[Damon]

Hi there everyone, I have previously received wonderful advice from you stunning folks and I once again am in need of your assistance and expertise.

I was looking at getting a new portrait lens and have basically come down to these two as lenses with very slim DOF with lovely out of focus area rendering. I do know that it becomes quite hard to suggest things when I am choosing two pretty different focal lengths but to be honest I do not know which I would like more.

Basically things I am interested in learning about are:

1- Difference between the two coatings if anyone has knowledge on them both, I know the 50mm is an older lens but it is still SMC and the Samyang is a cheaper brand which I am not sure about in the way of coatings.

2- How much extra light will 50mm 1.2 let in compared to 1.4 and with the extra length of 85mm will the two deal quite differently in low light with the 85mm needing a longer exposure?

3- Which is better at rendering backgrounds in general (I know this is quite hard to answer, just putting it out there incase one is known to produce bokeh quite superior to the other. I've tried looking at pictures but there just aren't a huge amount covering the entire range (f-stops, similar conditions etc) that is easily accessible)

I will probably think of more questions.

Thank you for helping me out.

P.s. I choose MF for two reasons 1. Cheap (but still quality) 2. MF makes me feel more involved in the picture even if I do get angry because it's wrong sometimes.
and I can get these two for about the same price.

[lytrytyr]

2- How much extra light will 50mm 1.2 let in compared to 1.4 and with the extra length of 85mm will the two deal quite differently in low light with the 85mm needing a longer exposure?

The f/1.2 will give you about 1 click of EV compensation advantage over f/1.4.
Not really a major difference.

Since apertures are given as a fraction of the focal length,
f/1.4 is the same as far as light is concerned,
regardless of whether it's 50mm or 85mm.

I don't have either of those specific lenses,
so can't help you with the other questions.

[Lowell Goudge]

The biggest thing to consider is shooting distance, the 85mm will need 50% more working distance for any shooting situation when compared to a 50mm

From that point on, consider next that the samyang will be a KA mount and as a result you have all the exposure and flash functions not just manual exposure and manual flash. It you are serious about portrait work this is more important than F1.2

[indyphil]

something no-one has mentioned yet:

In both cases the wide aperture will give you a very shallow depth of field. So shallow in fact that in a head and shoulder photo youll need to nail the focus on the eyes, the nose and ears will be noticeably soft. Nailing critical focus like that with a manual focus lens and a viewfinder screen that was designed for autofocus is tricky at best. A split prism viewfinder would help, but either way its going to be hard, if you or the subject move a little you miss focus

This of course assumes you are shooting wide open, but since you are comparing a 1.2 and a 1.4 I thought it might be prudent to mention it.

[Docrwm]

I have a 50/1.4 (actually several) and the 85/1.4 you asked about in Vivitar flavor. If I have the distance to work with, as Lowell mentioned already, then I much prefer the 85/1.4 and its rendering. You mentioned cheap in your reasoning - there is no 50/1.2 that is cheap

The 1.2 is legendary and gives a very nice creamy bokeh from all examples I have seen that are composed correctly. The 50s are also significantly smaller and lighter than the 85. Pentax reps apparently told folks at one of the last big conventions that SMC is being matched by other makers with modern multi-coating methods - hence the move the HD as the high end coatings for Pentax lenses. I find the coatings on the 85 to be fine and the lens is a fully supported A lens so I have good control through the camera and it works and plays well with my flash.

If it's a matter of learning, the 50/1.4 might be easier as it requires less space and therefore makes it easier to practice inside with lots of objects and people where the 85 does ask for at least a meter but the 50 only requires .45m.

If you find a 1.2 in good shape for a bargain - grab it.

[NeverSatisfied]

something no-one has mentioned yet:

In both cases the wide aperture will give you a very shallow depth of field. So shallow in fact that in a head and shoulder photo youll need to nail the focus on the eyes, the nose and ears will be noticeably soft. Nailing critical focus like that with a manual focus lens and a viewfinder screen that was designed for autofocus is tricky at best. A split prism viewfinder would help, but either way its going to be hard, if you or the subject move a little you miss focus

This of course assumes you are shooting wide open, but since you are comparing a 1.2 and a 1.4 I thought it might be prudent to mention it.

Good points from IndyPhil. I've had the Pentax A 50/1.2, at the same time as the Cosina 55/1.2. I've sold the Pentax as I prefer the Cosina's bokeh, but there's no way I'd use either one for portraits- at least not wide open. I consider the Cosina an "artsy", special-purpose lens. Most of the time for head & shoulders portraits, I use the DA*50-135, at about 70-80 mm and f3.5 or so. Having an f1.2 lens is certainly desirable, but I wouldn't say it's necessary at all, for portraits.

[Na Horuk]

The 85mm focal length is probably better, but I've read some critiques about the Samyang, that its focus ring is too stiff to be used comfortably and stuff like that. On the other hand, the Pentax is confirmed to be great in build and quality. You might want to look into a 55mm f1.4, those are a 'classical' portrait FoV on APS-C and maybe have less distortion than a 50mm. And the difference between f1.2 and f1.4, for portraits, will be pretty negligible. You will probably stop down anyway, like others already mentioned, so you at least get the whole face in DoF.

