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03-11-2008, 05:06 AM   #16
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QuoteOriginally posted by falconeye Quote
Maybe, an APS-C lens would resolve 500 lp/mm. But for normal lengths and shorter, not with a 35mm mount (distance of rear lens to sensor). Olympus has a small advantage here, Leica M a big one.
Rear lens element can get closer regardless of mount. It does however help if the mount is closer to start with.

03-11-2008, 06:43 AM   #17
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QuoteOriginally posted by Matjazz Quote
Rear lens element can get closer regardless of mount. It does however help if the mount is closer to start with.
Ok, but it cannot get closer than the mirror allows. On the other hand, an APS-C mirror is smaller. But it doesn't rotate at its corner. Difficult to know for sure. I was just guessing.
03-11-2008, 07:13 AM   #18
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who says there has to be a horizontaly positioned mirror...
03-11-2008, 04:15 PM   #19
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QuoteOriginally posted by Gooshin Quote
who says there has to be a horizontaly positioned mirror...
Good point. I made a proposal for an additional electronic VF (making the mirror optional for some lenses) myself.

But if you keep the mirror, where would you put it then?

03-14-2008, 05:31 AM   #20
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QuoteOriginally posted by mutley Quote
And, fortunately for Oly people, Olympus considers getting rid of CA very important, and Pentax lens designers just don't think its a big deal, and leave it substantially in most lenses.

Even Oly's new 70-300mm $350 consumer zoom has eliminated CA, but the Pentax 55-300mm, and $1000 200mm have good amounts of it.

It is a big deal.
Olympus' 70-300mm zoom is a rebadged Sigma. You can get the same lens for less than $350 if it has a Sigma label on it instead of an Olympus label.
03-14-2008, 06:23 AM   #21
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QuoteOriginally posted by wiyum Quote
Finally, in my experience, 6x7 slides on Provia 100F compared with a loupe to 35mm slides taken with Provia 100F perform basically the same, resolution-wise. The bigger negative is great if you want to print bigger, but the lenses of the systems (Canon EOS, Pentax K, and Mamiya RZ) seem to hit around the same marks in terms of lens resolution. Either I have some killer RZ glass, some shoddy Canon and Pentax glass, or format doesn't affect lens resolution as much as so many people claim.
The medium format slide does not have to be magnified as much when projected or when making enlarged prints. So, it can even have less resolution than a 35mm slide and still look sharper. A medium format slide with 45lp/mm resolution will look sharper when enlarged only 10 times vs. a 35mm slide with 60lp/mm resolution when enlarged 15 times. The former will have 4.5 lp/mm resolution in the final print, while the latter will have 4lp/mm resolution.

The same is true with digital sensors. Full frame sensors are about twice the size of an APS-C sensor, so that an image made from an APS-C camera would need to be enlarged twice as much as that from a full frame sensor. An image from an APS-C sensor would therefore need about 1.5x as many pixels to look as sharp as one from a full frame when making prints. It would mean that a 12mp full frame sensor can yield prints that are as sharp as those made from a 18mp APS-C sensor, if the prints are the same size.
03-14-2008, 06:52 AM   #22
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QuoteOriginally posted by Anastigmat Quote
The same is true with digital sensors. Full frame sensors are about twice the size of an APS-C sensor, so that an image made from an APS-C camera would need to be enlarged twice as much as that from a full frame sensor. An image from an APS-C sensor would therefore need about 1.5x as many pixels to look as sharp as one from a full frame when making prints. It would mean that a 12mp full frame sensor can yield prints that are as sharp as those made from a 18mp APS-C sensor, if the prints are the same size.
I think you got it mixed up. 12mp is 12mp period. Also Leica format sensor (marketing name: full frame) is not about twice as big but 1.5x bigger than as APC-C.
03-14-2008, 08:42 AM   #23
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QuoteOriginally posted by Matjazz Quote
I think you got it mixed up. 12mp is 12mp period. Also Leica format sensor (marketing name: full frame) is not about twice as big but 1.5x bigger than as APC-C.
12mp is 12mp, but when one makes enlargements, it is negative size vs. print size that counts. And an APS-C sensor is physically smaller than a full frame. An APS-C sensor is about 24mm x 16mm in size (actually a fraction of a millimeter less in both dimensions), so that means two of them put together end to end would approximately equal to the surface area of a full frame sensor, which is 24mm x36mm. The 1.5x is the field of view crop and it is not a measure of the size area of a sensor.

If you make a 10x15 inch print, you would need to enlarge the image formed by the APS-C sensor twice as much as an image formed by a full frame. It is expressed in the equation below.

10x15/24x16 = 1/2 x 10x15/24x36

that means when you make a 10x15inch print from an APS-C sensor, you would need to make a 20x enlargement, but you only need to make a 10x enlargement with a full frame sensor. The 20x enlargement would therefore require a "negative" (or file) with higher resolution, and more pixels than a 10x enlargement made from a full frame file. This sort of math is not done very often, but it helps explain why full frame sensors need not have a lot of pixels to outresovle APS-C sized sensors. A full frame can have fewer pixels and yet it can generate sharper prints than an APS-C camera. Fewer pixels also mean larger pixels, which in turn means more dynamic range and lower noise at high ISO settings. Hence it is no wonder I am not going to "upgrade" to high pixel count APS-C sensors.

