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07-15-2012, 04:20 AM   #511
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QuoteOriginally posted by eurostar Quote
What do you think about the successor to the K-5? With the birth of the K-30, don't you think that the top-level APS-C reflex from Pentax will be specced quite above the K-5, and not just in term of pixel pitch? If so, don't you think that a full frame from pentax should be at least equal in specs to that APS-C camera? I can't believe that Pentax top camera (not counting 465D) could be a D7000 with full frame.
QuoteOriginally posted by eurostar Quote
It's a camera at the end of its life on the shelf. In a mere two months there will be a K-3, with a price that will be at least back at what the K-5 cost at birth: 1499$. That would be the benchmark.
My claim boils down to this:

It is increasingly hard to charge $1500 for an APS-C camera. Probably impossible for Pentax.

The step from K20D to K-7 was a major one, introducing a new body with new mirror box and shutter. If they entirely redid the AF module and viewfinder now (with more info to be displayed) then it may be able to compete for birding, still lacking the high fps though.

But I doubt it. It is a major engineering effort, which would have been started under Hoya who started nothing, and it is much tougher to achieve than full frame, for a niche much smaller than full frame. So, why should Pentax have done it?

I rather foresee the K-3 as a K-5 with higher resolution sensor and some more tweaks to the AF. I hope they refrained from giving it an integrated vertical grip.

07-15-2012, 05:08 AM   #512
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It boils down to this in fact: a 24MP APS-C sensor is pushing the limits of optics and pixel/sensor density and is probably a step backwards despite the best intentions. The only thing an APS-C vendor can offer without losing their reputation with an 24MP sensor is added features at this point. I just can't see a 24MP APS-C sensor being better than a 16MP one due to my favourite friend the Airy Disc. Pentax might just surprise everyone by offering a larger format sensor in September.
07-15-2012, 05:34 AM   #513
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QuoteOriginally posted by bossa Quote
Pentax might just surprise everyone by offering a larger format sensor in September.
I agree with your logic, and I hope you're right.
07-15-2012, 07:01 AM   #514
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QuoteOriginally posted by bossa Quote
I just can't see a 24MP APS-C sensor being better than a 16MP one due to my favourite friend the Airy Disc.
I had to look up Airy Disc, pretty interesting. So, now I'm wondering how many lenses out there are diffraction limited and which ones they are! I'd say the closest I have to a diffraction limited lens is my FA77 Limited. Perhaps the name isn't a coincidence. Many have wondered what was meant by the Limited designation. If Pentax updates their FA Limiteds to be DFA Limiteds it might be a safe bet to say that DFA really is just short for diffraction.

07-15-2012, 10:33 AM   #515
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QuoteOriginally posted by TomTextura Quote
So, now I'm wondering how many lenses out there are diffraction limited and which ones they are! I'd say the closest I have to a diffraction limited lens is my FA77 Limited..
ALL LENSES are diffraction limited and the FA77 isn't any more subject to it than any other lens. Diffraction limits are only subject to the aperture size in the lens and the size of the pixel cell on the sensor, if memory serves. For APS sensors, i've read that diffraction starts becoming a problem at F8 or F11. I suppose if one had a lens with no apertures smaller than an F8, one could say it was free of diffraction - and one could charge more for it.

When Canon's G series PS camera for enthusiasts went from 10mp to 12mp, reportedly there was enough complaints that they went back to the 10mp size for the next in the series. It will be interesting to see if there are complaints about diffraction from Nikon's 36mp aps camera - was it the D3100?
07-15-2012, 10:38 AM   #516
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07-15-2012, 10:44 AM   #517
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07-15-2012, 11:20 AM   #518
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IMO the pixel peepers are the ones that are diffraction limited

07-15-2012, 11:25 AM   #519
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QuoteOriginally posted by philbaum Quote
ALL LENSES are diffraction limited
I don't think you understood my point, which was mostly humorous and meant as a complement to the beloved FA Limiteds but also apparently too vague and/or corny. If you follow the link to the Wikipedia article on Airy Discs you'd see it says: "In optics, the Airy disk (or Airy disc) and Airy pattern are descriptions of the best focused spot of light that a perfect lens with a circular aperture can make, limited by the diffraction of light." It also says: "An optical system in which the resolution is no longer limited by imperfections in the lenses but only by diffraction is said to be diffraction limited." The implication I was running on was that a lens that is only limited by diffraction is the closest there is to perfect. Hence me wanting to know which lenses are diffraction limited. If I had good jokes I wouldn't have to explain them, but I don't know how to make good jokes so...

Last edited by TomTextura; 07-15-2012 at 11:32 AM.
07-15-2012, 03:34 PM   #520
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Before anybody plays another round of diffraction game ...

More than anything else ... does AF accuracy limit resolution when it comes to high MP numbers. And APS-C has MUCH lower AF accuracy than full frame (as I must have explained in one of my papers). It is the same reason why you can manually focus for sharp results with medium format, and not at all with APSC.
07-16-2012, 12:14 AM   #521
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QuoteOriginally posted by falconeye Quote
It is the same reason why you can manually focus for sharp results with medium format, and not at all with APSC.
Wait what? We can't manual focus for sharp results at all with APSC?!?

So what about all the Pentaxians with the MF legacy glass and their great/sharp results?

I'll admit, manual focussing is easier with a medium format camera, but the difference is not THAT big.
07-16-2012, 02:40 AM   #522
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QuoteOriginally posted by Clavius Quote
Wait what? We can't manual focus for sharp results at all with APSC?!?

So what about all the Pentaxians with the MF legacy glass and their great/sharp results?

I'll admit, manual focussing is easier with a medium format camera, but the difference is not THAT big.
The viewfinder of an APS-C shows the DoF of f2,8, so if you do manual focus at f1,2-1,4 you will not nail every shot. You might learn just about where the focus is, even if you can't see it.

I've had major problems with manual focusing on my k-10 and especially the k-20, the k-7 and k-5 works better for me, don't know why tho. I've done a lot of manual focusing with a 5D and it's easier, the viewfinder doesn't look like a small tunnel on a ff. The only problem I had on the 5D was focusing wide angles at larger apertures, that was almost impossible.
07-16-2012, 02:42 AM   #523
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QuoteOriginally posted by falconeye Quote
And APS-C has MUCH lower AF accuracy than full frame (as I must have explained in one of my papers).
I've seen you claim this a few times and wondered why. Can you please post URL or explain? :-)
07-16-2012, 02:55 AM   #524
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QuoteOriginally posted by fikkser Quote
I've seen you claim this a few times and wondered why. Can you please post URL or explain? :-)
One reason is equivalent FL lenses are more contrast on FF, thinner DOF is a great help here as well.
07-16-2012, 04:07 AM   #525
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QuoteOriginally posted by fikkser Quote
I've seen you claim this a few times and wondered why. Can you please post URL or explain? :-)
LumoLabs -- Camera Equivalence -- Whitepaper section §4.3.1

LumoLabs -- True reasons for Full Frame -- Whitepaper section §1.3.3

You may additionally want to consult
LumoLabs Article -- Understanding Image Sharpness section §2.3.3

Last edited by falconeye; 07-16-2012 at 04:27 AM.
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