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02-23-2009, 01:17 AM   #61
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QuoteOriginally posted by ogl Quote
FA43 is not fast, but as I understand DA*55 is one of the slowelest among Pentax lenses and slower than FA43.
Confirm, please.
Way slower, yes.
For me, this is the one big disadvantage of the lens.

Optically it is better. I wouldn't say another league, but better.
I had hopes for a better bokeh (foreground/background reversed = Gaussian background). But perhaps there are optical obstacles.

02-23-2009, 01:18 AM   #62
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QuoteOriginally posted by blende8 Quote
Looks awesome. I had been waiting for this lens for a long time. If you want your lens to be sharp at wide apertures you have to pay for it. That is the reason I never went for the FA50mm. The old FA lens is still a great deal because its so cheap but it would not suit my purposes.

People who don't need pro glass don't buy it because they think its overpriced. I think $700 for a lens that looks like that is a great deal.

Thanks for doing this testing.

As for focus speed - Its a portrait lens. I'll have to tell my brides to slow down as they run down the isle
02-23-2009, 04:13 AM   #63
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QuoteOriginally posted by TKH Quote
Is it a shame that Pentax can only do a little better PF job for $730 than Carl Zeiss for $1300?!
The other way to look at this: We all know that Zeiss are well overpriced because of their name. Is it not a shame if Pentax starts following the same path?
02-23-2009, 04:19 AM   #64
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QuoteOriginally posted by TKH Quote
Is it a shame that Pentax can only do a little better PF job
Rainer, I don't want to comment on this if blende8, famous creator of the acronym FadS doesn't ( DigitalFotoNetz.de :: Thema anzeigen - FadS = Farbsäume außerhalb der Schärfeebene ).

Let me just say this ... as members of DFN, we may know that this is not CA.
(but maybe, let's not repeat the DFN discussion within this thread...)

02-23-2009, 04:33 AM   #65
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I just want to know one thing: Who really shoots at f/1.4 in the middle of the day, outside, in a scene with high levels of reflection?

Seriously? Anyone on a regular basis?

And these days, PF/CA can be easily corrected in post if you're willing to put the time in. Or if it's that big of a problem, then just shoot film. :P
02-23-2009, 04:53 AM   #66
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Slow AF or better manual focus?

Has anyone tried manually focusing with this lens? Is it a pleasure, or is it a chore?

It seems to me that this lens might be marketed to people that actually remember the 85mm and probably did a bit of manual focus work in their time. It could be that AF shooting of snot nosed, stinky bottomed, disease carrying vermin wasn't in the plan at all. No, I'm not talking about YOUR precious little one that is currently screaming it's head off demanding that the mac & cheese be served with TinkyWinky and not broccoli. God forbid you thinking so.
02-23-2009, 10:38 AM   #67
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QuoteOriginally posted by Ivan Glisin Quote
It seems that DA* 50-135 is the only SDM lens everyone appears to be happy with in terms of SDM AF benefits.
Errr... nope!

Slow AF too.
02-23-2009, 12:59 PM   #68
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QuoteOriginally posted by poco Quote
Has anyone tried manually focusing with this lens? Is it a pleasure, or is it a chore?
It's ok.
It is not as good as the DA200 which has a gear ratio of 2:1 for manual focussing.
The DA55 has no transformation, it's 1:1.

Throw:
FA85: ca. 90 degrees (superfast AF)
DA55: ca. 110 degrees (slow AF)
FA50: ca. 120 degrees (fast AF)
Nokton: ca. 210 degrees
DA200: ca. 260 degrees

The argumentation that the AF of the DA55 is slow because it is a portrait lens does not hold.
The 85mm, which the DA55 should replace, is very fast.

02-23-2009, 01:12 PM   #69
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QuoteOriginally posted by falconeye Quote
Let me just say this ... as members of DFN, we may know that this is not CA.
For the benefit for those who cannot read German, here is my summary:

CA is defined as dispersion errors at the focus plane. The hypothesis for "FadS " is that even if a lens manages to correct for dispersion errors at the focus plane, i.e., manages to let rays of different (up to four) wave lenghts coincide at one point (rather than laterally and/or longitudinally separated), then dispersion errors may well still appear outside the focus plane.

