Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!

SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Pentax 110 18mm PAN FOCUS lenses
View previous topic :: View next topic  


PostPosted: Tue Aug 12, 2014 12:34 pm    Post subject: Pentax 110 18mm PAN FOCUS lenses Reply with quote

I am posting in hope of eliciting comment on the Pentax 110 18mm pan focus lens.

On background, I already own a single copy of the familiar Pentax 110 18mm lens. These are ubiquitous and, IMO, unremarkable. I see copies for sale nearly every day. This post is not with regard to the more familiar 18mm lens, but instead:

I only very recently stumbled across the subject pan focus lens. I have never seen a copy of this lens, which apparently has both fixed aperture and fixed focus. The focus is set, at the factory by Pentax, to the hyperfocal distance.

If you own or have used this lens, it would be interesting to learn your opinions and experience.

For anyone with more interest in the lens, here are a few links:

http://en.wikipedia.org/wiki/Pentax_Auto_110

http://www.techtheman.com/2011/11/pentax-auto-110-pan-focus-18mm-f28-on.html

http://www.ebay.com/sch/Cameras-Photo-/625/i.html?_from=R40&_nkw=Pentax+Pan+focus&LH_Complete=1&rt=nc


Noted in passing:

The Pan Focus 18mm is obviously rare and expensive, whereas the more pedestrian variable focus lenses, with equivalent optics, are far more reasonable. One wag I read pointed out that, for folks with thin wallets (and we are everywhere! Smile), you can own a pan focus lens at lower cost as follows:

Buy the variable focus Pentax 110 18mm lens, set the focus to the hyperfocal distance (circa 3.5 feet), create and insert the required fixed aperture of roughly f6.3, and shoot happily away with your newly minted, far lower cost, pan focus lens!! Very Happy


PostPosted: Tue Aug 12, 2014 3:23 pm    Post subject: Re: Pentax 110 18mm PAN FOCUS lenses Reply with quote

guardian wrote:

Buy the variable focus Pentax 110 18mm lens, set the focus to the hyperfocal distance (circa 3.5 feet), create and insert the required fixed aperture of roughly f6.3, and shoot happily away with your newly minted, far lower cost, pan focus lens!! Very Happy



precisely!


PostPosted: Tue Aug 12, 2014 3:27 pm    Post subject: Reply with quote

The 18mm isn't anything special though. On APS-C it lacks contrast and is only sharp in the centre, the edges are very poor.

Adding an aperture might improve that a bit. However, placing an aperture behind the lens is likely to cause vignetting. The aperture in the Pentax110 was in the body though so maybe not, however 110 film is smaller than APS-C.


PostPosted: Tue Aug 12, 2014 7:04 pm    Post subject: Reply with quote

I`ve seen this Fix focus 18mm lense for sale a few times, but it is a bit more expensive if remember correct Wink

The ordinary 18mm is stunning with the built in aperture adapter Very Happy



OM-D with Pentax 110 18mm stopped down a little


PostPosted: Tue Aug 12, 2014 7:58 pm    Post subject: Reply with quote

Guys, I appreciate all of your responses. I agree with iangreenhalgh1 that the Pentax 110 lenses, across the board, could be problematic with APS-C cameras. Beyond that I have a couple of other observations in this arena:

First, there is a noteworthy aspect of the Pan Focus 18mm I did not mention, or discuss, in the OP. It is one of the three 1981 lenses, not a member of the earlier group. I think this is a good and hopeful attribute. Why?

The original three Pentax 110 lenses are plagued by dreaded barrel cracks. I see this in the photo of Nordentro's 18mm. My 18 is OK (so far), but my 24mm Pentax 110 lens has a barrel crack. I oftentimes spot barrel cracks in Pentax 110 lenses (earlier series) being offered for sale. My assumption is that there was some sort of problem with the plastic in these earlier lenses. Or else the design was not quite right, with insufficient allowance having been made for the different coefficients of expansion as between the glass and the plastic barrel. Whatever the problem, the barrel cracks are unwanted, albeit likely harmless as to function.

