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05-14-2020, 01:34 AM   #1
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Is the Pentax 60-250 the same Lens as the Oly 50-200 SWD?

I recently purchased the Oly 50-200 SWD (4/3 mount) and immediately I recognized many similarities to my Pentax 60-250.

- Front element looks exactly the same

- Same girth

- Same filter size

- Same length and weight

- Oly is 16 elements in 13 groups, Pentax 15 elements in 13 groups, Both have ED glass elements

- Both have ultra sonic motors

- Oly is 2.8-3 5, Pentax is F4

- Oly manfactured 2007, Pentax manufactured 2009

Although the Pentax is said to extend to 250mm focal length, it does not (I've been told its focus breathing). From my tests its about 200 to 210MM. I have not tested the wide end. Im waiting on my adapter to be able to take some test shots.

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Last edited by Lmcfarrin; 05-14-2020 at 05:07 AM.
05-14-2020, 02:23 AM - 4 Likes   #2
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I'm calling Bunk on this on the basis that it is pure speculation. Photozone (now optical limits) made a similar statement years ago. Many of the physical similarities are purely coincidental, the Olympus lens focuses by wire the Pentax lens does not. The Pentax lens has a physical aperture connection, the Olympus lens uses electronic aperture control.

While it is true they have similar element counts and types of glass used in them the optical design can reveal a great deal about both lenses: Unfortunately, I have been unable to source a reliable optical schematic of the Zukio 50-200mm on the internet for such a comparison. So I'd say any connection between the two lenses is purely speculative.


QuoteOriginally posted by Lmcfarrin Quote
the Pentax is said to extend to 250mm focal length, it does not (I've been told its focus breathing).
The true focal length of lenses is only accurate when the lens is focused at infinity, any distance closer than that and you will get an incorrect figure. IF lenses are inherently prone to focus breathing as the focus group moves independently within the optical axis.

QuoteOriginally posted by Lmcfarrin Quote
From my tests its about 200 to 210MM.
At what focus distance? Back your statements up with data, show us how you are working your problems out.

Last edited by Digitalis; 05-14-2020 at 03:08 AM.
05-14-2020, 02:52 AM   #3
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QuoteOriginally posted by Digitalis Quote
I'm calling Bunk on this on the basis that it is pure speculation. Photozone (now optical limits) made a similar statement years ago. Many of the physical similarities are purely coincidental, the Olympus lens focuses by wire the Pentax lens does not. The Pentax lens has a physical aperture connection, the Olympus lens uses electronic aperture control.

While it is true they have similar element counts and types of glass used in them the optical design can reveal a great deal about both lenses: Unfortunately, I have been unable to source a reliable optical schematic of the Zukio 50-200mm in the internet for such a comparison. So any similarities are purely speculative.



The true focal length of lenses is only accurate when the lens is focused at infinity, any distance closer than that and you will get an incorrect figure. IF lenses are inherently prone to focus breathing as the focus group moves independently within the optical axis.

At what focus distance? Back your statements up with data, show us how you are working your problems out.
Thank you for the more in depth details. I shouldve added a ? to the Very Possible title thread. I apologize for the error - I should've posed the title thread as a question.
05-14-2020, 03:04 AM - 4 Likes   #4
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Very NOT possible:


Pentax on the top...


Last edited by Adam; 05-14-2020 at 03:15 AM. Reason: fixed embed
05-14-2020, 03:14 AM   #5
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QuoteOriginally posted by Lmcfarrin Quote
Although the Pentax is said to extend to 250mm focal length, it does not (I've been told its focus breathing)
You are partially correct here. At infinity the Pentax lens is a 250mm FL. At close focus distance it is less, 210 may be correct. But most zooms in this range will exhibit the same behaviour.
05-14-2020, 03:22 AM   #6
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Thanks for clearing things. I now know I have another unique piece of kit. Thanks for taking the time for providing corrected information.
05-14-2020, 04:01 AM   #7
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QuoteOriginally posted by Apas Quote
Very NOT possible
I agree, there is a massive difference between the two lenses.

05-14-2020, 04:53 AM   #8
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we can probably either change the title of this thread or close it completely....
05-14-2020, 05:08 AM   #9
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QuoteOriginally posted by pepperberry farm Quote
we can probably either change the title of this thread or close it completely....
I changed the thread title. I agree we can move on. I wish I could get this type of vigor/attention with my bif pics -.
05-14-2020, 07:38 AM - 1 Like   #10
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QuoteOriginally posted by Lmcfarrin Quote
I wish I could get this type of vigor/attention with my bif pics
The Internet is fueled mostly by outrage and voyeurism, just post a controversial/unpopular opinion and watch the views come in. Just be careful what you wish for: the internet is a rather unforgiving place for pariahs.
05-14-2020, 07:46 AM   #11
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QuoteOriginally posted by Digitalis Quote
The Internet is fueled mostly by outrage and voyeurism, just post a controversial/unpopular opinion and watch the views come in. Just be careful what you wish for: the internet is a rather unforgiving place for pariahs.
I agree. I posted a 1 in a million picture of two birds fighting mirroring each other and get minimal response. I make a mistake and everybody wants to know me. No biggie. I can show better than I can tell.
05-14-2020, 07:53 AM - 2 Likes   #12
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QuoteOriginally posted by Lmcfarrin Quote
I agree. I posted a 1 in a million picture of two birds fighting mirroring each other and get minimal response. I make a mistake and everybody wants to know me. No biggie. I can show better than I can tell.
Any time I respond to a post and tell you to look for a photo contest to enter it in, that's not minimal..
It's happened 3 times in 10 years.

In the last 5 years I've taken no photos I consider to be contest worthy.

But it does remind me of a birder buddy with an on-line blog. At one point I caught him setting up squirrel shots. I said "What are you doing?" He said, "I post fantastic bird images, I get 3 likes, I post one half ass squirrel image, I get 100."

The lens of us who will be most impressed are those of us who sit out in blinds, week after week year after year and never get anything close to that.

Last edited by normhead; 05-14-2020 at 08:03 AM.
05-14-2020, 07:58 AM   #13
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QuoteOriginally posted by normhead Quote
Any time I respond to a post and tell you to look for a photo contest to enter it in, that's not minimal..
It's happened 3 times in 10 years.

In the last 5 years I've taken no photos I conservative contest worthy.

But it does remind me of a birder buddy with an on-line blog. At one point I caught him setting up squirrel shots. I said "What are you doing?" He said, "I post fantastic bird images, I get 3 likes, I post one half ass squirrel image, I get 100."
Thank you. I meant the number of responses. I appreciate a sincere accolade.
05-14-2020, 07:59 AM - 2 Likes   #14
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QuoteOriginally posted by Lmcfarrin Quote
I changed the thread title. I agree we can move on. I wish I could get this type of vigor/attention with my bif pics -.
QuoteOriginally posted by Lmcfarrin Quote
I agree. I posted a 1 in a million picture of two birds fighting mirroring each other and get minimal response. I make a mistake and everybody wants to know me. No biggie. I can show better than I can tell.
I have to say that your bird shots are quite impressive... to get more attention on them, misidentify the bird... pages of discussion will then follow...
05-14-2020, 08:04 AM   #15
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QuoteOriginally posted by bertwert Quote
I have to say that your bird shots are quite impressive... to get more attention on them, misidentify the bird... pages of discussion will then follow...

Hahahahhahahaha. A great trap. Thanks.
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