gmaurizio Posted September 20, 2007 Share #1 Posted September 20, 2007 Advertisement (gone after registration) Dear friends, I know UV/IR filters are needed for wide angle (35mm and less) lenses. Let's leave those focal lengths out of the question. For very fast close-to-normal lenses (40mm-50mm-75mm), I am finding that using a UV/IR filter actually does visibly improve sharpness when wide open (let's say f larger than F2.8). This is kind of reasonable, due to the fact that the M8 is extremely sensitive in the IR side of the spectrum. Case in point: For highly IR-reflective subjects (like people and grass...), when you use the lenses without filter, let's say at F1.4, you focus and get ready for the shot. Then you use a UV/IR-only pass filter, without changing the focus or the speed/aperture, and you take a shot. The image is not black, not even close to total black. Then you take the UV/IR-pass filter and use the UV/IR-cut filter. The image you get is sharper than the original, filterless one. Opinions, ideas, experiences? Link to post Share on other sites More sharing options...
Advertisement Posted September 20, 2007 Posted September 20, 2007 Hi gmaurizio, Take a look here Sharpness and UV/IR filters. I'm sure you'll find what you were looking for!
jaapv Posted September 20, 2007 Share #2 Posted September 20, 2007 I share your experience. The filter removes the overlaid out-of-focus IR image that destroys microcontrast. It is about -5 stops, plenty within the dynamic range of the camera. Even in black and white photography. Link to post Share on other sites More sharing options...
gmaurizio Posted September 20, 2007 Author Share #3 Posted September 20, 2007 I share your experience. The filter removes the overlaid out-of-focus IR image that destroys microcontrast. It is about -5 stops, plenty within the dynamic range of the camera. Even in black and white photography. Your experience and mine seem to indicate that the initial evaluations both by Erwin and Sean might be, let's say incomplete? I think this issue deserves further research and more opinions. Come on guys! Link to post Share on other sites More sharing options...
Photoskeptic Posted September 21, 2007 Share #4 Posted September 21, 2007 I have not found any filters to be an impediment. Link to post Share on other sites More sharing options...
sean_reid Posted September 21, 2007 Share #5 Posted September 21, 2007 Dear friends,I know UV/IR filters are needed for wide angle (35mm and less) lenses. ??? Why only 35 mm and wider? I think you might be thinking about coding, not filters. If one wants to remove the camera's sensitivity to IR, filters are needed for all lenses. Using filters to reflect IR has nothing to do with focal length. Link to post Share on other sites More sharing options...
sean_reid Posted September 21, 2007 Share #6 Posted September 21, 2007 Your experience and mine seem to indicate that the initial evaluations both by Erwin and Sean might be, let's say incomplete?I think this issue deserves further research and more opinions. Come on guys! Let's say, in this respect, not. I first wrote about this aspect nearly a year ago. Can't speak for Erwin. A lens focused for visible light is not focused for IR. This can decrease resolution of some subjects in some lighting, at some times. Whether or not its of much consequence to the final picture is up to the photographer to determine. What "initial evaluations" are you referring to? You may find it useful to reread some of those articles. Link to post Share on other sites More sharing options...
gmaurizio Posted September 21, 2007 Author Share #7 Posted September 21, 2007 Advertisement (gone after registration) Let's say, in this respect, not. I first wrote about this aspect nearly a year ago. Can't speak for Erwin. A lens focused for visible light is not focused for IR. This can decrease resolution of some subjects in some lighting, at some times. Whether or not its of much consequence to the final picture is up to the photographer to determine. What "initial evaluations" are you referring to? Given some of your comments on the thread so far, you may find it useful to reread some of those articles. You are right Sean, I was confused with coding... My mistake, please accept my apologies. I was more thinking about Erwin's article about filters, where he stated that IR filters actually deteriorated image quality. On a side note, it seems that people tend to get a little upset about comments in the forum. The idea is not to upset anybody, just to try to determine what is the better way of using the M8, a rather difficult camera to master and use in its complete potential. So far, the IR issue was mostly related to the black/purple problem, but I find that it impacts considerably in portraiture too. I just wanted to see what the opinions are. Again, it was not my intention to show disrespect. Sorry. Link to post Share on other sites More sharing options...
sean_reid Posted September 21, 2007 Share #8 Posted September 21, 2007 No disrespect perceived. This may be a language issue, the phrase "in this respect" simply means "in consideration of this aspect". It doesn't relate to respect in the sense you're discussing. I do think you might find it useful to reread some of those articles because it might give you some more information about these aspects. Your realization about the filters is certainly relevant and that's why its been looked at in other discussions. Link to post Share on other sites More sharing options...
marknorton Posted September 21, 2007 Share #9 Posted September 21, 2007 Leica's comments have always been made with reference to black artificial fabrics as if to try to minimise the issue. Like Jaap, I find the removal of the out of focus IR induced haze improves image quality and there are marked improvements in the rendition of foliage and people's complexions. Link to post Share on other sites More sharing options...
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