Brief info about K-5 and KR

macTak · 08-25-2010, 08:14 AM

Originally posted by Ishpuini

Correction (see my earlier post, and the exchange on DPR): 30% light loss because of the mirror, this corresponds to roughly 1/2Ev (half a stop) less light reaching the sensor. Sorry to repeat this, just trying to avoid wrong information being propagated.

So it's not as dramatic as what you write, but of course the deductions from the resulting images stand.

Wim

It's amazing how DPR got it wrong, and at any rate (now corrected) buried that information in one spot in the review. I would still think that this would be an important drawback worth mentioning in the negatives at the end, considering how many pixel-peep these days and really do care about a 1/2 stop advantage.

Pixel Pusher · 08-25-2010, 08:16 AM

Lots people clamoring for higher and higher ISO capabilities, but what about lower ISO?

Whatever happened to ISO 25, 50, 64, 80?

I'd love to see ISO 25 or 50 available in a future Pentax release.

Agnostic · 08-25-2010, 08:33 AM

Noise comparison impressions from the images in the imaging resource comparometer:

A560 is at least one stop better than the A33 at 1600 and 3200 ISO.

A55 is about half a stop or less worse than the A560 at 1600 and 3200 ISO.

The KX looks similar to the A560 at 1600 and 3200 ISO.

The Sony images look consistently less sharp than those from the KX, looks like jpg smoothing to remove some noise but it could be the lens.

From that I'd say that if the difference for the A560 and A33 hold for the A55 and the K-5 the K-5 should be able to reach Kx high ISO levels or even surpass them slightly by about half a stop max at high ISO.

The A55 also has a much, much cleaner blue channel than the K-7 at all ISO settings. Good news for landscape shooters who like b&w.

Now the wait is for Raw shots!

thibs · 08-25-2010, 08:34 AM

Originally posted by Pixel Pusher

Whatever happened to ISO 25, 50, 64, 80?
I'd love to see ISO 25 or 50 available in a future Pentax release.

Nobody's interest, you won't see that IMO (it is a pity I agree).

Or maybe on an extended setting, but you'll get more noise then.

Pixel Pusher · 08-25-2010, 08:43 AM

Originally posted by thibs

Or maybe on an extended setting, but you'll get more noise then.

More noise? Interesting...I would think it would be less.

Agnostic · 08-25-2010, 08:46 AM

Originally posted by Pixel Pusher

Lots people clamoring for higher and higher ISO capabilities, but what about lower ISO?

Whatever happened to ISO 25, 50, 64, 80?

I'd love to see ISO 25 or 50 available in a future Pentax release.

What would be the reason for that? On film the number one reason to shoot low ISO is less grain and better sharpness but does it make for perceptible differences in digital sensors below 100 ISO? The only other reason I can think of is wanting slow shutter speeds in very bright conditions perhaps to have some movement in a shot?
Just curious

Originally posted by Pixel Pusher

More noise? Interesting...I would think it would be less.

I'd say if it is an extended setting it would include some way to limit the amount of light falling on the sensor or some post processing of sensor data which would degrade picture quality....

tomsparks · 08-25-2010, 08:51 AM

I waited, and thought about whether I was going to stick with Pentax or not. I wanted a better camera than the K10d. Specifically, I wanted better iso, better/faster af, higher fs. Video wasn't a big deal for me, but nice to have.

I like the Pentax glass. I decided to buy the K7 knowing it was better than what I had, but still not all that I wanted because I was confident that Pentax would come up with a better camera. Do they have a FF D3s competitor? no, maybe they never will be there, but I make nice photos with the K10d and something like the Canon 7D would fit my needs. I was sure Pentax would get there.

Looks like my thought process was vindicated. I will plan to buy a K5 in December if the rumors pan out. I will keep buying Pentax glass, old and new. The K7 I have is a better camera than I am a photographer. The trick here is to get better than the camera.

My biggest complaint with Pentax is that it is hard to get friends to buy one because they can't go to a store and hold it.

**Aristophanes** · 08-25-2010, 08:53 AM

Originally posted by Pixel Pusher

More noise? Interesting...I would think it would be less.

Shadow noise. The K-x has the most DR at ISO 400. Only in the brightest light do I set it down to 100.

