usm Posted September 24, 2007 Share #1 Posted September 24, 2007 Advertisement (gone after registration) Hi there! Who knows a tool to correct the distortion of the CV 15mm lens used on a M8. For Mac, please!! Thanx! Mario Link to post Share on other sites More sharing options...
Advertisement Posted September 24, 2007 Posted September 24, 2007 Hi usm, Take a look here How to correct the distortion of the CV 15mm?. I'm sure you'll find what you were looking for!
stunsworth Posted September 24, 2007 Share #2 Posted September 24, 2007 What distortion are yoy referring to? It's a serious question. Do you have an example you can post? Link to post Share on other sites More sharing options...
usm Posted September 24, 2007 Author Share #3 Posted September 24, 2007 Watch the red line! Maybe there is an action for PS? Thanxs Mario Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/34228-how-to-correct-the-distortion-of-the-cv-15mm/?do=findComment&comment=361619'>More sharing options...
jaapv Posted September 24, 2007 Share #4 Posted September 24, 2007 Keystoning; that can be easily done in Photoshop and Photoshop Elements. I'm lazy and use a plug-in, DCE tools, but that is for Windows, but I'm sure there are several others for Mac as well. If you are not familiar with these kind of things in Photoshop or Elements (which is really quite enough for 99% of the shots, I find full versions overkill for amateur use), Scott Kelby writes a series of excellent books on the subject. Link to post Share on other sites More sharing options...
Skippy Sanchez Posted September 24, 2007 Share #5 Posted September 24, 2007 ideally, the sensor plane should be perfectly square with room you are shooting. even with a tripod it is tricky, because it's not just a matter of being level all four sides of the sensor should square with all four walls of the room. the photoshop crop tool has a "perspective" check box along the top of thre screen, to the right of width/size/resolution. you'll see it after you put crop marks on the image. the corner handles will move that corner anywhere you want without affecting the other corners (up/down/in/out). the center handles move each specific crop line. read your photoshop manual or go to a photoshop tutorial website. you should be able to find what you're looking for. it's not a cure-all, and it can be tricky as hell if you're trying to correct something with a lot of distortion. this image was perfect for it: Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/34228-how-to-correct-the-distortion-of-the-cv-15mm/?do=findComment&comment=361631'>More sharing options...
luigi bertolotti Posted September 24, 2007 Share #6 Posted September 24, 2007 Uhm... is it correct to call this a lens distortion issue ? If you depicted the vertical red line, observing that the wall is not so... this may be not a problem of lens distortion... how was the position of the camera ? Was it horizontal and, above all, UNTILTED (downward) ? These are critical factors with WAs... anyway, in PS the "transform" "perspective" functions can be of great help (I use a rather old version of PS, maybe now they can be under other menus, but surely still they are) Link to post Share on other sites More sharing options...
Mauribix Posted September 24, 2007 Share #7 Posted September 24, 2007 Advertisement (gone after registration) Hi Mario, I think this distortion is not due to the lens itself, probably uncorrect horizon alignement? regards Maurizio Link to post Share on other sites More sharing options...
sm23221 Posted September 24, 2007 Share #8 Posted September 24, 2007 Try a spirit level in your hot shoe. Link to post Share on other sites More sharing options...
gtmerideth Posted September 24, 2007 Share #9 Posted September 24, 2007 Here you go, Open your file in PS. First click on select all. Then go to edit/transform/distort. This puts handles at all four corners. You need space around the image to pull the corners. Go to view/show /grid and you can pull the image to straight. You will need to experiment some. gary Link to post Share on other sites More sharing options...
stunsworth Posted September 24, 2007 Share #10 Posted September 24, 2007 If you use Photoshop you can correct this with the lens correction filter. Link to post Share on other sites More sharing options...
sbelyaev Posted September 24, 2007 Share #11 Posted September 24, 2007 A bubble level is the simplest and best tool. Link to post Share on other sites More sharing options...
jaapv Posted September 24, 2007 Share #12 Posted September 24, 2007 Uhm... is it correct to call this a lens distortion issue ? If you depicted the vertical red line, observing that the wall is not so... this may be not a problem of lens distortion... how was the position of the camera ? Was it horizontal and, above all, UNTILTED (downward) ? These are critical factors with WAs... anyway, in PS the "transform" "perspective" functions can be of great help (I use a rather old version of PS, maybe now they can be under other menus, but surely still they are) Point is, it is not a distortion, but natural perspective. However, our brain perceives it as distortion, so we want to correct it or exaggerate it. Link to post Share on other sites More sharing options...
