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01-07-2013, 05:26 PM   #31
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QuoteOriginally posted by falconeye Quote
Rings a bell. If it isn't due to too small an aperture, then you may have a focus issue. Did you already AF finetune your lenses?
Repeatedly, and thankfully the two pentax lenses I do a majority of my work with FA77 f/1.8 and FA31mm f/1.8 ASPH Limited lenses required no adjustments. though my DA15mm f/4 ASPH Limited - which focuses past infinity, and does not have a remotely flat focus plane was troublesome. My sigma 180mm f/3.5 APO EX DG has been rather problematic in terms of focus accuracy - but since It is a macro and I use it with manual focus it isn't a deal breaker. The AF confirmation I get when using the Pentax 50mm f/1.2 is more reliable on the K5IIs even at f/1.2

01-07-2013, 05:33 PM   #32
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QuoteOriginally posted by bkpix Quote
But shooting a camera with an AA filter assumes you're going to do some sharpening to put the image back together, so it seems odd to me to compare one without sharpening at all.
Correct.

With respect to which approach deserves to be called "fair" or "correct": I do not believe that whether to use the same amount of sharpening (including none) on both images, compared to different amounts of sharpening, is difficult to answer.

From a pragmatic viewpoint, a photographer is after the best image possible. Ergo, one should try to take whatever comes out of the camera to its best possible looking conclusion. Whether this takes different steps for different cameras or not is rather immaterial.

Assume one camera automatically truncates black levels below a certain threshold (some cameras do that, even for RAW files). Would you compare the output of such a camera with the same "black level" processing parameter as you are using for a camera that does not truncate black levels? It is clear to me that you shouldn't as the difference would be accidental but nevertheless prevent one camera's images from looking as good as they could.

Clearly there is a point after which images start to look bad when they are over-sharpened. This point is reached earlier with a K-5 IIs compared to a K-5. It therefore is not the case that whatever headstart the K-5IIs has in terms of micro-contrast, it will continue to keep as sharpening levels are increased in a synchronised processing approach.

Not using any capture-sharpening for a camera with a Bayer-AA-filter in a comparison to a filter-less camera can only be justified by stating either that a) "I don't want to process at all", or b) "I want to see which is the better camera under conditions I arbitrarily specify". Not using any capture-sharpening cannot be justified when the goal is to see which camera produces the best possible image (which implies that the best possible processing is used, which of course will be different).

As Falk wrote, it may still be the case the K-5IIs comes out ahead of a comparison that allows all cameras to show their full potential. I'd of course be happy with that. What I'm not happy with are comparisons that proclaim a "night & day" difference based on artificially limiting the potential of both cameras. Of course, the camera with a Bayer-AA-Filter is much further away from showing its full potential than the filterless one is. That's why such comparisons are not fair.

QuoteOriginally posted by Digitalis Quote
However, that does not excuse the moron who designed the 100-300mm f/4 APO EX DG - and not including a focus limiter: BAD design!.
I feel bad for you that you have to put up with a lens that was designed by a moron. I'd be more than happy to put you out of your misery by buying your Simga 100-300/4.

Seriously, though, please show more respect for the people who designed this great lens (which I'd love to own, so if you want to sell, let me know). How many non-macro lenses have a focus limiter? Wouldn't it be better if you could tell the camera which focus range you'd like to operate in for a particular shot? Wouldn't that be a lot more useful than a fixed focus limitation on a lens? Does the fact that the K-5 does not feature such a dynamic focus limitation make the K-5 designers morons?
01-07-2013, 06:37 PM   #33
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well here are the sharpened studio images, Just by looking at the date window on the watch makes it clear which camera is pulling in the most detail - though I have to say the K10D does very well under studio conditions.

100% crops from left to right: - K10D - K-7 - K-5IIs

Each image Images processed in Lightroom 4 with default output sharpening, all images received additional sharpening in Photoshop CS5 - USM Amount=190 Radius 0.8px Threshold=0
Increasing sharpening beyond this point would have been unfavourable to the K7, all of these images were shot under studio lighting conditions at 1/180th f/11 ISO100

Last edited by Digitalis; 01-07-2013 at 09:01 PM.
01-07-2013, 07:06 PM   #34
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QuoteOriginally posted by Class A Quote
Seriously, though, please show more respect for the people who designed this great lens
I have great respect for the people who designed the optics of this lens - it is a excellent performer - However the person who designed the lens barrel and focus clutch mechanism without thinking to include a focus limiter..... I mean, a zoom lens with focal length ranging from 100-300mm with a focus travel of 1.8m to infinity - even if there was a fixed focus limiter say from 5m to infinity - it would make working with this lens so much better, especially if you are tracking a subject with distracting elements in the foreground and background.

