Manoleica Posted October 26, 2016 Share #1 Posted October 26, 2016 (edited) Advertisement (gone after registration) I remember some time ago someone was asking Why their sky had dark areas.. I'm not even sure it was this section.. Anyways I was out today just snapping for fun , (Castle Air Museum, Atwater, Ca) - so, I set my M-P240/28mm Elmarit ASPH to Classic/Spot.. woe and behold:- the sky was patchy with dark areas.. I have never used Spot when at the Air Museum, Classic/Center Weighted is my choice.. 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! Edited October 26, 2016 by Manoleica Quote 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/265876-sky-dark-areas/?do=findComment&comment=3136215'>More sharing options...
Advertisement Posted October 26, 2016 Posted October 26, 2016 Hi Manoleica, Take a look here Sky:- Dark Areas. I'm sure you'll find what you were looking for!
Exodies Posted October 26, 2016 Share #2 Posted October 26, 2016 Spot is one of the advanced metering options, not classic. Did you have a polariser on? Quote Link to post Share on other sites More sharing options...
Guest Posted October 27, 2016 Share #3 Posted October 27, 2016 All I see is a classic vignette from the Elmarit-M ... and it enhances the object of your picture ... were you to have captured this at F8 - 11 it would be less compelling. I believe that you can correct this in LR with a + vignette setting ... not that I would recommend that correction. JMHO ... need PICO to tell you how far off I must be. Bob Quote Link to post Share on other sites More sharing options...
Manoleica Posted October 27, 2016 Author Share #4 Posted October 27, 2016 Spot is one of the advanced metering options, not classic. Did you have a polariser on? No Polarizer.. Quote Link to post Share on other sites More sharing options...
Manoleica Posted October 27, 2016 Author Share #5 Posted October 27, 2016 Let me just say guys, I was just enjoying my day and playing about with settings etc.. Quote Link to post Share on other sites More sharing options...
Manoleica Posted October 27, 2016 Author Share #6 Posted October 27, 2016 Spot is one of the advanced metering options, not classic. Did you have a polariser on? My camera is set to Classic/Spot.. I can also select -> center or multi.. Quote Link to post Share on other sites More sharing options...
Exodies Posted October 27, 2016 Share #7 Posted October 27, 2016 Advertisement (gone after registration) I think this means that you will get spot when you switch to advanced metering. With classic selected you will be centre weighted. Quote Link to post Share on other sites More sharing options...
pgk Posted October 27, 2016 Share #8 Posted October 27, 2016 I've never really analyzed the precise reasons, but I am well aware a blue sky is not uniformly blue probably depending on a number of parameters such as nearness to the horizon, positioning relative to the sun in the image, etc. Your image shows an 'underexposed' (ie relatively dark) blue sky with an very brightly lit foreground/subject, so the sky is quite dark due to the exposure bias towards the subject matter ('plane). Underexposure tends to magnify any unevenness in the blue (towards the top of the image) - I suspect that this is due to the blue channel's linearity being suspect at low exposure levels, and you will probably find noise has increased significantly if you pixel peep too. Added to this you have lens vignetting (dark corners - most obvious in the bottom left) which increases the contrast between the lightest blue part of the sky and the darker underexposed area (top of the image) even more. So as ever there's not one simple explanation but a mix. Wide angle images will show more angle of sky so are more likely to produce this effect. FWIW the 21SE used with a polarising filter can produce some spectacular images with unbelievably intense blue skies darkening to almost black at times - this can be used to good effect. Quote Link to post Share on other sites More sharing options...
jaapv Posted October 27, 2016 Share #9 Posted October 27, 2016 Our eye sees the sky as a uniform brightness. It isn't, the camera is just recording reality and our brain filters the variation out.. The thickness of the atmosphere varies with the angle one is looking through. The lightness is determined by the sunlight being reflected and bounced around by the dust and moisture contained in the air.Straight up is the thinnest, so the amount of haze and dust is the least, obscuring the darkness of space the least. A wideangle lens covers the widest angle of view (obviously) so it will show the largest variation. Quote Link to post Share on other sites More sharing options...
pgk Posted October 27, 2016 Share #10 Posted October 27, 2016 So if you read my and jaapv's posts you will appreciate that you are essentially magnifying natural phenomena photographically, which is why it is so apparent in the resulting image. 1 Quote Link to post Share on other sites More sharing options...
albertknappmd Posted November 4, 2016 Share #11 Posted November 4, 2016 simply put try the following... attach M to tripod along with lens. shoot toward sky and vary f stop. You should see the vignetting disappear as the aperture closes (ie the f stop increases). this should reassure you.. Albert Quote Link to post Share on other sites More sharing options...
jaapv Posted November 4, 2016 Share #12 Posted November 4, 2016 No you won't. Because this is not lens vignetting. Although it may add to the effect towards the corners. Quote Link to post Share on other sites More sharing options...
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