[alamo5000]

I have been on some serious LBA here lately. I have bought a ton of lenses but I am still lacking one (irony I know)...

Actually I am lacking more than one I have looked at almost all the lenses that I can think of that are auto focus 50mm... and at least according to the reviews the FA 50mm f1.7 is the best of them all. As to the ratings here it out does all the competition.

All the other 50mm lenses are rated lower than this lens, even the lenses that cost substantially more or that have larger apertures. I have a manual f1.4 but I am just now getting the hang of shooting with that one...

I want to get an AF fast prime lens and so far the FA 50mm f1.7 is the clear winner as to the reviews here...but is there any real reason to even consider the DA 50mm f1.8? Or even the 55mm f1.4?

On the latter I am not sure if I even want to mess with SDM which I assume does not use the camera's internal focusing screw drive. From what I hear it is less reliable than the screw drive...

Aside from the obvious price difference (which is major) why would I even consider the 55mm? I could probably buy it eventually, but I don't shoot in the rain, being weather sealed makes little or no difference for me...

I have seen the prime lens shootout but it still leaves wide open the question as to which lens of this nature is superior. It looks to me as though the FA model is where its happening. I am shying away from the DA 50mm f1.8. I would like to have a brand new DA lens, but I would rather have a used one that is tried, true, and proven to be good. For roughly the same or even a little cheaper I can get something that is top notch.

Pentax 50mm Prime Lens Shootout - Introduction - PentaxForums.com

What if any is the downside to the FA 50mm f1.7? Why would I even want to mess with these other lenses when that one is out there floating around? Including the f1.4 version...

---

Last edited by alamo5000; 12-24-2012 at 04:20 PM.

[robtcorl]

Just wondering why the F f1.7 is not in the mix.
53 reviews, with a 9.9 for sharpness.
I love mine.

[alamo5000]

It could be in the mix. Hence the reason for this thread

(And to wonder why Pentax doesn't just keep on making perfectly good lenses)

[timo]

I used to have the FA50/1.4, and currently own the FA50/1.7, as well as M versions of both. As between the 1.4 and 1.7, I would go for whatever you can get the best deal on. You can get the 1.4 new, which could be a factor (warranty and all that). I don't think the difference between them is sufficient to justify agonising over the decision. Arguably the 1.7 is a bit better wide open, and I find the 1.4 a bit better stopped down a bit, but really this is a non-distinction in reality. The differences are zilch compared to the variability in shooting circumstances and your own actions on the day.

[alamo5000]

I used to have the FA50/1.4, and currently own the FA50/1.7, as well as M versions of both. As between the 1.4 and 1.7, I would go for whatever you can get the best deal on. You can get the 1.4 new, which could be a factor (warranty and all that). I don't think the difference between them is sufficient to justify agonising over the decision. Arguably the 1.7 is a bit better wide open, and I find the 1.4 a bit better stopped down a bit, but really this is a non-distinction in reality. The differences are zilch compared to the variability in shooting circumstances and your own actions on the day.

Hmmm... You are making me think here. I am going by the ratings on the lens rating database. I have a manual f1.4 lens that does pretty darn good, but I want a auto focus lens. I am pulling my hair out so to speak trying to decide. I would like the 55mm f1.4 but I am not so sure about the motor in the lens...or the price.

I would say the reason behind getting the lens that is sharper wide open is because that is when and where I would want to use it more. I want to have something fast so I can have control. With the manual f1.4 depending on your proximity to subject the DOF is tiny. For a crop camera I think the f1.7 will actually be more practical.

In ways you kind of validated what I was thinking.

I had some of the A series lenses and those were able to be adjusted by .1 increments. F1.7, 1.8, 1.9 etc etc I am not sure if the FA or the current 50's will allow you to do that.

In the end I am looking for sharpness wide open or on the low end of things...

BTW I lived in Singapore for a few years and had a wonderful time. It is the land of beautiful women that's for darn sure. I miss all the eye candy....

[mushin]

I've owned both the F50/1.7 and the FA50/1.4 and sold the latter because the F was VERY sharp and fast-focusing. If you search on PF there are a lot of threads about these lenses, with good arguments for either lens. If sharpness at wide open apertures is your goal then I, too, would also suggest you consider the F50/1.7.

[alamo5000]

I've owned both the F50/1.7 and the FA50/1.4 and sold the latter because the F was VERY sharp and fast-focusing. If you search on PF there are a lot of threads about these lenses, with good arguments for either lens. If sharpness at wide open apertures is your goal then I, too, would also suggest you consider the F50/1.7.

That's it. That is my aim right there. I would love to have all of the above but alas I am not a member of Donald Trump's family. With the lens (whatever I end up with) I want it sharp as a tack (or as sharp as possible) from wide open to about f4 or so.

Below is a shot that I took with my Rokinon P 50mm f1.4 (its completely manual)...

The photo was shot wide open at f1.4...

I wonder how my lens stacks up to other lenses when wide open....but I am really after the AF because its just so much easier.

[boriscleto]

The main advantage of the FA over the F is that the FA transmits MTF data to the camera.

I have made my feeling about this lens clear, but they may be affected by the fact that I only paid $100 for it

https://www.pentaxforums.com/forums/lens-sample-photo-archive/174806-super-mu...0mm-1-7-a.html

[alamo5000]

The main advantage of the FA over the F is that the FA transmits MTF data to the camera.