03-14-2008, 09:59 AM   #24
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QuoteOriginally posted by Anastigmat Quote
[...]That means when you make a 10x15inch print from an APS-C sensor, you would need to make a 20x enlargement, but you only need to make a 10x enlargement with a full frame sensor. The 20x enlargement would therefore require a "negative" (or file) with higher resolution, and more pixels than a 10x enlargement made from a full frame file. This sort of math is not done very often, but it helps explain why full frame sensors need not have a lot of pixels to outresovle APS-C sized sensors. A full frame can have fewer pixels and yet it can generate sharper prints than an APS-C camera. Fewer pixels also mean larger pixels, which in turn means more dynamic range and lower noise at high ISO settings. Hence it is no wonder I am not going to "upgrade" to high pixel count APS-C sensors.

That's true, but when a FF sensor reaches 24 megapixel, like the annunced Sony, soon to appear in the next FF Nikon and Sony cameras, and that will obviously be followed by a bigger-count Canon one, its pixels will be same-sized than the ones of a 12 megapixels APS-C. There will be no advantages in dinamic range and noise at any print-size, and better resolution will be noticeable only in very large prints.
03-14-2008, 11:25 AM   #25
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QuoteOriginally posted by Anastigmat Quote
that means when you make a 10x15inch print from an APS-C sensor, you would need to make a 20x enlargement, but you only need to make a 10x enlargement with a full frame sensor. The 20x enlargement would therefore require a "negative" (or file) with higher resolution, and more pixels than a 10x enlargement made from a full frame file. This sort of math is not done very often, but it helps explain why full frame sensors need not have a lot of pixels to outresovle APS-C sized sensors. A full frame can have fewer pixels and yet it can generate sharper prints than an APS-C camera.
I don't know where you picked up this FF myth but I assure you it has very little to do with math. APS-C is 1.5x smaller than FF. Period.


APSCx1.5=FF

....24x1.5=36
....16x1.5=24

That being said FF has 2.25x bigger surface but the sensor is still "just" 1.5x larger.
About "enlargements", if both sensors produce AxB resolution chances are that APS-C sensor would surpass the lens resolution and produce softer images. In this case higher resolution would not make images any better. Period. And if the lens was sharper than both sensors they would produce equally sharp images.

QuoteOriginally posted by Anastigmat Quote
Fewer pixels also mean larger pixels, which in turn means more dynamic range and lower noise at high ISO settings. Hence it is no wonder I am not going to "upgrade" to high pixel count APS-C sensors.
Larger sites => better ISO makes sense to me. I'm not sure about DR thou. It could be that better DR is a result of more advanced and expensive sensor technology that is still reserved for high priced FF sensors.
03-14-2008, 11:59 AM   #26
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QuoteOriginally posted by Matjazz Quote
Larger sites => better ISO makes sense to me. I'm not sure about DR thou. It could be that better DR is a result of more advanced and expensive sensor technology that is still reserved for high priced FF sensors.
DR of a sensor is a function of its surface area- i.e., how many electrons can a pixel hold before it's full.
03-14-2008, 02:10 PM   #27
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you cant compare film size vs sensor size, they are not the same thing

its the pixel count

i can make a sensor thats twice the size of a 35mm negative but it will have 3 (thats THREE) pixels on it....... you go and enlarge that... LOL



QuoteOriginally posted by Anastigmat Quote
12mp is 12mp, but when one makes enlargements, it is negative size vs. print size that counts. And an APS-C sensor is physically smaller than a full frame. An APS-C sensor is about 24mm x 16mm in size (actually a fraction of a millimeter less in both dimensions), so that means two of them put together end to end would approximately equal to the surface area of a full frame sensor, which is 24mm x36mm. The 1.5x is the field of view crop and it is not a measure of the size area of a sensor.

If you make a 10x15 inch print, you would need to enlarge the image formed by the APS-C sensor twice as much as an image formed by a full frame. It is expressed in the equation below.

10x15/24x16 = 1/2 x 10x15/24x36

that means when you make a 10x15inch print from an APS-C sensor, you would need to make a 20x enlargement, but you only need to make a 10x enlargement with a full frame sensor. The 20x enlargement would therefore require a "negative" (or file) with higher resolution, and more pixels than a 10x enlargement made from a full frame file. This sort of math is not done very often, but it helps explain why full frame sensors need not have a lot of pixels to outresovle APS-C sized sensors. A full frame can have fewer pixels and yet it can generate sharper prints than an APS-C camera. Fewer pixels also mean larger pixels, which in turn means more dynamic range and lower noise at high ISO settings. Hence it is no wonder I am not going to "upgrade" to high pixel count APS-C sensors.
03-14-2008, 03:01 PM   #28
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QuoteOriginally posted by JMS Quote
DR of a sensor is a function of its surface area- i.e., how many electrons can a pixel hold before it's full.
Sort of. Its also very subject to the noise floor. IE you can have higher DR with smaller sites as long as you can reduce the noise floor.
03-14-2008, 05:12 PM   #29
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QuoteOriginally posted by Matjazz Quote
I don't know where you picked up this FF myth but I assure you it has very little to do with math. APS-C is 1.5x smaller than FF. Period.


