Andrea B. Posted March 23, 2015 Share Posted March 23, 2015 Klaus has kindly sent us a transmission chart for these Oly Pen-Fs. Thank you, Klaus! Looks like these two lenses can transmit between 350nm - 400nm. The 25mm lens has about 30% (?estimated) transmission around the 365nm line. And less so, maybe 20%(?), for the 20mm lens. So the lenses would be UV-capable for landscapes and floral signatures with longer exposure times expected than from a dedicated UV lens. © Klaus Schmitt, Ph.D, Weinheim, Germany, www.uvir.eu.Two Lenses for Olympus Pen-F: G Zuiko Auto W 20mm f/3.5 and E Zuiko Auto W 25mm f/4.0Note that the G Zuiko Auto W 25mm f/2.8 lens has a more complex design with cemented elements (and may perhaps be less useful as a UV lens?). Link to comment
Alex H Posted March 23, 2015 Share Posted March 23, 2015 Nice lenses. I had my first pictures taken with those, and posted almost two years ago... http://www.holovachov.com/img/s9/v95/p1593119346.jpg http://www.holovachov.com/img/s12/v180/p831089727.jpg Link to comment
JCDowdy Posted March 23, 2015 Share Posted March 23, 2015 I do not recall seeing transmission plots of these lenses before.Thank you Dr. Schmitt. Link to comment
JCDowdy Posted March 24, 2015 Share Posted March 24, 2015 Great images Alex!I really like #2, is that another of your Florida photos? Link to comment
colinbm Posted March 24, 2015 Share Posted March 24, 2015 Nice shots Alex, the second one looks like a mercury pond.Col Link to comment
Alex H Posted March 24, 2015 Share Posted March 24, 2015 Yes, John, it is my worst shot from my recent Florida trip - worst of the two, as I did not take any more UV shots worthy of keeping. Link to comment
Andrea B. Posted March 24, 2015 Author Share Posted March 24, 2015 Well if that were my "worst" UV landscape shot, I would be happy. :DThe palm leaf reflections are interesting. Link to comment
JCDowdy Posted March 24, 2015 Share Posted March 24, 2015 Well, I like it so I guess there is no accounting for taste, or lack thereof on my part at least.Take away the saw palmetto and it could be a flooded river bottom in Tennessee or Mississippi where I spent many a happy day hunting and fishing. Link to comment
Andrea B. Posted March 24, 2015 Author Share Posted March 24, 2015 And now you have to go hunting or fishing with a small UV kit in the backpack. Just in case you spot an interesting flower !! Link to comment
kds315 Posted March 30, 2015 Share Posted March 30, 2015 Both are nice and useful wide angle lenses for UV, compact and lightweight, but only cover APS-C format (24x24mm to be precise) Link to comment
Andrea B. Posted March 30, 2015 Author Share Posted March 30, 2015 oh I should go add that to the Lens Sticky. Thanks for reminding me. Link to comment
Alaun Posted April 3, 2015 Share Posted April 3, 2015 I think, it fits in here: The Oly Pen 25 f4 at f4 plus Baader U on a Pan.GH3uvir at ISO 3200 some spring flowers and grass, sensor at about 45° towards the ground and 45° towards the sun (clear sky with strong sun) processed with PN, both with the same setting (copy and paste, WB taken at the second one) first one at 1/6 s and without a hood and second one at 1/4s and with a hood 1) 2) Link to comment
colinbm Posted April 3, 2015 Share Posted April 3, 2015 That is a vast difference Werner......#2 for sure.Col Link to comment
nfoto Posted April 3, 2015 Share Posted April 3, 2015 An excellent demonstration why sunshades always should be used, also in UV ! Link to comment
kds315 Posted April 10, 2015 Share Posted April 10, 2015 Why would you even shoot w/o lens shade? Am I missing something?? Link to comment
Andrea B. Posted April 11, 2015 Author Share Posted April 11, 2015 Oh I dunno. I don't always use them. It's hard to change filters with a lens shade. Or maybe I'm just lazy. :)It is usually obvious when one is needed, and then I go try to find something which will fit given this hodge-podge collection of UV lenses I have. Link to comment
JCDowdy Posted April 19, 2015 Share Posted April 19, 2015 Klaus,Would you please confirm which 25mm your transmittance plot shows, f/4 or f/2.8?I am assuming f/4. Link to comment
JCDowdy Posted April 21, 2015 Share Posted April 21, 2015 Klaus, Which 25mm does your transmittance plot show, the f/4 or f/2.8? Please advise, thanks! Link to comment
Andrea B. Posted April 21, 2015 Author Share Posted April 21, 2015 I wrote Klaus to get the answer. IIRC, I think he is in the middle of some big engineering project.I'll add the info to the original post when I hear from him. :) Link to comment
JCDowdy Posted April 21, 2015 Share Posted April 21, 2015 Thanks Andrea, I figured after a couple of days I would bump the question. Link to comment
kds315 Posted April 22, 2015 Share Posted April 22, 2015 It is the f4/25mm; the f2.8/25mm has a much more complex lens design with cemented elements so I did not try that (nor do I plan to). Link to comment
Andrea B. Posted April 22, 2015 Author Share Posted April 22, 2015 Thanks, man !!!I'll make a note of that in the first post. Link to comment
JCDowdy Posted April 22, 2015 Share Posted April 22, 2015 Klaus, the 25mm f/4 was what I assumed you showed, since that was the lens we were discussing. I asked because I expected the transmittance of the 25mm f/4 to extend a bit deeper (shorter) into the UV than the 20mm f/3.5. This is because the 25mm f/4, with 5 elements in 5 groups, is a simpler uncemented design than the 20mm f/3.5, with 7 elements in 6 groups. Thanks again. Link to comment
Alex H Posted April 23, 2015 Share Posted April 23, 2015 I would really like someone to tell me about this "uncemented" versus "cemented" statement. Where is this information coming from, that says that lenses with cemented lens elements should have lower UV transmission than lenses without cemented elements? Do we really know the properties of lens cement used in each particular lens to make such a judgement? Link to comment
Alex H Posted April 23, 2015 Share Posted April 23, 2015 Note that the G Zuiko Auto W 25mm f/2.8 lens has a more complex design with cemented elements and is less useful as a UV lens. Has it been tested by anyone here for that purpose? We know Klaus did not test it. We can only assume that, and, although it is most probably true, I would not be so definitive. Link to comment
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