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Archive 2010 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

deadwolfbones
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p.1 #1 · p.1 #1 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

...and mounted on my new K-5.

This is one of three Ai-s lenses I bought that have been converted to K-mount. The others are the 105/2.5 and the 24/2.8.

In short, this lens has stellar sharpness from wide open, pretty low distortion, and fantastic bokeh. It's maybe not quite as good at infinity as it is at close range, but it's still pretty damn good for landscapes. I'm really loving this one.

I don't claim any great artistic quality for these shots. Just showing what it'll do with the K-5's sensor (and presumably the D7000's):

Edited on Nov 17, 2010 at 01:19 PM · View previous versions

Nov 11, 2010 at 11:30 AM

rsolti13
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p.1 #2 · p.1 #2 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

Awesome! How was the conversion? How do you do it? The 28 2.8 CRC and 105 2.5 are probably the 2 best AI/AI-S lenses in that range

Nov 11, 2010 at 12:01 PM

bluetsunami
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p.1 #3 · p.1 #3 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

Lovely! For some reason the K-5's remarkable sensor has made me search Flickr for some interesting pairings as far as MF lenses. The 28/2.8 AIS looks fantastic on this body. The colors are nice and vivid. It also really makes me consider the K-5 as the body I'd upgrade to from my Rebel XT.

But that aside, I really dig the 7th photo. Shows the great sharpness and bokeh from this lens and color.

Edited on Nov 11, 2010 at 12:11 PM · View previous versions

Nov 11, 2010 at 12:08 PM

deadwolfbones
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p.1 #4 · p.1 #4 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

rsolti13 wrote:
Awesome! How was the conversion? How do you do it? The 28 2.8 CRC and 105 2.5 are probably the 2 best AI/AI-S lenses in that range

The conversion was done by a Pentaxforums member (username: augustmoon) out of Toronto. His description of the conversion:

It basically consisted of removing the nikon mount and placing it back to back with the Pentax mount and grinding the diameter of the Pentax mount because it is larger, then redrilling and countersinking the holes in the Pentax mount to line up with the Nikon mount, grinding off the Nikon AI tab, making a spacer or gasket to place under the new mount (as the registration distance is shorter with Nikon) to get proper focusing, then light sanding of that gasket until the infinity is perfect for your body.

So it's a permanent conversion—not possible to go back to Nikon (which is a shame since I also shoot with a D700), but I'm glad to have it in my Pentax system.

edit: I'm considering buying a 180/2.8 Ai-s and sending it to him to be converted, but I'm not sure yet...

Nov 11, 2010 at 12:11 PM

deadwolfbones
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p.1 #5 · p.1 #5 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

Some shots from the 105/2.5 + K-5 combo, btw:

Nov 11, 2010 at 12:14 PM

j.liam
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p.1 #6 · p.1 #6 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

deadwolfbones wrote:
I'm considering buying a 180/2.8 Ai-s and sending it to him to be converted, but I'm not sure yet...

Wouldn't recommend that. Lots of axial CA in the Nikkor 180 ED AIS. Purple wherever you look. Get yourself a CV SLI 4/180 in Pentax mount if you can find one.

Nov 11, 2010 at 03:02 PM

deadwolfbones
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p.1 #7 · p.1 #7 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

j.liam wrote:
Wouldn't recommend that. Lots of axial CA in the Nikkor 180 ED AIS. Purple wherever you look. Get yourself a CV SLI 4/180 in Pentax mount if you can find one.

I had the 180/2.8 AF-N and liked it a ton. From what I understand the optics are near identical in the AI-s version, so I'm not too worried about the CA. Appreciate the advice, though!

Nov 11, 2010 at 03:31 PM

j.liam
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p.1 #8 · p.1 #8 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

The optics of the AF versions are of a COMPLETELY diffferent design than that seen in the AIS version. The AF versions are better corrected for CA.

http://kenrockwell.com/nikon/180mm-history.htm

Nov 11, 2010 at 03:49 PM

deadwolfbones
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p.1 #9 · p.1 #9 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

Oho, looks like I was misinformed, then. Thanks for the correction.

