|
Forum: Pentax SLR Lens Discussion
12-18-2015, 01:38 PM
|
| |
Thanks for the reply. I am familiar with phase vs. contrast detect auto-focus. I just wanted to make sure anyone reading this thread knew that I had tried both and achieved different results. Like you, I was not shocked that there were different results between the two methods. I was just surprised how consistently it missed through the viewfinder. I don't expect perfection, just usability with some degree of trust at f1.4-- or else why bother? It feels more like a mistake when it actually achieves focus. I won't always be shooting at f2.0 or wider, but it would be nice to be somewhat confident in those situations.
I have a K5 and a K5iis and tried it on both bodies. I have tested in on several still subjects around my house, as well as a few people. If I go for the eyes, I get the ears. Maybe I should start focusing on the nose. ;-)
---------- Post added 12-18-15 at 03:54 PM ----------
At least I am not alone, haha. Thanks for the reply. This is a shame, really. There are not many alternatives in the 35mm f1.4 space. There is the 31mm Limited, which by most accounts is a great lens but is dated, noisy, somewhat soft wide open, and pricey given those marks against it. (Odds I offended some of the 31mm faithful: 100%) Of course, there is Samyang. But...um...auto-focus is nice to have.
I guess I keep it and let it frustrate me from time to time (but get some killer photos as well), or return it and let the dream of a fast, quiet, well-made 35mm prime die an unfortunate death. Decisions...
|
|
Forum: Pentax SLR Lens Discussion
12-18-2015, 11:39 AM
|
| |
Hey, everyone. I am having an issue with my Sigma 35mm f1.4 Art lens and thought maybe the Pentax community could provide some insight. The scoop:
I recently purchased the Sigma and immediately noticed it was back-focusing. 7 out of 10 shots -at least- were back-focused. I tested this on subjects very close to the lens and on subjects up to about 50 feet away. Same result. I was shooting anywhere from f1.4 (mostly this) to f2.0, no tripod (but being very careful and steady), focusing through the viewfinder. Center point, no recomposition. AF fine adjustment, no matter what adjustment I dialed up, seemed to have no effect whatsoever.
So, I tried focusing through live view. Suddenly, the script flipped. The vast majority of shots were spot-on, perfect focus. Switching back to the viewfinder, the lens seemed to focus more accurately for awhile, but very quickly reverted to back-focusing a lot.
I have since ordered a second copy. Through the viewfinder, the new copy is less predictable, back-focusing some, front-focusing a little, and probably hitting it perfectly 15-20% of the time. Same parameters, same improved result in live view. It still does not feel like AF fine tuning does anything- doesn't make it worse or better no matter what I do.
So, either I am missing something and the problem lies with me being ignorant of a potentially obvious detail (completely possible), or I am cursed with two defective copies of the same lens that have very similar faults.
Any thoughts or recommendations? Thanks!
|
|
Forum: Pentax SLR Lens Discussion
08-28-2015, 12:42 PM
|
| |
My experience with this lens has been hit and miss too. First copy I received was flawless optically, but had trouble focusing on anything at a distance of more than 20-30 feet unless I pointed the lens straight up or down several times. And then I ended up with a few unfocused shots. 2nd copy focuses perfectly and is 95% optically perfect--the upper right corner is slightly softer than the rest of the image at 16mm. I was able to compare it to the first copy which was sharp everywhere.
Also interesting is that the 2nd copy with the soft upper right corner (nothing crazy, just softer when viewed at 100%) is noticeably wider at 16mm than the first copy. I am torn at this point--should I swap the 2nd copy for a 3rd, hoping for a copy that focuses well and is uniform corner to corner, or just keep the 2nd copy which is still quite good and not risk getting another copy with issues?
