[clackers]

Try taking a real simple picture of a brickwall and don't use that remote trigger *unless it can do 2s delay*, Haroon.

The reason I say this is to test for shutter and mirror shock, and to rule out haze to distant objects.

[mikesbike]

As to the first photo, the fir trees are not a good subject to look into a sharpness evaluation, some even being backlit. However, I do notice the rocks, etc. along the shoreline are frequently in good lighting and look quite decent, and uniformly so across the frame.

As I always say, for best quality of images right out of the camera, be sure to set up "Fine Sharpening" in the Custom Image menus, especially in the most often used "Bright" category. This will yield superior fine detail in your images, and this seems to be true across Pentax DSLR models. If you have any difficulty doing this, just say so and you will get help. The sensor in your K-50 is a good one, as all examples posted here have shown.

I suggest just using normal AF via the VF (set to spot AF so you can train it on a particular part of your scene that will give the best overall result). This Sigma lens I have found has very quiet, accurate, fast AF capability. I believe the K-50 also has a pro-grade pentaprism VF with 100% coverage.

A scene like this one, shot at this distance and at wide angle, should have very good depth of field (DOF) at f/8 so getting good focus should be easy. And with 1/250 sec shutter speed, I see no need to se a tripod, unless you are quite shaky, or if the tripod is more convenient for prolonged shooting. Hand held, have the camera's SR turned on; or if using a tripod, turn it off.

[stevebrot]

As I always say, for best quality of images right out of the camera, be sure to set up "Fine Sharpening" in the Custom Image menus, especially in the most often used "Bright" category. This will yield superior fine detail in your images, and this seems to be true across Pentax DSLR models. If you have any difficulty doing this, just say so and you will get help. The sensor in your K-50 is a good one, as all examples posted here have shown.

Of course this hint only applies to JPEG created in-camera and/or RAW conversion done using the Pentax software for the K-50.

I believe the K-50 also has a pro-grade pentaprism VF with 100% coverage.

Yes, the K-50 has a pentaprism viewfinder with excellent coverage and good magnification. Unfortunately, the stock focus screen lacks adequate focus sensitivity* to properly support lenses faster than about f/4 maximum aperture. It is for that reason that the general suggestion for fine focus with f/2.8 and faster lenses is to use focus confirm with the center focus point or use magnified live view.


Steve

* The ability to detect out-of-focus is about the same with f/4 maximum aperture as with faster lenses. The result is poor reproducibility with fast lenses when compared to more sensitive methods.

[SSGGeezer]

The 30mm F/1.4 non HSM Sigma I had was a bit schizophrenic in its focusing behavior so I returned it. One shot would nail the focus and the nest two or three would vary between front and back focused. A wonky aperture didn't help.

[stevebrot]

Well I wasn't referring my post to exact this photo, this first photo of mountains with lake is just one example in which sometimes nothing is in focus. This photo was on tripod and a remote control shutter release was used. I focused manually using live-view. I am referring to overall experience.

The second photo is handheld. I can declare but I didn't expect his much out of focus or less sharp images from my prime lens at 1/250 shutter speed.

A few comments regarding your photos and lenses:

• The Sigma 30mm f/1.4 was noted in the Pentax Forums in-depth review as having severe problems with AF on at least three Pentax bodies (K-50, K-5IIs, and K-3). For more information see

  Sigma 30mm F1.4 DC HSM "Art" Review - Autofocus | PentaxForums.com Reviews

• It was unclear what the intended point of focus was in either of your landscape photos. If using AF (Tuscany photo) and allowing the camera the choice, be prepared for it to settle on the first point that it can work with.
• When working on-tripod, take care to either disable the SR feature or use the 2-second delay which also turns off SR. Failure to do so carries the risk of introducing motion artifact.
• Normally, using magnified live view is the gold standard for fine focus with the emphasis on magnified. Even then, atmospheric haze (present in the top photo) may make it difficult to attain focus with any precision.
• With many modern zooms, your Sigma 17-50/2.8 included, the focus throw is too short for precise manual focus at other than moderate distances; it is probably best to let the AF give it a try for that case.
• If shooting hand-held using AF, be sure that the camera has actually signaled that focus has been acquired (green hexagon) and locked. Usually this means AF-S mode.
• We are assuming a sturdy tripod for the Dolomites photo...enough said
• When shooting hand-held and expecting the SR to do magic, make sure the hand icon in the viewfinder is displayed before taking the shot

