[Frank29]

I have been snapping away with my new Pentax K-S2, using both the kit 18-50 mm lens and some vintage lenses I bought. I am very unsatisfied with the sharpness of the photos. Doesn't seem to matter what I do, but to me, the images are fuzzy at infinity and even mid range. Even at ISO 100, with a vintage Pentax 50 mm at F8.0, with a tripod and high shutter speeds, I get fuzzy trees in the distance. It seems to be getting worse, unless I am imagining it.

I have had the camera out in quite cold temperatures (down to -20C) so I'm wondering if I have introduced moisture to the sensor or there is some other cause. (I let it warm up in a plastic bag each time) I also put the camera through a scanner at airport security - could that do some kind of weird damage? Any ideas on things I can try to trouble shoot this? I will attach a few images.

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Last edited by Frank29; 10-22-2019 at 07:56 PM.

[MarkJerling]

Hi Frank

Welcome to the forum.

Your first shot, at 1/40s is probably suffering from camera shake. And, while I can't see your F-stop, with ISO at 100 that seems to suggest a wider aperture which will give you very shallow depth of field, hence a very small part of the photo will be in focus at the best of times.

Your second and third shots are probably suffering from a bit of diffraction at F16. For best results, with a DSLR, you could try recreating those types of shots with your F-stop somewhere in the middle, say, F5.6, F6.3.

While I can't see the F-stop with your last shot, a shutter speed of 1/500 seems to indicate a small aperture, likely resulting in a shallow depth of field, so you'll see some parts of your photo is in focus, but others, of course, not.

I doubt the airport scanners or temperature fluctuation have caused these issues.

Kind regards,
Mark

[TwoUptons]

How are you focusing? Live view or through the viewfinder?

And for your outdoor shots, was the lens set to infinity? Or did you focus to what looked nice?

I’ve had issues with lenses front/rear focusing relative to the viewfinder, and that can be adjusted. Using the live view skips that potential error source as you’re focusing based on the sensor, not the viewfinder.

Finally, I had a lens with a messed up infinity focus. It wouldn’t focus properly on anything more than about 15 m away. It gave the same results, but I doubt that would affect both your lenses...

-Eric

[Frank29]

All these shots were focussed in viewfinder, using a couple of different versions of the autofocus. (spot and 5 point) However, I've done a bunch also with the 50mm prime vintage lens, focussed at infinity on the aperture ring, at up to 1/5000 of a second. Even with fast shutter speeds and/or a tripod, I am getting out of focus at infinity, but I can get clear close shots. (with three different lenses!)

I will try the kit lens with live view focus.

I guess what I am asking first of all - IS THE K-S2 capable of much clearer landscape shots than I am getting? (ie - is there a problem somewhere with what I'm doing or my lens or camera) I certainly hope so, because I'm dissapointed with my images so far.

Do cold temperatures drastically affect image quality? (However, I seemed to have the same problem two weeks ago, in Cuba)

Frank

[Adam]

Yes, the K-S2 is certainly capable of taking very clear photos.

As long as you keep your aperture and shutter speed in the middle of the range, even with imperfect focus, you should be fine.

Also, for even more clarity, shoot in raw, because the Pentax JPEG engine does generally gobble up fine details in favor of noise reduction.

[Frank29]

I tried the kit lens with live view focus. Doesn't seem to make a difference. Am I being too critical? The images just don't look that sharp at long distance. When I zoom in on the tree bark it is definitely not pin sharp or even close. Yet I can take a pretty sharp closeup shot. See examples, first two out my back door, third one a closeup.

[jatrax]

Do cold temperatures drastically affect image quality?

No, not at least in the way you are thinking. Cold does affect battery life and bringing a cold camera into a warm, humid environment can cause condensation but it would not manifest as blurry pictures.

focussed at infinity on the aperture ring,

Infinity on the ring of a vintage lens may not really be infinity. The lens may not be in adjustment and on many lenses the stop of the focus ring is beyond infinity.

All these shots were focussed in viewfinder,

Have you calibrated your viewfinder? That needs adjusted to your eye, otherwise manual focusing will not be accurate.

[UncleVanya]

Infinity marked on lens doesn't always line up. Try live viewand see if you cab get clear slots with that and a tripod first.

[thazooo]

Yes the KS2 can deliver nice shots without too much effort. I find the kit lens just OK, there are better.

You never mentioned if you shoot Jpeg or RAW.To me it looks like lack of contrast. Maybe you changed a setting. Maybe switch to Vivid.

Suggestion....... Put the sun to your back, use tripod, 2 sec timer, either lens, Take you some shots. If you still getting some washed out looks, might be the camera.

Lastly, Infinity in a shot isn't always Tack sharp. Distant objects have a whole lotta atmosphere between them and the camera.

[MarkJerling]

I tried the kit lens with live view focus. Doesn't seem to make a difference. Am I being too critical? The images just don't look that sharp at long distance. When I zoom in on the tree bark it is definitely not pin sharp or even close. Yet I can take a pretty sharp closeup shot. See examples, first two out my back door, third one a closeup.

I think these shots are far better than the first bunch you posted. The lens used may not be that sharp, so I don't think the issue is with the camera.

[paulh]

Infinity focus on the lens may be off. Try the old photographers rule of thumb for landscapes - set single focus point about 1/3 of the way into the frame at f/8, and see what happens. I also agree this might be a lens issue, since the camera is capable of fantastic photos.

[CarlJF]

In the first series, as pointed by other, it looks more like diffraction caused by small aperture or narrow DOF due a too large aperture. Not withstanding the fact that old vintage lenses aren't always that sharp, compared to modern standards, when used open wide open.


In your second series, the Exif indicates that the focusing was "close". I've no idea how close it was, but at f5.6 it could mean that distant objects are simply slightly out of the plane of sharpness. It's also backlit, which can cause some flare and reflections resulting in a loss of contrast and sharpness. The other picture show that focus was "distant". But the aperture is 5.6, which is full open for the kit lens and thus not at its best.

Also, when shooting in cold weather, fog can often form on the front lens. Just be sure to check that the lens isn't foggy before shooting.

[Frank29]

Thanks for all the information folks. To answer a few of the questions, I've been shooting in RAW. I seem to be making a little bit of progress. Tried the kit lens with zoomed in live view and did a manual focus, and got one of the backyard where the bark on the trees is fairly sharp. Makes me think the kit lens is slightly out of calibration. Perhaps I should adjust the fine focus on it a bit? Secondly, threw on my vintage Takumar F2.5 135 mm and took a photo of the branches behind the house, on a tripod, 2sec delay, F8.0. Small branches are fairly sharp I think - see attached. I had to pull it slightly back from infinity focus to get this so that makes me think some of the posters here are right about going beyond infinity focus.

[Kobie]

Keep in mind as well that in the winter with the sun beaming on the thick snow covering the ground, we may not see it with our eyes, but evaporation/condensation/haze is floating around which can/will make it more difficult for the camera to capture a sharp image.
I realized this during an evening when a massive amount of fog came billowing out from a snow covered field, coupled with a frigid drop in temperature and a lot of moisture in the air. I couldn't see all of it and some shots I took didn't work due to the moisture hovering in the air. I just had to keep taking shots here and there in the hopes that at least one of them had no haze.

[swanlefitte]

I want to point out shake reduction makes thing worse on a tripod so turn it off when using one. The delay automatically turns it off.
Check out this thread for ks2 photos. Post your K-S2 Shots Here - PentaxForums.com