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UltravioletPhotography

Melting Snow Suburban UV-Scape


JCDowdy

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The snow in my neighborhood is melting in the bright sunlight. Crystal clear sky, no wind and 36°F (2°C) so it will all be gone soon in typical southwestern Tennessee fashion. It is so bright I can't see in the electronic viewfinder without cupping my hand to my eye!

 

Perfect time to play with one of my recent acquisitions, a 25mm f/4 Olympus E.Zuiko Auto-W Pen-F half-frame lens. This little gem looks right at home on my Panasonic G3 (full spectrum) but I'll wager it would make for a sweet family reunion on an Olympus µ4/3 body.

 

The image circle of this half- frame PEN-F lens should be large enough to cover a µ4/3 sensor but shots show some slight vignetting in the corners. This is probably due to my use of a front mounted 1.25” Baader-U planted in a Nikon K4 as a lens hood. All shots were white balanced at f/4 through my PTFE lens cap pointing directly at the sun and shot at f/8, ISO 400, aperture priority mode with a bit of exposure compensation dialed in. Images were only minimally processed in iPhotoPlus (handy old 1996 editor I still keep after all these years) with +10% highlight in tone adjustment and resampling the image size to 20%.

 

f/8, ISO 400, aperture priority, 1/25th sec, +2/3 exposure compensation

post-24-0-10915300-1425672577.jpg

 

f/8, ISO 400, aperture priority, 1/20th sec, +2/3 exposure compensation (car is white)

post-24-0-60012000-1425672599.jpg

 

f/8, ISO 400, aperture priority, 1/265th sec, +1 exposure compensation

post-24-0-75759300-1425672612.jpg

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Thanks guys!

 

I am rather pleased with this lens, superb Olympus quality. The register depth is short with a µ4/3 adapter only 9.7mm long. Being a bayonet mount it is not prone to accidental loosening. The smaller image circle is not wasting as much off sensor light as a full frame adapted lens.

 

AlexH and Enrico got me interested in the PEN-F lenses with the 20mm Wide Angle they posted about. When I was studying the PEN-F/FT lenses I found that the 25mm f/4 is the only PEN-F/FT lens that does not have any cemented groups, with 5 elements in 5 groups.

 

AlexH & Enrico's 20mm f/3.5 has 7 elements in 6 groups and if it is UV-capable the 25mm was certainly worth trying.

 

The PEN-F 25mm f/4 was not the only 25mm, the later PEN-FT 25mm f/2.8 has 7 elements in 5 groups. The earlier PEN-F lenses are only marked with standard stops and the later FT lenses are marked with both standard stops and the PEN "Through-The-Lens-Numbers". My two copies of the 25mm f/4 only have standard stops, so I am thinking they must be earlier PEN-F not FT.

 

So, no cement, late 1960's coating technology fits the profile of a UV-capable lens.

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Is this what it looks like ?

Col

 

Exactly, but that is ~4x what I paid.

 

Unfortunately I was traveling when this one slipped under my radar or I would probably have three now!

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Thanks John

I'm expecting to get a Panasonic G3 in a couple of weeks, so a useful lens will be desirable.

If you see another can you give me a nudge please.

Cheers

Col

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Sure Col, I will let you know it one winks at me.

Prices on these vary widely, I was patient for shooters <$100.

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Thanks John

eBay down-under, doesn't always show what is available up north there, England, Europe or USA.

Sub $100 will be nice.

Col

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I have tested this lens for UV photography about two years ago and it worked the same as 20mm lens from the same series. It covers APS-C sensor and will work on NEX cameras but it was not wide enough for me so I sold it last year.

 

Please not that the differences between F and FT are not so clear - the aperture ring in F lenses could have been "upgraded" (replaced) with the one to show TTL numbers and nrmally shown in FT lenses. At least one of PEN lenses that I had had this aperture installed upside down.

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Col,

By far the most plentiful of these lenses is the 38mm f/1.8. I think it was that standard "kit" lens sold with the PEN-F/FT body.

These are selling recently for <$50 USD.

 

It has 6 elements in 5 groups (one cemented 2 element group) and, as I said before, AlexH & Enrico's 20mm f/3.5 has 7 elements in 6 groups (also one cemented 2 element group). If that 20mm f/3.5 is UV-capable then..... well, then others might be worth a look if the price is low.

 

Even if it proves less than you need for UV it will likely still likely make a very fine VIS lens on the µ4/3 you have on order. Here is a review of a collection to envy, except it lacks the 25mm f/4.

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That is interesting Alex, so the presence of TTL numbers does not necessarily mean it is a later FT lens.

 

I seem to recall reading somewhere the aperture ring of some FT lenses could be pulled forward and disengaged to allow one to rotate it 180° to show TTL numbers or standard stops indexed to the top of the lens according to owner preference.

 

I remember asking you about the 25mm f/4 and your opting for a wider lens. Have you any experience with other PEN-F/FT lenses with regard to UV? Do you think the 38mm f/1.8 worth a try?

