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12-16-2010, 04:41 PM   #16
axl
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QuoteOriginally posted by TKH Quote

The chair in the background tells you very quick witch lens is the Planar (FA43) and witch is the Tessar (DA40). The pics are not 100% correct focused, so please dont discuss about what lens is sharper. Also I didnt worked perfect in the LR2 for whitebalance, the colours are not perfect. My mistakes.
thanks for posting these again. These were some of the first shots back when I owned DA40 that made me question my decision.....

anyway, as far as the colours go, I know they are not accurate but they clearly show the lens preferences IMO. DA40 favors reds and magentas, and FA43 favors greens and yellows. This cast difference is easily noticable not just in your shots but generally, the colours of these two are quite different indeed IMO....

12-16-2010, 06:39 PM   #17
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QuoteOriginally posted by TKH Quote
The chair in the background tells you very quick witch lens is the Planar (FA43) and witch is the Tessar (DA40).
Not quite. There is no writing on the chair identifying the lens.

Seems like the first set is from the FA43 and the second from the DA40?
(going by what Axl wrote about the colour casts.)

I find it hard to compare the bokeh with these images because the second set of images was shot at a closer distance which will hugely affect how the bokeh is rendered.

From these images, I guess I'd prefer the lens that took the second two images but I'm not sure I'd be making the right decision.

Last edited by Class A; 07-17-2011 at 03:21 PM.
12-16-2010, 09:37 PM   #18
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QuoteOriginally posted by Class A Quote
Seems like the first set is from the FA43 and the second from the DA40?
I actually thought it was the reverse. Now, I'm not so sure.

It was the colour that tipped me off. The FA renders warmer from what I have seen.
12-16-2010, 10:21 PM   #19
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Yes. As you can see from the name of the pics, the second two pics are from the FA43.
The focus distance may be not perfect for a scientific test. But as I wrote, I only did a quick and dirty shooting. The goal was to show the background in the same "frame" and so I differed the distance to the rabbit a little (because of the 3mm difference of the two lenses). Again, nothing scientific, but imho a real world example of what a real live photographer will see when he uses both lenses in the same situation.

12-17-2010, 02:42 AM   #20
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QuoteOriginally posted by TKH Quote
As you can see from the name of the pics, the second two pics are from the FA43.
Ah, thanks. Glad that's the case as I actually prefer the second two pics. The first two have a green tinge and less contrast and hence looked as if they came from an older design. For a moment I thought I had to revise my opinion on the DA40 but now I'm back to much preferring the FA43.

Thanks for posting the images and the clarification.
12-17-2010, 09:35 AM   #21
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All I can say is that my S-M-C Macro Takumar 50mm f4 (a tessar design) is by far my favorite lens (and I have a bunch). Great sharpness, rendering, and bokeh (especially in the close range, which is was designed for. I have more than a couple of macro lenses, but this is my favorite). By the way, with so few elements, and SMC, transmission is very high--when modern photography (I think) tested this lens, its transmission was 98.3%, better than just most good UV filters!
12-17-2010, 10:22 AM   #22
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QuoteOriginally posted by macTak Quote
with so few elements, and SMC, transmission is very high
This has been my experience with the DA 40. It actually allows for 1/2 stop more shutter speed over an equivalent lens of the planar type... making it slightly faster than you would think with a maximum aperture of 2.8.

The comments about the colours of the images previously posted are interesting to me. I prefer the cooler "real" rendering to the warmer rendering. I suppose I value accuracy over anything else. For the most part, the images are pretty much identical to my eyes, including contrast (maybe not terms of resolution, though). The colour is the major differentiator, and I think that it has a lot to do with the DA vs. FA lens designation... it seems Pentax tweaked the coatings for digital sensors or something. The "cooler" look is a common attribute of all pentax DA lenses.

I wonder why they would do that. Maybe it has to do with RAW processing flexibility? Another thought is that it makes optimal use of the the bayer colour sensors?

