donald_ingram1 Posted December 18, 2004 Share Posted December 18, 2004 I've just got my first Xpan 30mm results back. Overall the lens looks good - sharp and free of flare or major distortions.However, the lens exhibits a slight, but sometimes noticeable, increase in angular magnification. This causes distortion in the last few mm. See attached examples taken from the top image - these show LHS: a drawn out tower and RHS: overly wide people.I think the distortion applies to all lenses - see Hasselblad's Forum magazine 1-2001 p4,5. Is the a Photoshop plug-in written to adjust the horizontal magnification in a non-linear way ? Link to comment Share on other sites More sharing options...
donald_ingram1 Posted December 18, 2004 Author Share Posted December 18, 2004 where did the add image - after confirm box go ? Link to comment Share on other sites More sharing options...
donald_ingram1 Posted December 18, 2004 Author Share Posted December 18, 2004 here's a link <P><A href="http://homepage.mac.com/donald_i/.Public/xpandistortions.jpg"> Xpan30distortions </A></P> Link to comment Share on other sites More sharing options...
eric friedemann Posted December 18, 2004 Share Posted December 18, 2004 Don, at 30mm, the Xpan lens is, as Mike Reichman notes, "the widest angle lens available for any camera shooting film of (its) width." It is fully 13mm wider than the 21mm/35mm equiv. 43mm lens I have for my Mamiya M7IIs. The Xpan 30mm may be the most amazing ultrawide lens design on the market. I'm not surprised that there is some distortion towards the edges. I'm surprised that there is so little distortion exhibited. The only thing that hacks me off is that the Xpan 30mm isn't offered on an MF camera. If they put the Xpan 30mm on a dedicated MF rangefinder body, I'd buy two. Congrats on your purchase, E Link to comment Share on other sites More sharing options...
will_legge Posted December 18, 2004 Share Posted December 18, 2004 It is called the "wide-angle effect." You will have to live with it as it cannot be eliminated. It is simply a problem with very wide- angle lenses. It is not a problem caused by magnification but rather 3-dimensional shapes projected onto a 2-dimensional plane. The problem with correction is that a two dimensional shape is not stretched, only 3-dimensional ones. When the subject plane is parallel to the film plane, a potted plant at the edge of the field is distorted, but the 2-D circle on the parallel wall is not. Link to comment Share on other sites More sharing options...
wyverndude Posted December 19, 2004 Share Posted December 19, 2004 Like Will and Eric said: it's inherent in the lens design, and is not a defect. The alternatives are fisheye lenses, and swing-lens panoramic cameras. Both will avoid the distortion you see, but add their own -different- distortions. I know there is a PhotoShop filter to correct rectilinear distortion as seen with a fisheye lens, I'd be surprised if there wasn't one to correct for this effect... though for all I know, maybe the very same fisheye-correction filter could be simply adjusted differently to correct this one. Link to comment Share on other sites More sharing options...
roland_vink Posted December 19, 2004 Share Posted December 19, 2004 As has been mentioned this type of distorion is an effect of wide angle rectalinear lenses - the wider the lens, the stronger the effect. It probably is possible to correct for this type of distortion in Photoshop. However if you do, it will cause barrel distortion similar to a fisheye. Which distorton is worse? In panoramic images, horizon lines usually go close to the center of the image, and fisheyes don't distort lines which go through the center. You may be able to correct the "edge stretching" without introducing too much noticeable distortion. Worth a try. Good luck! Link to comment Share on other sites More sharing options...
ilkka Posted December 19, 2004 Share Posted December 19, 2004 "If they put the Xpan 30mm on a dedicated MF rangefinder body..." it would unfortunately only cover 6x4.5 cm, not 6x7 as sometimes some seem to believe. 35 mm lenses are available for 6x4.5 so this 30 would not be that much wider. Link to comment Share on other sites More sharing options...
eric friedemann Posted December 20, 2004 Share Posted December 20, 2004 "'If they put the Xpan 30mm on a dedicated MF rangefinder body...' it would unfortunately only cover 6x4.5 cm, not 6x7 as sometimes some seem to believe. 35 mm lenses are available for 6x4.5 so this 30 would not be that much wider." For others, I understand that this subdiscussion is academic. At this point, I doubt we'll ever see another new medium format camera introduced. And since Fuji, which produces the 30mm Hasselblad Xpan lens is discontinuing MF production, the chance of a new MF rangefinder utilizing the 30mm is between slim and none. Ilkka, I would note that the long edge of an Xpan wide frame is 65mm- and I'm not great at math. Wouldn't the Xpan 30mm covera a 6x6cm frame? Beyond that, the widest lens I've seen on a 645 rangefinder production camera has been 45mm on Fuji rangefinders. It would be excellent to have the Xpan 30mm on a 645 Rangefinder. That would be like a 20mm lens on a compact MF camera. Link to comment Share on other sites More sharing options...
eric friedemann Posted December 20, 2004 Share Posted December 20, 2004 I meant "I doubt we'll ever see another new medium format (FILM) camera introduced." Link to comment Share on other sites More sharing options...
donald_ingram1 Posted December 20, 2004 Author Share Posted December 20, 2004 Eric and all, As panoramic format does not suit all situations, I was thinking that it would be a fun idea to mount the 30mm on a large COPAL shutter and make a SWC like camera. Perhaps there would even be scope for a little tilt, shift and swing - if the format was masked down to 40-50mm square. Looking at the photos, I would be happy with the geometry for images including architectural features, in a smaller square. I've tried a couple of PS plug-in's but not found what I'm looking for yet :-( Link to comment Share on other sites More sharing options...
eric friedemann Posted December 20, 2004 Share Posted December 20, 2004 "I've tried a couple of PS plug-in's but not found what I'm looking for yet :-(" Don, if you find software that works, please post about it. From time to time, I have to shoot a large group of people in a small room and wind up using the Mamiya 7 43mm lens. The people at the edges come out elongated, like yours, and I haven't found any digital operation that can make them look more normal. The only advice I can give is to keep people as far away from the edges of a frame as possible when shooting ultrawide lenses. People towards the center of the frame will look normal. Link to comment Share on other sites More sharing options...
ilkka Posted December 21, 2004 Share Posted December 21, 2004 Eric, I am not sure of the exact actual image area produced by the 30mm XPan lens, but 69mm image circle is enough to cover the 24x65 mm image area of the XPan. 6x6 would need 79mm so it is unlikely the XPan lens would cover that. 645 would need about 70mm so for that it should be sufficient. Link to comment Share on other sites More sharing options...
eric friedemann Posted December 22, 2004 Share Posted December 22, 2004 Ilkka, I broke down and did the math. You're right, the 24x65mm frame requires a surprisingly small image circle. Link to comment Share on other sites More sharing options...
ilkka Posted December 22, 2004 Share Posted December 22, 2004 That's the whole idea behind the camera and its compact lenses. Link to comment Share on other sites More sharing options...
in the eye of a holga 120 Posted May 10, 2005 Share Posted May 10, 2005 here's Xpan 30mm sample image http://www.pbase.com/xpan Link to comment Share on other sites More sharing options...
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