[gazonk]

I notice a kind of purple halo and a lower contrast on the K-5 shot. Lens or focusing differences?

Some people also noted that the K-5 exhibit more purple fringing than the K-7/K20D. Could it be related to the AA filter as well?

Well, as I've pointed out in several places several times today: Those IR shots are obviously back-focussed to me! Not only is the clothing behind the bottles slightly sharper than the bottles, but the purple fringing in several places (see e.g. the highlights on the metal part of the salt jar) is most probably due to longitudinal CA.

And here's proof that objects in front of focus show exactly this kind of CA with the Sigma 70mm, a sample image from Photozone's test of the Sigma 70, shot with a Canon 350D:
http://www.pzimages.com/8Reviews/lenses/sigma_70_28_canon/samples/IMG_2481-01.jpg

[janneman]

Canon 60d wins

Nope... Does not.
Two reasons:
- the edges between black and white on the B amd A seem a bit halo like and maybe artefacty like... (that said, I am quite sure you won't be able to notice that in real life, like on prints or on screen. Well maybe on a A2 sized print but you have to touch the print with your nose and that is not the intention of A2 sized prints....)
- the reflection on the gold and metallic red near the bottom just looks "flat"compared to the D7000 and the K-5.

But on the whole I say there is not much difference among all camera's shown and for real life purposes (print, screen, NOT pixelpeeps) I think 60D, D7000 and K-5 equally prove that whoever was criticizing APS-C IQ performance has been proven wrong. If you prefer the handling of a Canon, go for the 60D, if you are a Nikon lover , go for the Nikon and if you are like me, and like it dirty, go Pentax.
I bet in the end the users will be equally happy....

[Vaikis_]

maybe we have soft images from SR ? telfish try on tripod with MUP enabled (mirror locked up) SR OFF.

[telfish]

Also, I can't say for certain, but your own sample seems to have the same(sort of) softness to it as wel

In these bottle label test shots often the apparent softness at 100% is due to the poor quality of the printing.

I just did a print and shot a standard resolution test. here is the downsized image and a some 100% crops.

Not trying to make excuses for the K5. In real world use its a fine camera. Overall somewhat better than my old K7, but to expect a major difference in IQ apart from the improved DR is not realistic.

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Last edited by telfish; 01-30-2011 at 10:17 AM.

[kittykat46]

.....
Would you happen to have a K-7 that you could test it against?
In the Imaging Resource samples, I've found the K-7 to render sharper edge contrast(pixel per pixel) than the K-5 ones. Not saying that this is a definite case, but it could be an indicator as to whether or not a discrepancy truly exists.

For months, even up to today, there are outspoken commentators who have been saying the K-7 (yes!) was pretty much incapable (yes !) of producing sharp photos, all due to the dreaded "shutter blur" urban legend.....

I personally never had any complaint with the K-7 , and I have not seen anything to complaint with the K-5 either...

Its true that I don't pay much attention to these endless Comparator shots.

My 2 days workout with the K-5 and Pentax DA Limited lenses have been nothing short of magical...
The K-5 + good Pentax glass = no sharpness problem to me...

[gazonk]

And they're far from soft! Looks absolutely breathtakingly fabulous to me, e.g.
Digital Cameras, Pentax K-5 Digital Camera Test Image

And it wasn't difficult to find an area with more details than in the D7000 version of the same image (K-5 is left, of course):

[falconeye]

That's just very strange. Is this consistent with any other K-5 pictures at all?

JohnBee fooled me
He posted 200% crops w/o saying so. I now corrected my post and the sharpened result looks a bit better.

I noticed the colorful lines as well, but the K5 still have the false pixels in between the lines which also is a sure sign of a weak AA-filter. So I'm thinking they have done some color noise reduction even on base iso.

I don't think color noise reduction is at work. False line demosaicing is normal near the Nyquist limit and the AA filter is meant to get rid of color Moiré because it can remain visible even at low magnification (for a texture large enough).

Well, okay, these are 200% crops for some reason. Both the K-5 and D7000. The extra "pixels within pixels" are just JPEG artifacts. Nevermind.

yeah ...

Falk, perhaps it would be better if you worked with the originals?

I fixed it anyway. Maybe next time, you leave a notive when posting 200% crops

However, since the results seem consistent with other testing sites also, I think it gives use good cause for investigation.

I am sorry to say but this isn't the way to proceed.

