[NeverSatisfied]

My story.....

I had the Cosina 55 first, and then went out for the A-50....obsessed about it.
I loved the Cosina, but somewhere in my mind i believed that the A-50 was better at everything. The belief was not based upon anything other than the reputation and pictures i had seen from the A-50.

When i finaly got it, i was amazed with its colors, bokeh and slightly better sharpness at 1,2. The biggest difference was the lack of the sometimes visible "purple vail" that the Cosina had at f1,2. So the A-50 is better than the Cosina.

But...

I sold the A-50 the other day. Why? Im mad.....

But the honest truth is that the Cosina had my heart from the start, and the A-50 could simply not live up to the character and personality of the Cosina.
The A-50 has a very creamy and soft bokeh, while the Cosina has a more busy, exciting and just, always surprising bokeh.
I would describe the Cosina as a rebel or outsider with an edge. While the A-50 is the Queen in all its majesty and glory.

So at the end of the day....its all about taste!

Now i want to get the Cosina again.

Cosina 55 1,2

Oh no! Swede, this story is really hitting home. Still trying to do some solid comparisons but so far you're spot-on, right down to the "purple vail" comment. Technically the A-50/1.2 is the superior lens, but when you get right down to it, a 1.2 lens is all about "art" and especially bokeh (IMO). And there I think the Cosina wins...

[Quicksand]

The holidays bring out the best in the Cosina . . .

[shiner]

When was the Cosina 1.2 made, and just how rare is it? I'd love to own one, but all searches turn up nothing. And why does Pentax not currently bother to make a 1.2?

[Pentaxor]

When was the Cosina 1.2 made, and just how rare is it? I'd love to own one, but all searches turn up nothing. And why does Pentax not currently bother to make a 1.2?

I think they resumed production of the A50/1.2. atleast that's what I heard around the forum.

anyway, I'd rather have Pentax make an AF version of it.

[NeverSatisfied]

Took a few comparison shots with Pentax A-50/1.2 vs Cosina 55/1.2. All shots from tripod, using remote shutter release, at f1.2, ISO 100, center-weighted metering. The first two were on Aperture Priority, 0 EV, tungsten WB, and manually focused with a split-screen focus screen; the Pentax chose 1/6 sec. while the Cosina chose 1/8. The second two images were shot on Manual, 1/100, WB set to "flash", and using a 540 flash unit set to manual at 1/64 output; focus was done via Live-View on a K20D. The order of the images is 1713 Pentax, 1714 Cosina; 1722 Pentax, 1721 Cosina. See what you think.

[NeverSatisfied]

Here are two shots taken back-to-back just through my front window, focusing on the text on my neighbor's van. Pentax first, then Cosina. Both at f1.2, 1/15 sec., ISO 100, daylight WB. These were hand-held and so if anyone thinks they see any camera shake I can always re-do them. Just quick 'n' dirty.
EDIT: FYI these are 1:2 crops.

[Pentaxor]

Thanks for the samples. looks like that Pentax is sharp and has more contrast. the Cosina seems to suffer with the halo/glow effect or looks hazy. what is interesting about the Cosina however, is it's bell shape highlights.

[NeverSatisfied]

Thanks for the samples. looks like that Pentax is sharp and has more contrast. the Cosina seems to suffer with the halo/glow effect or looks hazy. what is interesting about the Cosina however, is it's bell shape highlights.

Well, the Cosina has produced some pretty nice images, but probably the subject matter is what makes the biggest difference as to what is acceptable to one's taste. I do agree with your observation.

[NeverSatisfied]

Well I wish I had some oh-so-pretty flowers or something to shoot, but the season prevents that here! Again this is Pentax vs. Cosina, all at f1.2. I tried to frame these identically but the MFD is a little different (0.45m for Pentax vs 0.6m for Cosina). All shot on manual, matrix metering, flash WB, bounce-flashed 540 on manual set to 1/16 power, ISO 100, 1/60. The first two are manually focused while the second two were using Live View, on a K20D. All were taken as close to MFD as possible. Maybe I'm just bored, not sure what a bunch of macro shots at f1.2 proves, but what the heck! The order is Pentax, Cosina; Pentax, Cosina.

[NeverSatisfied]

P.S. Pentaxor you were asking about light transmission, etc. It seems counterintuitive since the Cosina is 58mm objective while Pentax is 52mm, yet I find that the Pentax is the brighter lens. With all other variables eliminated, it seems to be about 1/3 stop brighter than the Cosina, at f1.2. The Pentax histograms all fall a bit to the right of the Cosina's, as well.

[NeverSatisfied]

I think they resumed production of the A50/1.2. atleast that's what I heard around the forum.

anyway, I'd rather have Pentax make an AF version of it.

A buddy of mine at work recently bought the Canon version, 50mm f1.2 AF "L" lens, and paid over $1500 for it. He's into portrait work and second-shooter at a few weddings; I don't know that he's had a lot of success with it yet but apparently it's the Holy Grail or something...

[Pentaxor]

P.S. Pentaxor you were asking about light transmission, etc. It seems counterintuitive since the Cosina is 58mm objective while Pentax is 52mm, yet I find that the Pentax is the brighter lens. With all other variables eliminated, it seems to be about 1/3 stop brighter than the Cosina, at f1.2. The Pentax histograms all fall a bit to the right of the Cosina's, as well.

thanks for that piece of information.

[jake.astig]

Pentax MX + SMC K 50/1.2 shot wide open
Fuji Superia 400

[jsherman999]

.

[shiner]

What are the differences between the different A-50s?