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Forum: Maintenance and Repair Articles
03-01-2014, 12:19 PM
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Update for this topic..
I almost never use other than middle focus point, so I didn't notice one thing: adjusting the AF using the one screw "C" (bottom right screw, when lens mount is towards you) of course will introduce some tilt to the AF sensor. Stupid me :)
Solution: just adjust all three screws same amount. But if the AF sensor is tilted (i.e. camera back- or front-focuses depending on which AF point is used), the screws seem to work "reversed" compared to the viewfinder image. So, if you have back-focusing with the rightmous AF points, adjust the left screw (screw "A" in the photo above) to correct it. Clockwise to bring focus closer.
Also seems that the Pentax build can withstand multiple dismantlings quite well. I have done it now 3 or 4 times for my K-7, first just out of curiosity, then AF adjust and now again to correct that annoying tilt.
Note that one should use a good lens to adjust AF. I noticed that my 35mm limited macro has a tiny amount of focus plane tilt and the 21mm limited wide-angle has too much curvature of field (or something), resulting non-consistent auto focus. I used the 100mm D-FA macro lens to adjust AF.
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Forum: Pentax News and Rumors
02-11-2014, 01:42 AM
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Also my thoughts! :)
Hey Pentax, why new slow 20-40 zoom? 24..30mm fast(ish) prime with WR, thanks! :)
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Forum: Pentax Full Frame
01-22-2014, 02:09 AM
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Having browsed through all these FF threads.. there's quite a lot of thinking for Pentax to do, it seems :)
FF might be the right way, or maybe not. What price and size people might buy? There's the legacy K mount. And MF mount. Need for FF lenses and not hurting medium format sales. SLR might disappear, but not yet. But soon. I believe that almost all cameras will lose mirrors, but not just now. Battery life issues.. and EVF lag. And focus speed problems. But traditional SLR has the size and tolerance issues, metering and AF do not work as reliably as mirrorless, more like "thereabouts".. And the FF sensors still have a bit of corner sharpness and vignetting issues, if the mount distance is short. But soon maybe not anymore..?
I think Pentax does just right, when it waits. They should have done FF a long time ago, now is the wrong moment to hurry. A new direction should be very, very carefully thought out.
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Forum: Maintenance and Repair Articles
01-07-2014, 10:15 PM
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Hi and glad that it helped! :)
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Forum: Pentax DSLR Discussion
11-27-2013, 09:10 PM
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Okay, thanks a lot! :)
Yes, that might be the case, that exp.meter being accurate and all..
However, from the pictures of K-3, the AE-L button seems to be quite hard to press whereas the AF button seems much easier to press (than k-5), which led me to think that hopefully AE would lock using the shutter button if I use the AF button to focus.
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Forum: Pentax DSLR Discussion
11-27-2013, 02:39 AM
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Forum: Pentax DSLR Discussion
11-19-2013, 04:08 AM
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Forum: Pentax DSLR Discussion
11-14-2013, 05:30 AM
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On my K-7 I have settings put so that AE is locked when AF is locked.
Now, sometimes it can be useful that AF is done using the back panel AF button only (not the half-press of the shutter). Then it would be useful and quick, if I could lock the exposure using half-press of the shutter button, recompose and shoot. But, my K-7 doesn't seem to do this. If I set the AF to be done using shutter button haf-press, only then the AE is also locked. Seems that there's no way around it? If the AF is on the back button, AE has to be locked using AE-L button, which is not as easy as shutter only would be.
I have been thinking of updating to K-5ii or K-3 next year. Can someone test and tell how this above configuration works with K-5 (ii) or K-3?
And yes, I mostly shoot in traditional aperture priority and have found that it's quick to set the exposure where I want by pointing matrix-metering "thereabouts" to lighter or darker parts of the scene and then locking AE.
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Forum: Troubleshooting and Beginner Help
10-23-2013, 11:16 AM
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Yes, it limits the ISO and is no use if you shoot RAW. Essentially it physically underexposes by one stop, and then the JPEG processor pulls the exposure back up while compressing highlights so that they don't blow into white so badly. Same as pulling afterwards from RAW with computer.
Dunno about those gamma calibration softwares, maybe someone else has an opinion about them? :) I've had one Fujitsu, two Viewsonics and now an Eizo display. All of them with MVA/PVA panels and they were quite OK after a bit of getting used to the settings. I would say find neutral looking settings from display itself and maybe set gamma from computer's display card settings a tad darker (higher gamma number), because usually the displays are a bit too bright in the shadow areas. My spyder calibrator also darkens shadows a bit.