**Digitalis** · 08-25-2010, 09:24 AM

"What would be the reason for that? On film the number one reason to shoot low ISO is less grain and better sharpness but does it make for perceptible differences in digital sensors below 100 ISO? The only other reason I can think of is wanting slow shutter speeds in very bright conditions perhaps to have some movement in a shot?"

ISO values as low as 25,and 50 enable a photographer to use wider apertures for daylight flash work. For instance the 645D has a synch speed of 1/125th. At EV12 an ISO of 25 equals f/2.8 @ 1/125th. Iso 200 -the actual base ISO of the 645D, at the same EV; that figure would become f/8 it makes a surprising amount of difference.

Agnostic · 08-25-2010, 09:29 AM

Originally posted by Digitalis

"What would be the reason for that? On film the number one reason to shoot low ISO is less grain and better sharpness but does it make for perceptible differences in digital sensors below 100 ISO? The only other reason I can think of is wanting slow shutter speeds in very bright conditions perhaps to have some movement in a shot?"

ISO values as low as 25,and 50 enable a photographer to use wider apertures for daylight flash work. For instance the 645D has a synch speed of 1/125th. in broad daylight with an ISO of 25 equals f/2.8 @ EV 12. Iso 200 the actual base ISO of the 645D, that figure would become f/8 - it makes a surprising amount of difference.

I understand. Figures why I didn't think of that. I hate flash

ogl · 08-25-2010, 09:38 AM

The announcement of K-R could be very soon....

Steelski · 08-25-2010, 10:30 AM

Originally posted by Ishpuini

Correction (see my earlier post, and the exchange on DPR): 30% light loss because of the mirror, this corresponds to roughly 1/2Ev (half a stop) less light reaching the sensor. Sorry to repeat this, just trying to avoid wrong information being propagated.

So it's not as dramatic as what you write, but of course the deductions from the resulting images stand.

Wim

How am I wrong, only 70% of the light gets through, if it was 50% it would be half the light. AKA 1 stop. 70% of light getting through is a loss of 3/5ths of a stop, which is larger than 1/2. It is 60% of a stop light fall off.
I am not wrong. Its just a different way of stating it.
I could state that its more than a 50% of a stop light fall off. which would also be right. Roughly 1/2 a stop is also right, although less accurate.

Steelski · 08-25-2010, 10:31 AM

Originally posted by ogl

The announcement of K-R could be very soon....

How soon. and how do you know?

Netsoft · 08-25-2010, 10:38 AM

Originally posted by Steelski

How soon. and how do you know?

OGL has been quite reliable with his rumors. I personally believed he's the unofficial pentax news release

wowtip · 08-25-2010, 10:41 AM

Originally posted by Digitalis

"What would be the reason for that? On film the number one reason to shoot low ISO is less grain and better sharpness but does it make for perceptible differences in digital sensors below 100 ISO? The only other reason I can think of is wanting slow shutter speeds in very bright conditions perhaps to have some movement in a shot?"

ISO values as low as 25,and 50 enable a photographer to use wider apertures for daylight flash work. For instance the 645D has a synch speed of 1/125th. At EV12 an ISO of 25 equals f/2.8 @ 1/125th. Iso 200 -the actual base ISO of the 645D, at the same EV; that figure would become f/8 it makes a surprising amount of difference.

...or to use f1.4 lenses wide open, without flash in sunshine without ND filters, for really thin DOF.

08-25-2010, 09:24 AM	#339
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	"What would be the reason for that? On film the number one reason to shoot low ISO is less grain and better sharpness but does it make for perceptible differences in digital sensors below 100 ISO? The only other reason I can think of is wanting slow shutter speeds in very bright conditions perhaps to have some movement in a shot?" ISO values as low as 25,and 50 enable a photographer to use wider apertures for daylight flash work. For instance the 645D has a synch speed of 1/125th. At EV12 an ISO of 25 equals f/2.8 @ 1/125th. Iso 200 -the actual base ISO of the 645D, at the same EV; that figure would become f/8 it makes a surprising amount of difference. Last edited by Digitalis; 08-25-2010 at 09:29 AM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
More info on new K7	rburgoss	Pentax News and Rumors	30	05-03-2009 01:24 PM
PZ-1 help or info please	woof	Film SLRs and Compact Film Cameras	9	10-25-2008 02:08 PM
any info?	gokenin	Pentax SLR Lens Discussion	5	12-23-2007 05:25 PM
any info?	gokenin	Pentax SLR Lens Discussion	1	12-03-2007 08:37 PM
Help info need	stickman	Site Suggestions and Help	5	03-26-2007 08:17 PM