All of the above are just general comments and not heavily based on the examples (too little information). As for my opinions:

• The top photo appears to have been taken under hazy conditions with most of the lack of sharpness being due to that haze. There is little to be done except to try a polarizing filter. I don't believe that the photo is grossly out of focus, if at all. This happens sometimes and makes it hard to get good photos.*
• The middle photo appears to have focus placed at the grass at the bottom with acceptable focus extending to the first row of trees 1/4 way up. Whether this is missed focus or a failure to acquire is not known. The EXIF will tell what AF mode was being used and which point was used and "in focus". The sensor also has dust spots
• The bottom photo is what I would expect from your K-50. I suspect your 17-50/2.8 would do as well with the same subject, distance, and lighting.

Steve

* I found myself shooting through an agricultural haze a few weeks ago. The results were technically in focus, but had an "artistic pastel" look.

[mikesbike]

Indeed, center-point AF is the way to go for accuracy. And with the DOF available in a wide angle shot at some distance, sharpness should come in fine.

[rogerstg]

this first photo of mountains with lake is just one example in which sometimes nothing is in focus.

IMO, that problem is haze, not lack of focus. A small amount of post processing can take care of much of it. The tree tops seem to be in focus considering the reduced resolution of the photo posted. Here it is with a little help in post:

Attached Images

View Picture EXIF

File Date

 

[haroon88]

First of all, thank you very much for your courteous and helpful replies.

As I always say, for best quality of images right out of the camera, be sure to set up "Fine Sharpening" in the Custom Image menus, especially in the most often used "Bright" category. This will yield superior fine detail in your images, and this seems to be true across Pentax DSLR models. If you have any difficulty doing this, just say so and you will get help. The sensor in your K-50 is a good one, as all examples posted here have shown.

Are you referring to the AF Fine calibration? If yes then for each lens I have tried to calibrate it myself using "home-made" calibration kit. Still although the Sigma 17-50 f2.8 has sometimes given me great results, but given that Sigma 30mm f1.4 is a prime lens, bought from Japan and paid more money than the either of the zoom lenses, I am disappointed with my investment mainly due to its focusing problems and not great results in some conditions.

Try taking a real simple picture of a brickwall and don't use that remote trigger *unless it can do 2s delay*, Haroon.

The reason I say this is to test for shutter and mirror shock, and to rule out haze to distant objects.

For sure, this is the next thing to do, I'll try to get better calibration out of my lenses and try to do this next.

The 30mm F/1.4 non HSM Sigma I had was a bit schizophrenic in its focusing behavior so I returned it. One shot would nail the focus and the nest two or three would vary between front and back focused. A wonky aperture didn't help.

Exactly. What would you suggest as replacement for this lens if I were to replace this?

A few comments regarding your photos and lenses:

• The Sigma 30mm f/1.4 was noted in the Pentax Forums in-depth review as having severe problems with AF on at least three Pentax bodies (K-50, K-5IIs, and K-3). For more information see

  Sigma 30mm F1.4 DC HSM "Art" Review - Autofocus | PentaxForums.com Reviews

• It was unclear what the intended point of focus was in either of your landscape photos. If using AF (Tuscany photo) and allowing the camera the choice, be prepared for it to settle on the first point that it can work with.
• When working on-tripod, take care to either disable the SR feature or use the 2-second delay which also turns off SR. Failure to do so carries the risk of introducing motion artifact.
• Normally, using magnified live view is the gold standard for fine focus with the emphasis on magnified. Even then, atmospheric haze (present in the top photo) may make it difficult to attain focus with any precision.
• With many modern zooms, your Sigma 17-50/2.8 included, the focus throw is too short for precise manual focus at other than moderate distances; it is probably best to let the AF give it a try for that case.
• If shooting hand-held using AF, be sure that the camera has actually signaled that focus has been acquired (green hexagon) and locked. Usually this means AF-S mode.
• We are assuming a sturdy tripod for the Dolomites photo...enough said
• When shooting hand-held and expecting the SR to do magic, make sure the hand icon in the viewfinder is displayed before taking the shot

All of the above are just general comments and not heavily based on the examples (too little information). As for my opinions:

• The top photo appears to have been taken under hazy conditions with most of the lack of sharpness being due to that haze. There is little to be done except to try a polarizing filter. I don't believe that the photo is grossly out of focus, if at all. This happens sometimes and makes it hard to get good photos.*
• The middle photo appears to have focus placed at the grass at the bottom with acceptable focus extending to the first row of trees 1/4 way up. Whether this is missed focus or a failure to acquire is not known. The EXIF will tell what AF mode was being used and which point was used and "in focus". The sensor also has dust spots
• The bottom photo is what I would expect from your K-50. I suspect your 17-50/2.8 would do as well with the same subject, distance, and lighting.

