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12-15-2010, 08:16 AM   #1
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Planar vs Tessar

Hi,

I had a question regarding planar and tessar lenses. Can anyone explain the differences between the two? What are advantages between one and another? What kind are Pentax limiteds?

I recently saw a post that briefly talked about this, and it got my curiosity up. Anyone who cares to elaborate, the stage is yours!

12-15-2010, 08:20 AM   #2
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Let me google that for you

12-15-2010, 09:27 AM - 4 Likes   #3
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I recall bringing this one up, but I am no expert.

The DA limited 21, 40, and 70 are tessar designs. They have a smaller maximum aperture, really even sharpness across the frame, lower peak sharpness than planar, but better sharpness wide open or closed all the way down. In short, they tend to be very "even" throughout the aperture range. This lens design is a century old. In my experience, the slower tessar lenses (with modern coatings) let in slightly more light at a given aperture than their planar counterparts at the same aperture, because there are less lens elements in tessar designs.

Most other lenses are planar of some sort, although not all of them. They are a little larger, have more lens elements, are considerably faster, but also much softer wide open than tessar lenses. Peak sharpness is often higher for the planar lenses. Corners tend to be softer on planar lenses than on tessar lenses, which can actually be seen as a desirable, or undesirable, trait (depends on whether you are attempting to isolate the subject or not).

You can get really, really deep into this stuff and, arguably, it will have little effect on your abilities as a photographer. I can attest to the difference in Tessar rendering over the Double Gauss design (the FA 50 1.4)... they are very different and each have their place, really. There is no correct choice IMHO.

Boiled down: Tessar lenses are old-reliable pals. Nothing shocking about their performance, but really dependable all the way through the aperture range. Planar lenses tend to be more temperamental geniuses. They can outperform everyone when the stars align, but are more prone to producing "mistakes"... things like softness, or chromatic aberrations. However many of these "mistakes"(such as aberrations and flare) have been largely corrected by lens coatings, which explains why the planar design philosophy accounts for a very large percentage of modern lenses.

In the end, there is a good reason why Planar lenses have become the standard design of modern lenses. Tessar's are considerably more rare.

Last edited by paperbag846; 12-16-2010 at 12:02 PM.
12-15-2010, 02:16 PM   #4
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That's rather nice sum up Paperbag....

12-15-2010, 09:19 PM   #5
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QuoteOriginally posted by paperbag846 Quote

The DA limited 21, 40, and 70 are tessar designs.

Boiled down: Tessar lenses are old-reliable pals. Nothing shocking about their performance, but really dependable all the way through the aperture range.

Planar lenses tend to be more temperamental geniuses. They can outperform everyone when the stars align, but are more prone to producing "mistakes"... things like softness, or chromatic aberrations.

In the end, there is a good reason why Planar lenses have become the standard design of modern lenses. Tessar's are considerably more rare.
So whats with the FA limiteds? Are they Planar designs?
12-15-2010, 11:07 PM   #6
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QuoteOriginally posted by TKH Quote
So whats with the FA limiteds? Are they Planar designs?
If I understand this technical stuff correctly, and I'm not sure I do, I believe the FA ltds. are all Planar designs.

Regardless if this is technically true, everything I used to describe the differences between the Tessar and Planar designs is true of the differences between the FA and DA limiteds.

What is really interesting to me is that high ISO digital has breathed new life into the older tessar design. In the days of film, a maximum aperture of say, 2.8, was considerably more restrictive than it is today. However, the differences with respect to image qualities (evenness of sharpness across the frame, maximum sharpness, and depth of field flexibiity) are all not effected by high ISO digital. Tessar is certainly no replacement for Planar, but it is a more viable solution than ever before with cameras like the KX, KR, and K5 kicking around.

They really do look quite different to my eyes. I think that is why I have talked to people who have owned both the DA 40 and FA 43, and they told me that they liked them BOTH for their own unique look. The planar designs do tend to have more "character" though, which is a common point people make when they compare the FA limiteds favorably to the DA limiteds.
12-16-2010, 07:02 AM   #7
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Hey thanks paperbag

That was really good summary!
12-16-2010, 10:20 AM   #8
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related to this (so probably this is not the right place to ask, but anyway), I often come across these terms, and there usually are some people 'in the know' and they can explain what the difference is between tessars, sonnars, planars, and place of the focusing elements and diaphragm in this and this design, and why inverted retrofocus lenses are awesome. Sometimes I google a bit, and I mostly find forums where someone explains it, but there's got to be some sort of source for all this information. What I would really like to find is a book, maybe a technical book about the history of photography, for photographers. Would anybody know where to look for something like that?


Edit: Looks like this is what I would like, except it's a little expensive (and 20 years old) http://www.amazon.co.uk/gp/product/0124086403


Last edited by urje; 12-16-2010 at 10:31 AM. Reason: added link
12-16-2010, 10:25 AM   #9
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it would be nice to see 2 same pictures taken with both: planar and a tessar
12-16-2010, 10:35 AM   #10
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QuoteOriginally posted by greymda Quote
it would be nice to see 2 same pictures taken with both: planar and a tessar
This would be a hard comparison to make, because the focal lengths and maximum apertures would be different. I could go and make some test shots of the DA 40 vs. the K55, but it might be useful to really draw on a larger body of evidence.

Therefore I would suggest looking through the DA limited and FA limited club threads. You can make some basic comparisons between the FA 43/DA40, and FA77/DA70 there.

