lost cat Posted February 6, 2016 Share Posted February 6, 2016 In our collective neverending quest for yet more UV capable lenses I present to you a photo comparison of a Super-Lentar 35mmm f/3.5 lens vs a Soligor KA Kuri clone Soligor KA Lens:http://m42lens.com/m...5mm-f-3-5-22-v2 Soligor 28mm: Camera: Unmodified Nikon D40. Lens Configuration: Macro configuration with an additional helicoid and/or short extension tubes to try to normalize the subject to camera distance as much as possible. White balance: All photos were white balanced against a slightly defocused PFTE tape wrapped block of wood with at least three layers of tape. Visible shots with an exposure of 1/30s UV shots with an exposure of 1/8 sec. Note - the WB was performed using the in-camera "use photo" function. although no error message was generated it does not appear to have worked properly. Illumination: Visible images taken with two 25W incandescent bulbs with reflectors 22 and 26cm distance from subject +/- 45 degrees from camera-to-subject plane. UV images as above but with incandescent bulbs replaced with two 26W CFL blacklight blue bulbs. ISO: 400 for all imaging Aperture: f/8 for all imaging Shutter speed(s): 1/30s for Vis images, 1/8s-30s for UV Distance to subject: 15 cm for Soligor KA, 12cm for Soligor 28mm (flower to camera body) UV Filter: Front mounted Astrodon "U" 1.25" Mounts: Both lenses have a T mount Filter Sizes: Soligor 28mm uses a 58mm filter, Soligor KA uses a 46mm filter Left/Top: Soligor 28mm Right/Bottom: Soligor KA-------------------------------------------------------Visible 1/30s: UV 1/8s: UV 1/4s:UV 1/2s: UV 1s: UV 2s: UV 4s: UV 8s: UV 15s: UV 30s: To my eyes the performance of the Soligor 28mm- at least under my testing methodology - is a bit over 2 stops less sensitive than the KA. There is a bit of apples to oranges comparison here since the focal lengths are a bit different. The distances between the camera and the flower are also different and despite the Soligor 28mm being closer to the flower the Soligor 28mm is only transmitting ~1/4 the amount of light of the Soligor KA. Would I recommend the Soligor 28mm lens for the sticky? Yes (for now) but with the caveat there may be better 28mm lenses out there. I hope to test a couple more 28mm lenses soon, stay tuned. :) Link to comment
Cadmium Posted February 7, 2016 Share Posted February 7, 2016 Lost cat, Nice tests, thanks! :-) Link to comment
Alex H Posted February 7, 2016 Share Posted February 7, 2016 28mm Soligor transmits "less deep" in UV, no doubt. I would like to know its optical configuration. Link to comment
Andrea B. Posted February 7, 2016 Share Posted February 7, 2016 Well, let's all think for a minute about how we might like to compare two lenses of different focal lengths?Do we go for the same distance from the subject?Or do we go for the same field-of-view covering the subject?Or do we show both methods in a test like this?How does the gathered light change between the two methods?As they say in mathematics texts, the proof is left to the interested reader. That is, go experiment and decide for yourself. :D Link to comment
Alaun Posted February 7, 2016 Share Posted February 7, 2016 Might depend on your subject.Proposed first a little simplified mind experiment at the extrema:1) You shoot a point light source;2) You shoot perpendicular to a infinite uniform bright flat surface. You will get quite different answers to your questions, unfortunately our real subjects are somewhere in between. Link to comment
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