but only when the larger format can use a lens of longer focal length but about the same minimum f-stop (so using a larger aperture diameter). I will not repeat my long list of cases where the larger format is forced to use a higher f-stop (or to use the same focal length with a crop), canceling out the DOF/shutter speed/hand-holding advantage.
Instead I will take the example of the FF users who have adopted the 24-105 f/4 lens (including you, I believe). Compared to f/2.8 options for APS-C formats, the one stop difference should more or lens cancel out any difference in minimum DOF, and in usable shutter speed and thus any hand-holding advantage.
The decision by many demanding photographers to sacrifice the speed/DOF advantage of the Canon 24-70/2.8 suggests that f/4 in FF (and thus f/2.8 in APS-C) is a big enough aperture enough for a great proportion of photographers in practice.

Some FF advantages persist, but as technology advances, the differences are only significant for an ever shrinking circle of photographers and photographic needs.
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Ben Rubinstein
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« Reply #51 on: June 05, 2006, 06:04:48 PM »
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The 24-105L didn't last long, damn it the 24-70 @ 70mm f2.8 just is too much DOF when you want to isolate a subject. That said I bought it back (the 24-70L) and it is again my main lens.

I think that your choice of the 24-105L misses the point. Many photographers have chosen it for their non DOF critical work. But the majority have a 50mm or 85mm in their bag. You can't control DOF sufficiently with that lens period.

Pre the days of the 17-55 I would have argued the WA thing more, the newer crop of lenses does help. That said I'm using a 17-40L frequently on my 5D, that is a serious issue that hasn't gone away yet. If you need a distortion free fast WA then you have nowhere to go period. That is a problem being faced by photographers daily, it's not a minority. The only reason the problem is not bigger is due to the crop of the 1D mkII, if PJ's had to deal with a 1.6X crop you bet the issue would be raging high and far. The 16-35L on a 1D mkII is the PJ's staple lens together with the 70-200L IS and there is nothing at all that would replace it in crop. I have a friend who shoots PJ with Nikon. His complaint? The 12-24 is a great lens but just not fast enough!

The 1Ds wasn't particularly good for DR (actually really awful in the blacks), about equal to my 10D though the tonality was better. My 5D is indeed a revelation.

I've not abandoned my need for the level of resolution provided by the 5D, the D200 wouldn't be enough in many cases I'm afraid. I haven't changed my tune about the resolution needs  of the 5D, just saying that it is a seperate argument to that of the FF chip.

I haven't got any tests to prove it but being a wedding photographer dealing with extremes of DR maybe more than other genres, the 5D is superior to the 20D (which I shot for a couple of months between the 1Ds and 5D) for DR up until and including iso 1600. I don't have the tests but I do shoot the damn thing and process the RAW files with the counter on 21,000 frames on the 5D so far. I'm not making up what I see.

FF is not a niche, it is not ever shrinking by any means. Those who understand the need are buying the 1Ds mkII and will buy the sucessor, they understand why. If what you are saying would be the case then the D2X would have overtaken the 1Ds mkII, the 5D would not be in studios and wedding photographers hands across the world (Every wedding photographer I know who was shooting Canon now has the 5D, every single one!). Those who have them don't bother having to defend them, they know why.

TBH I wouldn't bother myself if it wasn't brought up in an unconnected thread.
« Last Edit: June 05, 2006, 06:07:15 PM by pom » Logged

BJL
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« Reply #52 on: June 06, 2006, 04:09:59 PM »
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FF is not a niche, it is not ever shrinking by any means.
[a href=\"index.php?act=findpost&pid=67481\"][{POST_SNAPBACK}][/a]
Rather than debate the meaning of "niche", let us just look at some facts about market share.


In film 35mm format had almost 100% of the SLR market, losing share mostly to larger rather than smaller formats.

When Canon and Kodak "FF" arrived about four years ago, the 1Ds has about 5% market share (24,000 annually when total DSLR sales were about half a million).
The Kodak 14/n seemingly had higher unit sales due to its far lower price, wit one estimate being 80,000/yr. So more than 5% market share for the 14/n, and maybe as much as 15%, giving FF a total of more than 10% and maybe as much as 20%.

Today, the 1DsMkII apparently has the same stated production level of 24,000/yr, but with total DSLR sales volume now about 4 miilion/year, the single model "professional 35mm format DSLR" sector is down to about 0.6% share of the total DSLR market. Also, Canon has reportedly stated a production level  of 100,000/year for the 5D which would put it at 2.5% share, distinctly less than the 1Ds or 14/n. That gives a current FF total of about 3%, far less than the 10-20% estimate for four years ago.


Clearly market share for 35mm format SLR's is shrinking, with a trend from almost 100% to 10-20% to 3%.

Restricting to the professional sector, the D2X is clearly far more competitive with the 1DsMkII than the D1X was with the 1Ds, so professional SLR market share for 35mm format has surely declined with the arrival of the D2X. Indeed, the 1DMkII also improved resolution over the original 1D to the point where many professionals choose it rather than the slower, more expensive 1DsMkII or the slower, less rugged 5D as a general purpose SLR, and the 1DMkII is a "1.3x crop camera", not "full frame", not 35mm.

