[sherohara]

I've been using Pentax system for years k1000, k200d and now k30. The only lens I ever use is my trusty manual 50mm 1.7 lens despite owning a few new lenses including tamron 17-50 and pentax da 50 (1.4?). I get very nice results from my trusty old manual 50mm lens but I mostly take pics of my kids and take portraits. I have never been able to get my pics taken on auto settings to look anywhere near decent. They are always out of focus or underexposed significantly. I'm sick of chasing kids around with a manual lens. Help!

[pepperberry farm]

I have a DA50/1.8 and have used it both on my K-50 and K-3 with very few issues as far as the AF or exposure is concerned...

can you post some example shots with EXIF data so we could help you a bit more?

[reh321]

I've been using Pentax system for years k1000, k200d and now k30. The only lens I ever use is my trusty manual 50mm 1.7 lens despite owning a few new lenses including tamron 17-50 and pentax da 50 (1.4?). I get very nice results from my trusty old manual 50mm lens but I mostly take pics of my kids and take portraits. I have never been able to get my pics taken on auto settings to look anywhere near decent. They are always out of focus or underexposed significantly. I'm sick of chasing kids around with a manual lens. Help!

Are these problems happening with your Pentax-DA lens?

[marcusBMG]

Is your 50mm the "M" series or the "A" series? If it's the "M" series then you don't have aperture priority auto exposure and my suggestion is to get good at using manual exposure. The text book technique is the "green button" to meter but the more I try to use that the less I want to - I really only use it to get an initial "chimp" ie test exposure. Then it's just a matter of mentally halving or doubling the shutter speed to match a change in f-stop. Things only get more tricky if the light is changing moment by moment eg intermittent sunlight, children moving in and out of shadow. Then you really want an "A" series 50mm so you can use Av aperture priority. I still find I have to chimp with my 50mm f1.7 - my most used lens BTW - and typically find I am dialling in +2/3 eV exposure compensation. Gotta learn to use the exposure compensation! Although its always possible to adjust the pics later, particularly if shooting RAW there is no difficulty bumping or reducing exposure by a stop using software like lightroom or (FREE!) faststone.
If you are regularly using MF lens(es) like the 50mm f1.7 then its worth considering some focus aids/tweaks. First off make sure you have done the best on camera diopter adjustment you can to match your eyes. Carelessly leaving that slightly maladjusted will grievously handicap your MF efforts. I have a tenpa 1.36x viewfinder magnifier, one of the reasons being is that I need slightly more diopter correction than the camera does and this unit provides a bit more. Pretty much it lives on my K5 and it is particularly effective with a lens like my "A" 50mm f1.7. I have also tried a split prism focus screen on the K-r I had, and a canon EES screen specifically designed for faster lenses. One of the problems is that the stock focus screen is designed to match the kit lens and gives good focus discrimination at f4-f5.6, not f1.7!
Not nailing focus manually could be due to a number of things, including possibly a need to callibrate/shim the focus screen. One important technique to use is to corroborate your focus through the viewfinder with focus on the screen in live view, magnified as necessary. With static subjects this is the most accurate way to focus.

Those some initial suggestions, some pics may allow us to zero in on some things eg not using fast enough shutter speeds = motion blur....

[sherohara]

