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06-22-2008, 02:11 AM   #1
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Hitting the wall with MP

Interesting article in Luminous Landscape

Do Sensors “Outresolve” Lenses?

I have to admit most of this is over my head so I skimmed it and skipped down to the conclusion. His conclusion is that we're hitting the wall with lens resolution and MP.

4/3 system 10MP
APS-C 15MP
full frame 35MP

Anything more than that and it's just bigger files with no real increase in resolution. If what he says is true then the K20D is about all you can get with APS-C. Not that I'm complaining. I'd like nothing more than Pentax and the rest of the DSLR makers to focus on DR and noise at high ISOs. Pentax can also move to 14 or even 16 bit raw files. Lots of places to make improvements.

I'll say again that this stuff of over my head. Perhaps someone with a better understanding of this can way in.

Alan

06-22-2008, 02:20 AM   #2
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I feel that my Tamron 18-200 Di II is not good enough glass for the K20D. I have a feeling the sensor is too good and the glass cannot resolve the image good enough. Either that or my K20D body is faulty coz I am still not convinced that the camers produces enough quality shots yet.

I am about to send it back to Pentax to be checked and if they say nothing is wrong i'll throw it in the garbage and go to a Canon 450D.
06-22-2008, 02:30 AM   #3
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QuoteOriginally posted by Alan 2 Quote
I have to admit most of this is over my head so I skimmed it and skipped down to the conclusion. His conclusion is that we're hitting the wall with lens resolution and MP.

4/3 system 10MP
APS-C 15MP
full frame 35MP

Anything more than that and it's just bigger files with no real increase in resolution. If what he says is true then the K20D is about all you can get with APS-C.
The article merely talks about the diffraction limits of a lens over the physical size of a pixel (the pixel pitch).

However, if we don't stop down the lenses too much, we maybe able to get more resolution as far as diffraction effect is minimized.

That's why if you attach a lens like the DA 16-45 and use the MTF program, the camera set at f/4 to f/5.6 at the wide side in order to maximum the resolution. I think Pentax know well about this diffraction effect (so that they avoid to stop down the wide lens in the MTF program mode, as far as possible).

Having said that, to make a lens has the highest possible resolution at fast aperture yet again is another thing that is rather difficult, anyway.
06-22-2008, 02:36 AM   #4
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QuoteOriginally posted by NicholasN Quote
I feel that my Tamron 18-200 Di II is not good enough glass for the K20D. I have a feeling the sensor is too good and the glass cannot resolve the image good enough. Either that or my K20D body is faulty coz I am still not convinced that the camers produces enough quality shots yet.

I am about to send it back to Pentax to be checked and if they say nothing is wrong i'll throw it in the garbage and go to a Canon 450D.
Off the top of my head I would have to say that a super zoom is not going to do it with a high resolution camera like the K20D. It's very likely that top quality zooms, or better yet top quality primes are needed to reach the potential of a 14.6 MP sensor.

Alan

06-22-2008, 02:42 AM   #5
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QuoteOriginally posted by NicholasN Quote
I feel that my Tamron 18-200 Di II is not good enough glass for the K20D. I have a feeling the sensor is too good and the glass cannot resolve the image good enough. Either that or my K20D body is faulty coz I am still not convinced that the camers produces enough quality shots yet.

I am about to send it back to Pentax to be checked and if they say nothing is wrong i'll throw it in the garbage and go to a Canon 450D.
You can't expect a 10.1x zoom to be have good sharpness, least of all one that sells new for less than $500 - they're definitely going for zoom range over IQ there.

Stick a f1.4 50mm on K20D, stop it down to f8 and see what happens.
06-22-2008, 02:43 AM   #6
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QuoteOriginally posted by RiceHigh Quote
The article merely talks about the diffraction limits of a lens over the physical size of a pixel (the pixel pitch).

However, if we don't stop down the lenses too much, we maybe able to get more resolution as far as diffraction effect is minimized.

That's why if you attach a lens like the DA 16-45 and use the MTF program, the camera set at f/4 to f/5.6 at the wide side in order to maximum the resolution. I think Pentax know well about this diffraction effect (so that they avoid to stop down the wide lens in the MTF program mode, as far as possible).

Having said that, to make a lens has the highest possible resolution at fast aperture yet again is another thing that is rather difficult, anyway.
That part I understand. My problem with that is I tend to be a deep field of view shooter (small apertures). Who knows, if the MP race continues I may be forced back into film.

