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05-06-2012, 10:41 PM   #1
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Manual lens limitation

We as pentaxians love our manual lens and always ready to show them off.

Now I heard last week from a guy that manual lens have a 10 megapixel limitation.

Anyone heard of this? What does it mean for 16 megapixel sensor and soon to come the 24 megapixel?

05-06-2012, 10:47 PM   #2
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What you heard is completely and utterly false.
05-06-2012, 11:00 PM   #3
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+1 on what twitch said.
05-06-2012, 11:15 PM   #4
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QuoteOriginally posted by Culture Quote
Now I heard last week from a guy that manual lens have a 10 megapixel limitation.
Sounds entertaining

05-06-2012, 11:56 PM   #5
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Is this true for other makers then. This person uses an old nikon camera with a manual lens.
05-07-2012, 12:06 AM   #6
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The only way can think it could be true is if they were using absolutely rubbish lenses. But that would have the same loss in IQ as film.

I think this particular person either couldn't manual focus properly or their focusing screen was in need of some shims
05-07-2012, 12:38 AM   #7
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You should do everything you can to perpetuate this myth though, maybe bring the prices down on the good stuff.

"Oh, yeah the Pentax A 50mm f1.2 was nice in its day, but it is useless on today's high resolution digital bodies."
05-07-2012, 01:54 AM   #8
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QuoteOriginally posted by elliott Quote
You should do everything you can to perpetuate this myth though, maybe bring the prices down on the good stuff.

"Oh, yeah the Pentax A 50mm f1.2 was nice in its day, but it is useless on today's high resolution digital bodies."
Yeh I heard that about the A* 400 f2.8 too :evil:

05-07-2012, 02:13 AM   #9
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K-5, M 85mm f2

100% crop:



Seems fine to me!
05-07-2012, 03:14 AM   #10
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For all I know, another manufacturer may only use the central part of the sensor if a mounted lens does not report its aperture. Can't find any evidence of this. This is almost certainly a confusion with what happens when you mount a modern lens designed to project an APS-C sized image circle onto a full-frame body. In this case the camera will only use the central part of the sensor to avoid vignetting.

Think about it: a lens is basically a tube that sends light out of the back in more-or-less parallel rays over an area with a certain diameter. So long as that diameter is >= to the longer side of the thing picking up the light, you have a chance of getting a correct exposure.

Another possibility is that modern sensors >10 megapixels or thereabouts may out-resolve film. In this case, an old lens may not be able to take advantage of increased resolution so you don't see any benefit.

There are some genuine disadvantages with manual lenses: primarily lack of automatic aperture control, not to mention the possibility of ghosting and flaring. However, crippling your sensor isn't one of them.
05-07-2012, 08:04 AM   #11
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QuoteOriginally posted by Culture Quote
Is this true for other makers then. This person uses an old nikon camera with a manual lens.
No, it is not true for Nikon, either. His statement is false for any manufacturer. The grain of truth that lies at the base of this false statement is that with any lens, there will come a point where increasing sensor resolution won't help much. This is just common sense - if you try using the bottom of a Coke bottle as a lens, you'll get a lousy picture and no amount of sensor resolution is going to help.

But it's not like there is going to be one magic threshold for a given lens where increasing sensor resolution helps ol,y up to that point then suddenly stops. And of course, even if there were such a point - which there isn't - it's not like the lens would stop working if the sensor has higher resolution. You just wouldn't be taking full advantage of the sensor resolution. But again, there is no hard and fast line; it would be more a matter of increased sensor resolution having "diminishing" advantage the higher you go, as upposed to the advantage suddenly becoming zero.

And whatever the point is where the advantage starts to diminish, it certainly isn't the same for all manual lenses, or even all Nikon manual lenses. But only an extremely poor lens wouldn't be able to take advantage of sensor resolution beyond 10MP.

Last edited by Marc Sabatella; 05-07-2012 at 12:04 PM.
05-07-2012, 08:16 AM   #12
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Sounds like something Ken Rockwell would say :evil:
05-07-2012, 09:10 AM   #13
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Completely false, and illogical. You simply cannot say that a manual lens only has a resolution of 10mp. Which lens? Which format? And yet I hear this all the time, even from highly respected photographers that if they thought about it would realize it is a silly statement.

Various articles I have read say that film, depending on the film, format and process, has a resolution of anywhere from 40mp to 400mp. So how is possible for a film era manual lens to not resolve more than 10mp when it was used to record on media with a much higher resolution?

The quality of the lens certainly comes into play, a cheap third party M42 lens may have a very low resolution, it looked awful on film and certainly no better on digital. But take an excellent film lens and it still has more than enough resolution for today's sensors. Maybe someday the sensor will exceed the lens, but we are not there yet.
05-07-2012, 09:12 AM   #14
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QuoteOriginally posted by Culture Quote
We as pentaxians love our manual lens and always ready to show them off.

Now I heard last week from a guy that manual lens have a 10 megapixel limitation.

Anyone heard of this? What does it mean for 16 megapixel sensor and soon to come the 24 megapixel?
Who dreams this stuff up?

05-07-2012, 09:15 AM   #15
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QuoteOriginally posted by LaurenOE Quote
Who dreams this stuff up?

Manufacturer trolls trying to sell you new glass (Nikon even specifies needed lenses for the D800 resolution lol - like their old lenses shooting Pan 25 and other high res films just weren't up to the job)
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