Would you buy a Pentax Full Frame DSLR?

Fogel70 · 07-10-2013, 12:34 AM

Originally posted by dtmateojr

Re aperture size, you forget that it's a ratio. f5.6 is the same for any format. It let's exactly the same amount of light. Doh?

Not if using same FOV, f/1.9 on the 8.5mm normal prime on Q is 4.5mm, and f/1.9 on FA43 is 22mm.

dtmateojr · 07-10-2013, 01:08 AM

Originally posted by Fogel70

Not if using same FOV, f/1.9 on the 8.5mm normal prime on Q is 4.5mm, and f/1.9 on FA43 is 22mm.

LOL! Fstop 101 for you:

An fstop is an fstop. Light intensity diminishes as the square of the distance (i.e. focal length). A point-and-shoot will have a smaller opening because it needs a shorter focal length to cover THE SAME FoV. An fstop is the same for all formats.

Fogel70 · 07-10-2013, 01:15 AM

Originally posted by dtmateojr

LOL! Fstop 101 for you:

An fstop is an fstop. Light intensity diminishes as the square of the distance (i.e. focal length). A point-and-shoot will have a smaller opening because it needs a shorter focal length to cover THE SAME FoV. An fstop is the same for all formats.

Yes, but a smaller sensor need the same aperture size as on a larger sensor to capture the same amount of light at a given shutter speed. Only if both sensors capture the same amount of light will IQ be the comparable on both.

Nesster · 07-10-2013, 03:58 AM

Those who believe in APS-C should not try to convert those who believe in FF, and vice versa. NONE of what we do (well, actually very little) is pragmatic or cost effective: these are either TOOLS if we make a living with them, or HOBBY OBJECTS if we don't. As a hobby object, all the money is out-go.

In the next 12 months, those who believe in FF and can afford it will get one or more; those who believe in APS-C will be tempted by the next generation of APS-C cameras; and those who can afford the 'upgrade' will buy one or more... Those of us who can't or won't afford either 'upgrade'? Surely we suck, our equipment is obsolete, and no amount of proof can change that

... NOT. But clearly we aren't of any use to Pentax in the short term

**Ash** · 07-10-2013, 04:38 AM

Originally posted by civiletti

Patronizing or not, he effectively turned your argument against you.

What argument? That FF cameras are only better than APS-C cameras if lenses with excellent IQ are used? If so, show me the proof that a consumer grade FF compatible zoom will produce noticeably better results on a FF camera compared to that from the K-5 IIs (let's say).

I have posted many times in the past that FF is superior for sports, and I failed to mention it in my last expressed opinion. So sue me.

Ash.

**Ash** · 07-10-2013, 04:39 AM

Originally posted by Nesster

Those who believe in APS-C should not try to convert those who believe in FF, and vice versa. NONE of what we do (well, actually very little) is pragmatic or cost effective: these are either TOOLS if we make a living with them, or HOBBY OBJECTS if we don't. As a hobby object, all the money is out-go.

In the next 12 months, those who believe in FF and can afford it will get one or more; those who believe in APS-C will be tempted by the next generation of APS-C cameras; and those who can afford the 'upgrade' will buy one or more... Those of us who can't or won't afford either 'upgrade'? Surely we suck, our equipment is obsolete, and no amount of proof can change that

... NOT. But clearly we aren't of any use to Pentax in the short term

Two thumbs up. Thank you for that.

Ash.

dtmateojr · 07-10-2013, 06:14 AM

Originally posted by Fogel70

Yes, but a smaller sensor need the same aperture size as on a larger sensor to capture the same amount of light at a given shutter speed. Only if both sensors capture the same amount of light will IQ be the comparable on both.

What?!!! Obviously you do not understand the physics of photography.

fstop 102 for you:
Aperture is NOT equal to fstop. Fstop is the ratio between focal length AND aperture.

normhead · 07-10-2013, 06:31 AM

Originally posted by Ash

Two thumbs up. Thank you for that.

Ash.

+1 to that.

ElJamoquio · 07-10-2013, 07:18 AM

Originally posted by dtmateojr

In good light, yes. I doubt if you can identify which image is which.

Re aperture size, you forget that it's a ratio. f5.6 is the same for any format. It let's exactly the same amount of light. Doh?

It doesn't let in the same amount of light. F/5.6 has ~2.3x as much light fall on a full-frame sensor than an APS-C sensor.