The cause is the same as for CA (dispersion of different wavelengths) but one can apparently minimise the effect for the focus plane (CA) but neglect correction for out of focus projection.

This is mainly a discussion about precise definition and usage of terms. If the lens shows colour aberrations and one finds these offensive then it is a lens fault, even if it is technically not CA ("CA" as in "dispersion errors at the focus plane"). The question is how many lenses manage to avoid out-of-focus dispersion errors. I would venture to say that the number is very low and may even be "zero". Depending on the lens design, though, the visible effect of out-of-focus dispersion errors may be more or less apparent.
02-23-2009, 01:22 PM   #70
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QuoteOriginally posted by ewalk Quote
I just want to know one thing: Who really shoots at f/1.4 in the middle of the day, outside, in a scene with high levels of reflection?

Seriously? Anyone on a regular basis?

And these days, PF/CA can be easily corrected in post if you're willing to put the time in. Or if it's that big of a problem, then just shoot film. :P
Oh man they must be passing out the kool-aid in this forum now too...

"Seriously" The PF that can rear it's ugly head on the FA 50 does not just happen at F 1.4... it happens at F4 & F5.6 and F8... To think it only happens in low light at F1.4 or that there are a bunch of us idiots out here shooting wide open in bright sun, is wishful thinking at best.
02-23-2009, 03:04 PM   #71
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QuoteOriginally posted by kunik Quote


As for focus speed - Its a portrait lens.
That's an apology for poor performance.
It's a short telephoto lens, it should have AF as fast as any other lens.
02-23-2009, 03:11 PM   #72
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QuoteOriginally posted by Class A Quote
For the benefit for those who cannot read German, here is my summary
Class A, I fully agree to your summary and I didn't want to offend anybody in not giving it myself. I just didn't want to bring the thread OT
Maybe, I would like to add one little detail, though

Even a lens with no CA (no color aberration for in focus objects) which is made of glass with finite dispersion (no other glass exists) will almost always show color aberration for out of focus objects. So, it is not entirely about terms. About what is physically possible as well. Since it isn't CA.

Reflections from the sun (infinite distance) in a nearby water surface are the most extreme example of this phenomenon. The sample image showed this exactly. Which is why I felt tempted to give the comment I gave.
02-23-2009, 03:23 PM   #73
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QuoteOriginally posted by rparmar Quote
The other way to look at this: We all know that Zeiss are well overpriced because of their name. Is it not a shame if Pentax starts following the same path?
Wow!

Thats an argumentation I can only give up!
You are right.

Its better for me to go this way @f1.4:





Rainer
02-23-2009, 04:51 PM   #74
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QuoteOriginally posted by Wheatfield Quote
That's an apology for poor performance.
It's a short telephoto lens, it should have AF as fast as any other lens.
Its not an apology, its just a fact. I know I won't notice a difference so why should I care. I have yet to see any numbers as to just how slow it is so I would hold off on final judgment until I see some numbers or try the lens myself. Do you know if or by how much this is slower than Sigma/Canon/Nikon?. Some people demand a minivan that handles like a sports car. I know that Pentax does not handle like a sports car and they do not need to apologize to me for that.

Without some sort of predictive ability the focus speed of a pentax lens will not matter to me. My fastest focusing Pentax lens (in my subjective opinion) is my 300/2.8. I can't really be certain if it focuses faster than my Canon 1DmkIII with its 70-200/2.8 lens, because the Canon has AI Servo. So ultimately the Canon does a much better job of focusing on fast moving objects but is that because of AI or focus speed?