Even with these issues I am a big fan of the lens.
|
|
Forum: Pentax SLR Lens Discussion
08-13-2015, 12:03 PM
|
| |
I noticed this day before yesterday while shooting a cityscape! If I point the camera straight up, the focus locks. But outside of that "fixing" it, the flashing focus lock problem still happens, happens with focus adjustments, happens in live view. And this fix only works for infinity focus, not so well on intermediate subjects. I'll be exchanging the lens. No biggie.
|
|
Forum: Pentax SLR Lens Discussion
08-10-2015, 12:40 PM
|
| |
Thanks for the replies, everyone. I am going to try some of the suggestions here. Since the lens seems to be a solid copy optically, it would be nice to not have a reason to swap it. I'll post the results in a couple of days. Thanks again!
|
|
Forum: Pentax SLR Lens Discussion
08-10-2015, 09:20 AM
|
| |
Hey everyone! I am looking for some input on an issue I have run into with my HD 16-85. I just purchased it last week and took it out over the weekend to get familiar with it. So much about this zoom is a pleasure, and I typically use primes. Solid feel, surprisingly good corners on the wide end, and quiet (not silent) focus.
But I quickly ran into an issue when focusing on more distant subjects. I was trying to auto-focus on a building about 75 yards away. This was not a low-light situation. I was using the following settings: Aperture priority, lens at 16mm, f8, auto ISO (100), evaluative metering, center point auto-focus, af-s, using the viewfinder, battery grip attached. When putting the focus point on the building and using the shutter button to auto-focus, I would get the central red indicator momentarily (as usual) but the green hexagon focus lock indicator would flash continuously. If I released the shutter button and tried again on the same building, I got the flashing hexagon again. If I tried focusing on a shrub 10 feet in front of me, perfect focus. Back to the building, flashing hexagon. If I refocused and recomposed enough, I could eventually get the shot. Some came back out of focus. As my day went along, I noticed it most often on subjects more than 100 feet away, but sometimes on closer things as well.
I changed settings, focal lengths (could happen across the range but more often on the wider third) turned the camera on/off, mounted/dismounted the lens, checked the contacts on the body & lens, tried it with the battery grip off, different auto-focus point modes (never tried live view), etc. It still happened. My fiance 20 feet away? Focused. The brick wall 30 yards behind her? Hit or miss. Again, when it locked focus it was very accurate. But about a third of my day involved a flashing focus lock indicator and an inability to trigger the shutter. It was frustrating. Never noticed this behavior with any of my other auto-focus lenses. Any help is greatly appreciated!
|
|
Forum: Pentax SLR Lens Discussion
11-19-2014, 08:51 AM
|
| |
I did look at the photos. And I agree that two of the group photos are particularly bad. As some of the prior posts indicate, there are a lot of variables here. But if we look at the shot of the gym -the most controlled recent shot, from what I gather- the sharpness difference in the crops seems pretty consistent with this lens.
|
|
Forum: Pentax SLR Lens Discussion
11-19-2014, 08:19 AM
|
| |
Based on my experience with this lens, the OP's problem seems normal. The 15 was my first prime lens and I bought it for landscapes. I actaully sent the first copy back due to softness in the borders/corners. The next copy was exactly the same. But after shooting with it for a couple of weeks, I became addicted to the rendering. I have to apply some specific sharpening or cropping in post, but the majority of my printed photos were taken with this lens. Landscapes and closeups are where this lens shines. Group photos will be a challenge and very much hit and miss.
|
|
Forum: Pentax K-5 & K-5 II
04-05-2014, 09:15 AM
|
| |
I was also quite lucky with a drop of my K5. My shoulder strap was dangling below the camera, and my dog decided to take an interest in what I was doing. She sprung up to check out the camera in my hands, and as she lowered herself back to the ground her paw went through the loop of the strap and yanked the camera from my hands. It smacked firmly onto the driveway. My heart stopped. I picked it up expecting a disaster. There was a tiny (not even half a millimeter) chip in the metal below the grip and a small scuff on the memory card door. That's it. Lens unscathed, body functions normally. Very lucky!
|
|
Forum: Pentax SLR Lens Discussion
03-18-2014, 05:46 PM
|
| |
Between the two Limiteds I own, I'd have to pick the DA 15. I love the FA 77 (although I agree with GoremanX that the fringing/CA is not always easy to fix) but the 15 spends more time on my camera.
|
|
Forum: Welcomes and Introductions
12-09-2013, 05:46 PM
|
| |
Thanks for the warm welcome, everyone.
|
|
Forum: Welcomes and Introductions
12-08-2013, 07:40 PM
|
| |
Hello everyone! I've been shooting with a K-5 since March and have often found myself perusing this forum for info & tips. Taking the step to become a member was overdue. I look forward to contributing to this great Pentax community!
|