08-25-2010, 08:14 AM	#331
macTak Veteran Member Join Date: Apr 2010 Photos: Gallery Posts: 759	Originally posted by Ishpuini Correction (see my earlier post, and the exchange on DPR): 30% light loss because of the mirror, this corresponds to roughly 1/2Ev (half a stop) less light reaching the sensor. Sorry to repeat this, just trying to avoid wrong information being propagated. So it's not as dramatic as what you write, but of course the deductions from the resulting images stand. Wim It's amazing how DPR got it wrong, and at any rate (now corrected) buried that information in one spot in the review. I would still think that this would be an important drawback worth mentioning in the negatives at the end, considering how many pixel-peep these days and really do care about a 1/2 stop advantage.

08-25-2010, 08:16 AM	#332
Pixel Pusher New Member Join Date: Aug 2010 Location: Illinois Posts: 19	Lots people clamoring for higher and higher ISO capabilities, but what about lower ISO? Whatever happened to ISO 25, 50, 64, 80? I'd love to see ISO 25 or 50 available in a future Pentax release.

08-25-2010, 08:33 AM	#333
Agnostic Veteran Member Join Date: Mar 2009 Location: Netherlands Photos: Gallery \| Albums Posts: 414	Noise comparison impressions from the images in the imaging resource comparometer: A560 is at least one stop better than the A33 at 1600 and 3200 ISO. A55 is about half a stop or less worse than the A560 at 1600 and 3200 ISO. The KX looks similar to the A560 at 1600 and 3200 ISO. The Sony images look consistently less sharp than those from the KX, looks like jpg smoothing to remove some noise but it could be the lens. From that I'd say that if the difference for the A560 and A33 hold for the A55 and the K-5 the K-5 should be able to reach Kx high ISO levels or even surpass them slightly by about half a stop max at high ISO. The A55 also has a much, much cleaner blue channel than the K-7 at all ISO settings. Good news for landscape shooters who like b&w. Now the wait is for Raw shots!

08-25-2010, 08:34 AM	#334
thibs Pentaxian Join Date: Jun 2007 Location: Belgium Photos: Albums Posts: 7,001	Originally posted by Pixel Pusher Whatever happened to ISO 25, 50, 64, 80? I'd love to see ISO 25 or 50 available in a future Pentax release. Nobody's interest, you won't see that IMO (it is a pity I agree). Or maybe on an extended setting, but you'll get more noise then.

08-25-2010, 08:43 AM	#335
Pixel Pusher New Member Join Date: Aug 2010 Location: Illinois Posts: 19	Originally posted by thibs Or maybe on an extended setting, but you'll get more noise then. More noise? Interesting...I would think it would be less.

08-25-2010, 08:46 AM	#336
Agnostic Veteran Member Join Date: Mar 2009 Location: Netherlands Photos: Gallery \| Albums Posts: 414	Originally posted by Pixel Pusher Lots people clamoring for higher and higher ISO capabilities, but what about lower ISO? Whatever happened to ISO 25, 50, 64, 80? I'd love to see ISO 25 or 50 available in a future Pentax release. What would be the reason for that? On film the number one reason to shoot low ISO is less grain and better sharpness but does it make for perceptible differences in digital sensors below 100 ISO? The only other reason I can think of is wanting slow shutter speeds in very bright conditions perhaps to have some movement in a shot? Just curious Originally posted by Pixel Pusher More noise? Interesting...I would think it would be less. I'd say if it is an extended setting it would include some way to limit the amount of light falling on the sensor or some post processing of sensor data which would degrade picture quality....