The only way to approach the topic is by doing controlled lab tests allowing to vary each parameter independently from other parameters. In my "lumolabs" Understanding Image Sharpness white paper I explained the procedure.

Failing to do so will allow to spread about every possible meme. Not a good thing.

That's the last thing I seriously say about K-5 image sharpness before I had a chance to really examine image sharpness and parameters influencing it. Currently, I don't have much time to do that but I plan to look at it.


Anyway, there is little reason to believe that differences in perceived sharpness are due to anything else than the quality of lens, tripod, focus and tester. Even if AA filters differ, an AA filter can be both, too strong or too weak. Some 645D shooters already noticed the caveats of the missing AA filter.

[JohnBee]

For months, even up to today, there are outspoken commentators who have been saying the K-7 (yes!) was pretty much incapable (yes !) of producing sharp photos, all due to the dreaded "shutter blur" urban legend.....

I personally never had any complaint with the K-7 , and I have not seen anything to complaint with the K-5 either...

Its true that I don't pay much attention to these endless Comparator shots.

My 2 days workout with the K-5 and Pentax DA Limited lenses have been nothing short of magical...no sharpness problem to me...

I agree...

But since the IR samples seem to show the K-7 producing better images than the K-5(in their respective samples), I thought it would be a great way to test the theory.

TBH. I never cared much about the K-7 critics. Though it did seem to have an effect on the overall appreciation for the camera. Either way, if we can find a willing K-7/K-5 owner, I think we could get to the bottom of the issue quite quickly.

[Parallax]

..................

In my opinion, to have professional test you should make special lens with interchangeable mount for all type of body.
Only that type of test will be real comparable tests for me.

Best regards and go make photos

You're exactly right. Even if using two identical model lenses it isn't a valid test. No two lenses will render a image exactly the same.

[JohnBee]

I am sorry to say but this isn't the way to proceed.

The only way to approach the topic is by doing controlled lab tests allowing to vary each parameter independently from other parameters. In my "lumolabs" Understanding Image Sharpness white paper I explained the procedure.

Failing to do so will allow to spread about every possible meme. Not a good thing.

Well aside from lumolabs, this is how I see it:

• If a group conducts testing with the K-5 and the results are soft then we can dismiss it as a 'insert whatever here'.
• If a second group conducts a test and the results come-up soft, then we have cause for suspicion.
• If a third group(and their is one btw) conducts tests and the results are soft... then we have valid reason to investigate.

So from where I stand, there is good cause to investigate the possibility of a discrepancy with the K-5.
Which isn't to say that this is empirical or a certainty. But it certainly isn't the time to be making excuses either.

So until lumolabs conducts controlled testing between the K-5 and competitors, I guess we are stuck with what we have at our disposition.
To which I say, lets make the best of it to try and uncover what's going on with the existing samples.

[dankoBanana]

this is why I'm glad I'm not an early adopter... I'll wait and see

p.s. cant wait for the lumolabs report on the K5

[falconeye]

Falk - do you plan to do a formal test of k-5? If so, when?

Yes, but I may not be able to do before Xmas. I'll see what I can do before.

I just did a print and shot a standard resolution test. here is the downsized image and a some 100% crops.

The standard chart only goes up to 2000 LW/PH which isn't enough today.

Either shoot at twice the distance (so, it only fills 50% of the frame) or find a version going up to 4000 LW/PH (IR) or 8000 LW/PH (lumolabs).


Anyway, a better way to compare resolutions side by side is my chart I published here:
http://falklumo.smugmug.com/Photography/Technology/Test-Charts/9940691_G6Zcp...958_Yh2Gc-A-LB

Unlike the slanted edge method, it won't produce figures. But it allows many conclusions to be drawn. Print out on A4 B&W laser, shoot from a distance and do a manual focus series, varying focus marginally from the position found in LV manual focussing. Then compare the sharpest sample, K-5 vs. K-7. The top of a heavy table may be better than a tripod. Use raw and identical raw conversion parameters.

[cbaytan]

Look here: https://www.pentaxforums.com/forums/pentax-k-5-forum/123082-pentax-k-5-images...ml#post1271131

Thanks, I had those before, I meant his own shot.

[Zubati Kit]

John, not sure if you have time but could you compare just K-5 files with several different RAW converters, just to see if there are any issues there, as there may well be.

[i83N]

I'm sorry if i misted it, but what's the cure against the soft image?