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05-03-2011, 11:07 PM   #151
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Pentax K-5 and the fine Pentax DA 35/2.8 Macro Ltd.



LG
.........

05-08-2011, 03:22 PM   #152
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Last edited by Couscousdelight; 05-28-2011 at 10:48 AM.
05-08-2011, 09:13 PM   #153
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Extreme lighting contrasts. Pentax K-5, with Pentax 43mm F/1.9 Limited lens, ISO 800, 1/2500th sec, F/5, autofocus, AE program. Detail is 100% crop.




Last edited by Skymist; 05-08-2011 at 09:27 PM.
05-08-2011, 09:36 PM   #154
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QuoteOriginally posted by Skymist Quote
Extreme lighting contrasts. Pentax K-5, with Pentax 43mm F/1.9 Limited lens, ISO 800, 1/2500th sec, F/5, autofocus, AE program. Detail is 100% crop.


Soft, I tell ya! Soft, soft, soft...

j/k.

I was shooting with the FA 35mm f2 and noticed that some of the 100% crops were indistinguishable from other images (of the same flowers) downsized.

I think part of the perceptual problem here is that the k-5 has higher dynamic range *and* higher resolution than its predecessors, but is still being DISPLAYED on monitors with the same old dynamic range and dot pitch. If you compress 9-11 stops (think K20D) into 8.5 stops (think most monitors), you don't see a GREAT deal of difference, but if you compress 13-15 stops (K-5) into those same ~8.5, you'll see (I think) a *significant* reduction in contrast *just to display the range of information available*. Since the human visual system interprets local contrast as sharpness, the K-5 might "look" less sharp to some people.

That's my guess, anyway.

05-09-2011, 10:50 AM   #155
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I was thinking something similar myself, even based on many of the shots shown within this very thread thread. I've seen some great examples of very sharp images here, making clear that the K-5 sensor is perfectly capable of resolving the fine detail produced by Limited, *, and other high-quality lenses at the per-pixel level.

But there are also a few images in this thread that are not very sharp at all, if you look at them closely. What they do tend to have, however, is high edge contrast. This comes as no surprise - enhancing edge contrast is the very trick unsharp mask filters use to increase the illusion of sharpness.

So if it is simply dynamic range/gamut compression at work causing the appearance of softness on the screen, how can we get around it?

Got 2500 bucks?

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QuoteOriginally posted by jstevewhite Quote
Soft, I tell ya! Soft, soft, soft...

j/k.

I was shooting with the FA 35mm f2 and noticed that some of the 100% crops were indistinguishable from other images (of the same flowers) downsized.

I think part of the perceptual problem here is that the k-5 has higher dynamic range *and* higher resolution than its predecessors, but is still being DISPLAYED on monitors with the same old dynamic range and dot pitch. If you compress 9-11 stops (think K20D) into 8.5 stops (think most monitors), you don't see a GREAT deal of difference, but if you compress 13-15 stops (K-5) into those same ~8.5, you'll see (I think) a *significant* reduction in contrast *just to display the range of information available*. Since the human visual system interprets local contrast as sharpness, the K-5 might "look" less sharp to some people.

That's my guess, anyway.
05-09-2011, 12:21 PM   #156
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QuoteOriginally posted by Skymist Quote
This time I paired my Tamron 70-300 with a Tokina 2X Teleconvertor
That is an amazing result, given that you've paired about the cheapest consumer telezoom out there (which I also own, btw) at it's softest point (300mm) with a 2X teleconvertor! I am very, very impressed.
05-09-2011, 01:30 PM   #157
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QuoteOriginally posted by dcshooter Quote
I was thinking something similar myself, even based on many of the shots shown within this very thread thread. I've seen some great examples of very sharp images here, making clear that the K-5 sensor is perfectly capable of resolving the fine detail produced by Limited, *, and other high-quality lenses at the per-pixel level.

But there are also a few images in this thread that are not very sharp at all, if you look at them closely. What they do tend to have, however, is high edge contrast. This comes as no surprise - enhancing edge contrast is the very trick unsharp mask filters use to increase the illusion of sharpness.

So if it is simply dynamic range/gamut compression at work causing the appearance of softness on the screen, how can we get around it?

Got 2500 bucks?