Color filter array - Wikipedia, the free encyclopedia

(My thinking is that it is biased towards blue because there are 2X as many green and red sensor points on a digital sensor).
12-17-2010, 02:12 PM   #23
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From the horse's mouth (in German):

Planar:
  • developed in 1896
  • symmetrical design
  • very flat field
  • very good correction of spherical and chromatic aberrations (including astigmatism)
  • the fastest lens in the world (CZ 50/0.7) is a Planar

Tessar:
  • developed 1902
  • high sharpness
  • very compact (small, lightweight)
  • used in mobile phones


12-17-2010, 04:12 PM   #24
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Interesting points.

It makes me wonder, though, why one of the DA 40's strengths over the various 50's and the 43 ltd is the absence of spherical/chromatic aberrations?
12-19-2010, 12:06 AM   #25
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One lens design being left out here is the sonnar, which is a design I suspect the FA77 takes after considering it's speed and the fact that it's design borrows heavily from the A*85mm f/1.4.

It makes sense for the FA43mm f/1.9 being a planar type, being optically better corrected when compared to the double gauss design of the FA 50mm f/1.4 - the EF 50mm f/1.2L from canon is also a double gauss design.

The FA31mm f/1.8 is an oddball lens. I'm not entirely certain what lens design family it belongs to because successful arguments can be made for it being either a distagon or a tessar. But one thing we can be certain of is that it is a superb lens.
12-19-2010, 05:55 AM   #26
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QuoteOriginally posted by paperbag846 Quote
It makes me wonder, though, why one of the DA 40's strengths over the various 50's and the 43 ltd is the absence of spherical/chromatic aberrations?
Not sure. Perhaps you don't see the aberrations as much since the DA 40 widest aperture is relatively "slow"?

I guess many would think that the DA 70 has less CA than the FA 77 but according to photozone.de the FA 77 is the clear winner.

QuoteOriginally posted by Digitalis Quote
One lens design being left out here is the sonnar, which is a design I suspect the FA77 takes after considering it's speed and the fact that it's design borrows heavily from the A*85mm f/1.4.
I'm not an expert but I think it is fair to say that the FA 77 is neither a pure Sonnar nor a pure Planar, but resembles a Planar a lot more due to the relatively symmetrical arrangements. The rear group of a Sonnar looks totally different.

QuoteOriginally posted by Digitalis Quote
It makes sense for the FA43mm f/1.9 being a planar type, being optically better corrected when compared to the double gauss design of the FA 50mm f/1.4 - the EF 50mm f/1.2L from canon is also a double gauss design.
Compare the optical design of the CZ 50mm Planars with the optical design of the FA43. The latter is practically a clone.

The optical designs of the FA43 and the FA50 seem to be very similar. In fact, I'd go as far as saying that I can see the "Ltd" genes in the rendering of many FA 50/1.4 images. Both are again very similar to the FA 77.

Tessars, on the other hand, are quite different and I think it shows in the rendering.

Last edited by Class A; 12-19-2010 at 06:16 AM.
12-20-2010, 08:37 PM   #27
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QuoteOriginally posted by paperbag846 Quote
The DA limited 21, 40, and 70 are tessar designs.
I don't think any of them is a Tessar. They may be Tessar derived designs, but none is strictly speaking a Tessar, which is a 4 element 3 group design. The Industar 50-2 is a Tessar.

The best reference I found so far on lens designs is this optical design thread on mflenses.com.

Note that there are many designs derived from Planar, so just saying a lens is a Planar design doesn't say much. The FA77 appears to fall under the 7 element Ultron category, same as the FA43. Biotars are also a category of Planars, but no one says that the Helios 44 and the FA77 are very similar.

The DA40 optical scheme looks different from that of the M40 or the classic Tessar scheme. The M40 looks a bit like a Tessar with an extra element at the rear, so that may be a Tessar derivative, but the DA40 looks quite different.

Anyway, have a look at those mflenses optical design charts and let me know what you think.
12-20-2010, 09:59 PM   #28
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Looking more over those schemes, the Pentax 40s are a Unar-Tessar hybrid (actually Unar-Elmar with Elmar being a variation on Tessar).
01-06-2011, 06:22 PM   #29
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What about DA* 55mm 1.4?
01-07-2011, 09:30 AM   #30
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QuoteOriginally posted by arm_jstp Quote
What about DA* 55mm 1.4?
Double Gaussian design, which is more similar to planar than to tessar, I believe.
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