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Forum: Troubleshooting and Beginner Help
10-23-2013, 04:05 AM
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Yes, you could process in cs2. Have u tried to have a look of your pictures with another monitor/computer? Because that monitor age and cream white thing really sounds quite alarming to me. Many times, when monitors get old they loose highlight gradiation altogether, so that there's not much tone separation. Also, gamma and other calibrations done by eye with calibration software or test images usually suck (just my experience), one might end up with display settings worse than out-of-box.. Regarding the histograms and f-stops, I'm sure u can find a lot of information as you keep shooting and learning :)
Btw. Here are some good test images:
White saturation - Lagom LCD test
Contrast - Lagom LCD test
How do those test images show with your display?
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Forum: Pentax SLR Lens Discussion
10-22-2013, 10:59 PM
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Me wants! :)
Exactly same thoughts as you. 21mm is nice (I have it), but a tad too wide and the 35mm:s are a bit long. 24-28mm small weather sealed all-around lens, f around 2.5 or maybe even f2.. would buy immedetialy. Then I would have a nice WR set: if zooms, 18-55 + the new 55-300 and if I want to go with primes, the new 24..28mm + 55mm SDM + 100mm macro wr.
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Forum: Troubleshooting and Beginner Help
10-22-2013, 10:03 PM
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Hmm. Your examples seem quite good to me. The first ones (straight from camera) seem "brightish" and the PPd ones "darkish" so somewhere in the middle could be natural..
I believe the issue here is the image contrast. One just can't fit the same kind of dynamic range in photos than there is in nature and what human eye can see. Also, I don't know about your monitor, it might blow highlights as well.. It is normal for the digital cameras, monitors and paper to have a dynamic range of under 10 stops (maybe 5 to 9 stops), while the subjects photographed can have it like 10..20 stops. The aperture and exp.times and ISO don't alter image contrast (dynamic range) much, just the exposure. Except that lens contrast is usually a bit lower at open apertures.
If you want to preserve the frog's parts from blowing to white, you should expose so that they don't (histogram peaks just before the right edge) and then pull up the shadows in post processing (shoot raw, preferably) so that they are to your liking (not too dark). If you don't want to shoot RAW, tou should use low contrast + highlight correction in the camera JPEG settings. At least with high contrast subjects like this.
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Forum: Pentax SLR Lens Discussion
09-02-2013, 11:09 PM
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Dunno if it's Pentax quality issues or what. I have understood that Pentax had some trouble with Vietnam plant QC and then some under Hoya?
Either way, I have a copy of 55mm and while otherwise a good lens, the focus is just what The Internet tells, it's sometimes there and sometimes here.. my most erratic lens. About +5 AF fine tuning needed (all my lenses needed +2..+8, mostly K-7 body error that is).
One thing I noted; most of my Pentax lenses have to be adjusted (body AF fine tune I mean) so that the DOF is mostly behind the subject. Maybe 3/4 back, 1/4 front of subject. Doing so results in most infinity sharpness. Google also tells that more of the DoF is supposed to be behind the subject anyway, with normal shooting distances. Just saying that if one sets DoF to be equal front and back, some infinity focus sharpness might be lost.
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Forum: Troubleshooting and Beginner Help
08-29-2013, 11:09 PM
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This seems most plausible.
Also, the K-30 doesn't have auto-pop up flash (manually enabled). So, if one keeps it down the camera might have to use quite slow shutter speeds in dim environments.
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Forum: Maintenance and Repair Articles
08-17-2013, 09:41 AM
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Here's some help if your K-7 needs AF adjustment (run out of AF fine tune range). Seems quite simple, there are same kind of screws in same locations as with the K10D (for which one can find service manual from the net, Downloads).
There's one difference however; with K10D/K100D it's enough to just remove bottom plate, but in the K-7 the "third" screw (C adjusts front/back focus) is under the front cover (maybe they thought that fine tune is mostly enough..). Image from the RiceHigh's blog: RiceHigh's Pentax Blog: Hardware Adjust a Pentax DSLR for the AF.
1. To remove bottom plate, just unscrew all visible screws. Two of them are under battery door.
2. To loosen the front cover, I would also recommend unscrewing the top cover (neither cover needs to be completely removed). So all visible screws again, but there's one deep in the battery cavity, two behind the eyecup, two under the pop-up flash and one under the left grip. Lens mount bayonet does not need to be removed!
