K3 sharpness and noise

[shaynejennings]

<p>Hello, i'm new to the site and this forum...<br>

I have recently just purchased a K3 and use the lenses from my K10,which are all SMC DA...im very disappointed with clarity and noise..<br>

Sometimes one lense will slightly auto focus when in M focus mode<br>

Do I need to update firmware for capability? Generally I use a Circular Polariser and F22 on all shots.<br>

cheers<br>

Shayne</p>

[Wouter Willemse]

<p>Shayne, I am no Pentax user, so I won't comment on the camera and lens specifics... just more generic remarks:</p>

<blockquote>

<p>Generally I use a Circular Polariser and F22 on all shots.</p>

</blockquote>

<p>Honestly, both aren't the best practises. A CP filter is really best only used when you really need to filter reflections (if you use it just to make the sky more blue, that's easier done in post processing), and f/22 is an aperture so small that diffraction robs a quite significant amount of sharpness, and this is increasingly clear as resolution of cameras increase. With 24MP on APS-C, I wouldn't go much beyond f/11 if clarity and sharpness matter.<br>

Also, each camera will require its own (different) defaults for sharpening and noise reduction in post-processing; what rendered great images on a K10 are not necessarily the optimal settings for a K3. Last but not least, if you zoom in to 100%, a higher resolution camera might indeed look worse, but this is easily offset by the higher resolution.</p>

[Jochen_S]

<p>Sorry, I haven't upgraded to the K3 yet. I second Wouter's concern about f 22 and worry about the CP too. It has some foil mounted between 2 tiny glass pieces so it adds 6 surfaces to goof up your image quality. I used Pentax for a while and for 20 years almost everything they made was labeled "SMC" - Not sure which DA lenses you are using but image quality varies between the kit zooms and macro lenses... Are you keeping your ISO low? Relying on SR or nuking the subject with strobes?<br>

Did you bother to do a row of test shots at different aperture settings with each lens? Can you crop a few significant pixels out of an image to upload them here?</p>

[sfcole]

<p><strong>Sometimes one lense will slightly auto focus when in M focus mod</strong><br>

<strong><br /></strong>This doesn't make sense at all. Do you really understand how to use the camera? Either it's on manual or it's on AF.<br>

Also, using a polarizer and f22, will result in a couple of nasty things: either the sensitivity has to always be cranked up, resulting in noise, or the shutter speed has to be really low, resulting in movement (no, SR is not perfect, and your subject can move also...). If the K3 has any faults, they are neither sharpness nor noise.<br>

Polarizers are really only appropriate for a limited number of circumstances. Leaving one on permanently is like using salt in your food...including your dessert, your coffee, and your morning cereal.</p>

[shaynejennings]

<p>ahh thanks for your response gents, my explanation could have been better.. I use the polariser on landscapes, as here in OZ, it cuts down a lot of reflection from very bright sunshine...yes Scott, My lens is on manual, but there is a small shift in focus that I can hear as I press the shutter..F22 is a fallback to using slide film, which I miss...ill try a larger F stop, thanks for your help..</p>

[james_lai]

<p>Circular polarizer + f/22 may mean you're pushing the camera into high ISOs. There is a video on youtube called "Pentax K3: Redemption" which I suggest you watch. Apparently, the default "auto" high ISO noise reduction setting on the K3 is very aggressive and wipes out a lot of detail. Changing to a lower setting or turning it off altogether fixes the issue.</p>

[htarragon]

<p>Whether you use slide film, print film or digital, some rules still apply. F/22 will cause diffraction problems, and is usually not the sweet spot of any lens. Polarizers will make it very difficult for the auto focus or even your eyes to manually focus at f/22. Why is f/22 a fall back to slide film? One thing has nothing to do with the other. At f/22, are you using a tripod, since you're dropping the shutter speed rather drastically (especially with a polarizer on the lens). Are you pumping up the ISO to compensate? That can introduce noise.<br>

You say one lens does the AF thing on the K-3. Does it do it on the K10? Given that only one lens does it, it sounds like the lens is the problem.</p>

[shots worth sharing]

<p>Yeah, I don't get why you'd want to shoot at f22 (come to think of it, why is that even an option?) but I can relate to the K-3 noise issue.</p>

<p>As some of you may recall, I was totally blown away by the way the K-5 handled noise and the K-5IIs shares that characteristic. The K-3 is a different animal: because of the greater pixel density, noise has a different texture and it's taking me some time to get a feel for that. At this point, I tend to go back to the K-5IIs, if I'm going to be shooting in a high ISO situation. </p>

[mike_earussi1]

<p>f22 is guaranteed to destroy both contrast and resolution due to defraction. Educate yourself by conducting a test with your best lens:</p>

<p>1.set your camera on a tripod with mirror lock-up and remote triggering</p>

<p>2. use the lowest iso (the higher the iso the worse the image quality)</p>

<p>3. then start with the lens wide open and take a series of shots at each f stop.</p>

<p>You'll find that (with a good lens) the contrast and resolution peak around 2 f stops from the widest aperture. So if you have a f2.8 lens the best f stop will be around f5.6.</p>

<p>Also if you want to use a polarizer then you need to use a good quality multicoated one (which can easily cost over $100 depending on size), as cheap ones will often make the image quality worse.</p>

<p> </p>

[RickW]

<p>Late to the party with another thought: <br>

Wouter, have you used a focus chart or the monitor-moire method to make sure the camera's AF is getting the best out of your lenses? Since the K-7, one has been able to optimize sharpness on lenses individually.<br>

Rick</p>