[cyberjunkie]

The Porst 55 1.2 is really very soft wide open and becomes psychedelic in bright light. The Revuenon 55mm1.2 is alleged to be better.
.....
Have you looked at the Pentax A 50mm 1.2?

I own all of them (but the Canon).
The Rikenon and the Revuenon have the same (Tomioka) optical layout.
Which means that they should have identical performance. Of course vintage lenses are not like new ones. Each example has its history... some were taken care of, others had "accidents".
MY Revuenon is a magic lens, same level of the Leitz Summicron 2/90mm, just to give an example.
It is way ahead of the Pentax (K or A) regarding bokeh fringing (LoCA).
The Pentax beats the Porst/Cosina, which is the funkiest, and the one to choose if you really want to go extreme.
With a little of patience the Revuenon can be had for less than all the equivalents (which are for the majority M42 mount).
The Revuenon is in PK mount and does not need any modification to shorten the data pin (unlike the Porst).
I have the SMC Pentax, not the Pentax-A, but it should make no difference, outside of the ergonomics.
IMHO, any Tomioka in PK mount (Revuenon, Rikenon, Vivitar) would be the best option to get an f/1.2 lens without complicate and expensive conversions.


Edit :
I understand that the OP is concerned about other things, though it might make sense to add a little thought.
Those who say that the only difference between f/1.2 and f/1.4 is just a touch more than a half stop, probably have never compared such lenses in reality.
As far as bokeh is concerned, the difference is evident. It's not about subtleties. I have been very surprised myself. I didn't think the difference would be so visible.
Of course you need a close subject, and the right kind of picture.
The OP seems to be mainly interested in getting a faster shutter speed, maybe bokeh is of no relevance, but if the amount of light is the main concern, I would pay attention to the level of transmission of the specific lens. A little yellowing, or some haze, could make the effective T value of the optic even smaller, compared with the geometrical max F stop.
A clean lens, with uncompromised multicoating, can still have a good transmissions of the light, long years after its construction.

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Last edited by cyberjunkie; 12-30-2018 at 04:53 PM.

[kernos]

I own all of them (but the Canon).
The Rikenon and the Revuenon have the same (Tomioka) optical layout.
Which means that they should have identical performance. Of course vintage lenses are not like new ones. Each example has its history... some were taken care of, others had "accidents".

Would love to see some samples from your Tomiokas. As for the Canon, I did manage to get the whole business purchased and converted for under $300, but with Brian Gohacki out of the picture (fire, lost everything) it would probably be more expensive. The Canon is a 7 element 5 Group design and has a few illustrious design mates including the Tomioka 55mm 1.4. Where the Canon really makes sense is for a mirrorless camera with no conversion and only an adapter,

[cyberjunkie]

Would love to see some samples from your Tomiokas. As for the Canon, I did manage to get the whole business purchased and converted for under $300, but with Brian Gohacki out of the picture (fire, lost everything) it would probably be more expensive.

I didn't know about the fire, nor I know about the circumstances that led to his banning. I have seen his work, though.
I especially like the anodised parts. It's not a complicated process, but to delivery the kind of customisations he made, it takes to be proficient in many fields, including of course being a good lens mechanic.

Regarding the Revuenon/Tomioka, I posted a few pics on this forum.
Unfortunately I don't have it with me at the moment. I rotate my three f/1.2 lenses, giving a chance to all of them to show what they are capable of.
Now I am shooting (not that much, only sometimes) with the Porst/Cosina f/1.2 55mm.
It is a very different lens, more extreme.
Maybe other examples would perform differently. Mine doesn't look damaged and has perfect glasses, just needs a regreasing of the helicoid to be perfect, but I had no chances to compare it with another example, so I can't say if it represents the best this model of lens can give.
I learned that being funky wide open, a lot of care has to be taken with focusing. Magnified live view is almost mandatory.
I realised that some disappointing results were for the most part due to operator error.
Having said all that, I believe it doesn't sharpen up at mid diaphragms as much as the others.
About the other two, I favor the Revuenon/Tomioka vs the Pentax.
Other forum users have a different opinion, so it might well be that the difference could be due to the different conditions of the single lenses.
What is absolutely true is that the Pentax, as show by numerous pictures posted on this forum (and elsewhere), is more affected by bokeh fringing.
The Revuenon shows much less LoCA than the Pentax.
If what you look for is bokeh quality, not just speed, the Tomioka design has a visible edge under this regard.


