Andy Perrin Posted February 28, 2017 Share Posted February 28, 2017 Chestnuts on a cutting board with salt and a square of Acktar Metal Velvet as white and black references. White balance was off the salt in the photo, in-camera. Lens was 80mm EL-Nikkor 5.6 except in the visible and SWIR cases. Visible reference (iPhone 6S Plus) 780BP30 filter, halogen light, F5.6 1/800" ISO400 1064BP25 filter, halogen light, F5.6 1/60" ISO800 Thorlabs 1" 50mm lens (AR 1050-1620nm) projected on upconverting phosphor screen, halogen light, roughly F4 (eyeballing it!), 10" ISO400 2mm UG11(or possibly unknown glass)+1.75mm S8612, Tuofeng nominal-365nm torch, F16 15" ISO100 Link to comment
Andrea B. Posted March 1, 2017 Share Posted March 1, 2017 These Chestnuts surprised me in IR. I guess I thought they would not be so IR-reflective. They look cool in UV. (So many things don't!)You could make a nice triptych portrait of just the Chestnuts. Link to comment
Guest Posted March 4, 2017 Share Posted March 4, 2017 Wow - that Acktar material sure does its job well. I might try some of that as a backdrop in my multispectral sets. Link to comment
Andy Perrin Posted March 4, 2017 Author Share Posted March 4, 2017 It's pricy, but they sell a sample size for about $100 or so and you really only need one piece, at least for small things. Link to comment
Andy Perrin Posted March 4, 2017 Author Share Posted March 4, 2017 Chestnuts on cutting board, sunshine (the previous pic was with the very-narrowband Tuofeng torch). Lens was 80mm EL-Nikkor 5.6, white balance was in-camera with PTFE. Filter was 2mm UG11 (probably knockoff), and 1.75mm S8612. F/16 5" ISO400 F/16 6" ISO400 Link to comment
Hornblende Posted March 4, 2017 Share Posted March 4, 2017 Wow, your lens looks very sharp on the edges, mine is blury on the edges even at f/16! Link to comment
Andy Perrin Posted March 4, 2017 Author Share Posted March 4, 2017 Well these are crops so I wouldn't read into that so much. (Cropped for artistic intent, of course.) But actually even the originals are very sharp at the corners at this F-number, so your conclusion is true. I was lucky on the 2nd try, with the EL-Nikkor 80mm/5.6. Link to comment
Andy Perrin Posted March 4, 2017 Author Share Posted March 4, 2017 Here is the actual corner at 1:1. 1:1 crop, unedited except for the auto-noise reduction, white balance, and exposure from PhotoNinja. Link to comment
Hornblende Posted March 4, 2017 Share Posted March 4, 2017 I made some test with a sharpness chart I found on gogle image: f/16 is very good in the center but not so much in the corner, where f/22 performes better. Surprisingly, f/45 is the best of all in the corner, but is worst in the center!In my case, f/22 is the best in the whole frame. Unfortunately it is not very convenient for shooting, it is just too dark!! I think I will try to save for another EL-Nikkor 80mm, maybe there is some difference between the old models.If only I could have the Coastal... or even better, the UV Nikkor clone.. but that's for later :D Link to comment
Andy Perrin Posted March 4, 2017 Author Share Posted March 4, 2017 At F/45, you don't have a lens, you have a pinhole camera! You may as well just get rid of the glass altogether and increase the transmission. Link to comment
Hornblende Posted March 4, 2017 Share Posted March 4, 2017 Haha you are right. I should try some UV pinhole image. Link to comment
Andrea B. Posted March 5, 2017 Share Posted March 5, 2017 Have you all tested those lenses to determine where diffraction sets in? I'm fascinated by these chestnuts. They're so photogenic. "-) Link to comment
Hornblende Posted March 8, 2017 Share Posted March 8, 2017 Oh, maybe your camera is an APS-C, which explains why the corner of your pictures are better than mines, since I use a full frame camera. Link to comment
Andy Perrin Posted March 8, 2017 Author Share Posted March 8, 2017 Yes that will do it. Mine is APS-C. Link to comment
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now