Bjørn Rørslett seems to like it, though (as did Mr. Rockwell, not that his opinions matter much): http://www.naturfotograf.com/lens_short.html

Anyway, the Nikkor is ~$200 used, while the Voigtlander is what... $500+?

Not to mention the max aperture differences.

Nov 11, 2010 at 04:05 PM

deadwolfbones
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p.1 #10 · p.1 #10 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

Just noticed that my $200 estimate for the Nikkor was for the pre-ED version (I think). Seems like the ED Ai-s versions go for almost as much as the AF ones...

Nov 11, 2010 at 04:50 PM

philip_pj
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p.1 #11 · p.1 #11 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

Enjoy your new 'normal' lens...always thought 28mms make excellent APS-C lenses. The 105 is less well-suited, being around 160mm on APS-C. Nice demo of the output, thank you. I am guessing your 28mm is the lower MFD version, 0.2m from memory.

Sony need processing lessons from Pentax for that sensor.

Nov 11, 2010 at 05:00 PM

j.liam
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p.1 #12 · p.1 #12 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

deadwolfbones wrote:
Oho, looks like I was misinformed, then. Thanks for the correction.

Bjørn Rørslett seems to like it, though (as did Mr. Rockwell, not that his opinions matter much): http://www.naturfotograf.com/lens_short.html

Anyway, the Nikkor is ~$200 used, while the Voigtlander is what... $500+?

Not to mention the max aperture differences.

...not to mention the size difference.
And I imagine the Pentax-version should have auto-aperture on Pentax cameras and not-stop down metering with a converted Nikkor.

An illuminating contrast in size is the following photo of the CV 180 next to a Leica 180 Elmarit APO, a lens roughly the size of the Nikon 180 ED AIS:

http://www.flickr.com/photos/31761614@N08/3574162386/in/set-72157608587105231/

The CV 180 in the used market should fetch about $700-800.

Nov 11, 2010 at 05:03 PM

deadwolfbones
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p.1 #13 · p.1 #13 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

philip_pj wrote:
Enjoy your new 'normal' lens...always thought 28mms make excellent APS-C lenses. The 105 is less well-suited, being around 160mm on APS-C. Nice demo of the output, thank you. I am guessing your 28mm is the lower MFD version, 0.2m from memory.

Sony need processing lessons from Pentax for that sensor.

Yeah, it's the CRC (0.2m) version. I already love it to death.

j.liam wrote:
...not to mention the size difference.
And I imagine the Pentax-version should have auto-aperture on Pentax cameras and not-stop down metering with a converted Nikkor.

An illuminating contrast in size is the following photo of the CV 180 next to a Leica 180 Elmarit APO, a lens roughly the size of the Nikon 180 ED AIS:

http://www.flickr.com/photos/31761614@N08/3574162386/in/set-72157608587105231/

The CV 180 in the used market should fetch about $700-800.

Yeah, that's a LOT more than I'm looking to spend at the moment, unfortunately.

Nov 11, 2010 at 05:19 PM

dimitris77
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p.1 #14 · p.1 #14 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

That looks great. I need to get mine out of the bag together with the other 5 Nikkors.

Nov 11, 2010 at 07:12 PM

deadwolfbones
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p.1 #15 · p.1 #15 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

Weather and other factors have prevented me from giving the 24/2.8 as thorough a test as the other two, but here are some initial, boring images:

Nov 17, 2010 at 01:18 PM

kakomu
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p.1 #16 · p.1 #16 · Nikkor 24/2.8, 28/2.8, 105/2.5 Ai-s converted to Pentax

j.liam wrote:
Wouldn't recommend that. Lots of axial CA in the Nikkor 180 ED AIS. Purple wherever you look. Get yourself a CV SLI 4/180 in Pentax mount if you can find one.

To be honest, I don't have this issue. I notice that some photos appear less contrasty than others, though.

Nov 17, 2010 at 02:57 PM


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