[paperbag846]

Unlike the FA50, the Sigma 30 is very usable at f1.4

I dunno, I think it is a huge exaggeration to say that the 50 1.4 is unusable wide open... not as sharp as stopped down, perhaps not as sharp as some other lenses wide open, but it is very usable...

[RioRico]

I dunno, I think it is a huge exaggeration to say that the 50 1.4 is unusable wide open... not as sharp as stopped down, perhaps not as sharp as some other lenses wide open, but it is very usable...

And IMHO too many mistake ultra-thin DOF for softness. I don't use my FA50/1.4 (nor my K50/1.2 -- planar Yashica ML 50/1.4 -- Tomioka 55/1.4 -- Nikkor 85/2 -- SuperTak 135/2.5) wide open to shoot subjects requiring edge-to-edge flatfield sharpness. I use those to GRAB LIGHT, and to hell with the edges! If the edges matter, then I stop-down, or use a macro or enlarger lens. Different tools & uses...

[Pentaxor]

I dunno, I think it is a huge exaggeration to say that the 50 1.4 is unusable wide open... not as sharp as stopped down, perhaps not as sharp as some other lenses wide open, but it is very usable...

I think what he meant was very sharp at wide open which he consider very usable.

[yeatzee]

I was never happy with the sharpness wideopen on my old copy of the FA. I still think the K 50mm F/1.2 is sharper @ 1.2 vs. FA @ 1.4.

[RioRico]

I was never happy with the sharpness wideopen on my old copy of the FA. I still think the K 50mm F/1.2 is sharper @ 1.2 vs. FA @ 1.4.

I must differ with you here. IMHO all my f/1.4 Fifty's (ST50, FA50, Yashica ML 50, Tomioka 55) are sharper wide-open than my K50/1.2. Maybe you had a bad one?

[yeatzee]

I must differ with you here. IMHO all my f/1.4 Fifty's (ST50, FA50, Yashica ML 50, Tomioka 55) are sharper wide-open than my K50/1.2. Maybe you had a bad one?

or maybe you have a bad F/1.2

Either way I doubt my FA was a bad copy. The K 50mm F/1.4 i had for a short while was the same way, though slightly better than the FA.

[JHD]

And maybe my copy was just flat out atrocious - but I think not! It was fine at f2.8 and higher, but regardless of the light at f1.4 it was very soft which IMO is unacceptable... The evidence is all over the web and anyone can see for themselves , at f1.4 the Sigma 30mm is clearly in a different league from the FA50.

[RioRico]

, at f1.4 the Sigma 30mm is clearly in a different league from the FA50.

Apples+oranges. DOF @30mm is much thicker than @50mm at the same aperture. For rough equivalence, 30/1.4 DOF is about the same as 50/2.4.

[paperbag846]

Either way I doubt my FA was a bad copy. The K 50mm F/1.4 i had for a short while was the same way, though slightly better than the FA.

Apples+oranges. DOF @30mm is much thicker than @50mm at the same aperture. For rough equivalence, 30/1.4 DOF is about the same as 50/2.4.

Exactly. The problem here is the difficulty in nailing focus at 50mm f1.4. It requires some fiddling with the AF mechanism (and great skill with manual focus). There are sharper lenses with equiv DOF (say, the FA 77), but its not like the 50 1.4 is useless at f1.4.

[RioRico]

The problem here is the difficulty in nailing focus at 50mm f1.4. It requires some fiddling with the AF mechanism (and great skill with manual focus). There are sharper lenses with equiv DOF (say, the FA 77), but its not like the 50 1.4 is useless at f1.4.

Any 135/2.8 or 200/4 has even thinner DOF but I don't recall many complaints about difficulty in nailing focus with such. And *I* don't seem to have difficulty with any AF or MF 50/1.4 or 55/1.4, even with my delaminating eyeballs -- although I admit that the K50/1.2 is a bit tricky. IMHO problems arise when focusing a fast-fast lens on something fairly near, and interpreting the resultant ultra-thin DOF as softness.

[JHD]

I'm not talking about depth of field, but resolution at f1.4. Even so, most people prefer a 30mm VOF to 50mm on APC-S.

[ManuH]

and interpreting the resultant ultra-thin DOF as softness.

Happened to me when I started with a K10D and FA50 f/1.4. I deemed the FA50 too soft at that aperture. Using a K-7 that focused much better in low-light I could easily see the difference. It's not that sharp but it's certainly very usable for portraits for example.

[yeatzee]

Exactly. The problem here is the difficulty in nailing focus at 50mm f1.4. It requires some fiddling with the AF mechanism (and great skill with manual focus). There are sharper lenses with equiv DOF (say, the FA 77), but its not like the 50 1.4 is useless at f1.4.

Actually in my case it wasn't. I had no issue focusing it, and with liveview or my K200d w/ split image screen I have no issue focusing the 1.2

Maybe for someone that doesn't really know what their doing than yes thats probably true but my FA 50mm F/1.4 wideopen was to soft for me and that was the lens, not the shallow DOF (again I own a 1.2, I know what shallow DOF is).

edit: per your post below I'd also like to note I used this hood on mine in addition to the pentax M 85mm hood:
http://www.flickr.com/photos/tanneryates/4896329624/in/set-72157624413182991

Any 135/2.8 or 200/4 has even thinner DOF but I don't recall many complaints about difficulty in nailing focus with such. And *I* don't seem to have difficulty with any AF or MF 50/1.4 or 55/1.4, even with my delaminating eyeballs -- although I admit that the K50/1.2 is a bit tricky. IMHO problems arise when focusing a fast-fast lens on something fairly near, and interpreting the resultant ultra-thin DOF as softness.

Thats actually really interesting and answered a question I've been having, will my F 135mm @ F/2.8 give me shallow DOF than the K 50 1.2. Now I know so time to get a bokeh pano going with the 135! Thanks rico

[paperbag846]

Happened to me when I started with a K10D and FA50 f/1.4. I deemed the FA50 too soft at that aperture. Using a K-7 that focused much better in low-light I could easily see the difference. It's not that sharp but it's certainly very usable for portraits for example.

I also think that the FA 50 gets bad reviews from people who forget to use it with a proper hood.

It is pretty sensitive to flare, and you actually need to buy a pretty deep hood for it on ASPC (look at the hood for the DA* 55mm.... you need something similar!) to get the sharp results wide open that the FA 50 is capable of (or any of the 50 1.4s, actually).

[ManuH]

I also think that the FA 50 gets bad reviews from people who forget to use it with a proper hood.

It is pretty sensitive to flare, and you actually need to buy a pretty deep hood for it on ASPC (look at the hood for the DA* 55mm.... you need something similar!) to get the sharp results wide open that the FA 50 is capable of (or any of the 50 1.4s, actually).

Maybe, I also got a deep rubber hood later, I think it helps but I didn't make direct comparisons. BTW it's quite rare for a Pentax lens to not come with a hood, except of course for the cheap DA L.