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07-16-2011, 03:00 AM   #16
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QuoteOriginally posted by luftfluss Quote
I think you are allowing the K-5's reputation influence your thinking... the dynamic range in this shot is pedestrian. It would have been greater had he shot at ISO 200. It probably doesn't need more than 8 or 9 EV, anyway.
Probably so although i do not measure it, but despite an equilibratd exposure, the whites on background small houses are not "grilled", i am not sure the result would have been the same with K20D, even if better exposure algorythm is the main reason for it.

QuoteOriginally posted by jstevewhite Quote
Unless you're using a 600mm lens!
Well, in that case the tripod is whatever speedshutter a necessary help for my too weak arm-muscles !!!

I also agree with te better sharpness that would have occur with lower ISOs, in this respect the comparison with K20D is stunning.


Last edited by Zygonyx; 07-16-2011 at 03:05 AM.
07-16-2011, 07:32 AM   #17
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QuoteOriginally posted by jstevewhite Quote
The rule of thumb being 1/fl for acceptably sharp images, ...
That's a rule of thumb for the 135 (35mm or "FF") format.

For APS-C the rule is 1/(1.5*fl). APS-C sized sensors require a larger magnification factor to achieve the same output size and the former makes it easier to see fuzziness in the source.

The rule should be regarded as providing a lower limit, not a guarantee for blur free images.
07-16-2011, 07:53 AM   #18
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QuoteOriginally posted by Class A Quote
That's a rule of thumb for the 135 (35mm or "FF") format.

For APS-C the rule is 1/(1.5*fl). APS-C sized sensors require a larger magnification factor to achieve the same output size and the former makes it easier to see fuzziness in the source.

The rule should be regarded as providing a lower limit, not a guarantee for blur free images.
That, of course, would depend on final magnification. No guarantees of sharp images, period - you can get motion blur with a 100mm macro at 1/500 sec if your magnification is high enough. Still, 1/FL works well enough on APS-c, also, and I can frequently go beyond that point and get sharp images. That's why it's a guideline, not a boundary.
07-16-2011, 09:00 AM   #19
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I think that the picture would be better with 1/250th and iso1600.

07-16-2011, 09:34 AM   #20
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I do believe you about the K-5 even though I own a K20D. Having that much DR and ISO is game changing and would open up many opportunities. That being said...

Here is a Sears (Ricoh) 50mm f/1.7 and K10D hand held. I don't know the aperture as the lens does not report it. Its a fully manual lens. I have to focus it and set EV level. However the pic is using SR and handheld. This is with the K10D or really Samsung GX10. That sensor had really good pixel sharpness. Moreover the jpeg engine in the Samsung was for 100% sure different than the Pentax SilkyPix engine. Even the supplied RAW converter for the GX10 is not Silkypix.

Here is the front of a church hand-held...

Here is a 100% crop. The detail is pretty darn good for a lens I paid $13 for. The reason 100% detail is good is partly the lens. This is only 10mp versus the K20D 14,6 or K-5 16.3mp. But it still shows good detail why? Its ISO 100!

If you really look at your example you can see that small details have been smoothed over by the K-5 noise reduction. Its great noise reduction because a casual glance would not notice. But think about how much more detail should be in the cement of the Bridge in the crop. Or how much detail is missing in the crop.

This is why really one would ask for a static scene why not use a lower ISO. Even the mighty K-5 will smooth detail at high ISO. Just at normal viewing size you don't see it. Believe me its superb and I would benefit from it. But just speaking of this scene... Very nice picture.



07-16-2011, 11:20 AM   #21
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QuoteOriginally posted by jamesm007 Quote
Here is a 100% crop. The detail is pretty darn good for a lens I paid $13 for. The reason 100% detail is good is partly the lens. This is only 10mp versus the K20D 14,6 or K-5 16.3mp. But it still shows good detail why? Its ISO 100!
Remember 100% on a K10 is considerably lower magnification than 100% on a K-5. Scale that 4828x3264 image down to 3872x2592 and you'll see a much closer comparison. Or scale that K10D image by 127%.

NR is not applied in raw format - or at least no formal NR. I don't remember whether the OP shot raw or jpg. If you shoot iso 3200 raw, you'll see a loss of detail due to noise, but not noise reduction.
07-16-2011, 01:47 PM   #22
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The K-5 applies noise reduction in the PRIME engine at ISO1600 and up. There is also NR used in Sonys sensor at all ISOs. This is a good thing. The K20D also has NR applied.
07-16-2011, 01:50 PM   #23
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QuoteOriginally posted by jamesm007 Quote
I do believe you about the K-5 even though I own a K20D. Having that much DR and ISO is game changing and would open up many opportunities. That being said...

