DA*55mm vs. FA43mm

losecontrol · 02-20-2009, 04:04 AM

much talks about bokeh, backround ect ect.....Comeon! One of the simpliest rules nr.1 in photography is to choose a clear backround, and now people is speaking about a hard bokeh, bokeh, soft bokeh.. bla bla bla....

I think that we are getting to fixed in what the lenses could do for our photos that we forgett the simple rules ....A lens can improve the photography maybe...but we look more like lens controllers then photographers...

it's really sad looking this

falconeye · 02-20-2009, 04:48 AM

Originally posted by jake123

The Sigma 50mm would be my choice at a lower price with much smoother bokeh.

Well, the Sigma is (only) 13% cheaper (in EU). My main concerns with the Sigma are that is is bulky and that I am concerned how precisely the AF would nail focus.

Has anybody heard about AF precision with DA*55 vs. Sigma50?

Originally posted by RaduA

you're wrong and this puppy will have both better and more even resolution than Sigma

I hope so

Originally posted by TKH

The mistakes I make with my camera and the DA*55 are greater than the mistakes the lens makes

Maybe, you didn't nail the focus and RaduA is correct. As I said, I hope so.

Originally posted by blende8

Judging bokeh can only be done in comparison with other lenses and this in a controlled environment (tripod ...)

This is only partly true. If you can see a point light source out of focus, you actually can see the defocus PSF. The standard PSF looks like a bright disk with a sharp border. Lenses optimized for great bokeh tend to have a PSF with a somewhat brighter center and a somewhat softer edge, while being perfectly round.

UPDATE:
Some of the DA*55 images actually showcase its PSF. I have cropped the PSF from two of the photos in this thread, and a PSF from photozone's test of the Sigma 50. On the attached image, the left two snippets are from the DA*55 while the right snippet is Sigma 50. All at f/1.4.

It definitely has a dimmer center and quite hard edges. Sometimes, the edge doesn't appear as hard as other times (cf. left and middle center). Nevertheless, a clear tendency to circular rather than disk like PSF.

The Sigma 50 shows signs of an onion-like PSF. Which is criticized as well (only at f/1.4). In comparison, the Pentax PSF is smoother in the inner part but has a much harder border. I think there is enough evidence to be at least concerned about the DA*55 bokeh.

blende8 · 02-20-2009, 05:15 AM

Originally posted by falconeye

This is only partly true. If you can see a point light source out of focus, you actually can see the defocus PSF. The standard PSF looks like a bright disk with a sharp border. Lenses optimized for great bokeh tend to have a PSF with a somewhat brighter center and a somewhat softer edge, while being perfectly round. Some of the DA*55 images actually showcase its PSF. It definitely has a dimmer center and quite hard edges. A tendency to circular rather than disk like PSF. I think there is enough evidence to criticize the DA*55 bokeh.

This is in theory correct, but I know of no modern lens that does not show such overcorrected SA to a certain extent.
Do you know of a lens that shows "brighter center and a somewhat softer edge" in the background bokeh? I don't.
(Perhaps the old 100mm Macro Heliars? Never tested them.)

Of course it would be nice to have a lens that shows such a bokeh.
But apparently it is not that easy to establish without sacrificing important other parameters.

Well, I am no expert in these matters ...

falconeye · 02-20-2009, 05:23 AM

Originally posted by blende8

Do you know of a lens that shows "brighter center and a somewhat softer edge" in the background bokeh? I don't.

Well, there seems to be a lens from Sony with a Gaussian PSF. Which is a special lens and has other drawbacks. There simply aren't many lenses "optimized" for great bokeh.

I only mentioned this to illustrate that a good PSF tries to keep its energy near the center, not its border.

I updated my prior post to illustrate why I think that Sigma may have done a somewhat better job in this regard.

P.S.
Lens tests of lenses with apertures wider than f/2 really should contain a radial energy plot of the PSF...

Last edited by falconeye; 02-20-2009 at 05:32 AM.

Asahiflex · 02-20-2009, 05:24 AM

Originally posted by blende8

This is in theory correct, but I know of no modern lens that does not show such overcorrected SA to a certain extent.
Do you know of a lens that shows "brighter center and a somewhat softer edge" in the background bokeh? I don't.
(Perhaps the old 100mm Macro Heliars? Never tested them.)