Here are two examples of the rendition of the Revuenon 1.2/55mm, shot wide open:






There is some purple fringing, and some blue-ish fringing in OOF highlights, but it's far from dramatic.

[pepperberry farm]

ah, the much-maligned Porst 55/1.2

victim of so much re-posted, unverified garbage.... if you have one, use it - shoot it day in and day out, get good with it.... then post your shots and a review...

(can you tell I love my copy?)

at f1.2:








beyond f1.2, this lens is quite sharp:

[cyberjunkie]

ah, the much-maligned Porst 55/1.2

victim of so much re-posted, unverified garbage.... if you have one, use it - shoot it day in and day out, get good with it.... then post your shots and a review...

(can you tell I love my copy?)

I hope you're not referring to me
For my own admission my initial judgement of the lens was affected by the choice to trust my eyes (and the phase-based focus confirmation led), focusing through the optical viewfinder.
I believe others have made the same error.
This lens is more difficult to focus than the other two, because of course the focusing is done wide open, not at the working diaphragm... and wide open this lens glows more than the others. So even if the shot is taken stopped down, the result is often marred by mis-focusing.
I'd say that in principle all super-fast fifties should be focused with great care using LiveView (better enlarged!). Though the Porst needs it more than the others.
Under a certain point of view it's even better than the other two, if the goal is to use it creatively. Which means to shoot almost exclusively wide open, making good use of the beautiful glow of the high lights.
I have revised my judgement about this lens after I decided to give it another chance.
I brought the lens with me for a few months, and I'm trying my best to focus correctly in low light conditions.
I had seen some pics posted by @pepperberry farm, which were clearly sharper than mines.
What was wrong? I wanted to know if my example was inferior, or there was an entirely different reason.
Maybe your lens is a little better, but I believe that most of the photos I shot with this lens could have been focused more accurately... which in turn could have led to much better sharpness.
Now I have a better understanding of the lens, but I still prefer the Revuenon. IMHO, it has better overall performance.
All the three lenses are a very good choice, for different reasons. If I had to give my score, 1 to 10, I'd give the Porst an 8 1/2, a 9 for the Pentax, and a 9+ for the Revuenon.
The evaluation is very similar, but these lenses are as different as the (same) basic optical design allows.
Cosina, more or less in the same period, decided to release both designs under its brand, one being the Cosina 1:1.2 55mm, and the other the Cosinon-S 1:1.2 55mm. The former a Tomioka design, the latter a Cosina design, siamese twin of the Porst.
If the two lenses were more or less the same, t would have made no sense to sell both.

Regarding the sharpness level stopped down, my example is not bad, I can't say it's lacking sharpness, but I believe that the other two have an edge in this regard, especially the Pentax.
Let's be clear, none of them is a sharpness champion. Even an humble f/2 single-coated can do better. To each its own...

Here is a recent picture, shot with the Porst wide open.
The photo highlights the problem of correctly focusing on the right plane, with subjects that have a certain volume.
The importance of nailing the perfect focus with such minimal DOF is evident in this pic.
The focus is a touch in front of the ear, should have been on the eye. The difference is minimal, but it affects the perception of sharpness.
The background is gorgeous, and becomes an important part of the image.



At f/2 it does not sharpen up that much:



While at medium apertures (in this case, f/5.6 or f/8) it gets a lot sharper:



All the pictures, either shot with the Pentax, the Revuenon or the Porst, have gone through minimal PP.
With some efforts the images could have been much better, but this was not the scope of my posts.
I want to show what the lenses can give, not how good Lightroom is!

[kernos]

I didn't know about the fire, nor I know about the circumstances that led to his banning. I have seen his work, though.
I especially like the anodised parts. It's not a complicated process, but to delivery the kind of customisations he made, it takes to be proficient in many fields, including of course being a good lens mechanic.



Here are two examples of the rendition of the Revuenon 1.2/55mm, shot wide open:






There is some purple fringing, and some blue-ish fringing in OOF highlights, but it's far from dramatic.

Lovely photos there for sure.

