[pschlute]

I had a discussion recently on Facebook about the FA* 24mm f2.0. The complaint being levelled against the lens by others, was that it lacked edge sharpness especially at wide or near wide open, and thus was not deserving of it's "star" appellation. This is not an unusual complaint made against this lens, and there is probably no other "star" lens that divides opinion as much as this one.

Lets get the facts out of the way first. The lens is already very sharp in the centre at f2.0 and gets to a peak at f5.6. Edge sharpness is different. It will be described in tests as poor/fair at f2.0, becomes good at f4.0, and peaks at very good only when f8 is used.

So those who say this is not a very good lens are right are they not ? Well, in my view they are missing the point about this lens completely, and the "point" of this lens is subject isolation. We all know that fast lenses give a narrow DOF and that is one reason they are prized. In respect of DOF this f2.0 lens is like any other f2.0 lens. But what makes this one different is that the edge sharpness has been deliberately kept subdued at the wide end of the aperture scale. This means you also get subject isolation in the focal plane itself, in addition to the depth of field.

It is for this reason that I think this lens is more than deserving of it's "star" status. For sure if you want to take a picture of a brick wall or a newspaper pinned to a wall (favoured by lens testers) you will need to stop down. Otherwise the lens is the wrong choice. But if you wish to explore a bit of Pentax magic and get unique results then this is a great historical lens to use. I present some pictures I took this afternoon in my garden which I hope displays the properties I refer to here.

[bdery]

Thank you for this piece of editorial.

When looking at a wide angle lens, I always think it should have edge-to-edge sharpness, because you want your whole sweeping vista to be sharp, right?

But then I look at this lens and realize it's an F2 lens. And I'm not going to shoot a broad landscape view at F2, most likely at F8 or F11. And THEN, the FA*24 is sharp across the frame.

So I fully agree with your analysis. Except for at night, when I'd be likely to shoot wide open, and would like to rely on edge-to-edge sharpness.

[house]

FA*24 images have always stood out to me. A nice mellow rendering that seems to be there even stopped down for landscape type images. I do need edge to edge sharpness stopped down so i never got one (it's also rare) but for people who's prime subject isn't architecture it looks very nice to me.

[dkpentax]

I think it performs fine for a 30 year old design. I don't know of any lenses except brand new stuff that are known for having full frame edge to edge sharpness when used wide open. to make a lens perform like that needs collosal numbers of elements and the resulting weight. here is the 80 1.4 lens performing with ultra open aperture performance. https://www.ephotozine.com/article/hd-pentax-d-fa--85mm-f-1-4-lens-review-36139/performance.

or as a closer comparison, a brand new Nikon Z 24 1.8. this gets full frame excellence, but to do it it needs 4 aspherical elements. https://www.ephotozine.com/article/nikon-nikkor-z-24mm-f-1-8s-lens-review--34224/performance

I've never seen any real lens tests of all of the vintage wide angle lenses, so its all still guesswork as to how they really perform. does the 1965 takumar f4.5 20mm look good at any f stop? no one knows.

[gofour3]

I've never seen any real lens tests of all of the vintage wide angle lenses, so its all still guesswork as to how they really perform. does the 1965 takumar f4.5 20mm look good at any f stop? no one knows.

These are some tests done on film, of various old Pentax wide angle lenses:

http://www.takinami.com/yoshihiko/photo/lens_test/pentax_superwide.html

Phil.

[Digitalis]

The complaint being levelled against the lens by others, was that it lacked edge sharpness especially at wide or near wide open, and thus was not deserving of it's "star" appellation.

I'll state for the record I'm no fan of the FA*24mm f/2 ASPH. In my mind the FA*24mm f/2 ASPH is a lens built for a very specific demographic, and to cut to the quick: Its a demographic I'm simply not a part of. Edge sharpness isn't everything to everyone and expecting it with such a wide lens at f/2 is mildly absurd.


My criticisms against the FA*24 shouldn't suggest I hate the lens* and think it should be stripped of the * designation - because for what it is designed for: it does exceedingly well and in the hands of those whom appreciate its qualities will produce excellent images that work to its strengths. Even in my comparison between the FA*24mm f/2 ASPH and the new DFA 21mm f/2.4 ED WR ASPH I stated as much. Mike Johnston of the The Online Photographer lauded the FA*24mm f/2 as one of the best 24mm lenses on the planet.


* Every good lens manufacturer makes a lens I dislike - even Zeiss and Leica, take it as a badge of honour.

[UncleVanya]

* Every good lens manufacturer makes a lens I dislike - even Zeiss and Leica, take it as a badge of honour.

That IS a badge of honor indeed. Fine company to keep.

[garywakeling]

I love the rendering from my copy, it really does remind me of the new 21mm, similar ability to isolate a near subject while still giving a sense of the surrounding



or even just a wide view

[Asahiflex]

It must be said - I really like the 3D pop of the first photos, especially the third. It reminds me of the SMC Pentax 1:2 28. Wish we could ask Jun Hirakawa (the guy in my avatar) what the design goal was with the FA* 24. But I guess background separation was high on his list.

[Digitalis]

Wish we could ask Jun Hirakawa (the guy in my avatar) what the design goal was with the FA* 24

I think it is pretty clear what the optical design intent was from the qualities of the lens. The same goes for the FA43 and FA77 Limited lenses.


Pentax K-1 SMCP-FA77mm f/1.8 Limited @ f/8 ISO 100 1/125th

[Class A]

I tried many times to find a good copy of this lens. IQ was always shockingly bad. One forgives designs of this era purple fringing but not very soft images, even in the centre.

I cannot say whether the copies were subpar, there are certainly bad copies of the FA 31/1.8 (mine is fine), maybe good ones exist, I just gave up.

[northcoastgreg]

I've never owned this lens and probably never will. But I've nevertheless been very impressed with the images I've seen from it. It produces images that have the kind of look and rendering that I find very appealing and aesthetically rewarding. So if there is a demographic for this lens, I'm probably part of it. I'm just currently on a limited budget and have other photography needs that will likely precedence over acquiring such a lens.

[Mikesul]

I owned one early on. It was a beautiful copy but I never bonded. I wish I had kept it.

[Sandy Hancock]

Wide open landscapes may not be your thing, but I'll throw this in for illustrative purposes. This is at f/2.0 on full frame. If you look at the line of rocks at the back of the little creek, the sharpness is pretty reasonable all the way to edges.



Stopped down, it is predictably excellent.



But this is the sort of situation where the FA*24 shines. Wide open again.

[ZombieArmy]

Why is my FA* 85 1.4 not sharp across the frame at f 1.4???? Perhaps an astro lens the FA* 24 is not, but it's clearly good at what it was designed to do. After owning the FA* 85 1.4 I *will* eventually own the 24.