Alan
06-22-2008, 02:45 AM   #7
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I brought this subject up a few weeks ago when I got a new K20D to replace a K100D.
The Sigma 28-70 constant f2.8 FF lens easily produces higher optical resolution images than the Tamron 18-200 Di zoom lens.
A $20 Pentax F 35-70 zoom is better than the Sigma DC kit lens on the K20D.
The pattern in this to me is the lenses made for full 35mm film frame are better than those made for APC sensors. I am thinking about getting Pentax Limited prime lenses - when I can afford them.

Last edited by garth1948; 06-22-2008 at 05:34 AM.
06-22-2008, 03:09 AM   #8
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Not Really

QuoteOriginally posted by garth1948 Quote
The pattern in this to me is the lenses made for full 35mm film frame are better than those made for APC sensors. I am thinking about getting Pentax Limited prime lenses - when I can afford them.
This is just about the deteriorating lens quality and performance for those modern low end ones nowadays.

With proper design, manufacturing process and QC, an APS-C lens with a smaller image circle should have a higher resolution as the image is not "magnified" (well, I mean effectively - so as the resolution obtained is not the highest).

p.s. I have the $20 zoom you mentioned, which I bought for more than $100 twenty years ago which is one of the "cheap" Pentax lenses which I love.

06-22-2008, 03:13 AM   #9
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QuoteOriginally posted by Alan 2 Quote
That part I understand. My problem with that is I tend to be a deep field of view shooter (small apertures). Who knows, if the MP race continues I may be forced back into film.

Alan
That makes absolutely no sense at all!

Firstly you dont have to stop down as far on APSC to get a greater DOF.

Secondly, you are not going to get more resolution on film as the same restriction applies, even if you could find 35mm film that gets anywhere close to 15MP.
06-22-2008, 03:13 AM   #10
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QuoteOriginally posted by Alan 2 Quote
That part I understand. My problem with that is I tend to be a deep field of view shooter (small apertures). Who knows, if the MP race continues I may be forced back into film.

Alan
I think when you're to shoot with small apertures, you have to scarify resolution in the end, so as to gain DoF. That has been an unchanged rule no matter you shoot film or digital (and in whatever digital format).

Fast lenses suffer from spherical aberrations and small apertures suffer from diffraction. That's Physics! :-)

(And then aspherical lenses often suffer from poor bokeh! The world has always been just anything need compromise!)
06-22-2008, 03:17 AM   #11
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Nope for both

QuoteOriginally posted by *isteve Quote
That makes absolutely no sense at all!

Firstly you dont have to stop down as far on APSC to get a greater DOF.
Nope. If the photographer need to control the exposure.. E.g. for fireworks shooting or on a very bright day! Do they need to always carry a ND filter to cut strong light instead of stopping down the aperture?

QuoteQuote:
Secondly, you are not going to get more resolution on film as the same restriction applies, even if you could find 35mm film that gets anywhere close to 15MP.
Nope. There exist the better FF lenses that can deliver more of the resolution. Have you read the essay as the OP posted?
06-22-2008, 04:20 AM   #12
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If you're disappointed in the IQ of the that lens with the K20D, I'm most certain the problem is the lens.


One can stick a kit lens on a K20D and not get outstanding pictures either. Swap that with a good copy of the DA* 16-50mm, though, and you'll sing a different tune.


Low scale optics + awesome camera = Low scale images.




QuoteOriginally posted by NicholasN Quote
I feel that my Tamron 18-200 Di II is not good enough glass for the K20D. I have a feeling the sensor is too good and the glass cannot resolve the image good enough. Either that or my K20D body is faulty coz I am still not convinced that the camers produces enough quality shots yet.

I am about to send it back to Pentax to be checked and if they say nothing is wrong i'll throw it in the garbage and go to a Canon 450D.
06-22-2008, 05:01 AM   #13
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All thse answers are spot-on.
In the end it's the lens that forms the picture.
I used slide and negative film as part of my job for many years and used every incarnation of digital media since the early nineties.
In remote-sensing every pixel is analized. Best film product I ever used (best quality slow slide film) had an output resolution of about 4000 by 3000 pixels for 35mm format media - the 'Holy Grail' for our world was a 12 megapixel camera.
Now we are using a 14 MP camera - K20D.
06-22-2008, 11:41 AM   #14
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QuoteOriginally posted by garth1948 Quote
In remote-sensing every pixel is analized.
Wow, that must hurt.

06-22-2008, 12:02 PM   #15
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http://www.zerorealm.org/NikonShooter.jpg
He wanted to try to see if i could get the reflections in his eye, since i had the K 50/1.4 on i didn't want to do it since it's not focusing that close, as is apparent on that noise i underexposed it in the hurry too.

http://www.zerorealm.org/NikonShooterEye.jpg so i did get something in his eye in the end.

That shot blew my mind, i wasn't ready for it, the amount of detail it retained in that underexposed shot is amazing.
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