You could compare the other lenses, but focal lengths would become too different, and it does not make sense to compare the FA 31 to the DA 35, because it is a macro.

Another comparison one could make would be between the DAL 35 2.4 and the DA 40. There are a lot of images out there, but remember that both of these lenses are so good that you might get a little disoriented throughout the process.

This might be your best bet for a Q&D comparison. Compare these features between the DA 40 : Pentax SMC-DA 40mm f/2.8 Limited - Review / Test Report - Analysis and FA 43: Pentax SMC-FA 43mm f/1.9 Limited - Review / Test Report - Analysis, or the FA 50: http://www.photozone.de/pentax/126-pentax-smc-fa-50mm-f14-review--lab-test-report?start=1

Minimum and maximum center sharpness, Center sharpness vs. corner sharpness, and chromatic aberrations.

On the final page of each test, some sample shots will show the difference in bokeh between the two types of lenses.

I think the easiest way to sum it up is that the FA limiteds have more character, more "pop", etc., and the DA limiteds are very steady and reliable, without ever showing off.

This line of thinking about the FA limiteds actually extends beyond the FA limited line into most of the other FA lenses, but there are other factors that make the FA limiteds unique amongst other planar design lenses.

Last edited by paperbag846; 12-16-2010 at 11:30 AM.
12-16-2010, 11:29 AM - 2 Likes   #11
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QuoteOriginally posted by greymda Quote
it would be nice to see 2 same pictures taken with both: planar and a tessar
No problem.
Two years ago I did the same shoot with the DA40 and the FA43.



Crop.







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.

The point is how the lenses render the out of focus areas.

One thing in the whole story is curios for me.

When I understand it in the right way, the Planar design is the more older one in lens technologies, why choose Pentax it for their more modern lenses??
12-16-2010, 11:33 AM   #12
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QuoteOriginally posted by TKH Quote
When I understand it in the right way, the Planar design is the more older one in lens technologies, why choose Pentax it for their more modern lenses??
Thanks so much for the comparison... I've seen this one before and it perfectly illustrates the differences between the lens lines.

I believe that Tessar lens designs are older.

I think they chose them because they are so compact. In the film era, the planar lenses were seen as a huge step forward due to their light-gathering abilities after the advent of lens coatings. In those days ASA 800 was really pushing it... and Tessar lenses were not extremely popular after lenses like the 50mm 1.4 were available. Nowadays, the rules have changed slightly. Pentax was likely thinking: "We can deliver a very high-contrast and sharp images in an absurdly small lenses if we use the Tessar design. The slow maximum aperture of these lenses is not going to be a huge hurdle because of high ISO, they are better wide open than their planar counterparts, tessar lenses are less expensive to manufacture and therefore can be sold for less, and we still offer the FA limiteds for those who are not happy with the tessar design".

This line of thinking would really fall flat if they discontinued the FA limited line, but I don't think they will without introducing planar DA limited alternatives first.

Last edited by paperbag846; 12-16-2010 at 11:59 AM.
12-16-2010, 11:37 AM   #13
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QuoteOriginally posted by TKH Quote
No problem.
thanks
12-16-2010, 11:46 AM - 1 Like   #14
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My pleasure to show the simple pics.

OK. Now Im on the right way, the Planar is the older one. I misunderstood your term "Tessar lenses are old-reliable pals".

I think we must be thankful that we are blessed to choose in our camera system between Tessar and Planar lenses.

Last edited by TKH; 12-16-2010 at 11:51 AM.
12-16-2010, 11:58 AM   #15
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QuoteOriginally posted by TKH Quote
My pleasure to show the simple pics.

OK. Now Im on the right way, the Planar is the older one. I misunderstood your term "Tessar lenses are old-reliable pals".

I think we must be thankful that we are blessed to choose in our camera system between Tessar and Planar lenses.
Sorry I actually had my facts wrong... planar lenses are the older design. I'll correct my original post.

Wikipedia:

Tessar:

Early Tessar designs by Paul Rudolph allowed a maximum aperture of f/6.3. Later development allowed an aperture of f/4.5 by 1917. In 1930, Ernst Wanderslab and Willy Mert of Carl Zeiss developed Tessar lenses with apertures of f/3.5 and f/2.8.


Tessar are frequently found in mid-range cameras, as they can provide a very good optical performance at a reasonable price, and are often quite compact. They are also frequently used in photographic enlargers, as they provide more contrast than many competing lens designs due to the limited number of air-to-glass surfaces.


Planar:

The Zeiss Planar is a photographic lens designed by Paul Rudolph at Carl Zeiss in 1896. Rudolph's original was a six-element symmetrical design.
While very sharp, the lens suffered from flare due to its many air-to-glass surfaces. Before the introduction of lens coating technology the four-element Tessar, with slightly inferior image quality, was preferred due to its better contrast. In the 1950s, when effective anti-reflective lens coatings became available, coated Planars were produced with much-improved flare. These lenses performed very well as normal and medium-long focus lenses for small and medium format cameras. One of the most notable Planar lenses is the high-speed f/2.0/110 mm lens for the 2000- and 200-series medium.

Note that tessar lenses had the upper hand in many circumstances prior to the development of good lens coatings. Nowadays, planar lenses tend to have the upper hand overall. In my experience, however, you can still see a little of the flare resistance and improved contrast at work when you compare a modern-coated tessar with a modern-coated planar. The question is whether these attributes win over the larger aperture and increased sharpness seen in planar designs.

Last edited by paperbag846; 12-16-2010 at 12:04 PM.
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