Here is a Sears (Ricoh) 50mm f/1.7 and K10D hand held. I don't know the aperture as the lens does not report it. Its a fully manual lens. I have to focus it and set EV level. However the pic is using SR and handheld. This is with the K10D or really Samsung GX10. That sensor had really good pixel sharpness. Moreover the jpeg engine in the Samsung was for 100% sure different than the Pentax SilkyPix engine. Even the supplied RAW converter for the GX10 is not Silkypix.

Here is the front of a church hand-held...

Here is a 100% crop. The detail is pretty darn good for a lens I paid $13 for. The reason 100% detail is good is partly the lens. This is only 10mp versus the K20D 14,6 or K-5 16.3mp. But it still shows good detail why? Its ISO 100!

If you really look at your example you can see that small details have been smoothed over by the K-5 noise reduction. Its great noise reduction because a casual glance would not notice. But think about how much more detail should be in the cement of the Bridge in the crop. Or how much detail is missing in the crop.

This is why really one would ask for a static scene why not use a lower ISO. Even the mighty K-5 will smooth detail at high ISO. Just at normal viewing size you don't see it. Believe me its superb and I would benefit from it. But just speaking of this scene... Very nice picture.


James, you've got a valid point and its well supported by your images.

I would point out that you were shooting on a well lit day at 100 iso. I was shooting on a cloudy day at 8PM with wind. 100 ISO was not available to me, even if it has much better DR.

3200 ISO was picked by Pentax's TAv mode, but there was nothing stopping me from usiing -1ev or some other exposure mode. Ron's 1600iso was well within reach. Point taken. K5 allows noise removal to be completely turned off, and it was. But there is noise in the final image.

Thanks for the discussion!

07-18-2011, 09:42 PM   #24
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QuoteOriginally posted by philbaum Quote
Thank you for all the comments - i appreciate the suggestions (even if i'm beginning to think there is a vague similarity between those that shoot photos and those that fish)

I went back and looked at another photo taken from the same position and time, and the bridge was not as sharp. In fact the lower right brush was heavily blurred because of gusty wind effects. That photo was done with 1/125s and iso 560. So I probably could have done better than iso 3200, even without going to iso 560, i'll give you all that . But even with my inexperience, it was an aha moment. (I think its good to talk about stuff like this because thats how i learn)

(And there are no blown areas, my laziness in not pulling out more.)
I'm with you---I've gotten a lot of flak about it, but I think that often running the ISO up to 3200 and taking a noise hit to get a faster shutter / smaller aperture is a worthwhile trade off with the K5. With previous models this was out of the question, but to my taste and to the sizes I generally use----I don't hesitate to go there. Indeed my Auto ISO range goes to 3200, ---whichI usually let fly first.
then if I have time, and the subject looks interesting, I'll crank the ISO down
a few stops and do a retake.

If you will 'bracket' the ISO settings for a while on significant photos and then study the results You can hone in your own opinions as to how high is too high
on the ISO.
07-18-2011, 10:38 PM   #25
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QuoteOriginally posted by jstevewhite Quote
That, of course, would depend on final magnification.
Of course. And on viewing distance, etc.

DOF calculators and rules of thumb like the "1/f" rule make certain assumptions about magnification, viewing distance, etc. With these assumptions in place, the "1/f" rule has to be adapted to "1/(1.5*f)" for APS-C. This is more than half a stop of a difference so it shouldn't be neglected.
07-18-2011, 11:10 PM   #26
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QuoteOriginally posted by Class A Quote
Of course. And on viewing distance, etc.

DOF calculators and rules of thumb like the "1/f" rule make certain assumptions about magnification, viewing distance, etc. With these assumptions in place, the "1/f" rule has to be adapted to "1/(1.5*f)" for APS-C. This is more than half a stop of a difference so it shouldn't be neglected.
I understand why you say that. However, the 1/fl rule predates its use in 35mm photography - goes all the way back to early 4x5 Speed Graphics at least (it was mentioned in the manual of my first 4x5, ca 1945), and THEY said 1/fl. People who shot medium format used the 1/fl rule with impunity, as well. People used the same rule with half-frame 35mm cameras.

I think it's a generically useful number because of many factors. Also, like so many things, it depends on which direction you work from; depends on your context. E.G., a ~30-35mm lens is "normal" for APS-c. A ~45-50mm lens is "normal" for 135 cameras. The motion blur produced by a 35mm lens at 1/35 on APS-c is roughly equivalent to the motion blur produced by a 50mm lens on 135 (given the same camera motion and same print size). So, it could be said, if we look at 1/fl like everyone does everything else, that is, based on FOV, then the 1/fl rule is still essentially correct.
07-19-2011, 02:56 AM - 1 Like   #27
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Nice photo, Phil. The high iso capability of the K5 is really impressive.

