[cyberjunkie]

This photo looks fantastic for such a "vintage" glass. I was looking for some nice glass like that one but couldn't find it at good prices. So, I was unexpectedly gifted Carl Zeiss Jena Flektogon MC 20mm f2.8. Unfortunately despite what its online price may suggest regarding its quality it can't match at all Pentax SMC coatings. It's also full of aberrations even stopped down. I was shooting mostly Pentax old lenses and now realize how Pentax excelled in quality in the days of thr past.

I believe there is something wrong with your Flektogon.
A certain number of late MC versions in black mount left the factory misaligned. The elements are tiny, correctly assembling a lens like that takes some time, and skilled workmanship. A quick check should follow. Those lenses were assembled manually, with no automation. Operator errors became quite common, approaching the fall of the Berlin wall.
In theory late MC versions should be better. In practice, most old lenses are impeccable, and give everything their optical design allows, while newer ones had a relevant number of defected lenses that should have been checked and rejected/reassembled.
On top of that, vintage lenses, even examples that look impeccable, could have been subject to vibrations and/or shocks that affected the correct positioning of the various groups... so in reality when you buy one you never know what kind of performance to expect.
I suggest to have the lens checked. It should perform AT LEAST at the level of the Pentax-M.
I had both, and now I have the Pentax-A 2.8/20mm. I think a good Flektogon would be very close to the A in performance (leaving alone ergonomics).

[northcoastgreg]

This photo looks fantastic for such a "vintage" glass. I was looking for some nice glass like that one but couldn't find it at good prices.

Thanks. Anything wider than 24mm that is any good at all is likely to fetch high prices, due to rarity combined with high demand. I was fortunate that I bought the M 20/4 and the FA 20-35 well before the K-1. While the M/20 is hardly a perfect lens (it's a trifle soft toward the corners, even when way stopped down), it does provide rather natural colors for a lens of its era.

Another image from this morning with the M 20/4:

[buberfan]

Meyer-Optik Trioplan 100mm f2.8 (original version)

[buberfan]

Helios 44m-7

[Durf]

Helios 44m-7

Wow, looks like you have a great copy of that lens!!!!

Nice shots!

[5r82]

Carl Zeiss Jena Flektogon MC 20mm f/2.8 at f5.6 on K-1. Some photos from tonight's walk as I was testing the lens after front element was cleaned and focus scale adjusted.

[5r82]

Helios 44m-4 58mm f/2 at f/2 on K-1

[robgski]

k-1 WITH smc-a 28-135MM [IMG][/IMG] and in color [IMG][/IMG]

[mattt]

Just discovered this thread... great idea.

Soligor 135mm f1.8 with T mount to K adapter

[northcoastgreg]

With the Pentax A 50 f2.8 Macro:

[robgski]

K-1 With Takumar 17mm FE [IMG][/IMG]

[cyberjunkie]

Just discovered this thread... great idea.

Soligor 135mm f1.8 with T mount to K adapter

I'm not entirely sure I'm capable of great ideas... maybe decently good ones

Btw, I love the picture, and I envy your Soligor.
As a Soligor collector, I'm very interested in a couple of early T2 preset lenses.
Yours is one.
I found one recently, but it's not so easy to find them at a decent price.

If you ever decide to part with that lens, I'd be interested...
I will visit my in-laws in the USA next April...and I might bring with me some interesting lenses. You know, just in case... I meet some pentaxian along the way

[5r82]

Carl Zeiss Jena Flektogon MC 20mm f/2.8 at f2.8 on K-1

[mattt]

If you ever decide to part with that lens, I'd be interested...

Duly noted

[5r82]

Carl Zeiss Jena Flektogon MC 20mm f/2.8 at f11 on K-1