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12-18-2010, 08:12 PM   #16
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QuoteOriginally posted by paperbag846 Quote
Oh boy, here we go again.
No, here you go again. You are the one that thinks that the SMC and Ghostless Coatings on the FA ltd are inferior to the ones on the DA ltd series even though the DA has been produced in parallel with the FA ltd from the beginning. All FA and DA ltd lenses ever designed are still in production.


QuoteOriginally posted by paperbag846 Quote
A) I said to compare them at equivilent apertures. If you don't own both, simply go to photozone.de to see the differences. Since they both score in the very good to excellent category, the statistical difference in sharpness will only matter to some.
Photozone does a good job crunching the numbers etc. However, they don't always do things exactly the same and the botched the comparison of the DA 70 because they did NOT torture test it while the pushed the FA to the extreme. Furthermore, 1 lens is not a statistical test. However, it would be expensive and time consuming to do 8 or 10 copies of a given lens.

QuoteOriginally posted by paperbag846 Quote
B) CA and PF are more prevalent on FA primes used on digital, no matter the aperture. Whether this is a coating issue, or otherwise, is uncertain to me. My hunch is that it is the coatings, at least somewhat. Especially since the lenses render colour so differently, suggesting that the coatings are, in fact, different to a degree.
:koolaid: Most lenses in the 70 to 85 mm range can be forced to PF including the autofocus Zeiss 85/1.4 made in Sony mount specifically for digital. PF is more pronounced in these at f2 and greater.

QuoteOriginally posted by paperbag846 Quote
C) None of this suggests that the FA lenses are bad on digital, period. Many, many, people here use lenses designed before computers were even available to NASA.
What the hell are you talking about? We are discussing FA Ltd lenses which were designed in the 1990s and went into production from 1997 to 2001 which is only 4 years separation from the DA 40 ltd.

QuoteOriginally posted by paperbag846 Quote
I'm not sure what your points here are, but I think I have illuminated the basic differences between the DA and FA lines without stepping on any toes. Lets put it this way:
The point is that 1) the SMC coatings on the lenses would have been the same for a production month and year since they were made at the same time; 2) both received Ghostless Coatings. It is quite possible that the 1997 made FA 43 lenses have a slightly different smc coating than the 2007 FA 43 lenses.

QuoteOriginally posted by paperbag846 Quote
The DA lenses are fantastic on digital, but are pretty slow for film.
With a few exceptions, I wouldn't use the DA lenses on film. Those exceptions being the DA* 200, 300, and DA 35/2.4.

QuoteOriginally posted by paperbag846 Quote
The FA lenses are fantastic on digital, but were designed to be best on film.
Very few were designing 35mm lenses specifically for digital in the 1990s since digital slr bodies weren't available.

12-18-2010, 08:23 PM   #17
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QuoteOriginally posted by Blue Quote
You are the one that thinks that the SMC and Ghostless Coatings on the FA ltd are inferior to the ones on the DA ltd series even though the DA has been produced in parallel with the FA ltd from the beginning. All FA and DA ltd lenses ever designed are still in production.
Never once used the word inferior. However, these faster FA ltds. shows more CA and PF at any aperture compared to a DA limited (specifically, 40 vs 43, 70 vs 77). My hunch is that one coating was optimized for film, and one coating is optimized for digital.

Whether it is a factor of coatings, or optical design, that is one of the most noticeable differences I have witnessed between these lenses. And yes, these are at equivalent apertures.

I'm not going to respond to most of your post because it isn't really what I was talking about. Most of the FA series lenses (non-limited) have much older optical designs, which is why I brought up older lenses. Furthermore, colour alone suggests that there are some differences in how lenses are designed and coated for digital as opposed to film. There are documented reasons for this, and I don't really see how this is a bad thing. Why wouldn't you want a lens optimized for digital if digital sensors see the world differently than film does?

And yes, the FA ltds. are designed for film. The reason for this decision has no bearing on how they perform on a modern camera.


QuoteOriginally posted by Blue Quote
Most lenses in the 70 to 85 mm range can be forced to PF including the autofocus Zeiss 85/1.4 made in Sony mount specifically for digital. PF is more pronounced in these at f2 and greater.