3. Once all screws are removed, the front cover should come out just by pulling it gently and pulling downwards slightly at the same time. The lens removal button and AF mode switch will come with it, so no worry about them. Note: AF switch will have to be in the same setting/location as when the covers were still together, otherwise the front cover doesn't go back in place.
4. I adjusted the "C" screw about 45 degrees clockwise to fix back-focus. This translated to about 4-5 steps of AF fine-tune from the menu. So, no big adjustment needed, careful with it..
5. For the work, you'll need preferably a "JIS" standard screwdriver (almost the same as #00 Phillips) and a 1,5mm hex tool.
6. Careful with wires. See the pictures, my camera had the one blue wire scratched against the tripod mount (sharp metal edges), probably by a service man (I had the thumb wheel warranty replaced) or already in the factory..
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Forum: Pentax SLR Lens Discussion
08-09-2013, 12:22 PM
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Here you can see the problem, there's some oil getting from the AF drive gears to the aperture control ring. The ring fits snugly between the mount and lens body, so any oil between there will dampen the action.
To fix it, just remove lens bayonet (upside down so that the electrical contact springs don't accidentally get inside the lens), pull up the aperture control ring (at the same time remove spring attached to it) and clean up.. works again :)
In the pic, aperture control ring has that looong pole that goes to the hole just close to the rear lens element, approx. there where it says "CE" on the lens barrel.
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Forum: Pentax SLR Lens Discussion
08-08-2013, 10:55 PM
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+1 !!
Maybe a 24mm 2.8 with some kind of weather sealing? :lol: Or maybe a bit faster one.. 24mm f/2.5. Either one would be nice!
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Forum: Pentax SLR Lens Discussion
08-08-2013, 10:05 PM
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I just bought a used one of these lenses, with no warranty of course. It too had sticking blades. But since I'm sort of in electronics & precision mechanics business, I decided to have a go (repairing).. seems that the problem is easy to fix. Thankfully there isn't oil in the blades themselves, but in the mechanics that open them. I'll post a couple of pics when I get home :)
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Forum: Lens Clubs
08-04-2013, 11:32 AM
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Just bought the 21mm limited to be my snapshot / "street" lens. I'm surprised how smooth the bokeh is, nobody said anything about that in the reviews :) Here's compared to the 35mm macro limited.. Reviewers mostly niggled about the mediocre corner sharpness, but I've found so far that the sharpness drop transition is so smooth, that one doesn't really notice it :) (21mm upper, 35mm lower)
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Forum: Pentax News and Rumors
07-04-2013, 01:41 AM
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Forum: Pentax SLR Lens Discussion
07-03-2013, 12:50 AM
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Sad, if no new primes. I think there is a place for a fast APS-C 24-28mm lens, preferably an affordable one. I have been searching and trying some used 21-28mm lenses. For general all-round use, traditional 35...40mm lens (135 film equivalent) is often the best.
There's the 35mm macro, which is only f/2.8 and is slightly over "50mm" fov (I own it, great lens). Then there's the 21mm limited, which is only f/3.2 and slightly too wide, maybe. Sigma has 20, 24 and 28mm f/1.8 lenses, which all have crappy corner sharpness. Same story with the 30mm f/1.4.
Now I have MF lenses, Cosina 24mm f/2.8 (otherwise very good, but no AF and slowish 2.8) and a rare Pentax SMC-M 28mm f/2.0. The latter is okay otherwise, but again lacks AF.
I have been trying to find a Pentax AF 24mm f/2 for a reasonable price, but no luck. And from the sample images I've seen, its corner sharpness isn't very good :hmm:
Time for a new 24mm f2 lens! :)
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Forum: Troubleshooting and Beginner Help
02-23-2013, 06:50 AM
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Yep, hot pixels are normal. Dependnig on exposure time and sensor, you may see quite a lot of them. This is normal.
For a reference, here's a 7-minute bulb exposure I took with an Olympus DSLR some years ago, without dark frame subtraction (click "o" in the gallery to view original size) :)
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Forum: Troubleshooting and Beginner Help
02-20-2013, 08:12 AM
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Thanks! Here's a photo of the bayonet.. for anyone not wanting to use alumium tape, I recommend sanding under one of the "ears" of the bayonet (in addition to sanding the data pin location), cannot be seen in the photo..
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