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02-27-2017, 01:32 AM   #1
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Horizon line detail: 645Z & 28-45, 120 macro, 45-85

I sold off all my Nikon gear to step up to MF in the hopes that I would gain the horizon line sharpness that was missing with the Nikon gear. I shoot moody landscapes and I'm not getting the sharpness i was expecting. I cant figure out if its technique, lenses or camera. I did not buy the camera new, it had 2500 frames on it when I purchased it. I use a heavy duty tripod, cable release etc. I am looking for some help from anyone who is using the camera and lenses for landscape work to see if i can figure out my issues.

Obviously a low res jpeg in this setting will be hard to offer any meaningful insights on. I am happy to correspond directly and exchange larger files, I can see from the preview post that the image looks horrible

I am hoping to get the sharpness sorted so I can print large on my HP 44" Z3200PS

I almost love this camera.....

Thanks from off the edge of the map in Namibia.

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02-27-2017, 02:31 AM   #2
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Looks like a simple focus issue to me. Having SR on while on a tripod can also introduce blur, so make sure it's off.

The easiest way to ensure perfect focus every time is to go into live view and magnify the image all the way, then focus manually. It might be a little challenging when there's little light, but it should work for a scene like this.

Adam
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02-27-2017, 03:22 AM   #3
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Thank You Adam, I only have one lens with SR and that is the 28-45 and the SR switch is permanently off. I will slow things down further and do as you suggest. I'll be very candid this technique is not what I have been using, Having been a Nikon guy for 14 years I am learning a new language and a new system and most importantly a new format that will expose your weaknesses, brutally. Can I presume that F-stop should be set to the optimum for detail on any given lens? the 28-45 seems to be F11. Also it seems that to use Mirror lock-up you have to turn off Live View and go to the view finder.
02-27-2017, 03:22 AM   #4
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Just sounds a little odd to me that you were not getting line sharpness with your Nikon gear as well. The 645z will not really improve sharpness over the Nikon.

I agree with Adam that this may be as simple as a focus issue and live view magnified is the way forward. In addition:

Does this occur with all lenses?

Are you using mirror up with delay even though you have a sturdy tripod?

Does this occur on an absolutely clear day? I ask because the image posted gives the impression of atmospheric conditions (heat haze or other) conspiring to make soft images

02-27-2017, 03:28 AM   #5
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SR is shake reduction, by the way. Like Nikon cameras and unlike Pentax K-mount cameras, the 645Z relies on in-lens stabilization. You should disable this whenever you are not hand holding the 28-45mm (there's a switch on the lens).

As for mirror lock up, you can also use the 2s self timer, which gives you the same effect. This should be available in live view. But even if not, there's nothing stopping you from setting the focus in live view and then going back to VF shooting.

Since that's a half second exposure, I'm tempted to speculate that an unstable setup may also have played a role. Do you have the IR remote? This will help eliminate vibrations that otherwise occur with a button press (the self timer can also mitigate this to an extent).
02-27-2017, 03:59 AM   #6
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QuoteOriginally posted by Namibchris Quote
Thank You Adam, I only have one lens with SR and that is the 28-45 and the SR switch is permanently off. I will slow things down further and do as you suggest. I'll be very candid this technique is not what I have been using, Having been a Nikon guy for 14 years I am learning a new language and a new system and most importantly a new format that will expose your weaknesses, brutally. Can I presume that F-stop should be set to the optimum for detail on any given lens? the 28-45 seems to be F11. Also it seems that to use Mirror lock-up you have to turn off Live View and go to the view finder.
Technically speaking, the optimal aperture for the sensor, if going by pixel pitch, is about f/10, but in practice you can very likely get away with a lot more, if an increased DoF would create greater perceived sharpness at the cost of some fine detail.
You can test this for yourself by setting up for a shot and running though a range of apertures from say f/8 to f/22 and then printing out a series of crops as they would be at final print size to compare.
The camera locks the mirror up on it's own if you shoot with a 2s timer from LV, so there's no need to switch it on at all. Use the magnification in LV to set up focus either way, as AF systems are often fooled in backlight, and the Pentax is no exception.

I'm also going to mention this ahead of time, but if you run into an issue shooting HDR brackets with both shutter speed and aperture changing, go into camera menu #4 -> E-dial prog. -> page 2 and under "M" change the function of the green button to TvShift.
It seems really weird, but apparently this obscure function is what tells the camera which parameter it's allowed to change for the purpose of bracketing, as opposed to which shooting mode you're in. So even if you're in Tv on the dial, if Tv is set up with P as the green button function, it'll bracket as though you were in P. If you set it up as above, you'll bracket with shutter speed while in M on the dial.
The green button is otherwise fairly useful as it lets you temporarily meter using a different mode, so you can be in manual but quickly set the camera to what it thinks should be a good exposure.

