[ChatMechant]

I haven't seen that kind of thing from mine. It is a surprisingly sharp lens.

[Adam]

I admit I'm flummoxed. I have tried all my lenses on the K-1, and they all perform as expected or better ... except for the D FA 28-105.

With that lens, I do get many shots that look great. However, some look weirdly maniacal when I zoom in, particularly images of foliage or bare branches. For example, here's a pretty simple image (28mm, 1/125 sec, f/7.1, ISO200):



But here's a crop zooming in on the branches, leaves and rushes:



It looks demented, disturbing! In fact, it looks like a slightly shifted double image. I keep getting this from the 28-105, but from no other lens.

Can anybody suggest a reason? Has anyone seen similar behaviour with their copy of this lens? No filter is attached.

With that lens, I do get many shots that look great. However, some look weirdly maniacal when I zoom in, particularly images of foliage or bare branches. For example, here's a pretty simple image (28mm, 1/125 sec, f/7.1, ISO200):

Definitely looks like motion blur. The lens isn't without its flaws, but I don't think the lens is to blame here. If it was a little windy you'd need a faster shutter speed.

And I'm assuming pixel shift was off

[Ole]

I admit I'm flummoxed. I have tried all my lenses on the K-1, and they all perform as expected or better ... except for the D FA 28-105.

With that lens, I do get many shots that look great. However, some look weirdly maniacal when I zoom in, particularly images of foliage or bare branches.



It looks demented, disturbing! In fact, it looks like a slightly shifted double image. I keep getting this from the 28-105, but from no other lens.

Can anybody suggest a reason? Has anyone seen similar behaviour with their copy of this lens? No filter is attached.

I get similar results. I'm going to investigate further, but my off the cuff theory is that the bokeh of this lens is less than stellar and out-of-focus areas render with this double-exposure look to them.

[lytrytyr]

So does ePHOTOzine in their review of it.

Equivalence alert:

"28-105mm on 35mm-format equates to 43-161mm on APS-C".

[Nickrs]

If I get a chance I will try to run some tests tomorrow, I have the lens and I have the trees but I have a K3 not a K1. I've had this lens for about a month and not noticed any bokeh problems.

NB. As my trees are in Wales they may appear upside down to people in Australia.

[Paul the Sunman]

Definitely looks like motion blur. The lens isn't without its flaws, but I don't think the lens is to blame here. If it was a little windy you'd need a faster shutter speed.

And I'm assuming pixel shift was off

Pixel shift was certainly off!

---------- Post added 25-07-16 at 06:36 AM ----------

I get similar results. I'm going to investigate further, but my off the cuff theory is that the bokeh of this lens is less than stellar and out-of-focus areas render with this double-exposure look to them.

It looks like no bokeh I've ever seen.

---------- Post added 25-07-16 at 06:40 AM ----------

Motion blur can be an unintended consequence of increased pixels. Somebody told me that, I didn't think it up myself.

But why should it be restricted to one lens? I was also shooting the D FA* 70-200 extensively yesterday, (and previously) and there was no sign of the issue.

Nevertheless, at least from yesterdays's shoot, the effect is absent or much reduced at 1/320. By the way there was essentially no wind at the time.

[Dlanor Sekao]

Obviously something ISNT Right !
I have the DFA 28-105 and am Extremely pleased with it and its quite sharp overall.
Sorry I cant contribute anything of significance other than my copy is Fantastic and I shoot at 28mm and handheld with alot slower shutter speed than this with no problems at all with SR.

---

Last edited by Dlanor Sekao; 07-24-2016 at 03:14 PM.

[BigMackCam]

Has anyone tried shooting at 1/125s while at 28mm and pixel-peeped the results, like the OP? I'm wondering, just wondering, if there's narrow shutter speed range where the problem might occur... as has been experienced on other cameras from time-to-time - per the article links i posted earlier... Would be worth proving or disproving that, in my view...

[Paul the Sunman]

Here's another crop where clearly there is no wind effect.

28mm, 1/50 sec, handheld with SR on, f/11. Note the double image on the platypuses.



I'll try a few shots today with SR turned off. But really, the K-1's SR should easily accommodate 28mm, 1/50 sec.

UPDATE: Left my battery at home! No shots today.

[BigMackCam]

Paul - can you test without SR also? Interested to rule out if it's SR related...

[C_Jones]

The tripod factor would contribute real "non-shake" results.

[Nickrs]

28-105mm Hand held.

ISO 800, 1/60sec, f/3.5, focal length 28mm. (Note: resized by no extra jpg compression)

I'll try some trees on the morrow.

[wissink]

That looks like motion blur to me, but here is some helpful advice from Matt Damon:

Thats the best thing I"ve read all day, thank you!

Has anyone tried shooting at 1/125s while at 28mm and pixel-peeped the results, like the OP? I'm wondering, just wondering, if there's narrow shutter speed range where the problem might occur... as has been experienced on other cameras from time-to-time - per the article links i posted earlier... Would be worth proving or disproving that, in my view...

Pretty sure I had this with the DA35 2.4 at 1/125. I know it was 1/125 because I noticed and am debatting with myself about turning SR off like I did with the K-7 but the Falk Lumo read has me rethinking. Food for thoughts... it is wide-angle.
David

[Paul the Sunman]

Paul - is it only happening at certain shutter speeds? For intance, if you keep the shutter speed considerably higher or lower, do you still get the problem? How about SR - does it only happen with it on, or off too?

I'm wondering if this is shutter induced. Have a read of this article - interesting... EDIT: Also, this article. Both are related to the K-7, but I suspect the problem is possible in any camera.

Interesting articles! That does look like it might be the culprit, and explain why I wasn't seeing it on my longer lenses. When I can, I'll try with and without SR, at different shutter speeds, and with the DA 16-85 @28mm as comparison.

But if this is the cause, I'm surprised others haven't noticed it before.