20/21mm on FF..........yet again!
/forum/topic/1133625/1

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timballic
Registered: May 21, 2011
Total Posts: 768
Country: United Kingdom

RustyBug wrote:

BTW ... if you are looking to avaoid vignetting in the WA/UWA camp ... the newer Tilt-Shift lenses have larger image circles that pretty much obliterates vignetting, have superb distortion control and excellent resolution and smooth tonal transition ... albeit a touch less contrasty (easy to bump in post) as the projection does spread out it little bit more.

Size, weight & $$$ all go up accordingly, but for WA/UWA ... my 24L TS-E II is virtually flawless @ distort/vignette/resolution. I can only image the new 17L TS-E is likewise benefitted by the larger image circle.


The 24L TS-E II is my "most drooled over" lens. One day!

I've been looking forward to a "report" on this lens from you ever since you got it Kent. Still waiting!

Does Lightroom have a vignette fix, or only PS?



melcat
Registered: Jun 13, 2008
Total Posts: 697
Country: Australia

timballic wrote:
Using on Canon MkII, I've found that my recently bought, little used Zuiko 21mm F2 has vignetting which never completely goes away with stopping down (no filters on!), although it reduces in size it gets sharper and more noticeable


My copy didn't do that on film - I checked some original slides. This was one of my favourite lenses on film and I have lots of those.

It is possible that the angle of incidence at the corners is enough to cause vignetting on Canon sensors but not film (the problem Leica had to solve with their angled microlenses). This may be one of the lenses Olympus was referring to when they said their OM lens designs were not "telecentric" enough to build a digital OM body. On the other hand, I have located some test shots I made on my 5D with the same copy of the 21mm f/2 I used for film and they look OK. Unfortunately the notes I made were a bit scrappy and I don't totally trust what apertures they were shot at. There is an example there with no vignetting marked as f/11 - for sure it's gone when fully stopped down. I decided to go with a Canon zoom, no longer have this lens, and never did more with it on digital than test it, so can't help you more there.

Otherwise, it could be a bad copy or maybe, as suggested, your adaptor.



ZoneV
Registered: Nov 20, 2008
Total Posts: 890
Country: Germany

It could be the microlens problem.
This could explain the different behavior in the edges - bacause microlens and the sensitive parts bellow are not in every case 100% symmetrical in every direction.

Or the different edge vignetting could be caused by a decenterd lens - probably due too the adapter. Did you made a decentring test, with the same ~ infinite object (with much detail) photographed in 5 images - one picture with object in the mid, and the oither images with object in the edges. If sharpness of the edges images is not the same -> lens is not centered enough.



timballic
Registered: May 21, 2011
Total Posts: 768
Country: United Kingdom

Interesting that the examples RustyBug showed with his18mm Zuiko were very similar to my 21mm and equally decentred vignette wise.

I suspect the problem with them is both the angle of light falling on corner microlenses, plus being very slightly decentered when used with adapters.
I bought fairly expensive Japanese Elefoto adapters, (40+) to try and avoid such problems, but it might only need to be fractional displacement to cause the differences seen. I certainly haven't noticed any difference in corner sharpness, but then I haven't tested specially for that either.

Surprised that vignetting isn't such a problem with the 20mm Voigtlander, beyond F5.6 It's still there but so much more gradual as to be acceptable, it's the acuteness of the Zuiko vignette that makes it so noticeable.



RustyBug
Registered: Feb 02, 2009
Total Posts: 12887
Country: United States

+1 @ acuteness = noticeable
+1 @ microlens / corner

No recall @ adapter used (i.e. cheapie vs. Fotodiox Pro)

LR4 does have vignette adjustment capability.



Gunzorro
Registered: Aug 28, 2010
Total Posts: 6496
Country: United States

ManWearPants wrote:
How about replacing DPP with another software that can cure vignetting. Otherwise, will performing a small crop solve the problem? Just frame larger than necessary, keeping the need to crop in mind.


+1

I agree, this is an inexpensive solution. Buy LR4 and use it to remedy. I had a similar problem with fairly strong CA and a bit of distortion in my original 24 TS-E lens. LR3 made it a viable lens for a while longer, until I could afford the version II.

If your lens is sharp enough otherwise, the software PP fix should be a no-brainer.

Also -- in my experience, sensors are seldom perfectly centered, as evidenced by using brand glass without adapters, and viewing corner vignetting. Easy to see with TS lenses racked all the way to extremes and then stitched together -- not all corners are created equal (equidistant!). Don't sweat that, just try to get the darkening reduced and you'll be better.

I'm still curious how the Canon EF 20/2.8 would do on your camera.



