Keith
The best camera is one that still works!
naaah ... that's called artistic license isn't it!
chris00nj
Young Luddite
Sometimes it can get really bad. That tower on the right just doesn't look right ....
But then, Photoshop can fix it ...
I might have overdone the tower though ....
(15 Heliar)
Roland.
Clever!
However, the back wheel on the cart has an oval shape to it.
rogue_designer
Reciprocity Failure
there seems to be a basic miscommunication here...
there is distortion due to it being a wide angle lens. That's normal, and must be dealt with as part of the focal length. That's what you're seeing stretching, trapezoids and leaning pillars and columns (especially if you are not using a tripod and a level)
pincushion and barrel distortion (which the OP was asking about) is when those trapezoids would start to exhibit slight curvature that isn't already present in the physical feature (ie. a doorframe, that suddenly has a bow in it, rather than showing straight lines)
That curvature is the kind of distortion that he (and others) are trying to minimize.
there is distortion due to it being a wide angle lens. That's normal, and must be dealt with as part of the focal length. That's what you're seeing stretching, trapezoids and leaning pillars and columns (especially if you are not using a tripod and a level)
pincushion and barrel distortion (which the OP was asking about) is when those trapezoids would start to exhibit slight curvature that isn't already present in the physical feature (ie. a doorframe, that suddenly has a bow in it, rather than showing straight lines)
That curvature is the kind of distortion that he (and others) are trying to minimize.
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Bob Michaels
nobody special
There is a use for a view camera (with movements for perspective control) and there is a use for a 35mm RF. Those uses have little overlap.
Are some of you trying to make a silk purse out of a sow's ear?
Are some of you trying to make a silk purse out of a sow's ear?
Keith
The best camera is one that still works!
Well ... I've seen plenty of sow's ears made from silk purses in the Noctilux threads (not all) ... maybe the trend needs reversing!
sebastel
coarse art umbrascriptor
Tom, those are the diagrams
VC:
Biogon:
they look very close you know...
i'd like to add, that distorsion is only partly related to the actual composition of a lens from optical elements. a big deal of distortion is caused by the position of the aperture. the general rule is, that symmetric construction make it easier to find a place for the aperture where it does not cause distortion.
cheers
sebastian
EDIT:
here is a link to the content of a book describing the effect.
http://books.google.com/books?id=c4RrwJ_baFYC&pg=PA60&lpg=PA60&dq=distortion+%22aperture+location%22&source=bl&ots=WJASUwT_j5&sig=AFSWhRp0fNBkqlCr58kRjx93X20&hl=de&ei=Mz2dSaqFCI-I_ga-iomVBQ&sa=X&oi=book_result&resnum=6&ct=result
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Sparrow
Veteran
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!
Are you sure that isn’t a curved wall Keith, it looks so obvious
In answer to the original question: No I don’t think it is not barrel distortion in the example posted, it is converging verticals, or I suppose diverging in that case. Converging verticals are due to the film plane being at an angle to the subject all lenses exhibit the same phenomenon to the same extent.
Keith
The best camera is one that still works!
Sparrow
Veteran
Wow! I’m surprised cv’s critics haven’t made more of that, well that or the architect had a drink problem, if you ever have an earthquake it might be better to just run rather than standing it the door frame
Keith
The best camera is one that still works!
It's funny ... I've mentioned the CV 1.2's barrel distortion in a previous thread and posted a pic but not a ripple of interest. You're the first person who's ever been a little startled at it ... I know I certainly was when I picked up on it!
You get what you pay for I guess. :angel:
Sparrow
Veteran
What’s more odd that I noticed it, I’m very rarely aware of that type of thing I start off trying to look at the geeky stuff but normally get distracted by the pretty-pictures, and it makes some very pretty-pictures
Keith
The best camera is one that still works!
I think it has a little to do with my shooting style ... I tend to seek out edges to naturally frame subjects within the viewfinder in certain situations. It's something I've just become aware of!
yanidel
Well-known
Ah ah ah, very good one ... weird how something straight becomes so strange suddenly !Sometimes it can get really bad. That tower on the right just doesn't look right ....
But then, Photoshop can fix it ...
I might have overdone the tower though ....
(15 Heliar)
Roland.
Al Kaplan
Veteran
That's not distortion! It's perspective. That's one of the joys of that beautiful 15mm Heliar, my favorite lens since I bought one a few years ago. It's great for making dramatic photos.