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09-24-2009, 06:17 PM   #196
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QuoteOriginally posted by jogiba Quote
jogiba, this is sooo much cooler than the 8mm fisheye

Thanks for sharing.

Any 24fps motors for Pentax film cameras?

09-24-2009, 08:05 PM   #197
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QuoteOriginally posted by Rondec Quote
I can't imagine the level of distortion that would be present on 12mm on full frame. I have to say, that my favorite landscapes are taken with "normal" lenses. To get more field of view, panoramic stitching works better than trying to cram extra angle into a smaller space.
Remarkably little distortion. Search flickr for photos of the sigma 12-24 on FF.

Herer are a few
Utah Capitol on Flickr - Photo Sharing!
Brigham Young Acadamy building on Flickr - Photo Sharing!
The twilight zone on Flickr - Photo Sharing!
09-24-2009, 09:52 PM   #198
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QuoteOriginally posted by jogiba Quote
Also with FF you could use a Sigma 12-24mm zoom with 122 FOV @12mm, The widest FOV zooms for APC DSLRs are about 102 FOV @10mm.
Note that Sigma quotes their FOV (rather AOV) for their own sensor size.

For the Pentax APS-C format, the Sigma 10-20 has an AOV range of 109-70 degrees. I'm using the sensor diagonal as a reference, as it is the case for the 122-84 degrees for the 12-24 on FF.
09-25-2009, 09:34 AM   #199
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QuoteOriginally posted by kristoffon Quote
I think this discussion is stupid.
...
I don't really care about low noise. I'll get a Pentax FF camera when/if it comes out only so I can have my 31mm become a wide angle.
That's sensible, but you have to realize - not everyone cares about emulating the shallow DOF and wide angle capability of FF more than they care about low noise. The discussion is about the noise differences, and hence is relevant for people who care about that. If you're not among them, then this discussion is not for you. That doesn't make it stupid, though - plenty of people *do* care about noise, more than they care about shallow DOF.

10-08-2009, 07:13 PM   #200
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Marc, believe me, I have long shared *exactly* the understanding you have, i.e., it shouldn't make a difference if I shoot a different format, any ISO/aperture/shutter speed combination should yield the same exposure. Experience, however, has challenged that understanding, and I'm just searching for a logical explanation. Since I have two different dSLRs that both do this, manufactured years apart and with completely different sensors, I have trouble believing that some "random calibration" issue is the culprit, and all the online testers seem to indicate accurate ISOs for the K10D, the camera I use most for digital at present. I can also assure you there is nothing wrong with my meter, as I get accurate exposures with slide film, which is very unforgiving and highlights any exposure errors. Someone opined similarly in a discussion elsewhere, and I kick myself for not bookmarking it at the time, since I've had trouble tracking it down again. I'll be sure to do more experimenting though.

Falconeye, I was indeed reading...and reading...and reading...and reading this discussion until my eyes were rolling like an old TV that lost its "vertical hold" control (probably dating myself there), and I understand the point being made completely. IF the exposure issue holds, it would negate the argument, but that doesn't mean I don't understand the point being discussed in this thread. Having said that, I'll add a little support to Kristoffen's comment, because the entire discussion amounts to a very long-winded strawman argument. Essentially, it begins with the assumption (not stated openly, but nonetheless) that the only/the primary/the main/the biggest reason that people want a FF dSLR is for the "noise advantage" being debated, when in point of fact there are many reasons people want FF dSLRs, many of which are not even image quality related, so this discussion hasn't accomplished much as the latest attempt to convince people that they should settle for APS-C when they want FF. Further, as has been pointed out, it also (in its contortions to produce a level of "equivalence" that makes a direct noise comparison "equitable") requires the use (in some instances, mainly when shooting at wide apertures) of non-existent lenses that will never be produced (because the cost/size/weight would make them unmarketable to the same people who indicate their lack of interest in FF is owed in no small part to how expensive/big/heavy they think the cameras/lenses are).
10-09-2009, 03:35 AM   #201
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QuoteOriginally posted by 24X36NOW Quote
I'm just searching for a logical explanation.
[...]
I have trouble believing that some "random calibration" issue is the culprit
[...]
Falconeye, I was indeed reading...and reading...and reading...and reading this discussion until my eyes were rolling like an old TV that lost its "vertical hold" control

24X36NOW, good summary of the thread

btw, I never considered this thread a contra FF thread. Speaking for myself, I just wanted to point out the real advantages of FF (and there are many). Because most of the time, the many false arguments pro FF hide the true ones.

With regard to your "exposure depends on sensor size" observation, needing an explaination. Well, you made an interesting observation and it may be the topic of its own thread. But you have been simply jumping to conclusion here and this didn't pass unnoticed.

A proper dealing would require exact facts (cameras compared), test shots etc.

Good starting points may be

- the Kodak paper (which is mentioning a different 18% gray calibration factor allowing for more headroom in highlights for "professional" cameras (read studio)).

- the DxO lab tests of ISO sensitivity (Welcome to dxomark.com (beta), a free resource dedicated to RAW-based camera image quality), showing large variations indeed. But not consistently depending on sensor size though.