08-25-2010, 08:51 AM	#337
tomsparks New Member Join Date: Aug 2008 Location: Murray, Utah Photos: Gallery Posts: 10	I waited, and thought about whether I was going to stick with Pentax or not. I wanted a better camera than the K10d. Specifically, I wanted better iso, better/faster af, higher fs. Video wasn't a big deal for me, but nice to have. I like the Pentax glass. I decided to buy the K7 knowing it was better than what I had, but still not all that I wanted because I was confident that Pentax would come up with a better camera. Do they have a FF D3s competitor? no, maybe they never will be there, but I make nice photos with the K10d and something like the Canon 7D would fit my needs. I was sure Pentax would get there. Looks like my thought process was vindicated. I will plan to buy a K5 in December if the rumors pan out. I will keep buying Pentax glass, old and new. The K7 I have is a better camera than I am a photographer. The trick here is to get better than the camera. My biggest complaint with Pentax is that it is hard to get friends to buy one because they can't go to a store and hold it.

08-25-2010, 08:53 AM	#338
Aristophanes Site Supporter Join Date: Jul 2008 Location: Rankin Inlet, Nunavut Photos: Albums Posts: 3,948	Originally posted by Pixel Pusher More noise? Interesting...I would think it would be less. Shadow noise. The K-x has the most DR at ISO 400. Only in the brightest light do I set it down to 100.

08-25-2010, 09:29 AM	#340
Agnostic Veteran Member Join Date: Mar 2009 Location: Netherlands Photos: Gallery \| Albums Posts: 414	Originally posted by Digitalis "What would be the reason for that? On film the number one reason to shoot low ISO is less grain and better sharpness but does it make for perceptible differences in digital sensors below 100 ISO? The only other reason I can think of is wanting slow shutter speeds in very bright conditions perhaps to have some movement in a shot?" ISO values as low as 25,and 50 enable a photographer to use wider apertures for daylight flash work. For instance the 645D has a synch speed of 1/125th. in broad daylight with an ISO of 25 equals f/2.8 @ EV 12. Iso 200 the actual base ISO of the 645D, that figure would become f/8 - it makes a surprising amount of difference. I understand. Figures why I didn't think of that. I hate flash

08-25-2010, 09:38 AM	#341
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382 Original Poster	The announcement of K-R could be very soon....

Thread Tools	Search this Thread
	Search this Thread: Advanced Search

08-25-2010, 10:30 AM	#342
Steelski Veteran Member Join Date: Jan 2008 Location: Varna Posts: 470	Originally posted by Ishpuini Correction (see my earlier post, and the exchange on DPR): 30% light loss because of the mirror, this corresponds to roughly 1/2Ev (half a stop) less light reaching the sensor. Sorry to repeat this, just trying to avoid wrong information being propagated. So it's not as dramatic as what you write, but of course the deductions from the resulting images stand. Wim How am I wrong, only 70% of the light gets through, if it was 50% it would be half the light. AKA 1 stop. 70% of light getting through is a loss of 3/5ths of a stop, which is larger than 1/2. It is 60% of a stop light fall off. I am not wrong. Its just a different way of stating it. I could state that its more than a 50% of a stop light fall off. which would also be right. Roughly 1/2 a stop is also right, although less accurate.

08-25-2010, 10:31 AM	#343
Steelski Veteran Member Join Date: Jan 2008 Location: Varna Posts: 470	Originally posted by ogl The announcement of K-R could be very soon.... How soon. and how do you know?

08-25-2010, 10:38 AM	#344
Netsoft Forum Member Join Date: Oct 2008 Location: Malaysia Posts: 58	Originally posted by Steelski How soon. and how do you know? OGL has been quite reliable with his rumors. I personally believed he's the unofficial pentax news release

08-25-2010, 10:41 AM	#345
wowtip Senior Member Join Date: Nov 2006 Location: West coast Photos: Gallery Posts: 261	Originally posted by Digitalis "What would be the reason for that? On film the number one reason to shoot low ISO is less grain and better sharpness but does it make for perceptible differences in digital sensors below 100 ISO? The only other reason I can think of is wanting slow shutter speeds in very bright conditions perhaps to have some movement in a shot?" ISO values as low as 25,and 50 enable a photographer to use wider apertures for daylight flash work. For instance the 645D has a synch speed of 1/125th. At EV12 an ISO of 25 equals f/2.8 @ 1/125th. Iso 200 -the actual base ISO of the 645D, at the same EV; that figure would become f/8 it makes a surprising amount of difference. ...or to use f1.4 lenses wide open, without flash in sunshine without ND filters, for really thin DOF.