Decide for yourself how low the market share must be before the word "niche" applies: for me, 3% does it, and is probably comparable to the SLR market share that medium format film cameras had a decade ago.
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DarkPenguin
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« Reply #53 on: June 06, 2006, 04:13:53 PM »
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This thread have anything to do with the new pentax?

If it does then does anyone know if Pentax has a decent 100-400 type of lens?  Seems like I might be able to get this camera (with its anti shake) plus lens for less than the L.
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MrIconoclast
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« Reply #54 on: June 06, 2006, 04:14:25 PM »
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I am not an enemy of full-frame.  I merely point out that many of us are still thinking in terms of traditional 35mm design.  Digital will allow many new ways of designing and using cameras.  

Two examples:  The Nikon Coolpix cameras that swivel in the middle, and the new Kodak cameras with two lenses and sensors, one for "normal" zoom and the other for wide angle.  

Both show that we can break away from the physical limitations of film.

That said, I can see the reason for full-frame, especially if I had a stable of expensive wide angle lenses left over from my 35mm days.

Fortunately, digital has evovled to the point where all of this equipment can be used to take wonderful pictures.  Enjoy!
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BJL
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« Reply #55 on: June 06, 2006, 04:19:24 PM »
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I think that your choice of the 24-105L misses the point. Many photographers have chosen it for their non DOF critical work. But the majority have a 50mm or 85mm in their bag. You can't control DOF sufficiently with that lens period.
[a href=\"index.php?act=findpost&pid=67481\"][{POST_SNAPBACK}][/a]
I can believe that; just as many users of the smaller mainstream DSLR formats probably use fast primes for extremes of shallow DOF (or otherwise use post-processing to soften backgrounds.)

Then again, many professional photographers only ever went beyond about f/4 or even f/5.6 when they needed the speed (in combination with low ISO films), not to decrease DOF. I see this in many books on nature photography, my particular interest. For them, f/2.8 in mainstream DSLR formats matches that minimum desired DOF, and high speed/low light performance is clearly better than it was with 35mm film.
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BJL
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« Reply #56 on: June 06, 2006, 04:38:07 PM »
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... does anyone know if Pentax has a decent 100-400 type of lens?
[{POST_SNAPBACK}][/a]
Not Pentax, but Sigma in particular fills this sort of gap for Pentax, Konica-Minolta/Sony and even Olympus/Panasonic to some extent. The Sigma 135-400 f4/5-5.6 is available in Pentax mount, as is the 100-300/4 for a "150-450 f/5.6 IS equivalent" thanks to SR.

Pentax seem to be going through a heavy culling of 35mm format designs and replacing them with new digital oriented designs, leaving some gaps for now at the longer focal lengths.

The definitive list of current Pentax SLR lenses (excluding medium format!) seems to be at
[a href=\"http://www.pentax.co.jp/english/products/filmcamera/lens/index35_ichiran.html]http://www.pentax.co.jp/english/products/f...35_ichiran.html[/url]
and
http://www.digital.pentax.co.jp/en/lens/
but many on the former list seem to have ended production, staying "current" only while stocks remain.
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Ben Rubinstein
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« Reply #57 on: June 06, 2006, 05:45:10 PM »
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BJL, do you not think that the price of FF has driven the statistics you quote? I'm sure that if FF were more affordable then we wouldn't be seeing anything of the sort. As MR said in a recent article, no one wanted crop sensors, they were forced on us. Then people started to try justifying them...

As a matter of interest, what kind of 35mm shooting did you do? As a nature photographer can you at all understand the needs of people photographers?
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MrIconoclast
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« Reply #58 on: June 06, 2006, 06:26:00 PM »
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BJL, do you not think that the price of FF has driven the statistics you quote? I'm sure that if FF were more affordable then we wouldn't be seeing anything of the sort.
[a href=\"index.php?act=findpost&pid=67572\"][{POST_SNAPBACK}][/a]


I am not so sure of that.  While cheaper prices for FF bodies would certainly increase their sales, one of the advantages to a newbie is the small size and light weight of the digital only lenses.  I doubt if many of them would be willing to buy, for example, the FF equivalent of Nikons 18-200mm zoom.  The fact that is this lense can be much smaller and lighter since it is intended only for the APS sized sensor.
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Elgsdyr
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« Reply #59 on: June 07, 2006, 04:58:53 PM »
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Moving the sensor becomes less effective with longer focal lengths - the sensor will have to be displaced further and further.
[a href=\"index.php?act=findpost&pid=66512\"][{POST_SNAPBACK}][/a]
Common misconception. Since the improvements of AS/IS/etc. is relative to the slowest possible shutter speed at the given focal length (the good old rule-of-thumb: 1/focal-length), the sensor doesn't need to move more at longer focal lengths to achieve the same improvement - just faster. The scenario you image requires the shutter speed to be the same at all focal lengths.

So the question is if it's fast enough at longer focal lengths. Personally I don't know as I haven't tested it, but many users of KM's DSLR's have reported, that AS works well at the tele end as well.
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Yours etc.
  Torsten Balle Koefoed
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