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Wednesday, May 07, 2014

DA70 Limited, FA77 Limited, and A*85 are of the Same Gene

First, have a look on these optical construction:

DA70/2.4:


FA77/1.8:


A*85/1.4:


So, the optical design of FA77 and A*85 are very close enough, with the same 7 elements in 6 group configuration. It is quite obvious that the FA77 is a miniature of the A*85, only with some minor modifications. And then the DA70 is yet another simplified version of the FA77, with one close-to-rear element omitted. So, everything are of the same Pentax gene actually. Indeed, when I first used my DA70 on my Pentax DSLR, I did feel the extraordinary film taste of it for its very good 3d feel and colour rendering, unlike other DA lenses that I may not that like.


Reference Links:

http://www.bdimitrov.de/kmp/lenses/primes/short-tele/index.html

http://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/2959-fa-85mm-f-1-4-vs-limited-77mm-f-1-8-a.html#post23940

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Comments (17)

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romay's avatar

romay · 567 weeks ago

Yeah, either that or you can just call them a double-gauss design: http://en.wikipedia.org/wiki/File:DoubleGauss4tex...
1 reply · active 567 weeks ago
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zosX's avatar

zosX · 567 weeks ago

Indeed. A lot of lenses share the same DNA.
+8 Vote up Vote down
YOKU's avatar

YOKU · 567 weeks ago

But bokeh and IQ are different.
And it's nothing new in your info. Absolutely dilettantish post.
A lot of lenses have very close optical design. Have a look at 50 mm lenses. :), for example.
-4 Vote up Vote down
Chris's avatar

Chris · 566 weeks ago

Bokeh MUST be different when comparing lenses with different max. aperture, even if the lens formulae are exactly the same.

BTW, the 77 is the Limited lens that I like the least - I definitely prefer the 70, and yes I had my 77 copy checked and Pentax said it is ok. For me the 77 was a big disappointment. (The Limited I like most are the 20-40, the 43, the 70, and the 35, plus the 100WR which to me is a "Limited" although it's not called so).

When using the 77, I was surprised how "long" it felt compared to the 70. Did anyone actually measure the focus length? I would not be surprised if the 77 is actually at least a 80 if not 85, and the 77 name was chosen for marketing purposes (to be "different" is one of the decision points for Pentax users, myself included).
4 replies · active 566 weeks ago
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RiceHigh's avatar - Go to profile

RiceHigh 110p · 566 weeks ago

The 77 performs much better when it is put onto FF, e.g., use it on the A7R, then you will see! :-D

Also, there exists some QC issues and inconsistency after the FA Limiteds' production was moved to Vietnam. I have had two copies of the 77 lens and found that they are somehow different in performance and manufacturing tolerance. That's also why Pentax failed these days, for one of the main reasons is the deteriorated QC.
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romay's avatar

romay · 566 weeks ago

The funny thing is, when you try to get a "made in Japan" limited on the used market, you are instantly labeled as racist.
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Kmounted's avatar

Kmounted · 566 weeks ago

My AIV 31 is poor, but AIV 77 flawless. You are right about QC and it's something Ricoh must sort out.
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fullframe_or_nothing's avatar

fullframe_or_nothing · 566 weeks ago

I have a poor AIV31 too.

Zzzzzzzzzzzzzzz, so boring latetly, when's the full frame camera coming?
-1 Vote up Vote down
Frank's avatar

Frank · 565 weeks ago

It's so silent in PentaxLand....Disturbing!
7 replies · active 565 weeks ago
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guest's avatar

guest · 565 weeks ago

the calm before the storm?
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RiceHigh's avatar - Go to profile

RiceHigh 110p · 565 weeks ago

Nope, it's the calm before death! ;-p
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Aspa's avatar

Aspa · 565 weeks ago

Rice - always when you talking about Pentax death somebody should pay me just 5 USD. Unti now I should be a rich man... :-D
+2 Vote up Vote down
Chris's avatar

Chris · 565 weeks ago

5 Cent each time would make you rich already, man.
Don't be greedy :-)
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Andrés's avatar

Andrés · 565 weeks ago

I can see more clearly that kind of calm on Nikon and Fuji.
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Bukaj's avatar

Bukaj · 565 weeks ago

K-3 and 645Z are too new to announce another groundbreaking camera right now. Let them rest before another wave of new products arrive:)
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Mike Kawasaki's avatar

Mike Kawasaki · 565 weeks ago

Come one, even next to Leica Pentax appearz to be asthmatic and quadriplegic old grandpa.
No new lenses — postponed ad infinitum. FA limidetz are no longer in production, good normal zooms gone, SDM issue still ruins the reputation, etc.
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Frank's avatar

Frank · 565 weeks ago

I menat there will be photokina this year, and there are a lot of rumors about all other manufactureres, and some already announced they will have new products to show...but with pentax it's... as if they fell into a deep sleep... i mean 645Z is a long awaited product for years now... i remember the last photokina we were all be very excited about the full frame rumors...but nowadays there aren't even fake rumors.

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