Yes, the Sony STF 135 f f/2.8 [T4.5] comes to mind. This lens has two diaphragms:

And it looks like this:

Samples of wat this lens can do, compared with other lenses:

Real world example:

dkittle · 02-20-2009, 05:32 AM

TKH, thanks for getting us all going :-)

I have no regrets buying this lens - I just love it. I think it's a perfect compliment to my 31 and 77.

I still hope to compare it to a Nokton and I'll be shooting side by side with a Nikon D700 user with an 85mm f/1.8 soon - that will be an interesting comparsion too.

RaduA · 02-20-2009, 05:56 AM

@dkittle and @TKH warm thanks for all your efforts in the benefit of the community!

Regards,
Radu

blende8 · 02-20-2009, 05:58 AM

Originally posted by Asahiflex

Yes, the Sony STF 135 f f/2.8 [T4.5] comes to mind.

Right, of course.
Awesome!

I would like to see such a thing from Pentax!

farfisa · 02-20-2009, 06:21 AM

Originally posted by blende8

Well, perhaps not well phrased.
What I wanted to say is that the bokeh will certainly not be particularly bad, if they put special emphasis on it.
And I don't think that this is only marketing talk.
But also we will not see wonders.
I suspect the bokeh to be similar to the FA50 or Nokton, which are basically identical.

I was thinking the same thing--they must know what they're doing, right?

farfisa · 02-20-2009, 06:37 AM

Originally posted by losecontrol

much talks about bokeh, backround ect ect.....Comeon! One of the simpliest rules nr.1 in photography is to choose a clear backround, and now people is speaking about a hard bokeh, bokeh, soft bokeh.. bla bla bla....

I think that we are getting to fixed in what the lenses could do for our photos that we forgett the simple rules ....A lens can improve the photography maybe...but we look more like lens controllers then photographers...

it's really sad looking this

Welcome to the "Lens Discussion" Forum.

k100d · 02-20-2009, 07:42 AM

Originally posted by TKH

First of Thanks Don for your pics.
Its very difficult to work with a lens in f1.4. Please note that the DOF is only 2 cm (later edit: wrote first 2mm) in a distance of 1m! So the most pics who dont satisfy can be possible only out of focus.

My result in playing around a few days with the DA*55? Just sold my FA43...

Rainer

how many times must you learn not to sell the FA43

TKH · 02-20-2009, 10:06 AM

Oh Simon, you got me...

Its the third time that I sell a copy of the FA43. I think its the last time.

For me the DA35 and the DA*55 are so f...ing good lenses I dont think that I will miss the 43 to mutch.

You Simon as a gunner will understand: I must hurry to reach my fellow believers in our prayer house. The mother of all local derbies: Royal Blues desperate for revenge against Dortmund

So only three new pics to feed the bokeh discussion. All at f1.4:

Keep you fingers crossed for my boys!

Rainer

farfisa · 02-20-2009, 10:13 AM

Originally posted by TKH

Its the third time that I sell a copy of the FA43. I think its the last time.

For me the DA35 and the DA*55 are so f...ing good lenses I dont think that I will miss the 43 to mutch.

...

Rainer

But now you won't be able to do this:

...you'll be back

(edit: yes, that was a f 2.8 43mm bokeh joke--took it on the way to the grocery store last night to see for myself)

jsherman999 · 02-20-2009, 10:17 AM

.

OK.

Now this is getting serious.

That bokeh is Nokton-quality, but different.

I'm hereby declaring "bokeh-not-good" declarations completely taste-based, because to my taste, that's excellent.

And I thought I could forget about this lens for a couple months... Thanks a lot. *&^U^%$&^$

.

kyrios · 02-20-2009, 10:41 AM

The flowers.. I saw another echoing bokeh.
But I must say THX, it will be my main reason not to buy this lens.

As a f/1.4 lens, bokeh quality must be really pleasant as it will be used wide open frequently.

