[Kunzite]

We should only read Japanese press releases; all the others are just some translations

[northcoastgreg]

I can only assume that both companies [i.e., Sony and Pentax] made the lenses for the sake of reputation and special projects only where price plays no role.

Well, that's part of it. But it's no coincidence that the two companies overcharging for superteles are marginal competitors in the high-end DSLR space. Sony and Pentax have much fewer customers capable of affording a supertele than does Canon, Nikon, or Sigma. Therefore they must produce much fewer superteles, which forces them to charge greater prices.

This is probably the main reason why Pentax has been relunctant to introduce an FF camera, despite admiting that they think about FF "all the time."

[Pål Jensen]

Well, that's part of it. But it's no coincidence that the two companies overcharging for superteles are marginal competitors in the high-end DSLR space.

Theres no overcharging here; a 560/5.6 cost this kind of money. I have prevoiusly assumed that a conventional ED IF lens of this focal lenght and speed would cost at least $8000. So the savings in Pentax version is about $1000 which seems about right.

[Pål Jensen]

It means that two recent additions (Sony 500/4 and now Pentax 560/5.6) ask for more than twice as much money as was normal at the time I originally published my formula.

And you are right and I was very wrong. I didn't anticipate this. But maybe, there is a new trend and buying reasonably-priced 500mm lenses would be a good investment?

Unfortunately, the Pentax 560/5.6 is no such lens.

At that price, weight, length, focussing distance, crop designation, a 100mm diameter and possibly only one ED element (the Sigma has two, the Pentax press prelease doesn't mention them, the name says ED and Pentax scopes typically have one ED element), the price cannot be called reasonable. It is as unreasonable as the one of the Sony 500/4.
.

Not unless you published your formula in the late 70's and didn't compensate for inflation (the habit of putting your highly subjective and unrealistic assumptions into formulas and graphs do you no credit and doesn't make them true; your dirt cheap FF theory doesn't seem to hold water either).
Long super telephotos have always costed this kind of money.
BTW the 560 has two ED elements. It is not a dumbed down cheap construction. The fact that it is a corrected lens based on spectacularly sharp and expensive telescopes only suggest a great optic defending it $7000 value compared to other lenses of this focal lenght range. Pentax will not charge $7000 for a lens that don't perform. Give them some credit in the stupidity department...

BTW has it occured to anyone that this lens function is not only as a conventional super telephoto but also a lens for the astro buffs?

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Last edited by Pål Jensen; 09-12-2012 at 11:30 AM.

[froeschle]

@ Pål Jensen: Sorry, even if you disagree with someone, I do not see a reason for such an aggressive reply.

PF-100ED
Pentax PF-100ED 4.0"/100mm Spotting Scope 70940 B&H Photo - price: 1700$ - as shown before...
100mm ED Lanthan glass three [!] elements in three groups

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/70638-pentax-pf-100ed-scope.html

Optically a scope is no match for a pricey tele lens, but with some luck with focusing one can get decent image quality that is as good in corners as in center. For better image quality I'd recommend a camera with good ISO performance.

[cali92rs]

I think we can assume that any TC will take this lens out of the range which the camera will autofocus, correct?

[froeschle]

any TC will take this lens out of the range which the camera will autofocus

No, it should (could) autofocus with a dedicated 1.4x AF (assumed to appear in early 2013 together with the 560/5.6).

[falconeye]

PF-100ED
Pentax PF-100ED 4.0"/100mm Spotting Scope 70940 B&H Photo - price: 1700$ - as shown before...
100mm ED Lanthan glass three [!] elements in three groups

Maybe, the astronomical Pentax scopes woud be a better reference, as they are more similiar constructions.

The Pentax 100 SDUF II f/4 Pezval APO listed at about 4700$ and Optcorp sold them for about 3000$ in the US (2007). The 105 SDP was a bit bigger and a bit more expensive. Pentax was considered excellent but a bit pricey in the astro community. Pentax left that market but for sure still own the optical designs.

The 560/5.6 looks like a Pezval design with additional (read: integrated) 2 element rear end group probably working as a field flattener.

[jpzk]

@ falconeye ...

you ruined my day !
(Your predictions were as good as mine about the weather).

JP

[froeschle]

[...] Maybe, the astronomical Pentax scopes woud be a better reference, as they are more similiar constructions. [...] Pentax 100 SDUF II [...]

Pentax 100 SDUF II - SkyandTelescope.com
($2,995, apochromat, 4 lenses, SD glass, SMC, illuminates up to 67)

Further reading (in German):
http://www.baader-planetarium.de/pentax/pdf/SDUF_30012006_baader.pdf
http://www.baader-planetarium.de/pentax/pdf/pentax_katalog_07.pdf

For a comparison (upper image source: baader-planetarium.de ):

[froeschle]

Note the curvature and size of the 3rd and 4th lens in the 100 SDUF II.

Imho, the function of the 4 lenses in the rear of the 560/5.6 is mentioned in Japanese patent A 2011-022280:
Klick here: Industrial Property Digital Library Home Page
-> Klick Patent & Utility Model Gazette DB
-> Insert Kind code: A, Number: 2011-022280, Klick Search
-> Klick on document number (left, blue)
-> Klick Detail (top)
-> Wait... (up to several minutes!)
-> Translation into English appears, drawing selection is on the right
-> Choose Section (CLAIMS, DETAILED DESCRIPTION, TECHNICAL FIELD, ...)

See here

.

[...] The AF would be solely realized by the lenses on the left in the scheme, the right group would be fixed. The aperture mechanism is in between. [...]

[falconeye]

@ falconeye ...

you ruined my day !
(Your predictions were as good as mine about the weather).

JP

I am as disappointed as you are probably. But in my case, it is Pentax who ruined my day

[froeschle]

Given

- that the 2 rear lenses of the Pentax 100 SDUF II do not match in size, form or position with ones in the 560
- the 4 rear lenses of the 560 lie outside of the scope design of the 100 SDUF II ("eyepiece")
- the Japanese patent describes a similar 4 rear lens layout
- the 2 lens (1 element?) Novoflex/Telyt-560mm assembly

couldn't this description ("2+4")

[...] it reminds me of the very simple 2 lens, 1 element [!] Leitz Telyts 560mm with added AF (back left) and correction (back right) lenses. [...]

be valid to some degree?

[Mistral75]

Given

- that the 2 rear lenses of the Pentax 100 SDUF II do not match in size, form or position with ones in the 560
- the 4 rear lenses of the 560 lie outside of the scope design of the 100 SDUF II ("eyepiece")
- the Japanese patent describes a similar 4 rear lens layout
- the 2 lens (1 element?) Novoflex/Telyt-560mm assembly

couldn't this description ("2+4")

be valid to some degree?

It certainly could. By the way, where does your scheme of DA 560mm f/5.6 optical formula come from?

[froeschle]

It certainly could. By the way, where does your scheme of DA 560mm f/5.6 optical formula come from?

The optical formula and lens diagram can e.g. be found in the German data sheet: http://www.pentax.de/media/16e7df3958ec872a3990ebfeffe11fa6/Datenblatt_HD_PE...A560mm_GER.pdf

And to report something positive: Pentax made my day by announcing this lens at this price point!

I just have acquired two FA* lenses instead: 400/5.6 and 200/4 Macro