AhamB
Registered: Jul 11, 2008
Total Posts: 4964
Country: Germany

With adapters for Canon I can usually move the lens laterally and see the FOV change in the viewfinder quite a lot.



AmbientMike
Registered: Feb 04, 2010
Total Posts: 1404
Country: United States

My 17-35 seemed to beat 21/3.5 om and 20/2.8 af nikko r. Don't know about vignetting though. I would try for mc if in 21/3.5 I love mine but older and not that hot, really.

Seems like you could dodge or clone stamp easily especially if you only process a few images.



timballic
Registered: May 21, 2011
Total Posts: 768
Country: United Kingdom

Gunzorro wrote:

I'm still curious how the Canon EF 20/2.8 would do on your camera.


I used to have the Canon EF 20/2.8 and found it rather large and uninspiring, (v. similar to the 17-40L which I got in its place) I then got the Zuiko to have a small MF lens at this FL with hopefully more character!

I keep trying to get into using Lightroom and giving up and returning to DPP!



rtester
Registered: Feb 04, 2009
Total Posts: 457
Country: United States

I have not experienced that problem with my 21/2 on the 5D or Ds

Top 2 and the 4th are the 21

the beach is the Jena flektogon 20 2.8 you may give that lens a try, I really had good results with it.



Noodlz79
Registered: Jun 13, 2011
Total Posts: 89
Country: Australia

My 21/2 on 5D Mk2 does alright also:

_MG_0457 by Sean H Choe, on Flickr

_MG_0469 by Sean H Choe, on Flickr



timballic
Registered: May 21, 2011
Total Posts: 768
Country: United Kingdom

Now I am confused! There certainly isn't any on any vignette on any of those examples with the 21.2 on 5Dc or 5DII. Many thanks for posting rtester and Noodlz79.
My lens is absolutely mint in every way too, and sharp. Perhaps I ought to get it checked out by an Olympus OM Lens Repairer though, just in case?



rtester
Registered: Feb 04, 2009
Total Posts: 457
Country: United States

Not sure why you are getting that it could be the adapter or body? My 18 even has some pretty nice results and I really do not have much of a problem with that as well. I am using big is adapters and eventually going to leitax the keepers.

two from the 18



timballic
Registered: May 21, 2011
Total Posts: 768
Country: United Kingdom

Thanks again rtester, I'll get it properly checked out at repairers.



timballic
Registered: May 21, 2011
Total Posts: 768
Country: United Kingdom

Lens on its way for checking by Olympus OM repairer. For peace of mind as much as anything else, at least if everything is fine I'll only have postage x2 to pay.

rtester, concerning the 18mm Zuiko and lack of Vignetting in examples above, I was interested in MrJoes comments about his 18mm in this thread: http://www.fredmiranda.com/forum/topic/1077627/0?keyword=oly,24#10255968
He also gets vignette even at F8.



RustyBug
Registered: Feb 02, 2009
Total Posts: 12887
Country: United States

Will be watching this one ... the posted pics don't have the strong "tips" that we've seen elsewhere.

I'm wondering to what degree contrast @ processing is keeping them at bay vs. lens vs. adapter vs.

From the same Oly 18 as the truck (not sooc)



rtester
Registered: Feb 04, 2009
Total Posts: 457
Country: United States

My 21 does seem to have very little to no "tips", My 18 sometimes does but really not bad. The first two are the 21 and the last the 18. Not much PP at all healed a couple sensor dirt and a little on the exposure.



RustyBug
Registered: Feb 02, 2009
Total Posts: 12887
Country: United States

Hmmm ... wondering @ adapter thickness coming into play @ the tips. Most times the discussion @ adapter thickness relates to infinity focus. How would adapter thickness relate / impact the corner vignetting.

BTW ... interesting to see your 21mm view of Horseshoe Bend vs. my 18mm view of the same from nearly the exact same vantage point.



timballic
Registered: May 21, 2011
Total Posts: 768
Country: United Kingdom

If the ∞ stop is perfect with an adapter, then I it can't be the adapter causing vignetting in my understanding. (Although the adapter can still be slightly decentering the lens causing the unevenness of the darkening in each corner.)
It must be lens or sensor variation, and as we're all on 5DII's here, it's more likely to be lens variation?
(Why am I assuming that Canon's sensors don't vary? )



melcat
Registered: Jun 13, 2008
Total Posts: 697
Country: Australia

timballic wrote:
If the ∞ stop is perfect with an adapter, then I it can't be the adapter causing vignetting in my understanding.


The stop can be past infinity, and AFAIK is on OMs that haven't been tampered with.

Considering the cost of the lens and labour, can't you find a film body OM to test it with?



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