I can definitely tell the SDM motors turn a little slow on long throws (on my DA* lenses) but its more quirky than annoying for me. Now when Pentax comes out with a sports oriented body it might start to matter more but until then it works fine for me.

edit - I don't intend to be argumentative but when people start complaining about Pentax on a public forum about things that matter to them but do not matter to me I think its valuable to include a note representing an alternative point of view. Pentax does not sponsor me and they never replied to my request for participation in their professional program but I sincerely enjoy their gear and I honestly don't consider the so-called negative points about Pentax to be a concern for me. I've been shooting a $4000 Canon for 4 months now and I can honestly say I still prefer my K20D (and I've take more than 20,000 pics in that time - between the two brands). The different bodies and lenses require different techniques to achieve good results but although saying "Pentax has slow focus" may be factually correct in relation to the Canon it does not prevent me from getting the images I want so does it really matter?

Last edited by cwood; 02-23-2009 at 05:02 PM.
02-23-2009, 11:46 PM   #75
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QuoteOriginally posted by kunik Quote
Its not an apology, its just a fact. I know I won't notice a difference so why should I care. I have yet to see any numbers as to just how slow it is so I would hold off on final judgment until I see some numbers or try the lens myself. Do you know if or by how much this is slower than Sigma/Canon/Nikon?. Some people demand a minivan that handles like a sports car. I know that Pentax does not handle like a sports car and they do not need to apologize to me for that.

Without some sort of predictive ability the focus speed of a pentax lens will not matter to me. My fastest focusing Pentax lens (in my subjective opinion) is my 300/2.8. I can't really be certain if it focuses faster than my Canon 1DmkIII with its 70-200/2.8 lens, because the Canon has AI Servo. So ultimately the Canon does a much better job of focusing on fast moving objects but is that because of AI or focus speed?

I can definitely tell the SDM motors turn a little slow on long throws (on my DA* lenses) but its more quirky than annoying for me. Now when Pentax comes out with a sports oriented body it might start to matter more but until then it works fine for me.

edit - I don't intend to be argumentative but when people start complaining about Pentax on a public forum about things that matter to them but do not matter to me I think its valuable to include a note representing an alternative point of view. Pentax does not sponsor me and they never replied to my request for participation in their professional program but I sincerely enjoy their gear and I honestly don't consider the so-called negative points about Pentax to be a concern for me. I've been shooting a $4000 Canon for 4 months now and I can honestly say I still prefer my K20D (and I've take more than 20,000 pics in that time - between the two brands). The different bodies and lenses require different techniques to achieve good results but although saying "Pentax has slow focus" may be factually correct in relation to the Canon it does not prevent me from getting the images I want so does it really matter?
Let's turn it the other way: would faster AF be a problem on such a lens? Would it prevent you to take the kind of shots you like?

If not, then why make it slow since it would suit everyone better?

Why the 4000$ Canon gear if you prefer your Pentax?

Pentax introduced a new AF mechanism in SDM, I thought it might not be faster than conventional screw-driven motor on some lenses but I certainly didn't think it would be slower.

The FA 50f1.4 is about as fast as the Canon 50f1.4 USM which has the same kind of micro motor than our SDM lenses, I expected the DA 55 to be about the same speed, not much slower: was that expectation unreasonable?

I know, I know:

It's a portrait lens, so it is optimized for MF !

Real photographers only use MF anyway!

Fast AF is useless without good AF tracking ! (good one!)

(Insert the corny usual justifications for slow AF here)

... ... ... ...


Canon has fast USM AF, Nikon has fast AF-S AF, Sony has fast SSM AF and even Olympus introduced fast SWD AF but Pentax has missed the opportunity to erase the only real recurring complaint USERS have with their brand by introducing the slowish SDM AF.

Of course, it's a good thing since it differentiate us, discerning Pentax users, from the Canikon crowd: see, slowish AF is a FEATURE, not a compromise imposed by wrong techno-economical choices...

But I suppose it's OK because Pentax is in a niche player or because Pentax users know better than using a portrait lens for anything else than static portraits or because some of us don't use AF at all...

Anyone else getting tired of hearing this kind of justification?

Last edited by lol101; 02-23-2009 at 11:52 PM.
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