I have made my feeling about this lens clear, but they may be affected by the fact that I only paid $100 for it

https://www.pentaxforums.com/forums/lens-sample-photo-archive/174806-super-mu...0mm-1-7-a.html

Sorry for the stupid question but what does MTF stand for? I assume that's the data like aperture and so on and so forth that gets embedded in the photo...

[boriscleto]

Sorry for the stupid question but what does MTF stand for? I assume that's the data like aperture and so on and so forth that gets embedded in the photo...

The MTF program line "prioritizes the best aperture setting for the attached lens". It is one of the options for P mode on the higher end cameras.

In [Program Line] of the [Rec. Mode 3] menu, you can choose from the following Program Lines. When [P LINE] is selected for the [Green] button setting in P/Sv mode or TAv/M mode (p.282), exposure is regulated according to the set Program Line.

MTF Priority

Program Automatic Exposure that prioritizes the best aperture settings for the attached lens when a DA, DA L, D FA, FA J or FA lens is used.

[msatlas]

The respective F and FA versions of the 50/1.4 and 50/1.7 are optically the same. Any difference in review numbers comes down to variations in different people's subjective ratings. The FA 1.4 is much more common than the F 1.4, and the F 1.7 is much more common than the FA 1.7.

The 1.4 lenses really need a hood, and a lot of people saying they get soft results at wide apertures don't use a hood. The front element of the 1.7 lenses is more recessed so it has a but of a built-in hood effect. The 1.7 is still a bit sharper at wider apertures but the hood helps the 1.4 a ton.

I chose the 1.4 over the 1.7 because the 1.4 has much smoother bokeh. The 1.7 has somewhat busy bokeh. 50mm on APS-C is a short-ish portrait focal length so bokeh was important to me.

The DA 50/1.8 is also worth considering because its bokeh quality is somewhere between the 1.4 and 1.7, but with its newer coatings it has the lowest CA/PF.

[alamo5000]

I know the lens does make a difference but I don't want to make my photography all about the gear. That said I have one 50mm manual lens that is f1.4. I like it a lot. Its built like a little tank. If I am really able to take my time that lens produces decent results in my opinion.

I am however going into the AF prime lens world... so who knows, I might develop some serious LBA and buy a ton of lenses

Money is my limiting factor right now. Manual focus is good, but it takes a lot of care to get the right focus...

I would like to see a DA limited screw drive prime lens with all the modern coatings and stuff f1:1.2

I do not know about the whole SDM thing. I would just buy the 55mm f1.4 but that thing is expensive. The new DA 50mm I am not so sure about. I am not convinced that its what I am after. I would also consider the f1.4 version currently in production but I am still not entirely sure.

On my manual focus lens I use a metal hood that stays attached to it. It does seem to help it... but as I learn more and more about photography I see the same things differently over time....

[NeverSatisfied]

I've had the FA 50/1.4, and later the F50/1.7 along with an M50/1.7. I always used a hood on the FA 50/1.4, but even so I thought it was a little soft and lacking in contrast. (I eventually replaced it with the FA 43/1.9 Ltd, a fantastic lens!) However, both the AF and MF versions of the 50/1.7 were tack-sharp from wide open. I did some comparison testing between those two, and the results were interesting. I used Live View on a K20D, with both on a tripod, and focusing both manually. The MF focusing ring on the F50 feels pretty cheap and nowhere near as smooth and precise as that of the M50, and as a result the M50 always won that trial. (Honestly I thought the focus ring on the FA 50/1.4 was just as horrible!) However, if I did the same test but allowing the F50 to autofocus, it always nailed the focus perfectly and the results were indistinguishable from the best Live View, manually-focused result of the M50. Not only that, the AF on the F50 is very quick. So if you want a sharp lens with quick, accurate autofocus, that won't break the bank, look no further than either the F, or FA50/1.7.

[alamo5000]

I've had the FA 50/1.4, and later the F50/1.7 along with an M50/1.7. I always used a hood on the FA 50/1.4, but even so I thought it was a little soft and lacking in contrast. (I eventually replaced it with the FA 43/1.9 Ltd, a fantastic lens!) However, both the AF and MF versions of the 50/1.7 were tack-sharp from wide open. I did some comparison testing between those two, and the results were interesting. I used Live View on a K20D, with both on a tripod, and focusing both manually. The MF focusing ring on the F50 feels pretty cheap and nowhere near as smooth and precise as that of the M50, and as a result the M50 always won that trial. (Honestly I thought the focus ring on the FA 50/1.4 was just as horrible!) However, if I did the same test but allowing the F50 to autofocus, it always nailed the focus perfectly and the results were indistinguishable from the best Live View, manually-focused result of the M50. Not only that, the AF on the F50 is very quick. So if you want a sharp lens with quick, accurate autofocus, that won't break the bank, look no further than either the F, or FA50/1.7.

Once again, validating what I 'thought I would be getting' based on what I have seen, heard, read, etc....

You summed it up nicely...

[Na Horuk]

If you already have a fast manual prime, but now want AF, the newer lenses are the way to go. The DA lenses have a shorter focus throw and are optimized for fast focusing (which is probably part of the reason why they arent so fast), at the cost of manual focusing and aperture ring. They also have the newest coatings, specifically for digital sensors. Old primes are great, don't get me wrong, but if you mostly want quality and AF, go for something new. If you want quality and manual controls, go for something older
Edit: Also, in terms of IQ and sharpness, you almost can't go wrong with a 50mm prime.