Again, I propose to discuss the ISO calibration topic in a separate thread and it shouldn't be claimed a priori that it is sensor size specific.
10-09-2009, 11:45 AM   #202
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Agreed. I don't doubt that you are seeing what what you seeing. I'm just saying whatever it is is specific to the cameras, lenses, and meter you happened to use for the test; it isn't an APS-C versus FF issue. Some camera expose brighter than others given the same settings - and in general, digital cameras might expose a bit more conservatively than film cameras to protect highlights (yes, even for the same settings). But it is just not the case that sensor size plays any role in this.
10-09-2009, 01:43 PM   #203
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QuoteOriginally posted by Marc Sabatella Quote
Agreed. I don't doubt that you are seeing what what you seeing. I'm just saying whatever it is is specific to the cameras, lenses, and meter you happened to use for the test; it isn't an APS-C versus FF issue. Some camera expose brighter than others given the same settings - and in general, digital cameras might expose a bit more conservatively than film cameras to protect highlights (yes, even for the same settings). But it is just not the case that sensor size plays any role in this.
yes, remember how the Pentax cameras are being regarded to underexpose or have dark exposure compared to Canikon? but even in the same camera manufacturer, a certain camera model let's say a D80 could have a different exposure or metering to that of a D90. mind you that both dslrs are APS-C sensors. and yet the other cam may exhibit a brighter exposure than the other one.

this is also true with the different lenses. primes of the same FL and speed but of different lens manufacturer, where one lens is brighter than the other even if the exposure settings (shutterspeed,aperture,ISO) are the same. mind you that this test was done only with APS-C dslrs versus APS-C dslrs or APS-C dslrs with varying lenses exposure and not a APS-C versus FF exposure.

so what can we draw from this?

10-13-2009, 07:59 PM   #204
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Canon actually under-rates its ISOs by a bit according to the indications I've seen in reviews (probably so they can angle a supposed "shadow detail advantage" or something), which I actually find annoying, as I'd like accurate ISOs, which Nikon and Pentax supposedly both have. Of course, I'd like accurate ISOs so that I get accurate exposures, but that hasn't exactly worked as I'd hoped so far.
10-15-2009, 12:06 PM   #205
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He does not understand what f-stop ratio really means. It is a ratio of opening size diameter to FL of the particular lens. This keeps the light density (light ray flux?) the same for all f-stop numbers that are the same, regardless of format size, film, etc.
01-20-2010, 05:50 PM   #206
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Wait until arrive and prove Pentax FF camera. Smile
01-20-2010, 09:58 PM   #207
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it's not just a matter of lower noise or wider FOV.

PERSPECTIVE is a big factor also.

~33mm on APS-C will have the same FOV as with a 50mm on Full-Frame. If you stop down the aperture on the FF and open it up on the APS-C, you'll get the same Depth of Field. BUT you sill have different PERSPECTIVE.
01-20-2010, 10:15 PM   #208
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I am just a little curious how many forks here have extensively shot a FF dSLR and a lot of FF film. If there were more of these folks - the discussion would be a whole lot different and the understanding of why Pentax shouldn't try to compete in that arena would be far greater. (Most of my life has involved shooting Pentax on film, followed by shooting the *istD, Canon 20d, Canon 5d, and the K20D over the last seven years).

Much like the Nikon comparison of FF and crop sensors, the difference in all measurable sensor characteristics between the 20d and 5d are negligible. If nothing else, you do get a small sense of the difference in depth of field vis-a-vis field of view - and that would only be when you are looking for it. (It is more apparent with the Olympus system where the crop factor is 2.0x.) What you lose in going to FF besides the obvious (bulk, slow fps, etc.) is that light falloff, CA and border softness is a much greater problem with all but the very highest quality and over-sized optics - especially so at wide angle. This has mostly to do with the angle of acceptance that is not an issue with film. Bottom line - for wide angle shooting it is very difficult to get superb wide angle IQ on FF.

Recreating a modern FF lens line for dSLR is really asking too much, given the small pool of potential adopters in Pentax. It literally would be a fatal mistake - and anyone here with a sense of business marketing and understanding of scale would agree.

By the way, the only dSLR I don't own anymore is the FF Canon 5d.
01-20-2010, 11:00 PM   #209
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QuoteOriginally posted by ScooterMaxi Jim Quote

Recreating a modern FF lens line for dSLR is really asking too much, given the small pool of potential adopters in Pentax. It literally would be a fatal mistake - and anyone here with a sense of business marketing and understanding of scale would agree.

By the way, the only dSLR I don't own anymore is the FF Canon 5d.
But why Pentax has to re-create a FF lens line? Great FA lenses there, with a few modern adjustment and rebadgng they would work like a charm on a FF camera IMO. They just have to be put into production line again, I guess this is most difficult part financially..
01-20-2010, 11:55 PM   #210
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I want to thank Hakaan, along with all the other contributors, for giving us this thread. I thoroughly enjoyed reading it, even when I look back and realize the time taken to do so. In the more humorous moments, I was reminded of a very old movie entitled (something like) This Is A Spinal Tap. There is a scene in that movie where people (stoned as can be) sit and ponder the implications of a stereo amplifier which measures volume on a scale of 1 to 12, instead of the typical 1 to 10. That scene underscores the pointlessness of numbers in and of themselves for discussion.

Like Hakaan, Falconeye, and Marc Sabatella so elegantly point out--numbers, in order to have any real meaning, must be presented in relativized language, or, "apples to apples." I leave this thread with a much better understanding than when I entered--THANKS.
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