Last edited by Kolor-Pikker; 02-27-2017 at 04:06 AM.
02-27-2017, 04:35 AM   #7
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QuoteOriginally posted by Adam Quote
Since that's a half second exposure, I'm tempted to speculate that an unstable setup may also have played a role. Do you have the IR remote? This will help eliminate vibrations that otherwise occur with a button press (the self timer can also mitigate this to an extent).
Yeah, with long exposures even a small vibration can show up. Like mirror slap or pressing the shutter button or walking around the tripod, or a strong wind blowing. I know for a long time I blurred my photos because of how strongly I pressed the shutter button.. seems like a no-brainer, but it helped me with low light photos
So, low ISO, 2 sec timer (and possibly remote trigger), f11 is fine, and then manual focus. Look through the viewfinder or Live view with Focus peaking and max digital magnification.

Another thing to keep in mind is that during a long exposure clouds can actually move around. Clouds move, sun sets, stars move, tree branches sway,.. so you can get all kinds of blur from that alone. What I recommend is you look at the photo at 100% and try to analyze what kind of blur this is. Is everything blurred in one direction? Is there motion blur on the objects themselves? Is something in focus, but other things aren't? Or is everything OoF?
02-27-2017, 06:38 AM   #8
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I want to take a moment to say huge thanks to all who have replied. For now I will take these suggestions and approach the problem academically and see if I can resolve the issue. As many of you will be aware, Namibia is a place of very large landscapes with little to interrupt the view to the horizon. I am far less concerned with foreground sharpness then I am with the relationship between the sky and the relaltve sharpness of the horizon, Accepting that atmospheric influences may reduce the sharpness.

02-27-2017, 08:53 AM - 1 Like   #9
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1. As many has noted, the first thing to check is technique: confirmation of focus with magnified live view; mirror lockup; remote triggering; sturdy tripod; shielding from wind, etc. You might try some controlled tests inside a large building. Also, you might want to double check focus at the edges relative to the center. I don't know how much field curvature is in the 28-45 (others here may be able to tell you) but if you see situations where the center horizon line is sharp and the edge lines are blurry, that may be the cause.

2. Atmospheric influences may be the real enemy here. I live in Colorado and my house has an unobstructed view of the horizon (varying between 10-30km). My view is certainly isn't as beautiful as Namibia but I do experience the kinds of horizon sharpness issues you seem to be facing. On many pre-dawn and post-sunset days, the lights of houses out of the horizon twinkle like stars and any pictures I take will have microdistortions which turn to blur at longer shutter times. Sunset pictures are affected by convention of air heated by the ground and sunrise pictures are affected by cold dense air layers at ground level especially in low-lying areas.

3. Assuming you've dealt with or eliminated issues #1 & #2, you might consider using the K-1 and using pixelshift. Although the 645Z has a higher resolution sensor, the fact that it (and virtually all DSLRs use a Bayer color filter) means the 645 really has only a 12.5 MPix red sensor, a 25 MPix green sensor, and a 12.5 MPix blue sensor. In contrast, pixel shift on the K-1 provides the same data as a 36 MPix red, 36 MPix green, and 36 MPix blue sensor although it has the strong proviso that the scene must be stationary over the time period of collecting all four pixel shift frames (which take 4 x the shutter time plus about 0.75 sec).


Good luck!
02-27-2017, 10:09 AM   #10
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I know a guy that will pretty much center his main subject in the middle of the lens, and crop later to get the composition he wants. He does this to take advantage of the maximum sharpness of the center of the lens. I don't advocate this one way or the other, but it seems that depending on your composition it could drastically reduce the overall resolution of the photo.
02-27-2017, 10:36 AM   #11
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Regarding the field curvature mentioned above with the 28-45 lens; that would only be an issue wide open because the increased depth of focus when stopping down masks the curvature at the focal plane.
02-27-2017, 10:39 AM - 1 Like   #12
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The 28-45 is sharp across the frame. This looks like either a focusing issue or a support that wasn't quite stable enough for the 1/2s exposure.

To add to what others have already mentioned, mirror lockup (I use the 2s self-timer generally for this) is also your friend. I use that in conjunction with a cable release and it works great.
02-27-2017, 08:47 PM   #13
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I would also guess atmospheric conditions over a (relatively) long exposure period are the culprit. Against all common sense, you could increase the ISO settings and open up the diaphragm little. ISO 3200 still works wonders on the 645Z and you could open up the aperture to 8 or even 5.6, and your image would still be way sharper than the one you got in your post.
02-28-2017, 12:51 AM   #14
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I went out again last evening to try the technique suggestions I received here and elsewhere. The results were substantially better, I'm still reviewing the files to see if there is any major variation with f-stop. All in all I am both relieved and much happier. Again I want to thank everyone who responded, living as I do off the edge of the map I find forums such as this indispensable.
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03-02-2017, 07:18 PM   #15
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Glad you are getting good results now Namibchris. I have found the 28-45 to have really excellent sharpness for distant objects and works really well between f11 & f16 though my go-to is f11. Atmospheric conditions is always going to be the bottleneck for sharpness for distant objects even after you have focus and depth of field nailed. You have the best kit for photographing Namibia! I have been to Namibia twice and I absolutely love it, You are lucky to live there as a photographer it has everything. Sadly my two trips were with Canon gear so I would dearly love to go back with my Z one day
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