Retina Xenon Barrel Distortion

[FallisPhoto]

The vertical wooden mullion on the right is at least as straight as my ruler.

 

[uhligfd]

using a bubble level and tripod, while a good thing, will not correct barrel distortion.

Yes, this shot was handheld and I doubt anything was perfectly plumb.

However, my point was: if not perfectly aligned at the time of shooting, one cannot conclude much about barrel or other lens distortions from a pic. Or, in other words: from this (unaligned) picture no inference can be made on the lens.

And : perfect shot alignment can never undo a lens error, of course.

 

[literiter]

I scanned some images on a Epson V700 scanner. The images were of random nature stuff so nothing was apparent. However, when I loaded the negatives into that somewhat ridiculous negative holder I did notice that the negatives were not held perfectly flat.
Where would that take us with this discussion? Will a scanner introduce distortion??

 

[mh2000]

I'm using a Coolscan V with the FH-3 so it's pretty flat... yeah, with MF in my Epson 4990 I get distortion from lack of film flatness.

Regarding a level and tripod, no matter how you shoot a straight line it should remain a straight line if there is not barrel distortion.

 

[FallisPhoto]

Just incidentally, barrel distortion is something typically found in wide angle lenses. Pincushion distortion is found in telephotos. The Retinas come with pretty good normal lenses (on a rangefinder even fairly good usually is superb, when compared to an SLR) and it shouldn't have either -- unless you are shooting something way too close to the lens.

 

[adietrich]

hugin

hugin

Hello mh!

You could try "hugin". Here is a nice tutorial about lens calibration:
http://hugin.sourceforge.net/tutorials/index.shtml

Let me know how it went, OK?

-a