[filoxophy]

If one look carefully, the onion ring bokeh ??? especially obvious in this one:

I'm no bokeh connoisseur, but it doesn't bother me at all in this shot.

But hey, these are the first shots I've seen, so there's still plenty of time to judge this lens...hard. ;-) :-)

[Digitalis]

To be completely honest there are highly regarded pentax lenses that can produce migraine inducing bad bokeh, so I would take the sample images with a pinch of salt.

With that in mind, I present this visual atrocity:


Pentax K5IIs - Pentax SMCP-FA77mm f/1.8 Limited ( MIJ) @ f/1.8 ISO80 1/3200th - unsharpened 100% crop

I am affraid it doesn't cover 24x36mm, i took my PZ-1p to check it also : results to come by a few weeks time.

I can't say I'm at all surprised to find that this lens isn't FX compatible - you didn't expect Ricoh to give the game away this early did you?

[wed7]

Oh my! and I thought that the DA 40 only produces that kind of boke, but from the highly regarded FA 77?

[Digitalis]

I thought that the DA 40 only produces that kind of boke

Actually, pretty much any lens can produce that kind of bokeh. At a close focus distance, at wide apertures, under harsh Australian sunlight, with bright specular highlights in the background - Images like that nearly always produce horrible results.The only exceptions to that rule are apochromatic lenses, which due to their superior optical correction are largely immune to producing bokeh like that.

[wed7]

Thank you for the enlightenment. I learn something new today.

[ogl]

Hi friends, 5 shots with this lens (pre-prod model) + K-3, hold in Current Paris's "salon de la photo 2013" :

Do you know where f/2.8 ends?

[Alizarine]

To be completely honest there are highly regarded pentax lenses that can produce migraine inducing bad bokeh, so I would take the sample images with a pinch of salt.
With that in mind, I present this visual atrocity:

Actually, pretty much any lens can produce that kind of bokeh. At a close focus distance, at wide apertures, under harsh Australian sunlight, with bright specular highlights in the background - Images like that nearly always produce horrible results.The only exceptions to that rule are apochromatic lenses, which due to their superior optical correction are largely immune to producing bokeh like that.

I get images like this most of the time with Christmas lights/stringed bulbs when taking close-ups of decor with the 77. Thanks for the explanation on how (bright specular highlights in the background). I'll try it with other lenses and see if they produce the same result.

[ak_kiwi]

The lens looks pretty sharp even for these low res images.
The fourth shot on Andy Warhol's hair shows good edge sharpness.
Damn LBA is biting hard....

Attached Images

 

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Last edited by ak_kiwi; 11-10-2013 at 09:35 PM.

[Mr Spocko]

Agree any lens can produce bad bokeh in some situations. Even the legendary 90mm Tamron I managed a few with that (though not often it's usually a gem bokeh wise)
40mm f2.8 isn't great, 35mm f2,8 macro is quite nervous for non macro shots

But even ho hum bokeh lenses can do decent stuff at times.
This isn't the type of lens you get for bokeh shots

[Mistral75]

To be completely honest there are highly regarded pentax lenses that can produce migraine inducing bad bokeh, so I would take the sample images with a pinch of salt.

With that in mind, I present this visual atrocity:

(...)

Actually, pretty much any lens can produce that kind of bokeh. At a close focus distance, at wide apertures, under harsh Australian sunlight, with bright specular highlights in the background - Images like that nearly always produce horrible results.The only exceptions to that rule are apochromatic lenses, which due to their superior optical correction are largely immune to producing bokeh like that.

The "bad bokeh" in the picture you are presenting results from the combination of:

- Longitudinal chromatic aberrations (non-coinciding focal planes of the various colours), leading to magenta (red + blue) outlining in front of the focus point and green beyond;

- Coma (aka comatic aberration: off-axis point sources appearing distorted, sort of having a tail like a comet); and

- Mechanical vignetting (specular highlights in the background taking the form of "cat's eyes" in the corners).

Truly apochromatic lenses don't show longitudinal chromatic aberrations but can still suffer from coma (aplanatic lenses don't) and mechanical vignetting.

[normhead]

The "bad bokeh" in the picture you are presenting results from the combination of:

- Longitudinal chromatic aberrations (non-coinciding focal planes of the various colours), leading to magenta (red + blue) outlining in front of the focus point and green beyond;

- Coma (aka comatic aberration: off-axis point sources appearing distorted, sort of having a tail like a comet); and

- Mechanical vignetting (specular highlights in the background taking the form of "cat's eyes" in the corners).

Truly apochromatic lenses don't show longitudinal chromatic aberrations but can still suffer from coma (aplanatic lenses don't) and mechanical vignetting.

I'm sure if I studied for a couple hours I could understand what you just said, well maybe a bit more than that.

[Mistral75]

I'm sure if I studied for a couple hours I could understand what you just said, well maybe a bit more than that.

Reading any and all words in my post, one by one, following the order they have been written in, with your braincells turned on, should be enough to allow you to understand most of it .

If not, I would be delighted to answer any questions you might have.

[LFLee]

To be completely honest there are highly regarded pentax lenses that can produce migraine inducing bad bokeh, so I would take the sample images with a pinch of salt.

With that in mind, I present this visual atrocity:


Pentax K5IIs - Pentax SMCP-FA77mm f/1.8 Limited ( MIJ) @ f/1.8 ISO80 1/3200th - unsharpened 100% crop


I can't say I'm at all surprised to find that this lens isn't FX compatible - you didn't expect Ricoh to give the game away this early did you?

The Sigma 18-35 also have onion bokeh, so that is a tie.

But I watch a video before where someone compare a similar range Canon and Sigma lens, Canon lens doesn't exhibit onion ring but Sigma did.

I am surprise to see the 77mm ltd bokeh is that bad, are you sure is not your filter problem (if you have filter on)?

I believe these sample picture of 20-40 were taken without filter on them, if so, it is unfortunate that the onion bokeh exist. Something to do with HD vs. SMC coating? Anyway, a $1000 lens should perform better.

[Digitalis]

Truly apochromatic lenses don't show longitudinal chromatic aberrations but can still suffer from coma

Correct, however most 35mm lenses that are apochromatic tend to be macro lenses, and usually have long focal lengths. So coma is essentially a non-issue.

The Sigma 18-35 also have onion bokeh,

I see what you did there. But in any event "Onion bokeh" is caused by poor polishing of the individual elements that make up the lens itself, In sigmas case the worst offenders are lenses that have aspheric elements in them. The Sigma 30mm f/1.4 EX is a good example of a lens with this issue.

I am surprise to see the 77mm ltd bokeh is that bad, are you sure is not your filter problem

No filter could cause that kind of performance from a lens, but for the record: no there was no filter on that lens. As if I would spend my money on such a lens only to hobble its performance by using a low quality filter.

[LFLee]

No filter could cause that kind of performance from a lens, but for the record: no there was no filter on that lens. As if I would spend my money on such a lens only to hobble its performance by using a low quality filter.

hm... need to pay attention to my 77mm bokeh next time.