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| Moderated by: chrisbet, | ||
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jk
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Value Angle is not a concept that I am familiar with but it seems that Fuji have adopted the concept. Definition: In short: the wider the value angle, the more precise and easier a lens can send light to the sensor. A wider value angle gives more flexibility for lens design and allows for more light and less digital correction. https://www.fujirumors.com/value-angle-of-mirrorless-cameras-explained-and-compared/ I am still trying to understand it, as well as it's real life advantages. Anybody got any thoughts? |
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Eric
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jk wrote:Value Angle is not a concept that I am familiar with but it seems that Fuji have adopted the concept.Is this the basis for the bigger lens mount on the Z series? |
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jk
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I guess so. |
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jk
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More information in this presentation. http://www.imaging.org/Site/PDFS/Conferences/ElectroincImaging/EI2018/EI2017-IMSE-CIS_pixel_design_optimization_Boyd_v2.pdf |
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jk
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I think I understand what they are talking about now. Simple description of situation is...... Each photo-site has a micro-lens on its surface and you want to optimise light entry into the photo-site well. To optimise the light entry to the photo-site ideally you want light to hit vertically but it has a curved surface to allow light at the edges as well as the centre to get to the bottom of the well of the photo-site. This is a practical/pragmatic design issue resolution. Otherwise you would need an infinitely wide camera lens throat to have vertical entry into the photo-site. However the bigger the lens throat the easier the lens design is as you dont have to refract the light so much to reach different parts of the sensor to be vertical to the micro-lens surface. Value Angle is the amount of diffraction needed to give near equal light for the edge photo-sites compared to the centre photo-sites. |
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Robert
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http://www.imaging.org/Site/PDFS/Conferences/ElectroincImaging/EI2018/EI2017-IMSE-CIS_pixel_design_optimization_Boyd_v2.pdf Sent me to sleep!!! I remember a discussion several years ago on the previous forum which covered this exact topic but not as technical, related to vignetting and the angle of transmission of light from the exit pupil of a lens. Film is less susceptible to the effect due to the shallow depth of the emulsion and lack of micro lenses etc. I distinctly remember creating graphics showing the effect (which I may still have), exacerbated by small exit pupil and larger FX format. When the 'Z' mount was announced, Nikon stressed the larger diameter and shorter mount would allow them much greater freedom to optimise their newest range of lenses for digital, presumably along the lines this thread is describing. I also suspect they are using this as a strategy to protect their lens sales, as to some extent the 'F' mount did. Preventing or obstructing third party makers from optimising their universal lenses to take full advantage of the opportunity the 'Z' Nikon mount presents, without making a dedicated version 'Nikon' lens specifically for the 'Z' mount, which presumably would be uneconomical. |
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Graham Whistler
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That's more like the old forum. Thanks for that interesting read! |
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novicius
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Very Interesting indeed...need to check up on this tho`, as I`m sure I did not even got the half of it.. |
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novicius
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Another thing I do not quite get is a thingie called " Speedbooster " ,aparently an Adapter which Increase the light output of Vintage Lenses ( making `em Faster ) on mirrorless camera`s..has this got something to do with that ? |
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Robert
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novicius wrote:Another thing I do not quite get is a thingie called " Speedbooster " ,aparently an Adapter which Increase the light output of Vintage Lenses ( making `em Faster ) on mirrorless camera`s..has this got something to do with that ?Never heard of that, the light output is a factor of focal length and entry pupil, so unless they found a way of defying the law of physics I will remain skeptic. |
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jk
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Been looking at some of the Z lenses test results from the lab. New Z mount 14-30 f4 compared with F mount 14-24 f2.8 that I have. It seems like the F mount lens is better. https://nikonrumors.com/2019/06/18/nikon-nikkor-z-14-30mm-f-4-s-lens-tested-at-dxomark.aspx/ Please can someone else take a look and confirm my reading of the results is correct. |
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chrisbet
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It looks that way - the Z lens is damned with faint praise in that review. |
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