They have the same lux.

**Rondec** · 07-10-2013, 07:38 AM

Originally posted by ElJamoquio

It doesn't let in the same amount of light. F/5.6 has ~2.3x as much light fall on a full-frame sensor than an APS-C sensor.

They have the same lux.

This, I have a problem with. The part of the sensor that is the same sees exactly the same amount of light with APS-C as with full frame. Sure, some of the sensor is cropped away, but that doesn't effect the fact that your shutter speed will be equivalent with APS-C and full frame if you use the same iso and aperture. That is what most people mean when they say that an f stop is an f stop.

Fogel70 · 07-10-2013, 09:35 AM

Originally posted by dtmateojr

What?!!! Obviously you do not understand the physics of photography.

fstop 102 for you:
Aperture is NOT equal to fstop. Fstop is the ratio between focal length AND aperture.

I fully understand what you say, but you don't seem to understand that the same exposure don't give same IQ on different sensor size.
Exposure do not take into account the sensors size, it's only about light per area unit size, but IQ is exposure x sensor area. So a smaller sensor need more light per area unit size to give same IQ as a larger sensor.

jogiba · 07-10-2013, 11:07 AM - **1 Like**

Originally posted by Ash

What argument? That FF cameras are only better than APS-C cameras if lenses with excellent IQ are used? If so, show me the proof that a consumer grade FF compatible zoom will produce noticeably better results on a FF camera compared to that from the K-5 IIs (let's say).

I have posted many times in the past that FF is superior for sports, and I failed to mention it in my last expressed opinion. So sue me.

Ash.

"You Can Use Cheap Lenses!

I get better results on full-frame with crummy lenses than I do with my very best lenses on DX.

Having bigger pixels on a larger format means you can use cheaper lenses and usually get better results than the best lenses on a smaller format. The only reason I use the weasel word of "usually" is because as of 2007 we're only talking about a 1.6x linear format difference among consumer (under $9,000) DSLRs. In film, with a 2x linear difference from one format to the next, the crappiest lens on the next bigger format always smokes the very best lens on the next smaller format."

The Full-Frame Advantage

robgo2 · 07-10-2013, 11:16 AM

Originally posted by Ash

Feeling 'useful' is different from gaining an IQ advantage. I agree that the FA 31 would be a very useful lens for wide angle applications, and it would suit it very nicely given its FF capability, but that wasn't my point. Images from DA 21 on APS-C vs images by the FA 31 on FF (at apertures giving equivalent DoF) would have reasonably comparable results - notwithstanding all that extra DoF capability of the FA 31 on the FF format.

Totally disagree. As I said in my previous post, the Sony 24MP FF sensor trounces the Sony 24MP APS-C sensor, as evidenced by the difference between the RX1 and the NEX 7. The same will hold true for the examples that you have given. I think that a big unknown is how well the FA Limited lenses will perform on high resolution FF sensors. Any lens flaws will become more evident.

Rob

ElJamoquio · 07-10-2013, 12:08 PM

Originally posted by Rondec

This, I have a problem with. The part of the sensor that is the same sees exactly the same amount of light with APS-C as with full frame. Sure, some of the sensor is cropped away, but that doesn't effect the fact that your shutter speed will be equivalent with APS-C and full frame if you use the same iso and aperture. That is what most people mean when they say that an f stop is an f stop.

I said they have the same lux. They don't transmit the same amount of light.

ElJamoquio · 07-10-2013, 12:09 PM

Originally posted by robgo2

Totally disagree. As I said in my previous post, the Sony 24MP FF sensor trounces the Sony 24MP APS-C sensor, as evidenced by the difference between the RX1 and the NEX 7. The same will hold true for the examples that you have given. I think that a big unknown is how well the FA Limited lenses will perform on high resolution FF sensors. Any lens flaws will become more evident.

Rob

For center performance, we could just test on the Q.

View Poll Results: Would you buy a Pentax Full Frame DSLR?
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No	43	22.05%
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07-10-2013, 12:34 AM	#316
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 3,062	Originally posted by dtmateojr Re aperture size, you forget that it's a ratio. f5.6 is the same for any format. It let's exactly the same amount of light. Doh? Not if using same FOV, f/1.9 on the 8.5mm normal prime on Q is 4.5mm, and f/1.9 on FA43 is 22mm.