jlancasterd Posted September 24, 2007 Share #13 Posted September 24, 2007 Here you go, Open your file in PS. First click on select all. Then go to edit/transform/distort. This puts handles at all four corners. You need space around the image to pull the corners. Go to view/show /grid and you can pull the image to straight. You will need to experiment some. gary Spot On - I do this all the time with my CV 15mm (and other WA lenses too at times). If you are shooting in a restricted space, especially indoors, there is often no way of avoiding it. The technique can also be used in lieu of a shift lens for photographing tall buildings - think of it in terms of a digital rising front. The trick is not to overdo the correction - leave a small amount of divergence/convergennce to avoid an artificial look Once you have corrected the verticals you may find that you hve to 'pull-in' (or occasionally pull out) the sides of the image to restore the correct proportions. An example of a CV15 image that has been manipulated in this way: Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/34228-how-to-correct-the-distortion-of-the-cv-15mm/?do=findComment&comment=361700'>More sharing options...
Guest guy_mancuso Posted September 24, 2007 Share #14 Posted September 24, 2007 lens distortion is usually referred to pin cushion, barrel, moustache etc distortion. This is different than prespective and keystoning as John points out above which can be corrected in photoshop or by the use of a shift lens basically it is converging lines from not having the camera level and your either pointing up or down. Pin cushion is a straight vertical line that bows inward and barrel goes the other way it bows outward. And moustache is like a wave pattern. Wish i had examples of this but PS can't really correct these . There are some programs for this Image align is one of them and there are several others but there main purpose is pin and barrel distortion which many extreme wide angles create. Link to post Share on other sites More sharing options...
stunsworth Posted September 24, 2007 Share #15 Posted September 24, 2007 Wish i had examples of this but PS can't really correct these The lens correction filter does a pretty good job in my experience - I have a 28-90 f2.8 lens that I sometimes use on the Canon 5D and the barrel distortion is bad at 28mm, the filter makes a decent job of correcting this. Not perfect, but a lot better than what the lens achieves by itself. Link to post Share on other sites More sharing options...
Guest guy_mancuso Posted September 24, 2007 Share #16 Posted September 24, 2007 The lens correction filter does a pretty good job in my experience - I have a 28-90 f2.8 lens that I sometimes use on the Canon 5D and the barrel distortion is bad at 28mm, the filter makes a decent job of correcting this. Not perfect, but a lot better than what the lens achieves by itself. Holy cow when did they put that in PS. I honestly never seen lens correction in PS and yes it looks pretty good. Is this a CS3 item. Link to post Share on other sites More sharing options...
stunsworth Posted September 24, 2007 Share #17 Posted September 24, 2007 CS2 or 3 I think - can't remember which, and yes it's very useful <grin> One thing is that it renames the background layer to 'Layer 0' which the Photokit sharpeners don't like. So I either rename it of flatten the image to restore the proper name - I do the sharpening just before saving for the web or printing on a copy so I still have an unflatened master. Link to post Share on other sites More sharing options...
Guest guy_mancuso Posted September 24, 2007 Share #18 Posted September 24, 2007 Need to get a 12mm shot out and play with it. Can't believe i missed that one. LOL Link to post Share on other sites More sharing options...
Olsen Posted September 24, 2007 Share #19 Posted September 24, 2007 John, We had trams here in Oslo, just like that, up untill 35 years ago. I miss them, really. Link to post Share on other sites More sharing options...
andybarton Posted September 24, 2007 Share #20 Posted September 24, 2007 CS2 or 3 I think - can't remember which, and yes it's very useful <grin> One thing is that it renames the background layer to 'Layer 0' which the Photokit sharpeners don't like. So I either rename it of flatten the image to restore the proper name - I do the sharpening just before saving for the web or printing on a copy so I still have an unflatened master. IIRC, it's a CS3 thing, and was what persuaded me that it was worth the £150 upgrade stick-up. Link to post Share on other sites More sharing options...
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