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08-25-2010, 08:14 AM   #331
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QuoteOriginally posted by Ishpuini Quote
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
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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
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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
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QuoteOriginally posted by Pixel Pusher Quote
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
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QuoteOriginally posted by thibs Quote
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
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QuoteOriginally posted by Pixel Pusher Quote
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

QuoteOriginally posted by Pixel Pusher Quote
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
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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
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QuoteOriginally posted by Pixel Pusher Quote
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, 09:24 AM   #339
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"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.
08-25-2010, 09:29 AM   #340
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QuoteOriginally posted by Digitalis Quote
"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
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The announcement of K-R could be very soon....
08-25-2010, 10:30 AM   #342
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QuoteOriginally posted by Ishpuini Quote
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
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QuoteOriginally posted by ogl Quote
The announcement of K-R could be very soon....
How soon. and how do you know?
08-25-2010, 10:38 AM   #344
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QuoteOriginally posted by Steelski Quote
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
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QuoteOriginally posted by Digitalis Quote
"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.
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