[drypenn]

A question out of curiosity. I'm just wondering if we have a Pentax lens that cannot be faulted by pixelpeepers and at the same time render bokeh majestically?

I mean, I have been reading how "flawed" the FA limiteds are , but in my simple mind, how can a lens be technically and acceptably sharp for measure-bators, and still render nice OOF, especially when wide open? Or, take the case of my current lust favorite: the DA 55, I have yet to read an observation faulting its sharpness, but I have seen a lot of pictures where the diminutive FA43 will blow its OOF rendering out of the water at large apertures.

Do we have a lens in the pentax lineup where the two traits, sharpness and smooth bokeh consistently coexist at all apertures?

[Adam]

I'm not sure about all apertures, but the two traits can certainly coexist: like in the DA* 55mm or DA 35mm Macro.

[arv]

Apo-Lanthar 125mm f2.5 SL Macro... Sadly, discontinued.


A.

[mtux]

DA35ltd

[Naruto]

For most photographs the "majestic bokeh", as you call it, is associated with the fact that bokeh discs have fuzzy edges and melt with other discs. Such a property can not come along with exceptional sharpness, because this soft disc edges come as the result of spherical abberation. You can see this in the fact that the lens gets sharper when the diaphragme is closed (also correcting some other abberation).

The best sharpness you can hope for is the technically good bokeh where the discs are uniform . It can give this impression of busy background (see photozone for the DA 35 macro)

For wide angle, look for a good aspherical lens. If the blades are "rounded", both bokeh and sharpness then can improve when you get rid of the remaining abberation by closing the diaphragm a bit. But, because of the way some aspherical glasses are build, be careful that this often lead to an onion structure in the disc.

[VisualDarkness]

For most photographs the "majestic bokeh", as you call it, is associated with the fact that bokeh discs have fuzzy edges and melt with other discs. Such a property can not come along with exceptional sharpness, because this soft disc edges come as the result of spherical abberation. You can see this in the fact that the lens gets sharper when the diaphragme is closed (also correcting some other abberation).

False! Here I give you the magical Sony/Minolta STF 135mm F2,8: Sony 135mm f/2.8[T4.5] STF Lens Review - photo.net
And Fuji is soon to be releasing a similar lens: Fujifilm introduces XF 56mm F1.2 R APD with apodization filter: Digital Photography Review

[Na Horuk]

False! Here I give you the magical Sony/Minolta STF 135mm F2,8: Sony 135mm f/2.8[T4.5] STF Lens Review - photo.net And Fuji is soon to be releasing a similar lens: Fujifilm introduces XF 56mm F1.2 R APD with apodization filter: Digital Photography Review

Apodization element?? So Extra dispersion, apochromatic, aspherical element, and now there is apodization? Whoa

Anyway, can a lens be sharp and have good bokeh.. I think so, but there are a couple of snags. The more corrected the lens is, the better its sharpness and other stats, but the worse its bokeh is. We can see that with macro lenses, which have smooth bokeh, but still have a very "clinical" look to them, next to no character. So it depends on the observer, what they want to see in their photo. Of course there are ways to balance the IQ and the bokeh, much like we can see with the FA limiteds, which were designed to be good all around, instead of dominating one aspect and forgetting the others. Look at some Sigma primes, they have excellent sharpness for a good price, but people often complain about their bokeh. Triangular bokeh of the old 30mm, or the onion ring bokeh, etc.

Also, there is a big difference between wide open and stopped down bokeh. Stopped down to f8, most lenses will look very similar in the bokeh aspect. Rounded aperture blades can help. But there are much bigger differences between lenses wide open. DA 40mm f2.8, wide open does not have spectacular bokeh. Its good, but its not as good as DA* 55mm f1.4 (faster aperture, longer focal length = shallower DoF, bigger bokeh magnification). But stopped down to f5.6 or f8, the rounded aperture HD DA 40mm will have nice bokeh anyway, and the DA* 55 might no longer be significantly better in bokeh terms. At f8, the difference between them is smaller.

Oh, and I really think Pentax should make something similar to the Fuji 56mm f1.2, and the other Fuji primes. Fuji is making great primes for its system. Pentax used to be great at primes, but hasn't released much lately.

