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Old Nov 25, 2008, 6:36 AM   #1
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According to dpreview new review of the 3 lens of very close optics formation



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The standout characteristic of the Pentax is arguably its extremely low distortion, which is the lowest of the 50mm F1.4s we've tested. And when the aperture is stopped down to F2.2 or smaller, it's impressively sharp corner-to-corner, right across the APS-C frame. It's important to understand here that the 50mm F1.4 is much sharper than typical consumer zooms; even at F2.8 it surpasses both the DA 16-45mm 1:4 ED AL and the DA 18-55mm 1:3.5-5.6 AL shot at 45mm and their optimum apertures around F8.

However this excellent showing when stopped down does come at the cost of an unconvincing performance at large apertures; the lens is very soft indeed at F1.4, and while we described the Canon 50mm F1.4 as 'dreamy', the Pentax renders scenes more as though you're looking through a fine veil of mist

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I hardly ever ever have need for anything under F2 the DoF is so tiny anyway




From my F50mm at F2.2. The DoF is so little that calls for critical focusing









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Old Nov 25, 2008, 10:51 AM   #2
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I guess they expect the lens to do everything. You acquire and use a lens for and within it's good performance range. That range is better with some than others. The Pentax does as expected. There is no perfect lens....Let me repeat...THERE IS NO PERFECT LENS. I keep having reminders of why I don't like DP review very much. Somewhat biased towards the Canon and Nikon crowd. Not that they don't produce fine lenses. They do.

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Old Nov 25, 2008, 10:53 AM   #3
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Oh...BTW...She is Gorgeous...And you really are good at these Daniel.

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Old Nov 25, 2008, 3:51 PM   #4
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Hey Daniel,
I continued our lil' PM conversation - I don't want to steal that thread, now that I now what you intended. DOF and focus point are perfect, no need for another aperture, really. As for my point of view regarding smaller apertures I already said enough in my PM

I have to agree with Dawg, she really is beautiful - the only thing I dislike hereare thesestaring eyes. Was she daydreaming? It almost looks that way...

Best regards,
Th.
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Old Dec 3, 2008, 5:19 AM   #5
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Dawg
Thanks


thkn777 wrote:
Quote:
Hey Daniel,
I have to agree with Dawg, she really is beautiful - the only thing I dislike hereare thesestaring eyes. Was she daydreaming? It almost looks that way...
Best regards,
Th.
Th

I posted the one with no direct eye contact as it was not posted before in here. Also the idea was to show the DoF only

Here is the one I posted way back with F50mmF1.7





Again as shown. Even at F2, the DoF was tiny tiny. Actually there is another photographer's socks at the top left corner. But it has been blurred up



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Old Dec 3, 2008, 7:16 AM   #6
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@Daniel
Ah - I must have missed the last one! I see your point with the DOF and everything else has been said via PM already - to my mind the last pic is great, very natural, very good skin tones... it doesn't hurt, that some of her hair is a bit blurred.

With some postprocessing you could emphasize that "sharpness/detail" feeling in her face, if that's what you are after... even some kind of "refocus" effect would be possible, but I know that this is not your point here so I won't touch it .

With christmas ahead the theatre / chorus / performances shots with my daughter will put me to a challenge again - let's see if I'll get some keepers this year!

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Old Dec 3, 2008, 8:30 AM   #7
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thkn777 wrote:
Quote:
@Daniel
Ah - I must have missed the last one! I see your point with the DOF and everything else has been said via PM already - to my mind the last pic is great, very natural, very good skin tones... it doesn't hurt, that some of her hair is a bit blurred.

With some postprocessing you could emphasize that "sharpness/detail" feeling in her face, if that's what you are after... even some kind of "refocus" effect would be possible, but I know that this is not your point here so I won't touch it .

Th.
Th
In the last image, even the ear ring is off focus not to mention the hair. This pict was taken in a rare way (at F2) effectively excluding focus of large area of her face. The key focus area are in one eye only .
You cannot increase the focus area if there is no detail there at all. If those area is needed for focus, I would have shot that at F4 or F5.6 exposing the dirty socks (at top left). The whole effect would have been completely different.


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Old Dec 3, 2008, 8:45 AM   #8
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The point that I wanted to make (in this thread) is that shooting at wider than F2.8 (like f1.4 , F1.7) is quite rare. People owing fast lenses seem to stress that their lenses should be shot wider. Otherwise what is the point of owning or using fast lenses?
The big plus of great fast lenses still lies in between F2.8 - F4 . By F2.8-F4, they have achieved 90% of the sharpness already and still rettains a lot of its bokeh character.
So are F1.4 or F1.7 shots useful? Yes they are. Particularly in tough dim light. But only in rare occasion.
See this thread on shooting F2.8 compared with F5.6

http://forums.dpreview.com/forums/re...ssage=30099689


I have proved that shooting further stepped down in aperture does help a lot and that is simple physics



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Old Dec 3, 2008, 12:59 PM   #9
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Hey Daniel,
maybe I wasn't clear on that, so I'll try again.