02-20-2009, 04:04 AM	#166
losecontrol Veteran Member Join Date: Jan 2009 Location: Gnesta, Sweden Posts: 373	Photographers or lens controllers?? much talks about bokeh, backround ect ect.....Comeon! One of the simpliest rules nr.1 in photography is to choose a clear backround, and now people is speaking about a hard bokeh, bokeh, soft bokeh.. bla bla bla.... I think that we are getting to fixed in what the lenses could do for our photos that we forgett the simple rules ....A lens can improve the photography maybe...but we look more like lens controllers then photographers... it's really sad looking this

02-20-2009, 04:48 AM	#167
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by jake123 The Sigma 50mm would be my choice at a lower price with much smoother bokeh. Well, the Sigma is (only) 13% cheaper (in EU). My main concerns with the Sigma are that is is bulky and that I am concerned how precisely the AF would nail focus. Has anybody heard about AF precision with DA55 vs. Sigma50? Originally posted by RaduA you're wrong and this puppy will have both better and more even resolution than Sigma I hope so Originally posted by TKH The mistakes I make with my camera and the DA55 are greater than the mistakes the lens makes Maybe, you didn't nail the focus and RaduA is correct. As I said, I hope so. Originally posted by blende8 Judging bokeh can only be done in comparison with other lenses and this in a controlled environment (tripod ...) This is only partly true. If you can see a point light source out of focus, you actually can see the defocus PSF. The standard PSF looks like a bright disk with a sharp border. Lenses optimized for great bokeh tend to have a PSF with a somewhat brighter center and a somewhat softer edge, while being perfectly round. UPDATE: Some of the DA55 images actually showcase its PSF. I have cropped the PSF from two of the photos in this thread, and a PSF from photozone's test of the Sigma 50. On the attached image, the left two snippets are from the DA55 while the right snippet is Sigma 50. All at f/1.4. It definitely has a dimmer center and quite hard edges. Sometimes, the edge doesn't appear as hard as other times (cf. left and middle center). Nevertheless, a clear tendency to circular rather than disk like PSF. The Sigma 50 shows signs of an onion-like PSF. Which is criticized as well (only at f/1.4). In comparison, the Pentax PSF is smoother in the inner part but has a much harder border. I think there is enough evidence to be at least concerned about the DA55 bokeh. Last edited by falconeye; 06-15-2011 at 05:28 AM.*

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02-20-2009, 05:15 AM	#168
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	Originally posted by falconeye This is only partly true. If you can see a point light source out of focus, you actually can see the defocus PSF. The standard PSF looks like a bright disk with a sharp border. Lenses optimized for great bokeh tend to have a PSF with a somewhat brighter center and a somewhat softer edge, while being perfectly round. Some of the DA55 images actually showcase its PSF. It definitely has a dimmer center and quite hard edges. A tendency to circular rather than disk like PSF. I think there is enough evidence to criticize the DA55 bokeh. This is in theory correct, but I know of no modern lens that does not show such overcorrected SA to a certain extent. Do you know of a lens that shows "brighter center and a somewhat softer edge" in the background bokeh? I don't. (Perhaps the old 100mm Macro Heliars? Never tested them.) Of course it would be nice to have a lens that shows such a bokeh. But apparently it is not that easy to establish without sacrificing important other parameters. Well, I am no expert in these matters ...

02-20-2009, 05:23 AM	#169
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by blende8 Do you know of a lens that shows "brighter center and a somewhat softer edge" in the background bokeh? I don't. Well, there seems to be a lens from Sony with a Gaussian PSF. Which is a special lens and has other drawbacks. There simply aren't many lenses "optimized" for great bokeh. I only mentioned this to illustrate that a good PSF tries to keep its energy near the center, not its border. I updated my prior post to illustrate why I think that Sigma may have done a somewhat better job in this regard. P.S. Lens tests of lenses with apertures wider than f/2 really should contain a radial energy plot of the PSF... Last edited by falconeye; 02-20-2009 at 05:32 AM.

02-20-2009, 05:24 AM	#170
Asahiflex Pentaxian Join Date: Jan 2008 Location: Netherlands Photos: Gallery Posts: 2,795	Originally posted by blende8 This is in theory correct, but I know of no modern lens that does not show such overcorrected SA to a certain extent. Do you know of a lens that shows "brighter center and a somewhat softer edge" in the background bokeh? I don't. (Perhaps the old 100mm Macro Heliars? Never tested them.) Yes, the Sony STF 135 f f/2.8 [T4.5] comes to mind. This lens has two diaphragms: And it looks like this: Samples of wat this lens can do, compared with other lenses: Real world example:

02-20-2009, 05:32 AM	#171
dkittle Inactive Account Join Date: Jun 2007 Location: Toronto, Ontario Photos: Gallery Posts: 429	TKH, thanks for getting us all going :-) I have no regrets buying this lens - I just love it. I think it's a perfect compliment to my 31 and 77. I still hope to compare it to a Nokton and I'll be shooting side by side with a Nikon D700 user with an 85mm f/1.8 soon - that will be an interesting comparsion too.