My hope with the 1981 lenses, to include the Pan Focus, is that perhaps by then Pentax had put this problem right.

Second, I note with interest that, at least so far, no forum member has reported personal, hands on, experience with the Pan Focus 18mm. It is a somewhat rare and very expensive lens, with an inexpensive workaround. But as you can see from the link in the OP, when these lenses do become available for sale, they SELL, oftentimes straightaway!!


PostPosted: Tue Dec 27, 2022 3:41 am    Post subject: Reply with quote

I see ( http://camera-wiki.org/wiki/Pentax_Auto_110 ; https://www.techtheman.com/2011/11/pentax-auto-110-pan-focus-18mm-f28-on.html ) that the optical formula of the Pentax-110 18mm Wide-angle (6 elements in 6 groups) is the same? that the Pentax-110 PAN Focus 18mm Wide-Angle, does this mean that the only difference of the second with respect to the first is that they have incorporated a fixed diaphragm to f/6.5?


PostPosted: Tue Dec 27, 2022 12:54 pm    Post subject: Reply with quote

iangreenhalgh1 wrote:
The 18mm isn't anything special though. On APS-C it lacks contrast and is only sharp in the centre, the edges are very poor.

Adding an aperture might improve that a bit. However, placing an aperture behind the lens is likely to cause vignetting. The aperture in the Pentax110 was in the body though so maybe not, however 110 film is smaller than APS-C.


While not impressive I didn't see issues with the edges when I tried mine on FF - yes the edges nearly form a circle as the coverage is so badly lacking I did see some limited vignetting on APSC.
110 film is very similar to MFT, which is the mount these lenses work best on once the aperture is sorted. IIRC the 24 covers APSC entirely and the 50 is reported to cover FF.

The smaller aperture of the pan focus will also increase the image circle, which might be a benefit on APSC, even so I don't plan to add the pan focus to my collection.


PostPosted: Tue Dec 27, 2022 1:54 pm    Post subject: Reply with quote

...thanks DConvert for the useful information; I didn't expect any of the lenses (18, 24 or 50) to cover FF (on my Sony A7 RII) although I did expect them to cover APS-C with some bearable vignetting (on my Sony F3). And I had thought of incorporating a semi-fixed diaphragm (type f/6.5) to the Pentax110 adapter to convert the 18 into a Pan Focus. And also the possibility of incorporating a variable diaphragm; something like http://forum.mflenses.com/pentax-110-18mm-24mm-50mm-by-mft-adapter-with-diaphragm-t81298,highlight,%2Bpentax+%2B110+%2B18mm.html . I have seen that it is sold done ( http://www.rjcamera.com/ocart/index.php?route=product/product&path=20_27&product_id=50 ), but it seems a bit expensive to me as a whim.
All theoretical, I still don't have the Pentax 110 lenses or the adapter: when they arrive I'll get a better idea.


PostPosted: Tue Dec 27, 2022 2:53 pm    Post subject: Reply with quote

Difficult for me to believe this thread, which I started over eight years ago, continues to draw comment . . . including this one from me! I would have thought back then that by now I would already have croaked! Wink

In any event, these Pentax 110 18mm lenses appear today to be as ubiquitous as ever . . . just more expensive.

Noted in passing, for collectors:

There appears to be an anomaly, regarding the pan focus lenses, centered on the name ring:

Some of the name rings include the letters "PF", while other pan focus lens name rings do not. I'm seeing this both ways among Pentax 110 18mm pan focus examples currently being offered at auction.

In addition as I mentioned years ago up thread, with any Pentax 110 lenses, beware of barrell cracks. This could only have become worse with time's passage as the plastic ages and shrinks.


PostPosted: Tue Dec 27, 2022 3:50 pm    Post subject: Reply with quote

guardian wrote:
Difficult for me to believe this thread, which I started over eight years ago, continues to draw comment . . . including this one from me! I would have thought back then that by now I would already have croaked! Wink


It always makes me feel uneasy to think that when refloating a thread after a few years it could happen -among other things- that I am questioning someone who has passed on to a better life and who, therefore, is not in a position to answer me.Shocked Laughing