- yes: there is DOF and the wider you open the lens the thinner it gets
- and: the closer you are the thinner it gets at a given aperture

That's physics as you already said and nobody can do something against it.

For every kind of photography, including portrait works, there is a good or even optimal aperture range for a given focal range so that the main object (a persons head, maybe parts of the upper torso) are "acceptable sharp".

See? I am completely with you here, no differences at all.

Now for "my" part of the story. Why can't I use the same lens (i.e. 50mm/1.4) in a different way, especially shooting at bigger distances. By doing so, a person would appear smaller on the image, ok. At some point we don't talk about pure portrait works anymore, ok. But:

- the bigger the distance to your object, the wider the DOF at a given aperture

--> For some combinations of focal length, aperture and distance you can achieve a DOF that is big enough to capture what you want.

That's all I want to say - thus the asking for fast lenses has some serious background.

Can we just shake hands and agree, that both scenarios might happen and in both cases we can't defy physics?

PART 2 - DETAIL

Detail and sharpness are something people tend to speak about and have very different opinions. I personally don't mind a "soft" look of an image, as long as there are image details in it, that you can bring out with postprocessing. That kind of PP just helps to overcome some technical limitations of a given lens. The problem lies in the fact, that most people just hit the "sharpen" or the almighty "USM" button and complain about bad pictures, although they've really got a detailed shot, but are just unable to use it.

I seem to have a complete different feeling for this, maybe it's me, personal taste, my eyes or whatever. I am way more tolerant when it comes to this discussion.

Of course you'll get better overall details, better resolution when you shoot at your lens sweet spot, I won't argue on that.

But my questions stands: how much detail is ENOUGH detail? A lens at a given setting is sharp/detailed ENOUGH for a specific shot or not, that doesn't depend on the maximal resultion value of this lense. It's the same as with other things in life. Example: You don't need the MAXIMUM light, you need ENOUGH.

PART3 - DOF

Now "DOF" or "area of acceptable sharpness" is somewhat, hm... different for different people. And on the other hand it is just a mathematical way to give an orientation what you can/should expect at different focal length and aperture.

As far as I understood you - your basic complaint for the last image is, that "almost everything" (exaggeration helps to explain things - no offense meant) is out of focus, you said:

Quote:
The key focus area are in one eye only
Also you wrote:

Quote:
You cannot increase the focus area if there is no detail there at all
Again - I am with you here, but my point is - there really IS enough detail in the shot! Now I don't know excatly what you are asking for, but some simple postprocessing gave me the attached picture. Put this one and yours as layers in the same image and switch the layers on and off, that way the changes are clearly visible. ( a little overdone, if you ask me, but I wanted to show the effect ) With some more effort you could get rid of some unwanted artifacts and achieve a higher quality, too. Also working from the original image would help - but this is only to show the basic idea anyway.

I want to repeat what I already said - maybe it's really me and I am just a "happy buyer" and it is way too easy to satisfy my needs and asking for details and sharpness, but aside from the pure technical DOF discussion the amount of detail/sharpness in that image is high enough for my needs, and that's what counts for me.

So in no way I want to say something against your experiences and technical knowledge, if I said something in a wrong way, please accept my apologies! I just have my own experiences and photographic preferences and these differ from yours. And I like fast lenses that give good details even wide open and can understand people that ask for those and compare them wide open. /shrug - I can't help it :roll:

Kind regards,
Th.
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Old Dec 3, 2008, 7:19 PM   #10
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thkn777 wrote:
Quote:
Now for "my" part of the story. Why can't I use the same lens (i.e. 50mm/1.4) in a different way, especially shooting at bigger distances. By doing so, a person would appear smaller on the image, ok. At some point we don't talk about pure portrait works anymore, ok. But:
By doing so, you may inadvertently go against a hidden rule - and a lot of serious photographers agree with it. It is called 1/3 rule. Having said that , I stress that I do not follow that closely too.



Quote:

Detail and sharpness are something people tend to speak about and have very different opinions. I personally don't mind a "soft" look of an image, as long as there are image details in it, that you can bring out with postprocessing.
I doubt if you (or any PP guru) can bring out details of the out of focus area (socks at the top left of the last image here). The detail is just not there and I have no desire of sharpening that at all. I want that to be blurred out

Quote:

As far as I understood you - your basic complaint for the last image is, that "almost everything" (exaggeration helps to explain things - no offense meant) is out of focus,
I have absolutely zero complaint of the last image. I wanted some area to be blurred out as they are distraction (like the dirty socks at top left)


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