[Rondec]

I guess I'm pretty bad at judging out of focus rendering. I feel like the FA 77 and DA *55 are both really sharp -- even wide open and give smooth backgrounds. The 55 doesn't look very good at f1.4, but by f1.8 it is plenty smooth and the FA 77 is nice at all apertures. Issues with the FA 77 mostly have to do with fringing and CAs -- most of which is easily fixable in post.

DA *55 at f2.2



FA 77.

[starjedi]

A question out of curiosity. I'm just wondering if we have a Pentax lens that cannot be faulted by pixelpeepers and at the same time render bokeh majestically?

I mean, I have been reading how "flawed" the FA limiteds are , but in my simple mind, how can a lens be technically and acceptably sharp for measure-bators, and still render nice OOF, especially when wide open? Or, take the case of my current lust favorite: the DA 55, I have yet to read an observation faulting its sharpness, but I have seen a lot of pictures where the diminutive FA43 will blow its OOF rendering out of the water at large apertures.

Do we have a lens in the pentax lineup where the two traits, sharpness and smooth bokeh consistently coexist at all apertures?

Apparently Tokina 90mm 2.5 .. Super sharp with wonderful bokeh...

[bdery]

Any macro will qualify. The DA*55 too. The DA limiteds as a rule have very even performances, and the bokeh of the 40 and 70 are very smooth. the 21's bokeh is interesting but not smooth.

[kh1234567890]

The DA limiteds as a rule have very even performances

Except the 'mind controlling' DA15 which has unbelievably bad bokeh.

[Na Horuk]

Well, ultra wides always struggle with bokeh. Its just not their strong point, due to the low magnification, wide field of view, and corrected optics. But the Pentax lenses are still not that terrible

[normhead]

No one has mentioned the 31 ltd. Heavily corrected lenses tend to have better bokeh. During various lens conversations I've posted comparisons of the DA*60-250 and the Sigma 18-250, where the most noticeable difference was the smoothness of the booked, in the much more heavily corrected DA*60-250. The subject sharpness was very similar, which is what you'd expect with and held images. Similarly there was a comparison posted by someone else comparing the 31 ltd to a 28mm lens, the obvious difference besides the 31's sharpness was the smoothness of the bokeh. In both cases, the more expensive lens was sharper, more corrected, and had better bokeh. The notion that a sharp lens can't have good bokeh is not supported by observation. Trying to justify why that might be true, honestly, I'm too old to care. I don't want to know what someone's theory says is true... I just want to know what's true.

This observation was originally made by Digitalis I believe, I just follow the stream and check it out as I move along. So far it has held up to scrutiny.

[Lowell Goudge]

I guess I'm pretty bad at judging out of focus rendering. I feel like the FA 77 and DA *55 are both really sharp -- even wide open and give smooth backgrounds. The 55 doesn't look very good at f1.4, but by f1.8 it is plenty smooth and the FA 77 is nice at all apertures. Issues with the FA 77 mostly have to do with fringing and CAs -- most of which is easily fixable in post.

DA *55 at f2.2



FA 77.

The FA 77 exhibits longitudinal CA in the out of focus, you can see this by the green fringing in the OFF zone behind the subject and the violet fringing In the OFF in front of the subject

Now, put this into B&W and it will look better.

What you need to remember is that bokeh is all about starting with some separation between foreground and background. Sharp objects, such as the end of the railing in the 77 photo are too close to the focus and too distinct to render nicely regardless of lens.

[Naruto]

I guess I'm pretty bad at judging out of focus rendering. I feel like the FA 77 and DA *55 are both really sharp -- even wide open and give smooth backgrounds. The 55 doesn't look very good at f1.4, but by f1.8 it is plenty smooth and the FA 77 is nice at all apertures. Issues with the FA 77 mostly have to do with fringing and CAs -- most of which is easily fixable in post.

DA *55 at f2.2

You can see what I was saying about the uniform discs on the top left corner? this is what I call good bokeh of a very sharp lens but not the best bokeh. Please do not confuse with the blur and separation of the subject/background.

May be you want to check for more precise information on the subject:
http://www.smt.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_35_Bokeh_EN/$File/CLN35_Bokeh_en.pdf