I think the problem, to be honest is that I have only ever shot in full manual mode and have never taken the time to learn the auto settings and how to get the best out of my auto lenses. I've never had a lot of time to stop and learn, so I've just stuck to what I know and can get images I'm pleased with (the M series 50mm 1.7). I do think there might be some issue with my Tamron 17-50 lens though as it's so unpredictable and always seems to underexpose. MarcusBMG - I have both the "A" and "M" series of the 50mm lens but never use the "A" and haven't done so for a few years to be honest. I have never learned to use the green button to aid me either. I'm pretty good at using the "M" lens and manually focussing quickly enough to get me by, but I have these auto lenses gathering dust, so I really need to learn how to get the best out of them
As for the DA 50mm lens, it's much more reliable in terms of getting reasonable exposure and accurate AF (more of the time than the Tamron) but it seems to suffer from a lot of purple fringing and the images end up looking unpleasant to my eye. I really like to get a good background blur when I'm shooting portraits and I can't seem to work out how to do that on an auto setting..the entire frame is in focus, or it's only a slight blur. What setting do I need to use in order to get the lens to blur the background without me having to manually focus it? That's probably a stupid newbie question, but I really am clueless when it comes to shooting anything other than full manual!
I'll attach a couple of pics I took the other afternoon in quick succession with the same settings. The kids were on the trampoline, so I was playing around with the tamron lens and had the settings on "action" for these 2 pics. One turned out reasonably with ok focus and exposure but the other was noticeably darker and out of focus. Every photo I took was way too dark, darker than either of these photos with only a couple of randomly well (or ok) exposed pics.

[marcusBMG]

Well, to start at the end: how much you will get out of a dslr and a good lens like that tamron will be directly proportional to investing in learning the ins and outs of the camera and the photographic principles underlying getting best results.

The useful rule of thumb for getting acceptable sharpness hand holding is to have a shutter speed of at least 1/focal length eg 1/50th for your 50 f1.7's, or 1/35 secs for the second pic posted. BUT: that needs to be adjusted for the smaller sensor (which basically = cropping, if you crop a pic in any way then blur or softness becomes more visible) ie x 1.5 = 1/75th. And then that assumes good technique and a relatively stationary subject. Cut a long story short - I'd be looking for ideally 1/500th or faster on an action shot like that. Also I'd be looking for more depth of field than at f3.2 to allow for the movement and size/shape of the subject - how good different cameras+lenses combinations are at holding focus on moving subjects is way off base for me, can't comment , but as a general principle this is sound. So: f8 say, and 1/500th. But now you run in to the relatively dull lighting of your scene. Your best option IMO with this subject and this lighting is to up the ASA to eg even 1600. Personally I do 90% of my pics in Av aperture priority mode. There is one button access to swiftly change ASA and exposure compensation, speed dial changes the aperture and the camera adjusts the shutter speed in sync.
There is another suggestion I can make with this; common technique would be to use burst mode and fire off 3 pics with each shutter press. Particularly effective if like me you are a bit twitchy with your shutter presses. Common experience is that the 2nd pic comes out best.
Which leads me to your ?? about exposure. In a (partially) backlit situation like your pic 2 you want to expose on your subject. So this would suggest centre weighted or spot metering rather than matrix.

It is one of the great boons of dslr's that you have all these options towards getting good results. The other great boon is the facility to immediately review your pic and adjust and retake as necessary.

Lots to learn. here's a great web site:

Cambridge in Colour - Photography Tutorials & Learning Community

I recommend reading all the "photo essentials".

[pacerr]

The transition from the 'Spotmatic film era' to current DSLRs can be quite frustrating. New descriptive terms and strange controls add to the confusion but the underlying principles haven't changed.

The two greatest 'tools' you have available are the ability to instantly review each shot on the LCD screen (chimping) while the intent and camera controls are still fresh in your mind and the the freedom to shoot A LOT without worrying about the expense of film.

Imagine the task of hitchin' up a mule to a wagon compared to goin' to town in a new 3/4-ton pick-em up truck. New rules-of-the-road and strange controls but same ol' shi - uh, stuff in the back. You don't make that change over night.

Read that FINE manual - break it down, one function at a time, into recognizable tasks and controls and convert each one into a discrete exercise to be learned. Most questions have been asked and answered in the Articles sections of Pentax Forums

Troubleshooting and Beginner Help and Pentax Articles

Go over the camera Menu items until you understand each one - it may help to assign a User Mode to camera defaults so you always have a known fall-back condition and comparison point when experimenting. (I initially assigned User 1 to what I configured and labeled as 'Spotmatic Mode' when I was still starin' at the DSLRs like a dawg at a wrist watch.)