[pepperberry farm]

I hope you're not referring to me.
For my own admission my initial judgement of the lens was affected by the choice to trust my eyes (and the phase-based focus confirmation led), focusing through the optical viewfinder.
I believe others have made the same error.
This lens is more difficult to focus than the other two, because of course the focusing is done wide open, not at the working diaphragm... and wide open this lens glows more than the others. So even if the shot is taken stopped down, the result is often marred by mis-focusing.
I'd say that in principle all super-fast fifties should be focused with great care using LiveView (better enlarged!). Though the Porst needs it more than the others.
Under a certain point of view it's even better than the other two, if the goal is to use it creatively, almost exclusively wide open, exploiting the beautiful glow of the high lights.
I have revised my judgement about this lens after I decided to give it another chance, bringing the lens with me for a few months, and trying my best to focus correctly in low light conditions.
I had seen some pics posted by @pepperberry farm, which were clearly sharper than mines. I wanted to know if my example was inferior, or there was an entirely different reason.
Maybe your lens is a little better, but I believe that most of the photos I shots with this lens could have been focused more accurately... which could have led to much better sharpness.
Regarding the sharpness level stopped down, my example is not bad, I can't say it's lacking sharpness, but I believe that the other two have an edge in this regard, especially the Pentax.
Let's be clear, none of them is a sharpness champion. Even an humble f/2 single-coated can do better. To each its own...

Here is a recent picture, shot with the Porst wide open.
The problem of correctly focusing on the right plane, with subjects that have a certain volume, is evident in this pic.
The focus is a touch in front of the ear, which is where it should be. The difference is minimal, but it affects the perception of sharpness.
The background is gorgeous, and becomes an important part of the image

no - not referring to you, Paolo...

I've read enough 'reviews' to see that there are some online that are simply copy-&-pasted from one website to the other, until the point that the FUD concerning this lens becomes the only info you can find on it...

it's not a perfect lens - I've seen better rendering and better bokeh from other 55mm lenses, and focusing at f1.2 is difficult (but is true with any super-fast lens)...

but when you get it right, it's sooo rewarding...

[niblue]

I really need to use my Porst 55mm F1.2 a bit more. I've only really used it wide open where it's a bit soft and low contrast, which makes it nice for portraits.

[pepperberry farm]

I really need to use my Porst 55mm F1.2 a bit more. I've only really used it wide open where it's a bit soft and low contrast, which makes it nice for portraits.

exactly - the huge aperture is nice to have, but beyond that it is really a competent lens...

[kernos]

Three photos
Porst 55mm 1.2 at 1.2 Just lovely in its own way, the smoky thing in the background is a pita chip bag, but the center is fairly soft.



Canon 55mm 1.2 at 1.2 Also a really nice bokeh blur, but what is in focus and centered is a lot sharper.



But when the light gets a bit brighter the Porst gets a bit wonky, which can be used to effect @1.2


Like anything photographic, it comes down to a matter of taste. For me the Canon (and I have no experience with the Tomioka clan) is just a more useful lens.

[niblue]

I carry a 50mm F2.8 macro with me most of the time so if I want sharp at 50mm I use that (I have quite a few other 50mm primes as well but they don't get a lot of use), which is why the Porst tends to mostly get used wide open. It's got its issues wide open but they can be attractive in the right context.

I might get around to doing a 50/55mm lens comparison one of these days!

[Wasp]

I have an SMC Pentax M 50mm f/1.4 and a Rokinon 85mm f/1.4. I love both and can recommend them. Manual focus is a bit of a challenge with them but live view is very useful.

[cyberjunkie]

no - not referring to you, Paolo...

I've read enough 'reviews' to see that there are some online that are simply copy-&-pasted from one website to the other, until the point that the FUD concerning this lens becomes the only info you can find on it...

it's not a perfect lens - I've seen better rendering and better bokeh from other 55mm lenses, and focusing at f1.2 is difficult (but is true with any super-fast lens)...

but when you get it right, it's sooo rewarding...

Yes, I believe that ALL f/1.2 lenses have something special, that modern optics don't.
Btw, there are NO modern lenses that fast, at least for Pentax. The Mitakon 1.2/85mm monster is the only one that comes to my mind.
I just got my new (to me) Sigma EX DG HSM 1.4/50mm. I already used it enough to understand that it does NOT blow away all the vintage fifties I own, and that especially at close range an f/1.2 lens "paints" the background in a way modern, slower lenses can't.

In the meantime, after your reply, I have edited my previous post and added a couple of pics to substantiate my opinions.
All in all, super-fast (f/1.2) fifties are all great fun, and all worth buying. Of all vintage lenses, they are for sure a great choice, if not THE CHOICE.