Hi everyone
thanks for the initial thoughts ...
'Have you tried manual focus? That will remove the AF system from the equation. You might also be interested in my personal experience with the Sigma 17-70/2.8-4 (C). It is not particularly sharp when focused close (say for flowers). This is evident on the K-3 and even on my 10 Mpx K10D using a KatzEye split-image focus aide.
Steve'
--> Yes .. tried manual focus on many of the same images to see if it was AF issue. Problem the same ... soft focus image even when it appears focused through the viewfinder. I'd seen good review of the Sigma including sharpness .. but I guess there are variations. If it was just that .. I'd be inclined to think the Sigma was the cause .. but given it is if anything worse with the DA*60-250 which is supposed to be the best glass available for the Pentax ... and I've seen many staggeringly sharp images on this forum with that lens on the K3 and with the 1.4x and that lens on the K3 ... it would suggest a broader issue than just the Sigma. I would be interested to see any images you have using the Sigma that show softness.
'do you perhaps have a battery grip on this setup? And is the on/off switch on the battery grip set to "on" perhaps?
M
Read more at:
https://www.pentaxforums.com/forums/172-pentax-k-3/258517-focus-issues-odd-au...2zo0zclzY' --> no battery grip. Given I get circa 300 shots (given I write RAW to one SD and JPG to the Flu-Card .. I guess it is really 600 shots) between charges with my Pentax batteries (I carry two) - I should consider a grip. Don't want to buy anything else in case it turns out it all has to go back.
'You didn't say but when on a tripod presumably you're using the 2-second timer, or remote with timer or mirror lockup. I do most of my flower shots on a tripod with 2-second timer, using live view to zoom in to 8x for manual focus. As long as the sun isn't washing out the LCD I'm able to get exceptionally sharp photos this way. If you do it this way and can't get sharp images, then something is wrong.
If you're shooting wide open, you might try stopping down to at least f/5.6 or even f/8.'
--> I am using 2-second timer. Didn't want to introduce any shake from me. I do frame with LV and then shoot with viewfinder. Not tried zooming to 8x and then manually focusing .. sounds like a good idea. I'm not getting good sharp images though .. in any example with manual or AF ... so I'm guessing it is something else. I will try that process though. Many thanks.
I'm shooting as close to wide open as possible - 2.8 with the Sigma, 4 with the DA* and 5.6 with the DA* and 1.4TC. My hope was that the wider open the crisper shorter DoF for the better overall image. I don't think it is DoF related as I get soft focus with more distant images at infinity as well as softness at mid distance with the telephoto (perhaps 5m) where a 100% would mainly be filled by the head of a single flower. In each case, nothing slightly closer or further away is sharp ... which indicates it's not me getting the focus point wrong or a DoF issue.
'The AF.S flipping to M and back sounds to me that you have bad connection between the body and lens.
--> Yes ... I assumed this ... but it was engaged and there is no way to make it firmer or otherwise.
---------- Post added 04-23-14 at 11:52 PM ----------
When testing the focus, try to use Live View and manual focus to get the most exact focus. Then you do not have to think about the back or front focus. Just to check if the lens is sharp or not.
--> Second suggestion to do this .... so definitely will try. For shooting static objects ... even if I get things resolved, this seems like sensible good practice, particularly with the zooming in LV. Given nothing in the image around the focus point is any closer to being sharp and DoF is small ... it would suggest it is not just AF as such .. but rather the ability for my K3 with the two lens (and TC) to achieve sharp focus at all.
---------- Post added 04-23-14 at 11:55 PM ----------
One more thing when it comes to focus. You need to keep an eye on the shutter speed.'
--> Yes Shutter always > focal length. This last week .. it was sunny and on the tripod with ISO <= 800 I was able to keep faster that 1/400 in all shots. Also made sure any sign of wind had stopped before firing. Certainly shouldn't have been enough at those shutter speeds to consistently result in soft focus.
'I had the same issue with a da* 300. Tried live view even called pentax to see if there were any known issues. Of course none. As a last resort before sending it all in for service I removed the protective filter and voila sharp photos consistently.'
--> I'm going to sound like a complete tit here (and not like the lovelies flying around the garden all week) .. what protective filter ? I do have Kenko UV filters that were supplied by SRS. I'd hope they were the good SMC ones. SRS seem like a great bunch to me. I can try and shoot without it you think it makes sense - certainly to rule them out. I'd be terrified to leave a filter off such an expensive lens for any long period.
I know there are some more hard core pro and semi pro people on the forum that understandably treat the cameras as the tool they are really supposed to be .. and therefore things like the odd bit of cosmetic damage or sending off to foreign lands for calibrating / fixing doesn't seem like something to worry about ... but I also detect a number like me who are just enthusiastic amateurs who see their camera kit as a staggeringly expense toy to be cherished ... and don't want anyone taking it apart, especially in it's first year of newness. I'd say both are completely understandable attitudes .. for me ... I just feel if I buy new .. and something is clearly faulty from new ... It should be replaced with new - not 'repaired',
Again ... many thanks for all your thoughts. I eagerly await others ... and will hopefully get to chat to SRS and Ricoh about it soon.
Paul.