Something very wrong with this lens

Olympus 8mm f/1.8 M.Zuiko Digital ED Fisheye PRO Lens

03/28/2017 08:32:34 AM · #1

I guess I rather over-complicated my last post, so let's try again.

I've never been happy with the sharpness of my Sigma 18-200 OS lens (2006 version), but never realised quite how bad it was until recently, when I decided to take a few test shots. Here's a composite comparing it to my Canon 60mm macro lens - both 100% crops.

I tried both autofocus and manual and that really is as good as it gets.

I've been considering buying the latest version of Canon's 18-135mm lens, which is said to have amazingly quick autofocus but would welcome any other suggestions for a walkabout lens.

Pentax D-FA* 70-200mm f/2.8 ED DC AW

03/28/2017 12:22:19 PM · #2

Have you tried a lens focus calibration test?

K3Master

Pentax K-3

03/28/2017 01:19:23 PM · #3

Well, not only is Sigma always going to be a lesser quality lens, but you're comparing a long zoom lens with a Prime, which is futility in and of itself.

Olympus 8mm f/1.8 M.Zuiko Digital ED Fisheye PRO Lens

03/28/2017 01:40:36 PM · #4

Originally posted by Ja-9:

Have you tried a lens focus calibration test?

Would a badly calibrated lens cause such bad results when using manual focus?

Originally posted by K3Master:

Well, not only is Sigma always going to be a lesser quality lens, but you're comparing a long zoom lens with a Prime, which is futility in and of itself.

Under normal circumstances I'd agree, but the result is so soft that I don't think any lens would produce such results. I've also posted comparison shots using my (cheap and outdated) 50mm 1.8 as well as my Olympus 12-50mm kit lens.

I've kind of given up on this lens though, so the real question is what I should replace it with. (I guess once again I worded my initial post badly but I did it in a hurry.)

03/28/2017 02:00:53 PM · #5

Originally posted by GinaRothfels:

[quote=Ja-9] Have you tried a lens focus calibration test?

Would a badly calibrated lens cause such bad results when using manual focus?

Im not sure but it's worth a try...could your vision be off? Diaper?

Olympus 8mm f/1.8 M.Zuiko Digital ED Fisheye PRO Lens

03/28/2017 02:11:30 PM · #6

Originally posted by Ja-9:

Originally posted by GinaRothfels:
[quote=Ja-9] Have you tried a lens focus calibration test?

Would a badly calibrated lens cause such bad results when using manual focus?

Im not sure but it's worth a try...could your vision be off? Diaper?

I only use manual focus in live view. I've just tried the same test shots again though, and I seem to be getting SOME better shots mixed in with the blurry ones. Now I'm really confused.

Just wanted to add I've started reading about lens calibration and will read further later on.

Message edited by author 2017-03-28 14:32:30.

Sony DT 18-70mm f/3.5-5.6 Aspherical ED Zoom Lens for Sony Alpha

03/28/2017 02:36:44 PM · #7

Originally posted by GinaRothfels:

Originally posted by Ja-9:

Originally posted by GinaRothfels:
[quote=Ja-9] Have you tried a lens focus calibration test?

Would a badly calibrated lens cause such bad results when using manual focus?

Im not sure but it's worth a try...could your vision be off? Diaper?

I only use manual focus in live view. I've just tried the same test shots again though, and I seem to be getting SOME better shots mixed in with the blurry ones. Now I'm really confused.

Just wanted to add I've started reading about lens calibration and will read further later on.

Well I have the lens calibration thingy.....but I've yet to use it....pfffffftttt there's that....lol

On the other hand it's a cheap way to check your lens , new/used?

kirbic

Canon EOS R5

Canon RF 24-70 f2.8 L IS

03/28/2017 02:39:36 PM · #8

Originally posted by GinaRothfels:

...I seem to be getting SOME better shots mixed in with the blurry ones. Now I'm really confused.

Just wanted to add I've started reading about lens calibration and will read further later on.

Sounds a lot like you are seeing erratic focus. If you're manually focusing using live view and getting erratic focus, it can't really be the lens. Live view is directly off the sensor, so if you're in focus on live view, it's as good as its going to get.
Now, if you don't get properly focused shots in AF, and you have proven that (at least sometimes) you can get better results in Live view with manual focus, then there is definitely an AF accuracy problem.

kiwinick

Sony DSLR-A550

03/28/2017 02:46:35 PM · #9

Take your lens to a reputable camera repair shop and have them check and recallibrate the lens. Ihad a lens that was a complete stop overexposing and the guys at the shop sorted that one for me.

Olympus 8mm f/1.8 M.Zuiko Digital ED Fisheye PRO Lens

03/28/2017 03:46:42 PM · #10

I've tried some micro-adjustments, and got some slightly better results mixed in. I also had the camera indicating that some shots were in focus when they were a total blur, and some bad hunting, an issue that I've been worried about with my new (second hand) 60mm macro lens, as discussed in this thread:
//www.dpchallenge.com/forum.php?action=read&FORUM_THREAD_ID=1342686

Now I'm starting to wonder if the problem is actually the camera. Time to drag my 400D out of retirement and do some more tests.

Olympus 8mm f/1.8 M.Zuiko Digital ED Fisheye PRO Lens

03/28/2017 08:46:18 PM · #11

It took me a while to find where I'd packed my 400D so the battery is still charging. Meanwhile I did a bit of reading and decided to try cleaning the lens contacts on both lens and camera using a dry cloth. Everything seems to be behaving a bit better now, so maybe this whole thing is much ado about nothing. Looks like I can't justify buying the Canon 18-135mm Nano USM after all.

03/28/2017 11:29:14 PM · #12

Hmmmmm