Distortion with the 21 VC?

chikne

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Hi,

I was looking at a shot taken the other day with this lens and wondering if it is actually barrel distortion that I see on the edges, it seems the window sills/edges/frame bend a bit inwards.

Not that it bothers me, just wondering.

3288335283_bd8cfc8b96_o.jpg


Thanks
 
I've noticed my 35mm Nokton exhibits a fair amount of barrel distortion so it doesn't surprise me to see that the 21 does also. It's much more apparent at very close range with my Nokton ... I correct in post processing if it's really noticable!

Have a look at the so called straight line at the top of the frame of this pic shot recently! :eek:

studiogameon011.jpg
 
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I find the 21f4 has very well controlled distorsion. In fact, I find it better in that aspect than the 21f2.8 Asph Elmarit and the 21f2.8 ZM Biogon.
If you want a virtually distorsion free 21 - the only one, at the moment, is the 21f4.5 ZM Biogon ( it is in the range of 0.01%!!!!!!). I haven't had a chance to try out the $6000 Summilux 21 in this aspect, but high speed lenses are usually more prone to distorsion at the best of time - though for $6000 I do expect well controlled optics - and I think at that price they should cook,clean and take out the garbage too.
 
Interesting, Keith. Does remind me strongly of the 35/1.4 which doesn't do worse than what you show.

Chikne, I think the 21 is OK. Maybe a teeny bit. See attachment.

Roland.
 
Given a choice, technically I'd prefer no rectilinear distortion (barrel or pincushion, or moustache), as it is an optical shortcoming I think; a compromise allowed by the lens maker in exchange for some other benefit. But a a little barrel distortion seems almost universal in normal-wide lenses, especially at the wide end of zooms. And some photographers express a preference for a little barrel distortion to lessen the "stretch" effect on objects imaged in the corners of the frame.

Chikne, with your shot I had to put a straight edge along the slanted lines to be sure my eyes were telling me the truth about slight barrel distortion... More obvious in Keith's shot because the parallel frame edge provides a straight reference.

Mick, I'm going to guess that you like the sense of wideness that is a natural optical consequence of all wide angle lenses: perspective distortion... not the rectilinear distortion that Chikne asked about?
 
Indeed it is very minimal....

Tom are you sure about the 4.5 biogon? The VC and biogon are the same construction.....
 
The Biogon ZM 21f4.5 is a modern version of the vintage Biogon 21f4.5. That lens was the champion wide angle for decades (50's and 60") and still will hold its own.
When the 21f4.5 ZM was announced Mr Kobayashi was very proud of it ( and that he could persuade Zeiss to let him make it). He told me "The old Biogon had a distortion of 0.02% and the new one is 0.015 or 0,015 " When I asked how we could tell, he answered "You have to print really big to see it".
I am very found of both my Biogon 21f4.5's - the old one usually sits on a Nikon S3/S2 and the new one on my R4M - though today I switched to the Biogon 21f2.8 as that one otherwise would feel left out!
 
Sorry, but I disagree without any offend.

I`ve done an indoor shooting of my appartment with the CV 21 and the distorsion is horrible. Specially when objekts are very close to the boarders. Some of the pictures are really ridiculous. As it was an art projekt I have accepted the distorsion as a part of the "flaire".

With my Rd1 it works with less distorsion and the fotos are really good.

George
 
Schneider's Super Angulon designs, both the older f/4 and the newer f/3.4, are reputed to have the least distortion of the 21's.
 
The distortion is something that I only noticed with the type of shot I posted and I think you can use a lens for a long time before you become aware of it. I've had my Nokton for at least a year and never became aware it until a few weeks ago so it's not really a huge issue ... the lens is still a killer in my eyes!
 
Tom, those are the diagrams

VC:

kosei-e_04.gif


Biogon:

21CBioL.jpg


they look very close you know...

But as they say, Close but no cigar! There are small differences in the glass composition and the shape of the elements - enough to make a difference in performance.
 
The distortion is something that I only noticed with the type of shot I posted and I think you can use a lens for a long time before you become aware of it. I've had my Nokton for at least a year and never became aware it until a few weeks ago so it's not really a huge issue ... the lens is still a killer in my eyes!

I do find the issue of distortion with wide angles a bit overblown. In most cases it is user mistake. Unless you spend your days shooting architectural or industrial images - you will rarely, if ever have a problem with it.
In 2001 or 2002, a friend and I did some extensive testing of several 21's, the 21f2.8 Elmarit Asph, the LTM 21f4 VC, 21f3.4 Super Angulon, Ricoh 35f3.5 LTM and the conclusion was that at that time the 21f2.8 Asph was the top of the heap, closely followed by the VC 21f4 and the SA and the Ricoh battling for third. One of the conclusions we came to was that the 21f4 VC had less edge distorsion than the 21f2.8 Asph. My friend makes his living shooting archictural stuff - so he knows what he is looking for.
To really get it - you have to use a spirit level (2 ways) and a tripod and pray that the subject is linearly straight too.
 
Mick, I'm going to guess that you like the sense of wideness that is a natural optical consequence of all wide angle lenses: perspective distortion... not the rectilinear distortion that Chikne asked about?

Doug, you are indeed correct. I love the way that wides mess around with perspective, I also like the distortion that comes with very wide lenses 15mm or 12mm at the edge of the frame. Many of Mr Kaplan's photographs exhibit this property.

There are some prime examples here: http://thepriceofsilver.blogspot.com/2008_10_01_archive.html

I've never heard of moustache distortion before. I had to Google it to be sure you weren't having a larf. :)
 
The distortion is something that I only noticed with the type of shot I posted and I think you can use a lens for a long time before you become aware of it. I've had my Nokton for at least a year and never became aware it until a few weeks ago so it's not really a huge issue ... the lens is still a killer in my eyes!

Don't get me wrong, Keith, I do fully agree with you. It just caught my eye since distortion and bokeh are usually what come up when the 1.2 is being favorably compared to the 1.4.

The 1.2 is a great lens and CV accomplishment; for 1.2 wide angle it's the only game in town, period.

Roland.
 
Don't get me wrong, Keith, I do fully agree with you. It just caught my eye since distortion and bokeh are usually what come up when the 1.2 is being favorably compared to the 1.4.

The 1.2 is a great lens and CV accomplishment; for 1.2 wide angle it's the only game in town, period.

Roland.


I see it as the 1.2 having a bit of character and the ability to throw the odd surprise at you! :p

My most admired lens in the CV range by far is my 15mm Heliar ... I can't fault this lens, not that I'm any expert, but it consistently produces results beyond my expectations!

I never thought I could possibly get to like a super wide as much as I like this little gem. :)
 
As a matter of interest here's a pic I took the other day with the 15mm ... it really is an amazing lens!

p323419379-4.jpg
 
I think there is minor distortion at distances, but is noticable when you are taking items upclose.


The pillars supporting this church are vertical and don't lean inward.
3058265217_58e5262e93.jpg



Obviously, my door isn't a trapezoid. You also can see a small curve to the door frame.
2900227506_e20e48ccf8.jpg


However, for most uses, such as a building from a distance, any distortion is negligible:
2993411818_2535e1b3e0.jpg
 
Sometimes it can get really bad. That tower on the right just doesn't look right ....

48880102_zJe8V-L.jpg


But then, Photoshop can fix it ...

48880103_jjvEe-L.jpg


I might have overdone the tower though .... :) :)

(15 Heliar)

Roland.
 
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