The FA 77 shoes more PF and CA at f2.8 than the DA 70.
12-18-2010, 08:38 PM   #18
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QuoteOriginally posted by paperbag846 Quote
Never once used the word inferior. However, these faster FA ltds. shows more CA and PF at any aperture compared to a DA limited (specifically, 40 vs 43, 70 vs 77). My hunch is that one coating was optimized for film, and one coating is optimized for digital.
Why do you think Pentax would use a different SMC coating on the DA 40mm and FA 43mm for the 2004 production runs or different SMC coatings on the DA 70mm and FA 77mm in the 2006 production runs? My hunch is they used the most up to date coatings on the lenses given they were making only digital bodies at the time. Again, both were already getting the Ghostless Coating.

There is no peer for the FA 31 in the DA series of ltd lenses. However, since it has aspherical elements, ED, F.R.E.E. and Ghostless Coatings, there isn't much left to update other than SP on the front element and the Price.

Likewise, the DA 15, 21


QuoteOriginally posted by paperbag846 Quote
Whether it is a factor of coatings, or optical design, that is one of the most noticeable differences I have witnessed between these lenses. And yes, these are at equivalent apertures.
QuoteOriginally posted by paperbag846 Quote
I'm not going to respond to most of your post because it isn't really what I was talking about. Most of the FA series lenses (non-limited) have much older optical designs, which is why I brought up older lenses. Furthermore, colour alone suggests that there are some differences in how lenses are designed and coated for digital as opposed to film. There are documented reasons for this, and I don't really see how this is a bad thing. Why wouldn't you want a lens optimized for digital if digital sensors see the world differently than film does? . . .

Name a pre-computer designed lens that is still in production. Name 1 pre-computer designed lens that was in production in the 1990s.





QuoteOriginally posted by paperbag846 Quote
The FA 77 shoes more PF and CA at f2.8 than the DA 70.
That doesn't mean it is a difference in SMC coating.
12-18-2010, 08:45 PM   #19
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Alright blue, you win. I have no idea if you are correct, but I have no time for a debate as silly as this.

I can tell you what the differences between the lenses are in practice. Not as a series of specifications. To be honest, the technical differences between a lenses are useless information. It's things like flare, colour, CA, PF, and sharpness, size, and price that are important.

12-18-2010, 08:53 PM   #20
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QuoteOriginally posted by paperbag846 Quote
Never once used the word inferior. However, these faster FA ltds. shows more CA and PF at any aperture compared to a DA limited (specifically, 40 vs 43, 70 vs 77). My hunch is that one coating was optimized for film, and one coating is optimized for digital.
Why do you think Pentax would use a different SMC coating on the DA 40mm and FA 43mm for the 2004 production runs or different SMC coatings on the DA 70mm and FA 77mm in the 2006 production runs? My hunch is they used the most up to date coatings on the lenses given they were making only digital bodies at the time. Again, both were already getting the Ghostless Coating.

There is no peer for the FA 31 in the DA series of ltd lenses. However, since it has aspherical elements, ED, F.R.E.E. and Ghostless Coatings, there isn't much left to update other than SP on the front element and the Price.

Likewise, the DA 15, 21 and 35 Limited lenses have no peer in the FA series. That said, it could be argued that the 1st two while good lenses should be updated to the FA performance standards. Photozone agrees with me on that.

QuoteQuote:
The Pentax SMC-DA 21mm f/3.2 AL Limited is a very good lens but it is not as special as its longer cousins (specifically the Pentax FA 31mm f/1.8 Limited) nor is this really possible because of the increasing design problems when pushing things towards wide and ultra-wide angles.
QuoteOriginally posted by paperbag846 Quote
Whether it is a factor of coatings, or optical design, that is one of the most noticeable differences I have witnessed between these lenses. And yes, these are at equivalent apertures.
QuoteOriginally posted by paperbag846 Quote
I'm not going to respond to most of your post because it isn't really what I was talking about. Most of the FA series lenses (non-limited) have much older optical designs, which is why I brought up older lenses. Furthermore, colour alone suggests that there are some differences in how lenses are designed and coated for digital as opposed to film. There are documented reasons for this, and I don't really see how this is a bad thing. Why wouldn't you want a lens optimized for digital if digital sensors see the world differently than film does? . . .

Name a pre-computer designed lens that is still in production. Name 1 pre-computer designed lens that was in production in the 1990s. I'm not talking about basic lay out but the whole gestalt.