07-10-2013, 01:08 AM	#317
dtmateojr Veteran Member Join Date: Jan 2012 Photos: Gallery Posts: 604	Originally posted by Fogel70 Not if using same FOV, f/1.9 on the 8.5mm normal prime on Q is 4.5mm, and f/1.9 on FA43 is 22mm. LOL! Fstop 101 for you: An fstop is an fstop. Light intensity diminishes as the square of the distance (i.e. focal length). A point-and-shoot will have a smaller opening because it needs a shorter focal length to cover THE SAME FoV. An fstop is the same for all formats.

07-10-2013, 01:15 AM	#318
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 3,062	Originally posted by dtmateojr LOL! Fstop 101 for you: An fstop is an fstop. Light intensity diminishes as the square of the distance (i.e. focal length). A point-and-shoot will have a smaller opening because it needs a shorter focal length to cover THE SAME FoV. An fstop is the same for all formats. Yes, but a smaller sensor need the same aperture size as on a larger sensor to capture the same amount of light at a given shutter speed. Only if both sensors capture the same amount of light will IQ be the comparable on both.

07-10-2013, 03:58 AM	#319
Nesster Veteran Member Join Date: Oct 2006 Location: NJ USA Photos: Gallery Posts: 13,072	Those who believe in APS-C should not try to convert those who believe in FF, and vice versa. NONE of what we do (well, actually very little) is pragmatic or cost effective: these are either TOOLS if we make a living with them, or HOBBY OBJECTS if we don't. As a hobby object, all the money is out-go. In the next 12 months, those who believe in FF and can afford it will get one or more; those who believe in APS-C will be tempted by the next generation of APS-C cameras; and those who can afford the 'upgrade' will buy one or more... Those of us who can't or won't afford either 'upgrade'? Surely we suck, our equipment is obsolete, and no amount of proof can change that ... NOT. But clearly we aren't of any use to Pentax in the short term

07-10-2013, 04:38 AM	#320
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Originally posted by civiletti Patronizing or not, he effectively turned your argument against you. What argument? That FF cameras are only better than APS-C cameras if lenses with excellent IQ are used? If so, show me the proof that a consumer grade FF compatible zoom will produce noticeably better results on a FF camera compared to that from the K-5 IIs (let's say). I have posted many times in the past that FF is superior for sports, and I failed to mention it in my last expressed opinion. So sue me. Ash.

07-10-2013, 04:39 AM	#321
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Originally posted by Nesster Those who believe in APS-C should not try to convert those who believe in FF, and vice versa. NONE of what we do (well, actually very little) is pragmatic or cost effective: these are either TOOLS if we make a living with them, or HOBBY OBJECTS if we don't. As a hobby object, all the money is out-go. In the next 12 months, those who believe in FF and can afford it will get one or more; those who believe in APS-C will be tempted by the next generation of APS-C cameras; and those who can afford the 'upgrade' will buy one or more... Those of us who can't or won't afford either 'upgrade'? Surely we suck, our equipment is obsolete, and no amount of proof can change that ... NOT. But clearly we aren't of any use to Pentax in the short term Two thumbs up. Thank you for that. Ash.

07-10-2013, 06:14 AM	#322
dtmateojr Veteran Member Join Date: Jan 2012 Photos: Gallery Posts: 604	Originally posted by Fogel70 Yes, but a smaller sensor need the same aperture size as on a larger sensor to capture the same amount of light at a given shutter speed. Only if both sensors capture the same amount of light will IQ be the comparable on both. What?!!! Obviously you do not understand the physics of photography. fstop 102 for you: Aperture is NOT equal to fstop. Fstop is the ratio between focal length AND aperture.

07-10-2013, 06:31 AM	#323
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	Originally posted by Ash Two thumbs up. Thank you for that. Ash. +1 to that.

07-10-2013, 07:18 AM	#324
ElJamoquio Veteran Member Join Date: Feb 2011 Posts: 4,873	Originally posted by dtmateojr In good light, yes. I doubt if you can identify which image is which. Re aperture size, you forget that it's a ratio. f5.6 is the same for any format. It let's exactly the same amount of light. Doh? It doesn't let in the same amount of light. F/5.6 has ~2.3x as much light fall on a full-frame sensor than an APS-C sensor. They have the same lux.

