40mm f/2 Posted November 28, 2013 Share #1 Posted November 28, 2013 Advertisement (gone after registration) Reading the Sony A7 tread I became again aware of the problems of WA lenses: strong vignetting, lateral color shift and low edge resolution. Leica seems to do better (especially M9) but it has inherently the same problems. Digital corrections help but sacrifice DR at the image periphery. More extreme retro focus lens designs with flatter incidence angles improve the performance especially for the Sony A7® but with the penalty of size and weight. Leica S WA lenses are very bulky and still have a much better image quality in the center compared to the edge. Micro lens offset on the sensor can improve the performance but is optimal only for a specific angle (I guess this explains why Leica M is better in WA and Sony in tele range - different design compromises). I came across two small blurbs which which I found very interesting for WA photography. both use a spherical image surface (optical fiber array projecting on a flat sensor): Miniature wide angle lens under development at UCSD: Digital Photography Review Google Translate What I can see the incidence angle is always 90º and spherical lens corrections are not necessary. Besides light field photography this not flat sensor technology is something which could be not done with film. Obviously the sensor shape has to be produced to a specific lens but I would not mind a WA specific camera. Link to post Share on other sites More sharing options...
Advertisement Posted November 28, 2013 Posted November 28, 2013 Hi 40mm f/2, Take a look here wide angle lenses and shape of sensor. I'm sure you'll find what you were looking for!
TomB_tx Posted November 28, 2013 Share #2 Posted November 28, 2013 I came across two small blurbs which which I found very interesting for WA photography. both use a spherical image surface (optical fiber array projecting on a flat sensor):What I can see the incidence angle is always 90º and spherical lens corrections are not necessary. Besides light field photography this not flat sensor technology is something which could be not done with film. Obviously the sensor shape has to be produced to a specific lens but I would not mind a WA specific camera. The simple Kodak Brownie box cameras I had in the 1950s used a curved film gate so they could use a simple lens and not correct for flat field. Curving the film in the long dimension stiffened it in the short dimension, so no pressure plate was needed. Cheap and effective. The curved sensor construction is novel, but the concept is old. Link to post Share on other sites More sharing options...
luigi bertolotti Posted November 29, 2013 Share #3 Posted November 29, 2013 The simple Kodak Brownie box cameras I had in the 1950s used a curved film gate so they could use a simple lens and not correct for flat field. Curving the film in the long dimension stiffened it in the short dimension, so no pressure plate was needed. Cheap and effective.The curved sensor construction is novel, but the concept is old. True : apart the Brownie (interesting, btw... I didn't knew of it) curved film has been used for decades in high-level astrophotography : I think that the concept of deforming the sensor matrix can be one of the technologies that will appear in the future : by logic, the first practical implementation in "normal" cameras could be in the MF Digital backs... or, even early, in the similar devices for aerophotography/surveying (in which wide angle coverage with no distortion and CA is critical and VALUABLE : to a certain extent, you can cover the same area with less flight mileage/hours, a costly factor) Link to post Share on other sites More sharing options...
40mm f/2 Posted November 29, 2013 Author Share #4 Posted November 29, 2013 As far as I understand it the curvature of the sensor most match a specific lens - so MF digital backs may be not the optimal starting point for this technology. One sensor technology at least Sony and Fuji/Panasonic is hinting at are organic sensors and these are made with a vapor deposition technique which can be applied to a curved surface or on a substrate which can be bent. Link to post Share on other sites More sharing options...
luigi bertolotti Posted December 1, 2013 Share #5 Posted December 1, 2013 As far as I understand it the curvature of the sensor most match a specific lens - so MF digital backs may be not the optimal starting point for this technology. One sensor technology at least Sony and Fuji/Panasonic is hinting at are organic sensors and these are made with a vapor deposition technique which can be applied to a curved surface or on a substrate which can be bent. That's true... but in the MF market lenses' providers are more "free" of restrictions... I think that if Dalsa or someone else would make a curved sensor, someone like Schneider could make a series of Super Angulons (3 or 4 focals) designed to have a "standard" field curvature focal-indipendent (of course, other factors like dependancy from focus distance must be taken into account... but it's their job to afford designinig tasks... ) Link to post Share on other sites More sharing options...
Torontoamateur Posted December 7, 2013 Share #6 Posted December 7, 2013 The size of the millions of receptors makes the difference. The finer the size of each receptor the more the vignetting. If you want to use wide on a digital then use a lower resolution sensor at the present time. Link to post Share on other sites More sharing options...
plewislambert Posted December 8, 2013 Share #7 Posted December 8, 2013 Advertisement (gone after registration) If you want to use wide on a digital then use a lower resolution sensor at the present time" I have been using a 20mm AF Nikkor and a 17mm manual Tokina on adapters on my M9. Neither lens suffers from heavy vignetting or shaded edge colours. Both lenses have a long back focus to clear the moving mirrors of the slrs for which they were designed and the rays leaving the lens in the direction of the edges of the sensor do so at a much less acute angle than those produced by my 12mm CV, whose rear element is very close to the sensor and which suffers both faults so needs Cornerfix. As an aside, the 12mm lens covers such an amazingly wide angle that often the edges need to be cropped in the interests of composition, so the defects mentioned don't appear in the finished picture. I hope this adds light to the subject. Philip Link to post Share on other sites More sharing options...
plewislambert Posted January 29, 2014 Share #8 Posted January 29, 2014 The simple Kodak Brownie box cameras I had in the 1950s used a curved film gate so they could use a simple lens and not correct for flat field. Curving the film in the long dimension stiffened it in the short dimension, so no pressure plate was needed. Cheap and effective. " I wish my Kodak Brownie had been this advanced. I did not know what a sharp 6x4 enlargement was until I upgraded in 1952 to an Ensign Ranger Special! The next technical advance was to buy a Weston...... Colour transparencies followed on a 35mm Ilford. I haven't bothered with monochrome since then. M9 is best. Philip Link to post Share on other sites More sharing options...
algrove Posted January 30, 2014 Share #9 Posted January 30, 2014 Philip Try a Monochrom M at a Leica Akademie just for the fun of it and bring back nostalgia. Link to post Share on other sites More sharing options...
Guest larryking6458 Posted January 31, 2014 Share #10 Posted January 31, 2014 I had in the 1950s used a curved film gate so they could use a simple lens and not correct for flat field. Curving the film in the long dimension stiffened it in the short dimension, so no pressure plate was needed. Cheap and effective. Link to post Share on other sites More sharing options...
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