02-20-2009, 05:56 AM	#172
RaduA Guest	@dkittle and @TKH warm thanks for all your efforts in the benefit of the community! Regards, Radu

02-20-2009, 05:58 AM	#173
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	Originally posted by Asahiflex Yes, the Sony STF 135 f f/2.8 [T4.5] comes to mind. Right, of course. Awesome! I would like to see such a thing from Pentax!

02-20-2009, 06:21 AM	#174
farfisa Veteran Member Join Date: Nov 2008 Location: Toronto, Canada Photos: Gallery Posts: 1,274	Originally posted by blende8 Well, perhaps not well phrased. What I wanted to say is that the bokeh will certainly not be particularly bad, if they put special emphasis on it. And I don't think that this is only marketing talk. But also we will not see wonders. I suspect the bokeh to be similar to the FA50 or Nokton, which are basically identical. I was thinking the same thing--they must know what they're doing, right?

02-20-2009, 06:37 AM	#175
farfisa Veteran Member Join Date: Nov 2008 Location: Toronto, Canada Photos: Gallery Posts: 1,274	Originally posted by losecontrol much talks about bokeh, backround ect ect.....Comeon! One of the simpliest rules nr.1 in photography is to choose a clear backround, and now people is speaking about a hard bokeh, bokeh, soft bokeh.. bla bla bla.... I think that we are getting to fixed in what the lenses could do for our photos that we forgett the simple rules ....A lens can improve the photography maybe...but we look more like lens controllers then photographers... it's really sad looking this Welcome to the "Lens Discussion" Forum.

02-20-2009, 07:42 AM	#176
k100d Veteran Member Join Date: Feb 2008 Location: Toronto Posts: 3,911	Originally posted by TKH First of Thanks Don for your pics. Its very difficult to work with a lens in f1.4. Please note that the DOF is only 2 cm (later edit: wrote first 2mm) in a distance of 1m! So the most pics who dont satisfy can be possible only out of focus. My result in playing around a few days with the DA*55? Just sold my FA43... Rainer how many times must you learn not to sell the FA43

02-20-2009, 10:06 AM	#177
TKH Veteran Member Join Date: Aug 2007 Location: Germany Posts: 371 Original Poster	Oh Simon, you got me... Its the third time that I sell a copy of the FA43. I think its the last time. For me the DA35 and the DA*55 are so f...ing good lenses I dont think that I will miss the 43 to mutch. You Simon as a gunner will understand: I must hurry to reach my fellow believers in our prayer house. The mother of all local derbies: Royal Blues desperate for revenge against Dortmund So only three new pics to feed the bokeh discussion. All at f1.4: Keep you fingers crossed for my boys! Rainer

02-20-2009, 10:13 AM	#178
farfisa Veteran Member Join Date: Nov 2008 Location: Toronto, Canada Photos: Gallery Posts: 1,274	Originally posted by TKH Its the third time that I sell a copy of the FA43. I think its the last time. For me the DA35 and the DA*55 are so f...ing good lenses I dont think that I will miss the 43 to mutch. ... Rainer But now you won't be able to do this: ...you'll be back (edit: yes, that was a f 2.8 43mm bokeh joke--took it on the way to the grocery store last night to see for myself)

02-20-2009, 10:17 AM	#179
jsherman999 Veteran Member Join Date: Dec 2007 Photos: Gallery Posts: 8,237	. OK. Now this is getting serious. That bokeh is Nokton-quality, but different. I'm hereby declaring "bokeh-not-good" declarations completely taste-based, because to my taste, that's excellent. And I thought I could forget about this lens for a couple months... Thanks a lot. *&^U^%$&^$ .

02-20-2009, 10:41 AM	#180
kyrios Senior Member Join Date: Apr 2007 Location: Indonesia Posts: 123	The flowers.. I saw another echoing bokeh. But I must say THX, it will be my main reason not to buy this lens. As a f/1.4 lens, bokeh quality must be really pleasant as it will be used wide open frequently.