NikonGear'23
Gear Talk => Lens Talk => Topic started by: Fons Baerken on March 17, 2017, 12:44:18
-
I have a 15mm f/3.5 ais here at my disposition with a rear bajonet filter type A2 attached, when i take the filter out it doesnt focus beyond less than a meter.
Strange, in my opinion the filter should not interfere with the focus just give it a warmer tone?
-
That is not correct. As the filter is part of the optical system (by virtue of being in the light pathway) it most definitively will influence focus. Expect a focus shift approx. 1/3 of the filter thickness. Perhaps not much in absolute figure, but for a short focal lens such as the 15 mm, that will throw infinity focus well and truly off, as you already discovered.
-
Should't you replace it with a clear filter? As with the 16/2.8 AI-S fisheye.
-
There is an L1Bc filter as part of the standard kit for the 15/3.5. Use that filter or do an extra click-white if the A2 is deployed.
The 15/3.5 uses the identical filter kit to the 16/2.8 Fisheye.
-
Thanks for the clarification. :)
-
Nikon made (makes?) both an L1Bc (very pale magenta "skylight") and an L37c (close to colorless) for that 39 bayonet mount.
-
True, but I think only L1BC was delivered with my 15/16 mm lenses.
L37C is practically worthless in terms of any UV attenuation, but it does serve a purpose in ascertaining the correct focus.
-
Searching on the internet the availbility of these filter sets brought up nope, may have to get a nikkor 16mm fisheye for that ;D; without the corrective glass element the minimum focal distance shortens.
-
Why not continue to use the A2? in the digital era, correcting w/b is a breeze.
-
By the way, the filter set is delivered in a leather pouch labelled CA-2.
-
Why not continue to use the A2? in the digital era, correcting w/b is a breeze.
True, driven by curiosity i suppose.
-
True, but I think only L1BC was delivered with my 15/16 mm lenses.
L37C is practically worthless in terms of any UV attenuation, but it does serve a purpose in ascertaining the correct focus.
The L1Bc was part of the standard filter set and installed on my 16/2.8 AIS Fisheye.as delivered. If memory serves me the L1Bc is approximately a CC025M filter.
The L37c was an available extra cost option. It doesn't add a yellow tint as it's very close to colorless. The L37c may be hard to find used. I may have had to special order mine.
Dave
-
By the way, the filter set is delivered in a leather pouch labelled CA-2.
Yes! That "CA-2" was the magic word. I got curious too and tried to find the filter but couldn't. But with "CA-2" as the search phrase there's plenty of them. This is just a random pick (not in Europe):
http://www.ebay.com/itm/Genuine-Nikon-39mm-Bayonet-Filter-Set-B2-O56-A2-for-13mm-15mm-f-3-5-16mm-f-2-8/322446736554?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140602152332%26meid%3De0aa9e58155a424bb56a58fe91d61978%26pid%3D100011%26rk%3D1%26rkt%3D1%26sd%3D321745333040
-
Do note the complete kit should comprise 4 filters.
-
Those rear filters are still listed in the online catalog of Nikon. L37C is readily available at some large retailers.
-
this is odd. it shouldn't alter the focusing at all. If your lens cannot focus beyond 1m then it means that it is too far from the film plane, like you have a PK-13 extension ring attached to it :o :o :o
-
My understanding is that all filters alter the focus. Most, in common use, alter it so little(in the plus diopter direction, by the way) that the effect can be ignored. This is not the case with the lenses under discussion, the rear-filter 15/3.5 AiS and FX fisheyes.
-
this is odd. it shouldn't alter the focusing at all.
Have a look at ... http://dougkerr.net/Pumpkin/articles/Glass_Plate.pdf
-
From the last equation therein, with refractive index 1.5, the displacement is 1/3 of the thickness of the filter. As already stated.
-
aha! :o :o :o
-
Searching on the internet the availbility of these filter sets brought up nope, may have to get a nikkor 16mm fisheye for that ;D; without the corrective glass element the minimum focal distance shortens.
http://www.ebay.com/itm/152306840847?ul_noapp=true
located in Japan though...
-
No problem. They ship world wide :D
Thanks for the link, I got an alternative filter to my current L1BC's.
-
An eBay search for "Nikon bayonet filter L37C" will, however, bring up a number of these items. All of which seemingly are located in Japan, but again, shipping is world wide. Prices were acceptable as well.
-
Question to the experts: which advantages if any provides the discussed lens over the AF-S 14-24mm? I had one of these 15mm/3.5 but unfortunately sold it >:(
-
Marginally smaller. Aperture ring for optimum control. High 'feel-good' factor. No zoom (doh). Flares more. Two-thirds of a stop slower. Can use rear-mounted filters. Very low geometric distortion unless used in the near range, where CRC kicks in.
It also has less efficient coatings and has a softer more rounded rendition than the 14-24. There is more CA but usually this is easily cured by the RAW processing software.
-
Question to the experts: which advantages if any provides the discussed lens over the AF-S 14-24mm? I had one of these 15mm/3.5 but unfortunately sold it >:(
If any is very questionable :D
I tried the 15/3.5 thanks to Bjørn in Scotland. It was mounted on the Df and I never clicked with that lens. I remember the terrible flares and ghosts that it produced. Not my cup of tea.
-
Have tried 2 copies sofar some differences i noticed on sharpness and distortion, flare and fall-off between these two.
Indoors architecture seem the better option.
-
This is either a lens you take a liking to, or the very opposite. Give it a try and decide for yourself, I cannot offer better advice than that.