I'd go along with development problems I'm sure I had some results like that in the 80's when I'd just started. Have a look at this page that gives some descriptions of development problems specifically uneven development www.silverlight.co.uk/tutorials/basicpf/filmprobs.html

My K-30 hasn't been my most reliable Pentax either. I had a problem with the mirror stopping half way up/down and the camera would just lockup every now and then. SRS sent it back for me under warranty and the mirror/shutter assembly was replaced along with some system board and johnstons photopia (the UK pentax repair centre I believe) did a great job recalibrating.

Just a point about the M and TAV on my K-30, if you set Auto ISO in M mode it automatically drops into TAv mode and even reports it in EXIF. Which when you think about it is the same. Manual mode is only used if I set ISO to a single value.

Good luck with your new choice.

As mentioned in the other thread I always try to have SR off for BIF's. Good to hear that things are progressing, practice, practice, practise.

I notice others have mentioned not using centre point AF, but 5 point. I've tried this and the af just wouldn't stay on subject enough for me and slows down on locking often picking the background first. Also sometimes when it looses af it just sits there refusing to AF, so you have to give it a help by refocusing somewhere else and when it happens just as the hobby falcon dashes right past you chasing a dragonfly you tend to not use it again! I also tried expanded AF area. This was better than 5-point af, but still slowed down the initial acquisition, I felt. If you want to try this you need to go into the AF settings sub-menu (from menu button), and tick then expanded AF area box. Then you need to press the info button and change the AF Active area to 'Select'. The AF will then prioritise the point selected (select the centre af point) and then if it looses the subject off the centre point it will use the surrounding points to track. Like I said though I think this slows down the speed of AF. However I would say use whatever works best for you. I know some who swear that the 11-point AF works for them when tracking BIF's but I prefer centre only.

I always try to remember to turn it off. It was easier with the earlier models that had a physical switch. For the K-30 I've set it up in a user mode for BIF so that I don't forget.

What a great set of unusual sports shots. You've got a good eye for it, kinda reminds me of Eamonn McCabe.

I agree, there are more choices and more opportunities for good AF telephoto's for others. I would recommend a 2nd hand FA*300 F4.5 that I have as a good step up in quality over the 55-300 if you were looking for a cheaper telephoto than the DA*300 F4, but they just don't come up often enough. Whereas looking on mpb at the moment they have 7 2nd hand canon 300 F4 L IS lens available. Plus they have 3 Sigma 100-300 F4 HSM's available which are a pretty rare beast in Pentax mount.
When I added Canon I was in a dilemma about upgrading to the K5 which was £999 at that time, whereas I got a Canon 30D new old stock and a new Sigma 100-300 HSM F4 for less than the price of the K5, bearing in mind my reasoning was to test Canon's AF for birding I thought this was a great deal.... So I can appreciate your reasoning.
I'm not sure that there is a sharper telephoto lens available for Pentax than your 55-300 until you step up significantly in price in pentax land though. If you don't want the newer pentax telephoto's I'd suggest you patiently troll the used market for either a Sigma 100-300 F4, a Pentax F*300 4.5 or FA*300 4.5, although others may feel different.....

In the recent past Pentax was a bit light on wildlife lenses, however with the addition of the DA 1.4x converter and the recent drop in price of the DA 560 F5.6 I'd say it's a lot better for us. For example
Using the DA*300 F4 and 1.4x, gives you a 420 F5.6
DA*60-250 F4 gives approx 80-350 F5.6
And sigma is still selling us their 500 F4.5 and 300 F2.8 which would presumably work with the Pentax 1.4x.
However perhaps you could get more specific advice if you explained why you are frustrated with your wildlife and birds photos?.

The weather never plays nice when I have a new camera or lens to test either.
I don't have the K-50 but maybe its similar to my K-30 menu. On the rear af button settings, under 'button customization' select enable af2 (af with shutter release button is disabled so af is performed with the af/ae-l button). I use it this way other than the cancel af modes others use because I find it more logical in my brain to press to af rather than release to af.
About the card error I've never had that, but if you haven't already I'd reformat the card in the camera, after you've saved the photos of course. Don't reformat on the PC only on the camera.
With regard to the centre af and metering questions: on my K-30 if you press the info button when in any of the P,Sv,Tv,Av,Tav,M modes the info screen allows you to set the 'AF Active area' to spot, select, auto 5 and auto 11. This info screen also allows you to set the metering mode, AE Metering, to Multi-segment, center-weighted or spot. I know spot is the term used in both, which doesn't help!
As I now use Pentax again you'll see I think it is still better overall than my Canon, the summary of my reasons are
Camera and Telephoto lens combo are smaller with Pentax
Lifting the shadows is far better in pentax which is often required for under the wings of birds in flight against the sky etc
All models have AF micro adjust for lens to camera calibration, Canon only provides this for top end models.

Is this the cost of a normal licence? I can only find this price for the student or upgrade version and as I'm neither a student or a upgrader..... Otherwise it's around £100 for me.