QuoteOriginally posted by paperbag846 Quote
The FA 77 shoes more PF and CA at f2.8 than the DA 70.
That doesn't mean it is a difference in SMC coating. Again, Photozone didn't push the contrast torture test on the DA 70.

However:

DA 70mm

Chromatic Aberrations (CAs)

Lateral chromatic aberrations (color shadows at harsh contrast transitions) are almost a non-issue for the Pentax specifically at large apertures. The problem increases a bit starting at f/5.6 to an average width of ~0.5px at the image borders but this is nothing to worry about in field conditions. As you may/will see in the sample image section the lens can also produce a slight degree of purple fringing (a color blooming effect) in extreme contrast situations.





FA 77mm

Chromatic Aberrations (CAs)

Lateral chromatic aberrations (color shadows at harsh contrast transitions) are very low for a lens designed in the film era. At around 0.2px on the average at the image borders the issue isn't field relevant.


Pentax SMC-FA 77mm f/1.8 Limited - Review / Test Report - Analysis

http://www.photozone.de/pentax/127-pentax-smc-da-70mm-f24-limited-review--test-report?start=1
12-18-2010, 08:59 PM   #21
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QuoteOriginally posted by paperbag846 Quote
Alright blue, you win. I have no idea if you are correct, but I have no time for a debate as silly as this.

I can tell you what the differences between the lenses are in practice. Not as a series of specifications. To be honest, the technical differences between a lenses are useless information. It's things like flare, colour, CA, PF, and sharpness, size, and price that are important.
It isn't about winning or losing an argument. Furthermore, show me a single post in this thread where I got into specifications. Photozone showed that both the 70 and 77 can PF and also demonstrated that CA wasn't really a field problem with either lens. Color rendering is a whole separate debate. The real issue for you is the price of the FA Limited series. Relative to DA LTD, that is true, but compared to L or some top Nikkor, not so much.
12-18-2010, 09:08 PM   #22
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QuoteOriginally posted by Blue Quote
The real issue for you is the price of the FA Limited series. Relative to DA LTD, that is true, but compared to L or some top Nikkor, not so much.
I don't have an issue with the FA ltds or their price. Colour rendering was actually what *sparked* this whole debate. There is a significant difference in the colour rendering of all FA lenses compared to DA lenses. I wonder what would cause that difference in ALL FA vs. DA lenses?

I don't give a damn what other people spend their money on. Price is not a huge issue here in this discussion. I'm going to buy what I'm going to buy, and you as well. However, if I'm going to spend close to 1000 on a lens that has aberrations clinging to my bokeh, while a 500 dollar alternative shows none, I would certainly take that into consideration. I'm giving my 2 cents based on my *actual* experiences with *actual* lenses. I found many more aberrations with the FA ltds than with the DA ltds. I also found that the FA's were better suited to some tasks than the DA ltds... but in general I just found the DA's rendered very "clean". Of course the FA limiteds had a major leg up on the DA's with respect to character. My hunch, seeing these results, was simply that digital sensors must be treated differently, hence designed for digital primes. Maybe this is BS. I don't really care. I'm happy.

PS when I was talking about older designs... I was talking about how they preform well... so I'm not sure why you got all defensive about how the modern designs are so much better. I've seen some stunning screwmount work here.
12-18-2010, 11:18 PM   #23
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QuoteOriginally posted by Blue Quote
There is no peer for the FA 31 in the DA series of ltd lenses. However, since it has aspherical elements, ED, F.R.E.E. and Ghostless Coatings, there isn't much left to update other than SP on the front element and the Price
The only FA limited to make use of F.R.E.E is the FA77. The FA 31mm f/1.8 uses a GMo -glass moulded aspherical lens, one ED element an one HRLD - High refraction Low-dispersion element. Curiously pentax noted the the Aspheric design with an "AL" on the lens barrel but failed to mention the use of ED or HRLD glass in the FA31LTD.

I'm willing to be proven wrong but I see a problem with people blaming the lens coatings for PF.

Firstly, if PF was caused by pentax coatings then why is it so prevalent in other lens designs? E.G: Nikkor 85mm f/1.8,Canon 85mm f/1.2L, 50mm f/1.2L the Leica summilux 35mm f/1.4 Pre-ASPH has it, the whole Zeiss line up from the 21mm f/2.8 to the 100mm f/2 all have it to varying degrees. And then there is the voigtlander 125mm f/2.5 APO Lanthar* which is completely free of PF yet it is made by cosina - the same company that makes the Zeiss line of lenses.