PA301W-BK, 30 Widescreen Professional Graphics Desktop Monitor
That monitor only gets you 9 stops, and my "cheap" ($799) 24" Cinema Display does 8.4, and the 27" Cinema Display ($999) does 9 stops (1000:1) also. I love the NEC displays, mind you, and when I was using PCs, I always bought NEC.

We've always had the dilemma of squeezing the dynamic range of transilluminated objects like negatives and slides into the dynamic range of reflective media ( 100:1 "or so"). You just have to decide where you want the contrast to be, and put it there - that's what the zone system was all about.
05-09-2011, 04:20 PM   #158
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QuoteOriginally posted by rawr Quote
That is an amazing result, given that you've paired about the cheapest consumer telezoom out there (which I also own, btw) at it's softest point (300mm) with a 2X teleconvertor! I am very, very impressed.
I was amazed too! Thanks. That was my 3rd visit to the lavender, and note that I needed to use ISO 6400, manual focus, and high speed burst shooting to get those results, after discarding 80-90% of the shots. However, I tried the same lens combination on the Moon (in non-macro mode of course), to see if I could get equivalent detail. Results were disappointing. Obviously this lens is much better close up than at infinity. Even at 10 feet, the results are pretty fine. But infinity just is awful, for some reason. The combo is just no good for astrophotography. When I get a chance I'll mess around with the Tamron without the 2X and see if that's better.

Pentax K-5 plus Tamron AF 70-300mm f/4-5.6 LD Di macro plus Tokina 2X teleconvertor, 600mm total, F/9, 1/15th, tripod, manual focus, manual exposure, dark frame subtraction = off, shake reduction = off. Minimal processing.






Last edited by Skymist; 05-09-2011 at 04:31 PM.
05-10-2011, 06:24 AM   #159
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For photos of the moon, you might try stacking software. It won't make up for the shortcomings of a lens, but if you can get decent sharpness at shorter focal length, and you stack about 10 images, you can maximize detail and minimize noise.
05-27-2011, 12:21 PM   #160
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Well, this photo pretty much speaks for itself. This is a strict test of resolution using a faint star trail, magnified 1600% (16 pixels per pixel) and then the half-maximums found and connected. The resulting two lines are separated by the effective FWHM resolution in pixels. The actual resolving power will be somewhat better than the strict resolution depending on the orientation of the image edges relative to the pixel grid. Anyway, if the K-5 were "soft" we wouldn't be able to get a result like this - it would be at least 3-4 pixels instead of 1.9. The test shows that the "staircase effect" (quantization artifact) is pronounced for features which are this sharp, but the pixels do not break into singletons as with some cameras - they form a distinct line. For astrophotography one would like to have many more pixels when using a lens this sharp - if the K-5 were about 64 megapixels the noise would be very fine grain and the artifacts would be less significant. But the users would then probably complain that the image is "soft" because the sensor out-resolves all their lenses. But the point is, a good lens focused right without movement-blur will make as sharp an image with the K-5 as any camera out there.

05-27-2011, 01:20 PM   #161
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I got bored and did not read every post in this thread. I do believe that some people are confusing contrast and sharpness. I have owned the *istD, K10, K20, K-7 and K-5 and the K-5 definitely records much better fine detail and sharpness than the others. However, it also has a broader dynamic range and therefore less contrast. If you want to have the same picture look the same from the K-5 and any other Pentax you are going to have to increase the contrast on the K-5 image in addition to adding the same amount of sharpness.
05-27-2011, 01:52 PM   #162
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Well, this is probably as much the lens (DA*200) as the camera (K5), but still pretty amazing to me. I was about 50-75 yards away from this guy fishing and took this shot. This is the full shot:



As I was processing it in Lightroom, I noticed that you could actually make out the mono filament fishing line in the picture. Here's a 100% crop:

05-27-2011, 09:44 PM   #163
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QuoteOriginally posted by rfortson Quote
As I was processing it in Lightroom, I noticed that you could actually make out the mono filament fishing line in the picture. Here's a 100% crop:
Amazing!
05-30-2011, 05:27 PM   #164
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Yes, it's sharp

Here's my contribution. This was shot today with a Sigma 70-300 DG Macro. A fairly cheap lens. But the sharpness is evident. 100% crop, RAW image converted to JPEG with no modifications or sharpening.
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