Pentax 6x7 lenses? Any?

[lukaszgryglicki]

Hi, has anybody tried Pentax 67 lenses for accidental UV capability?

I have 4 lenses, but all of them have thread size 67mm or more, so I need to wait for my reductions to 58mm to arrive, just wondering.

I have Pentax 67 -> Nikon-F adapter, lenses work OK in full spectrum.

I will soon test:

- SMC Pentax 67 45mm f/4 (thread is 82 mm).

- SMC Pentax 67 55mm f/4 (thread is 77 mm).

- SMC Pentax 67 105mm f2.4 (thread is 67 mm).

- SMC Pentax 67 165mm f/2.8 (thread is 67 mm).

 

More lenses are listed here: https://web.mit.edu/...lens-info.html.

 

EDIT:

SMC Reflex-Takumar 67 1000mm f/8 - can be interesting - it's a mirror lens, so "glass :D" absorption should be small...

[nfoto]

Mirror lenses tend not to work too well in UV. This is evidently caused by the silver coating on the mirror(s).

[lukaszgryglicki]

OK, that's something I didn't know, thanks.

[Andrea B.]

Pentax SMC lenses have coatings which might cut the UV.

 

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The link is not working.

[Andrea B.]

https://www.ultravioletphotography.com/content/index.php/topic/4822-mirror-lenses-for-deep-uv-imaging/page__fromsearch__1

 

Lots of good info in that link about mirror lenses for UV.

[lukaszgryglicki]

I'll report what I find for SMC lenses, once I can do this.

[Andrea B.]

SMC = Super Multi Coating.

[Bill De Jager]

I have not tried testing my P67 lenses. Nearly all of them are the SMC versions, especially later versions of those. I do have early non-SMC versions of the 200/4 (4/4 optics) and 400/4 (5/5 optics) but I haven't tested them. I would have to obtain suitable 77mm UV-pass filters, or at least filters nearly that size. Otherwise I'd only be testing the central region (52mm) with no idea if the rest of the image area is useful at all. [Edit: removed erroneous sentence about IR control. This would be on film!]

 

I actually have intended to dispose of all my P67 gear and it's only by luck (I wasn't feeling well the day of the KEH buying event) that I still have them.

[lukaszgryglicki]

I will test with S8612 2mm + Hoya U-360 2mm (both at 67 mm). I've also bought a filter conversion 77->67mm - there will be some vignetting of course.

[Doug A]

I will test with S8612 2mm + Hoya U-360 2mm (both at 67 mm). I've also bought a filter conversion 77->67mm - there will be some vignetting of course.

6x7 lenses are pretty large in diameter. Could you devise a way to mount smaller filters in the adapter? I'll dig mine out and take a look.

 

Thanks,

Doug A

[lukaszgryglicki]

I just have filter rings that go down from 77mm to 67mm - just metal filter threads, then I'm just going to use my U-360+S8612 - both are 67mm x 2 mm.