Jump to content
UltravioletPhotography

Lens Transmission Chart: Olympus Zuiko 20mm & 25mm Pen-F


Andrea B.

Recommended Posts

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/4.0

Note 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?).

Zuiko_Lenses_25mm_20mm_trans_i_(c)_(c).jpg

Link to comment

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
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

Well if that were my "worst" UV landscape shot, I would be happy. :D

The palm leaf reflections are interesting.

Link to comment

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
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
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
oh I should go add that to the Lens Sticky. Thanks for reminding me.
Link to comment

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)

post-21-0-72112000-1428053589.jpg

 

2)

post-21-0-23287300-1428053614.jpg

Link to comment

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
  • 2 weeks later...

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
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

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
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

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

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...