Steve

* I found myself shooting through an agricultural haze a few weeks ago. The results were technically in focus, but had an "artistic pastel" look.

I would try to reply for each point:
Now I can realise that my try of this result did prove the same result. For the tuscan photo, the trees were the subject of focus as far as I correctly remember since my norm of photography is to focus the main attraction of the scenery. For the SR gets automatically disabled when I put it in timer mode or shutter release mode, and for this reason I make sure that OS of the Sigma 17-50 f2.8 is switched off always. Yes the live view magnification is always my mode of focusing when shooting using tripod. Yes the green signal from the camera is when I snap the photo. No I can concede, not a top notch high quality tripod , but even with the basic tripod, all things perfectly tightened and a weight hanging at the bottom. The AF mode is the spot mode which means I select the spot to be focused rather than the camera selecting it. The bottom photo is from the Pentax DA 55-300 f4-5.8 which has really impressed me and given me the opportunity to shoot amazing photos until 200mm (APS-C 300mm) range which is more than enough for me.

Lastly, as I said before, if I were to choose better lenses without throwing a lot of money which I can't (there I said it), which lenses you frankly advise me to buy even second hand?

Thanks once again.

[stevebrot]

Lastly, as I said before, if I were to choose better lenses without throwing a lot of money which I can't (there I said it), which lenses you frankly advise me to buy even second hand?

Your Sigma 17-50/2.8 is probably fine. I would not expect much change in results, even with a non-zoom, at anything close to moderate price points. I am a bit biased, however, in that the 17-50/2.8 EX DC was my close #2 pick when I bought my Sigma 17-70/2.8-4.0 (C) back in 2014. You may want to check whether the AF adjust was needed on that lens and also might want to consider a polarizer filter. I know, they are expensive for 77mm, enough so that I have been shooting without for some time. I just ordered a 72mm Hoya Pro1 circular PL last night for my 17-70 and even at $50 USD on Amazon, it was painful, but not as much as trying to find a more capable lens. You might expect to pay €50 or a bit more for similar.

As for the Sigma 30/1.4 (A), it is likely you can find a more usable lens at that focal length for similar or less money. Much depend on whether you really want f/1.4; if not, 30mm on your 17-50 may be a quite reasonable alternative. A two lens zoom kit, along with your DA 55-300/4-58 might just cover your needs. If a "normal" FOV fast prime is your intent, my suggestion would be the HD FA 35.2.0. I have been shooting with the non-HD version for over a decade and can offer my recommendation without reservation. If you want to spend more money for incredible build and optical quality, get the FA 31/1.8 Limited.


Steve

[csa]

Better buy a Tamron 17-50mm F2.8

Why? I have the Sigma, and am more than happy with the results it gives!

[mikesbike]

Are you referring to the AF Fine calibration?

No. This is regarding the Custom Image finishing pallets which vary according to certain preferences and for some specific purposes. The "Bright" setting is preselected as default, and is best for most scenes. You can go into its menu and make changes at will, as you could in the "Natural" category and others as well.

Do you have your camera's owners manual? If not, you can download one through the Ricoh/Pentax website, under support, I believe. Your K-50 probably operates like other models in this class. First, do not have your camera set on the "green" auto mode, as this does not allow access to many functions. Instead setting the mode dial to the "P" mode would be ok. You would probably access your controls panel quick link screen via the info button. Then the 4 buttons around the ok button become 4-way controls for navigation. The first section on the control panel is likely the Custom Image section, and you will likely already have it selected since it is first. Hit the ok button to open the section. The first category of Custom Image is likely the "Bright" and is likely already selected, so you hit the info button to open its menu for adjustments. Tab down to Sharpening, and using your thumb dial put an F by the S to implement "Fine Sharpening" and you are done. Hit ok and turn off the camera which will exit the screen.