Hey guys I have recently dug out old Pentax K-X with kit lenses, but I noticed I struggle with sharpness of the photos. No matter what settings I try I get my photos blurry when I crop it to make small things more visible, even my mid-tier phone takes sharper shots (even when cropping). To make things easier on you guys I will make a list:

  • Impossible to get crispy sharp photos both using auto focus and manual focus
  • Very noticable on closeups on bugs and stuff, taken from around 0.5m away.
  • I have taken a photo of a bug from around 0.5m away.
  • Photo below is example of what I got, in time I am using the camera (around 1000photos) I don't think I have a single one that is really sharp and crispy.
  • Shooting raws, but same happened with jpgs.
  • Settings:
    • Flash - ON
    • f/36
    • ISO-400
    • Shutter 1/160

What else could I do to improve? Thanks! Bug full Bug crop


2 Answers 2

  • Using the smallest aperture is not optimal for sharpness, as that causes Diffraction. Go with f/8 or f/11 for best results (it depends on the lens, and some Pentax cameras have a special "MTF" setting in the P mode for that, to always prefer the best aperture.

  • It could be that your "phase detection" focus measuring system is maladjusted. Therefore, try to focus using Live Mode, where a different focus system (image sensor-based) is used. If that gets you sharper images, then look in the camera's menu for a setting to adjust the focus.

  • And check your lens. Disconnect them from the camera, see through them by opening the aperture lever at the rear, and look for dust inside. If you see a lot of fine dust particles, it might be that your lens has gotten the dreaded mold (fungus) that can damage even the most expensive lenses. This mold causes diffusion, which you might be seeing. This mold can be removed but requires disassembly of the lens, which is rather expensive and probably not worth for a kit lens. In this case, look on the used market for a replacement. Those kit lens are cheap to come by.

  • \$\begingroup\$ -I come from mobilephotography background so aperture is something I am still getting familiar with, thanks for your advice, I will see how it works in practice. -Phase detection - might be, but I prefer using manual focus, that should not be affected by maladjustement should it? -Lens - that is a possibility as well. \$\endgroup\$ Commented Aug 30, 2018 at 8:32
  • 2
    \$\begingroup\$ If you focus manually, how do you tell that it's sharp? Only using the live view sensor, with zoom, can tell you that - the view finder's screen is (a) not large enough to see the finest details and (b) might also be maladjusted, e.g. if the mirror is not sitting perfectly. \$\endgroup\$ Commented Aug 30, 2018 at 8:47
  • \$\begingroup\$ Looking through viewfinder is problematic - I wear eyeglasses so can't see well through it. But I get your point - I use screen to zoom on the detail and focus slowly until I get best possible outcome but resolution is poor on the screen and I indeed do not see the finest details. How can I tell if mirror is not sitting perfectly? \$\endgroup\$ Commented Aug 30, 2018 at 8:59
  • 1
    \$\begingroup\$ I still think you should allow Live View to find the best focus, at least for some tests to make sure you can get the sharpest results. Then focus manually through the view finder, and autofocus without live view (i.e. using the regular phase detection method), and then take a picture of each and compare them at a computer, to see if they are all equally sharp. I suggest using a printed image with sharp contrasts that you put on a well-lit well (prefer daylight) and rest the camera on a solid surface or tripod. \$\endgroup\$ Commented Aug 30, 2018 at 12:09
  • \$\begingroup\$ I will do that, thank you. Also thank you for pointing out that larger apertures can cause diffraction I did not know of that and will certainly look into that topic as well. \$\endgroup\$ Commented Aug 31, 2018 at 6:37

Maybe you are a bit too picky. At this enlargement, my guess is that the full photo would be about 1.2 meter wide, and you are looking at it from 10 cm away. Can we really expect complete sharpness from an old entry level camera and lens under those conditions? You probably have about 0.12 MP left after cropping. Cropping should only be used for perfecting the framing.

  • \$\begingroup\$ I would not be this picky if my mid-tier phone wasnt able to deliver crisper photos - and I do crop liberally everything I take :) \$\endgroup\$ Commented Aug 31, 2018 at 6:37
  • \$\begingroup\$ I measured a bit on the screen, but I really do think you cropped 99% away. I don't think any camera can give good results with that. Your phone probably has 12 MP too, and it has a wide angle lens, which gives a very large DOF. When there is a lot of light it should give similar results. The camera should be much be much better in low light, give you control over DOF and shutter speed and lets you change perspective by changing the focal length. It can probably get a little better with practice, but this is mostly as good as it gets. It should be fine to start with though. \$\endgroup\$
    – Orbit
    Commented Aug 31, 2018 at 16:07

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