[Docrwm]

The 85mm focal length is probably better, but I've read some critiques about the Samyang, that its focus ring is too stiff to be used comfortably and stuff like that. On the other hand, the Pentax is confirmed to be great in build and quality. You might want to look into a 55mm f1.4, those are a 'classical' portrait FoV on APS-C and maybe have less distortion than a 50mm. And the difference between f1.2 and f1.4, for portraits, will be pretty negligible. You will probably stop down anyway, like others already mentioned, so you at least get the whole face in DoF.

I find the 85/1.4's dampening very good for getting precision with the focus ring. At f1.4 it requires precision to the high level to nail the focus. A sloppy focus ring would make that nearly impossible to do consistently.

[grhazelton]

I have the 50mm f1.2 in the A flavor, which allows full aperture metering, etc. It is a wonderful portrait lens but, as others have noted, focusing with the stock K10 or K5 screen is problematic, at best. With 35mm gear and microprism/split image I always tried to focus on an eye or eyes, but the focus spot for autofocus isn't precise enough to zero in on an eye, unless one is right on top of the subject. I bought the KatzEye screen for my K10 which helps a great deal, but affects spot metering quite a bit.

Since the screens for the K10 and K5 are different - Pentax, what were you thinking! - I haven't yet decided whether to re-screen the K5; I've been too busy enjoying my new toy!

Unless the OP can find a 50mm f1.2A at a reasonable price I'd suggest a 50mm f1.4A, an excellent lens which is only slightly slower and far less expensive. While it doesn't have the bragging rights it will certainly do the job for portraits as well as its big brother.

[goubejp]

I have the 50 A f1.2, but for portraits I use either the DA 70 limited or the FA*85 1.4; Manual focus and very, very shallow depth of field wide open does not allow good results for portraits.
I consider the 50 f1.2 as a special lens for artistic effects.
Try the DA 70
Cheers

[Docrwm]

I have the 50 A f1.2, but for portraits I use either the DA 70 limited or the FA*85 1.4; Manual focus and very, very shallow depth of field wide open does not allow good results for portraits.
I consider the 50 f1.2 as a special lens for artistic effects.
Try the DA 70
Cheers

I've got both the 85/1.4 in MF and the DA70 limited. When I am being truly motivated the 85 is used and produces better results, but takes time and patience, over the DA70 IMHO.

[panoguy]

P.s. I choose MF for two reasons 1. Cheap (but still quality) 2. MF makes me feel more involved in the picture even if I do get angry because it's wrong sometimes.
and I can get these two for about the same price.

Even at the same price (which is rare), I'd still go for the 85mm. Extra working distance and equivalent DOF. For bragging rights, sure the 1.2 is "crazy fast" but hard to work...

[Ikarus]

85mm is my preferred focal length for head and shoulder portraits on full frame. On APS-C it enforces a subject distance that makes for a noticeably more compressed perspective on the face, so I'm more likely to grab one of my fifties instead.

[Just1MoreDave]

The 85mm focal length is probably better, but I've read some critiques about the Samyang, that its focus ring is too stiff to be used comfortably and stuff like that. On the other hand, the Pentax is confirmed to be great in build and quality. You might want to look into a 55mm f1.4, those are a 'classical' portrait FoV on APS-C and maybe have less distortion than a 50mm. And the difference between f1.2 and f1.4, for portraits, will be pretty negligible. You will probably stop down anyway, like others already mentioned, so you at least get the whole face in DoF.

All this means that the perfect APS-C portrait lens is the SMC Pentax 55mm f2.0, wide open. It's the right focal length. Same coatings and build as the K50/1.2. Great focus ring, 270 degree sweep. The same optics as a K55/1.8 except there's a ring that limits the lens to f2. This ring acts like a perfectly round aperture, slightly stopping down the f1.8 formula for better sharpness and colors, yet with round highlights, not hexagons. Depth of field at f2 is usually just right. Since you are using it wide open, pretend it has an A setting and use all the modes. This lens is dirt cheap, because the uninformed think it's a cheap kit lens like the M50/2. You could buy a K55/2, a DA 35/2.4 and a DA40XS for the price of a K50/1.2.

[Damon]

Wow, what a large amount of wonderful replies! Thanks everyone.

Something I probably should have specified is that this lens isn't being brought just for portraits but it will serve me as my go to portrait lens. It would likely be actually used less for portraits than everything else, I mentioned portrait lens as none of my other lenses serve incredibly well as portrait lenses. I definitely wouldn't shoot all the portraits in the lowest aperture, although certain situations I might try. I also do like the arty effects you can get with the 50mm 1.2, a large reason I am so drawn to it.

I do currently have a M42 mount 55mm f1.4 which I do love what it produces however when I got it was in really bad shape (fungus, few dents to body etc) which I fixed but it still has a really hard to turn focus ring which makes it quite a hassle to use. This is basically what I am upgrading from.

@focusing worries: I do have a split prism as the stock k5 one is terrible when it comes to manual and most of the people I take portrait I know so it doesn't matter about the time it takes to get the focus right, perhaps if this ever changes i'd probably just buy some nice af glass.. Oh that FA77...

I am still unsure on which focal range I prefer, I shall have a better look into this today and see if I can figure out if I fancy 50 or 85... It's a hard one though, I do feel like 85 can be quite restricting at times but certain situations I imagine the added length would be much preferred by me - I think the only way I can get around this is buying both.. Time to go buy a lotto ticket me thinks.

@Prices: I live in New Zealand, our prices don't make an ounce of sense in regards to lenses and availability is also poor so I can actually get a good condition 50mm 1.2 (K) for the same price as the samyang 85mm currently.

Thanks everyone, hope I have cleared a few things up.