* the Lanthar is probably one of the oldest and most archaic lens designs, though whether the voigtlander 125mm f/2.5 APO is a genuine lanthar is doubtful, considering the lanthar was a more common lens design employed with press and half plate cameras.


Last edited by Digitalis; 12-18-2010 at 11:43 PM.
12-19-2010, 12:12 AM   #24
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Different glasses have different light transmission characteristics, which means different lens designs are going to have somewhat different color. Aside from the main purpose of reducing reflection, lens coatings are used to make lenses more consistent in color throughout a lens line (Nikkor lenses, for example, tend to historically be cool in color). As far as coatings for digital vs. film I think Pentax lenses do well either way, since starting with SMC Takumar lenses, Pentax has always multicoated all of the lens elements, which cannot be said for Nikon and especially Canon. Non-multicoated lens elements in the rear of a lens were not too bad for film but are really bad for digital. As for FA vs DA, I still shoot film in my LX, so I am more of a fan of FA.
12-19-2010, 05:13 AM   #25
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To me, it basically comes down to money. Those who can afford/need the FA limiteds and their speed probably get them. Those who can't get DA limiteds (or even older, manual focus glass).

As to differences in coatings, does anyone actually know what coatings are used now and at what point during the years Pentax added different ones? That's what I thought.
12-19-2010, 10:49 AM   #26
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i feel that the DA Limited are an A

and the FA Limited are an A+
12-19-2010, 11:30 AM   #27
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DA LTD = budget version of FA LTD.

although the gap in pricing between lenses in general aren't that too far or too much from each other except for the FA31. I would say the DA LTD is for those who are financially depleted and can't spare a $100-$200 more. makes sense from a poor man's point of view.
12-19-2010, 11:38 AM   #28
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QuoteOriginally posted by Pentaxor Quote
makes sense from a poor man's point of view.


ok.

None of these lenses are cheap. The poor-man's option is to spend 500 on an all purpose zoom and be done with it.

Why make this a p***ing contest? Discuss the merits of each lens line. They both have merits, you know. Otherwise, you would not read about people who once owned FA ltds. and swapped them for their DA counterparts. You read about people going BOTH ways and I've never seen anyone mention the swap was dictated by finances.

Last edited by paperbag846; 12-19-2010 at 11:47 AM.
12-19-2010, 12:05 PM   #29
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QuoteOriginally posted by Pentaxor Quote
DA LTD = budget version of FA LTD.

although the gap in pricing between lenses in general aren't that too far or too much from each other except for the FA31. I would say the DA LTD is for those who are financially depleted and can't spare a $100-$200 more. makes sense from a poor man's point of view.
I don't know about poverty, I just have a couple of kids a couple hundred dollars times three or four adds up to real money in my household. I currently own three limiteds (DA 35, 40 and 70) and really have no desire for the FA limiteds. Would I take them if they were given to me? Sure, but I am quite satisfied (Take that, LBA!).
12-19-2010, 01:53 PM   #30
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QuoteOriginally posted by paperbag846 Quote


ok.

None of these lenses are cheap. The poor-man's option is to spend 500 on an all purpose zoom and be done with it.

Why make this a p***ing contest? Discuss the merits of each lens line. They both have merits, you know. Otherwise, you would not read about people who once owned FA ltds. and swapped them for their DA counterparts. You read about people going BOTH ways and I've never seen anyone mention the swap was dictated by finances.
this is not a p***ing contest and I dont know where you got that idea.
this is not just about people who are capable of swapping lenses or discussing the merits of each lens. this is for first time buyers who can only afford a single purchase in a year. I'm sure you have read quite a few inquiries on the board saying such dilemma. although zoom is a cheap option, but what if one is clamoring for a nice LTD class prime? let's say a person who can only spare $300 on a lens on a single year. would you push him more than he can bargain for and tell him to get an FA31? point is, there are people who are in this state. I know I was and I can't even afford me self a $200 FA50/1.4 during the recession. and some others in this board as well. and some students.

lens purchase is also influenced by financial capability. unless you are a part of corporate america that you max out your credit card and get yourself into trouble with the credit card companies and lose your home. or purchase stuff eventhough you are dead broke and dont have a job. well, good luck and I hope it is all worth it.
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