07-10-2013, 07:38 AM	#325
Rondec Loyal Site Supporter Join Date: Mar 2009 Location: Gladys, Virginia Photos: Gallery Posts: 27,653	Originally posted by ElJamoquio It doesn't let in the same amount of light. F/5.6 has ~2.3x as much light fall on a full-frame sensor than an APS-C sensor. They have the same lux. This, I have a problem with. The part of the sensor that is the same sees exactly the same amount of light with APS-C as with full frame. Sure, some of the sensor is cropped away, but that doesn't effect the fact that your shutter speed will be equivalent with APS-C and full frame if you use the same iso and aperture. That is what most people mean when they say that an f stop is an f stop.

07-10-2013, 09:35 AM	#326
Fogel70 Pentaxian Join Date: Sep 2009 Location: Stockholm, Sweden Photos: Albums Posts: 3,062	Originally posted by dtmateojr What?!!! Obviously you do not understand the physics of photography. fstop 102 for you: Aperture is NOT equal to fstop. Fstop is the ratio between focal length AND aperture. I fully understand what you say, but you don't seem to understand that the same exposure don't give same IQ on different sensor size. Exposure do not take into account the sensors size, it's only about light per area unit size, but IQ is exposure x sensor area. So a smaller sensor need more light per area unit size to give same IQ as a larger sensor.

07-10-2013, 11:07 AM - 1 Like	#327
jogiba Banned Join Date: Sep 2006 Location: Millstone,NJ Posts: 6,491	Originally posted by Ash What argument? That FF cameras are only better than APS-C cameras if lenses with excellent IQ are used? If so, show me the proof that a consumer grade FF compatible zoom will produce noticeably better results on a FF camera compared to that from the K-5 IIs (let's say). I have posted many times in the past that FF is superior for sports, and I failed to mention it in my last expressed opinion. So sue me. Ash. "You Can Use Cheap Lenses! I get better results on full-frame with crummy lenses than I do with my very best lenses on DX. Having bigger pixels on a larger format means you can use cheaper lenses and usually get better results than the best lenses on a smaller format. The only reason I use the weasel word of "usually" is because as of 2007 we're only talking about a 1.6x linear format difference among consumer (under $9,000) DSLRs. In film, with a 2x linear difference from one format to the next, the crappiest lens on the next bigger format always smokes the very best lens on the next smaller format." The Full-Frame Advantage

07-10-2013, 11:16 AM	#328
robgo2 Veteran Member Join Date: Jan 2007 Location: New Mexico Photos: Albums Posts: 1,125	Originally posted by Ash Feeling 'useful' is different from gaining an IQ advantage. I agree that the FA 31 would be a very useful lens for wide angle applications, and it would suit it very nicely given its FF capability, but that wasn't my point. Images from DA 21 on APS-C vs images by the FA 31 on FF (at apertures giving equivalent DoF) would have reasonably comparable results - notwithstanding all that extra DoF capability of the FA 31 on the FF format. Totally disagree. As I said in my previous post, the Sony 24MP FF sensor trounces the Sony 24MP APS-C sensor, as evidenced by the difference between the RX1 and the NEX 7. The same will hold true for the examples that you have given. I think that a big unknown is how well the FA Limited lenses will perform on high resolution FF sensors. Any lens flaws will become more evident. Rob

07-10-2013, 12:08 PM	#329
ElJamoquio Veteran Member Join Date: Feb 2011 Posts: 4,873	Originally posted by Rondec This, I have a problem with. The part of the sensor that is the same sees exactly the same amount of light with APS-C as with full frame. Sure, some of the sensor is cropped away, but that doesn't effect the fact that your shutter speed will be equivalent with APS-C and full frame if you use the same iso and aperture. That is what most people mean when they say that an f stop is an f stop. I said they have the same lux. They don't transmit the same amount of light.

07-10-2013, 12:09 PM	#330
ElJamoquio Veteran Member Join Date: Feb 2011 Posts: 4,873	Originally posted by robgo2 Totally disagree. As I said in my previous post, the Sony 24MP FF sensor trounces the Sony 24MP APS-C sensor, as evidenced by the difference between the RX1 and the NEX 7. The same will hold true for the examples that you have given. I think that a big unknown is how well the FA Limited lenses will perform on high resolution FF sensors. Any lens flaws will become more evident. Rob For center performance, we could just test on the Q.