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That is interesting Alex, so the presence of TTL numbers does not necessarily mean it is a later FT lens.

 

I seem to recall reading somewhere the aperture ring of some FT lenses could be pulled forward and disengaged to allow one to rotate it 180° to show TTL numbers or standard stops indexed to the top of the lens according to owner preference.

 

I remember asking you about the 25mm f/4 and your opting for a wider lens. Have you any experience with other PEN-F/FT lenses with regard to UV? Do you think the 38mm f/1.8 worth a try?

 

Yes, the aperture ring can be rotated after one unscrews the front retaining ring.

 

I have 38/1.8, 40/1.4 and 60/1.5 PEN lenses but I have not tested them for UV.

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You have a nice neighborhood John! Thank you for the photos with your lens find.

 

As per your PM I will add to the Sticky: Olympus 25mm f/4.0 E. Zuiko Auto-W

 

Can someone please remind me what exactly is a "half-frame" lens?

If FF = 24x36, then is half-frame 24x18 or 12x36? Or what? 12x36 makes no sense. 12x18 would be quarter frame I guess. I don't know how they did these things. :angry:

 

Also I need confirmation:

Front filter size = 43mm ??

Mount = Pen F ??

Register = 28.95mm ??

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You have a nice neighborhood John! Thank you for the photos with your lens find. As per your PM I will add to the Sticky: Olympus 25mm f/4.0 E. Zuiko Auto-W Can someone please remind me what exactly is a "half-frame" lens? If FF = 24x36, then is half-frame 24x18 or 12x36? Or what? 12x36 makes no sense. 12x18 would be quarter frame I guess. I don't know how they did these things. :angry: Also I need confirmation: Front filter size = 43mm ?? Mount = Pen F ?? Register = 28.95mm ??

 

Thank you Andrea, all the snow is gone, it rarely stays more than a couple of days.

I can confirm -

Filter size: 43mm (also on the 20mm F/3.5 according to several PEN F manuals)

Mount: PEN F

FFD = 28.95mm (several documented sources, I have not measured it myself.)

 

Half frame made the most sense to me when I understood that in 35mm half frame, PEN F, film advances horizontally (conventionally for an SLR) whereas in 35mm cinema cameras film feeds vertically with spools above and below the camera. So where the cinema camera takes a landscape orientation the half frame PEN takes a portrait orientation and you get twice the photos per roll of 35mm film.

post-24-0-77200700-1425867966.jpg

Also interesting is that the aspect ratio of half frame is closer to standard 8"x10" print aspect ratio than full frame so when printing the negatives were actually often not enlarged and cropped as much as the "half" moniker might lead one to assume. Olympus was really ahead of the times with these cameras.

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Thank you Andrea, all the snow is gone, it rarely stays more than a couple of days.

Oh LUCKY you-all down there in warmer climes. I haven't seen the ground for weeks now!

 

What happened when the Pen-F camera was turned? Would it fill two half-frames?

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Yeah, we don't have real winter down here where the snow stays on the ground until spring.

 

Turning the PEN-F 90° yields an 18mm high by 24mm wide landscape negative.

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Farther north in KY, they got 20"+ from this storm. A pity you had no opportunity to document that. (We only got rain from it.) The TiO2 in the paint really pops out in your photos in terms of color (not much else does, here.). It must be hard to find wide-angle optics for such a tiny sensor. Even a 24mm has just barely a "normal" angle of view.
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...

I seem to recall reading somewhere the aperture ring of some FT lenses could be pulled forward and disengaged to allow one to rotate it 180° to show TTL numbers or standard stops indexed to the top of the lens according to owner preference.

...

 

John, thanks for this info, yes, it seems that is exactly, what I can do with my lens! (serial no.119xxx)

 

When yo use an adapter, how do you "fix" the aperture lever, so that you actually can set an aperture value smaller than 4 ?

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When yo use an adapter, how do you "fix" the aperture lever, so that you actually can set an aperture value smaller than 4 ?

 

Adapter has to have a pin to keep the aperture closed. You may have an adpater without it. I have two different adapters, one without the pin and one with it.

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When yo use an adapter, how do you "fix" the aperture lever, so that you actually can set an aperture value smaller than 4 ?

 

The only adapters I have tried are these: eBay item 400644960181 which hold the lever over in stopped down position.

 

afterthought,

 

They were a little tighter than I expected, are you sure you are rotating you lens all the way into battery?

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They were a little tighter than I expected, are you sure you are rotating you lens all the way into battery?

 

It was discussed on another forum that the lens mount in these PEN-F/FT lenses may have variable thickness and shape of the edges. So, some adapters are too tight for some lenses, and work fine for others. While some adapters are oo loose. If the lens-adapter connection is too tight – please do not force it. I almost broke one lens in such way.

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Thanks Alex, that is good to know.

 

If those had been any tighter I would have sent them back. Just on the edge of firm -vs- force I guess. I plan on leaving the adapter on the lens anyway,so now it is on to stay.

 

Is it known if the variation in lens mount dimension is particular to a given focal length, manufacture date or something else?

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