I know everyone seems to focus on the fact that you can avoid camera shake with a shutter speed of 1/FL, but there are other reasons to bump your shutter speed, in particular to freeze motion.

As far as handholding ability, SR does help two to three stops, but as the number of megapixels in a camera goes up, the ability to hand hold it and get pixel level sharpness becomes increasingly more difficult. I feel like the rule of thumb that you use really depends (a) on the individual (how shaky are you really?), (b) on the pixel density of your camera and (c) on how much you pixel peep. Those who don't pixel peep are bound to be satisfied more than the rest of us.
07-19-2011, 07:40 AM   #28
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QuoteOriginally posted by Rondec Quote
Nice photo, Phil. The high iso capability of the K5 is really impressive.

I know everyone seems to focus on the fact that you can avoid camera shake with a shutter speed of 1/FL, but there are other reasons to bump your shutter speed, in particular to freeze motion.

As far as handholding ability, SR does help two to three stops, but as the number of megapixels in a camera goes up, the ability to hand hold it and get pixel level sharpness becomes increasingly more difficult. I feel like the rule of thumb that you use really depends (a) on the individual (how shaky are you really?), (b) on the pixel density of your camera and (c) on how much you pixel peep. Those who don't pixel peep are bound to be satisfied more than the rest of us.
Great points, Rondec. And before people started talking about "crop factors", the advice was *always*: Many factors can affect the slowest speed you can hand-hold your camera. The weight of the camera, your personal strength, whether you had coffee or not, your heart rate, your breathing rate. So start with technique: feet shoulder width, elbows in. Take two slow, deep breaths, and on the exhale of the second, stop halfway, then squeeze the shutter button slowly. Start at 1/fl and see if you get sharp images this way. If not, adjust speed upward; if so, adjust it downward. You'll find your own minimum shutter speed.

Then we discover that what appears sharp depends on final magnification, viewing distance, and the visual acuity of the viewer. Did I say that sharpness (and by extension, DOF and motion blur) are 'fuzzy concepts'?
07-19-2011, 12:40 PM   #29
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QuoteOriginally posted by rvannatta Quote
I'm with you---I've gotten a lot of flak about it, but I think that often running the ISO up to 3200 and taking a noise hit to get a faster shutter / smaller aperture is a worthwhile trade off with the K5. With previous models this was out of the question, but to my taste and to the sizes I generally use----I don't hesitate to go there. Indeed my Auto ISO range goes to 3200, ---whichI usually let fly first.
then if I have time, and the subject looks interesting, I'll crank the ISO down
a few stops and do a retake.

If you will 'bracket' the ISO settings for a while on significant photos and then study the results You can hone in your own opinions as to how high is too high
on the ISO.
QuoteOriginally posted by Rondec Quote
Nice photo, Phil. The high iso capability of the K5 is really impressive.

I know everyone seems to focus on the fact that you can avoid camera shake with a shutter speed of 1/FL, but there are other reasons to bump your shutter speed, in particular to freeze motion.

As far as handholding ability, SR does help two to three stops, but as the number of megapixels in a camera goes up, the ability to hand hold it and get pixel level sharpness becomes increasingly more difficult. I feel like the rule of thumb that you use really depends (a) on the individual (how shaky are you really?), (b) on the pixel density of your camera and (c) on how much you pixel peep. Those who don't pixel peep are bound to be satisfied more than the rest of us.
I get pulled in two different directions. I do volunteer work for a live theatre organization, and they're grateful for anything they get. Some of the pics we send to papers for publicity, and others we hang in the lobby for decoration. They were previously used to blurry pics, often necessitated by dark scenes and they don't allow flash. The most important thing is coming back with something. So High Iso is there to be burned and used, 12,800 is my limit for theatre work.

Then on the other hand, i like to submit photos to a juried statewide gallery once a year and also try to sell a few in local venues. Those i try to get as fine as i can make them. Tripods, low iso and all that.

So i agree heartily with all your comments, and would add that the picture is the priority, not sharpness. Last evening i was setting up a tripod shot on a trail to an ocean beach. A guy carefully walked by me on his way to the beach. I anticipated this might be a good image, so shot before i was fully dialed in just to get the image of this man standing at the top of the trail staring down at the beach. Quite a nice picture but not perfect. Some pictures are not about pixels
10-15-2011, 09:06 AM   #30
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I was used to the miracles of SR, but recently I got the 50-135 and the results are mazing with the k5. You can't be happier as a photographer because these were things you simply couldn't do before.



This was shot handheld with my elbows on a rail at 135mm f2.8 1/30 ISO3200. At 100% you can't tell any movement blur over the iso normal noise and may be some amazingly low loss of contrast for f/2.8 with such a concentrated light source. I could get 1 out of 3 like this. It's really hard to compare with a few years back, because at first seems effortless, but the difference in the game is abysmal.
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