APSCx1.5=FF

....24x1.5=36
....16x1.5=24

That being said FF has 2.25x bigger surface but the sensor is still "just" 1.5x larger.
About "enlargements", if both sensors produce AxB resolution chances are that APS-C sensor would surpass the lens resolution and produce softer images. In this case higher resolution would not make images any better. Period. And if the lens was sharper than both sensors they would produce equally sharp images.

Larger sites => better ISO makes sense to me. I'm not sure about DR thou. It could be that better DR is a result of more advanced and expensive sensor technology that is still reserved for high priced FF sensors.
Myth? The K10D APS-C sensor measures 23.5mm x 15.7mm. Flip it to "portrait" and put TWO of them side by side and you have 23.5mm x 31.4mm, and you still haven't covered a 35mm frame. APS-C is less than half the size of 35mm. No myth there. The 35mm sensor is 1.5X larger in each of two dimensions, making it (as you indicated) actually 2.25x as large, not 1.5x as large. Sounds more like an APS-C myth than a FF myth.

I think the point being debated in a roundabout way is that lenses have to resolve details much smaller to render them sharply on smaller sensors than they do on larger sensors. Pixel density doesn't save the day unless the lenses can make up for the format shrinkage, and better lenses can be made for 35mm as well as APS-C, so it's not like the issue will go away. As for the pixel density itself, you need to realize that even where Sony's sensor is coming in (at 24.8 magapixels) is just about the same pixel density as the K10D; the K20D pixel density would scale up to about 34.8 magapixels, so there isn't really any "crowding" of pixel density on FF chips yet, and they have the dual advantage of higher pixel count AND larger original image size, which APS-C won't be able to match. If affordable 35mm sensors were available at the beginning of dSLR introductions, there never would have been an APS-C dSLR and we wouldn't still be waiting for our film-equivalent format. I also highly doubt there is much realism in the resolution numbers being touted for some lenses, since those numbers probably require ridiculously high contrast that won't exist in the real world (as opposed to the testing laboratory).
03-14-2008, 07:07 PM   #30
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FF & MF Are Doomed

For the same reason APS-C, APS-H and any single sensor lens/camera is. It doesn't force us to buy all new lenses every year, like we are now expected to do with bodies. The future is the plenoptic camera lens. Photo industry braces for another revolution | Underexposed - CNET News.com
The reason Pentax/Samsung are on the right track is because they are concentrating on making the SENSOR ITSELF better, not concentrating on wasting time dealing with MANUFACTURING issues that are inherent in making larger sensors.
The future is multiple, small sensors, integrated with multiple small lenses where all processing is done in-camera. Moving to FF or MF is regressive, archaic, backwards and technologically antiquated. Looking backwards to design criteria (like FF or MF) standardized before you were born for FILM is folly. Buy NEW stuff man! Arguments for FF or MF are predicated on existing and/or old technology and assumptions that the laws of physics are paramount as they apply to single sensors, and single lenses capturing a view and NO digital processing. What happens when you have 5 overlapping sensors capturing the same light? 10 levels of dynamic range. No problem. Is that gonna happen with single sensors? Not at the same price! Sensor technology is getting better and better. With the new Samsung sensor, we are getting the same noise from a larger sensor. Do you really think that these types of improvements are going to stop. No. It's going to get better and better.
The K20D's new sensor has improved the APS-C sensor by reducing spaces between sensors. The camera itself has amazing in-camera processing capabilities. It foreshadows the future of where digital photography is moving, and where R&D funds are being spent - SMALL sensors, not big ones. Need lots of resolution? Well, it'll just be adding more sensors and processing power. A cell-phone will have one, or a few sensors, a hi-end camera will have dozens of the exact same sensor, and they won't be APS-C, APS-H, FF, MF or any film-derived format-size. It will start happening very soon if you also look at the new Intel chips. They're amazing. FF and MF advocates are living in the past. It's 2008! If Pentax/Samsung do release FF or MF cameras, it'll be for marketing reasons, not photographic reasons. You'll soon be stuck with a proverbial, over-sized lemon.
So today, buy APS-C from Pentax as they improve this sensor size, until they replace it with a multiple sensor lens 'system'. FF or MF, if they ever happend will be a short-term dead-end. If you "NEED" FF today, switch companies and stop posting on this forum. Soon, you will ask what kind of processor is in your camera, and how many lenses it has, not what the size of the sensor is. We'll be looking back at DSLRs like we now look at 70's muscle cars. Kids will make fun of you and your non-3D HUGE camera.
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