Non macro lenses from sigma that do have focus limiters - with their EX "excellence" series such a feature should be standard on telephoto zoom lenses:
Sigma 800mm f/5.6 APO EX DG
Sigma 500mm f/4.5 APO EX DG
Sigma 300mm f/2.8 APO EX DG
Sigma 300- 800mm f/5.6 APO EX DG
Sigma 200-500mm f/2.8 APO EX DG
Sigma 120-300mm f/2.8 APO EX DG


Last edited by Digitalis; 01-07-2013 at 09:00 PM.
01-09-2013, 07:14 AM   #35
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Not bad for a 50mm f/1.2 lens made in 1984...perfectly sharp all the way out to the corners. Though at f/8 100% I can detect a slight softening due to diffraction. I have noticed with the K5IIs that chromatic aberration is easier to keep in check - the on bayer AA equipped cameras like the K-7 50mm f/1.2 would often require -26 on the red/blue to counter transverse chromatic aberration, on the K5IIs this lens only needs -16 correction. This also extends to Purple Fringing - which is common on the Pentax FA77 Limited, PF is now much easier to remove because there is less of it. Manually focusing on the K5IIs is much more of a challenge now, because the critical point of focus stands out more especially with sharp,fast primes because of the lack of a Bayer AA filter you have to have very good eyes or a manual focusing screen with a split prism/micro prism collar. I do not use manual focusing screens because they play merry hell with spot metering and that is something I cannot do without when I am doing landscape work.

Pentax SMCP-K 50mm f/1.2 @ f/5.6 ISO 100 on the Pentax K5IIs - sharpened in LR4, inset 100% crop

Last edited by Digitalis; 01-09-2013 at 08:13 AM.
01-09-2013, 07:18 AM   #36
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Amazing detail at 100%.
01-14-2013, 03:11 AM   #37
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Having received a few messages on this site from concerned wildlife photographers who were concerned about moire appearing in the feathers of birds - which is a legitimate concern because bird feathers are almost perfect for creating these kinds of problems, I visited the Local Zoo - although I'm not a fan of animals in cages, I would at least be given the opportunity to photograph birds and other animal and be able to give some advice on this particular issue. and having waded through about 16 Gb worth of RAW images* I can safely say that it isn't as big a problem as so many people have been saying it is. However having said that there is a possibility it can occur at certain subject distances - but as of yet I have not seen it under what I consider a more or less normal wildlife photographic scenario. YMMV

Well that is the good part, now for the bad part: One issue I will point out is that since the K5IIs has no Bayer AA filter getting the subjects eyes exactly at the point of focus is of paramount importance, and with telephoto lenses most phase detect AF systems have a tendency to slightly front-focus. Lens calibration is critical when expecting to get the most out of the K5IIs, as it so happens there are two competing products that are designed to assist with this process : the Datacolor Spyer Lens Cal and Lens Align pro. Personally I work with the Lens Align Pro system with the optional four foot long ruler - which I consider a necessity for accurately calibrating lenses of focal lengths 300mm and over. Also the Lens Align pro uses a very clever method to get the focus target on the Lens Align unit and the sensor parallel to each other to improve accuracy of the calibrations. I have no experience with the Datacolor spyder but comments from colleagues inform me that it is better suited to lenses 100mm and shorter.

*I deliberately used an aperture of f/5.6 - at f/8 diffraction already starts to impact image quality so I sought to see if Moire would show up by sticking just under the diffraction limit, and it did. But in only two out of nearly 400 images and the colour moire was only visible when pixel peeping, so for all intents and purposes moire is essentially a non-issue. At least for subjects of the Avian variety- ED.


Pentax K5IIs - Sigma 100-300mm f/4 APO EX DG - 1/250th f/5.6 @ Iso 4000


Pentax K5IIs - Sigma 100-300mm f/4 APO EX DG - 1/320th f/5.6 ISO 200

Last edited by Digitalis; 01-23-2013 at 09:13 PM.
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