Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-02-2008, 05:04 PM   #1
Site Supporter




Join Date: Apr 2007
Location: Warwick, RI
Photos: Gallery
Posts: 740
sigma APO teleconverter 2X extender

I was just over at my favorite photo store today and they had just got some old pentax camera and lens in. The lens were mostly sigma but they did have a sigma APO 2X teleconverter . There is one review on the lens review page that indicated it had limited compatability with othe lens.

Can anyone else tell me its compatibility to other lens? I would like to pair it with my Pentax FA 80-320 f 4.5-.56 or my Pentax M-80-200 f 4.5 for some outdoor "wildlife" photography?

One of the lens was a Sigma 100-300? very light but I forgot to write down any other info on it. Is it any good? It was probable an APO and used with that teleconverter.

11-02-2008, 06:43 PM   #2
Veteran Member
palmor's Avatar

Join Date: Dec 2006
Location: North of Boston, MA
Posts: 798
The reason the TC isn't compatible with all lenses is because the front element of the TC extends pretty far out. If your lens doesn't have a deep rear element then the TC and lens will touch damaging both.

I have a feeling that it won't work with the 2 lenses you listed but it really something you'd have to try to make sure.


Hope that helps
John
11-02-2008, 07:22 PM   #3
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
the sigma TC is only listed as compatible with the 300 F2.8 and 400 F2.8 pentax lenses from memory. this is on the product sheet not the web site.
11-02-2008, 07:33 PM   #4
Veteran Member
palmor's Avatar

Join Date: Dec 2006
Location: North of Boston, MA
Posts: 798
QuoteOriginally posted by Lowell Goudge Quote
the sigma TC is only listed as compatible with the 300 F2.8 and 400 F2.8 pentax lenses from memory. this is on the product sheet not the web site.
It can be compatible with more though. For example, it fits my Tokina 400 f/5.6 just fine (not that I actually use it with that lens ). But it is a roll of the dice if it fits your lens or not.


John


Last edited by palmor; 11-02-2008 at 09:07 PM.
11-02-2008, 08:56 PM   #5
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
QuoteOriginally posted by palmor Quote
It can be compatible with more though. For example, it fits my Tokina 400 f/5.6 just fine (not that actually is it with that lens ). But it is a roll of the dice if it fits your lens or not.


John
The sheet with my 1.4X (non DG TC) states

Sigma APO 300 F4, APO 400 F5.6, and APO 70-200 F2.8

Pentax FA 200 F2,8 ED (IF), FA 300 F2,8 ED (IF), FA 400 F2,8 ED (IF)

By the time I bought my 2X they deleted all pentax references and add
180mm F3.5 Macro, 300mm F2.8, 500mm F4.5, 800mm F5.6 and the Bigma

They really don't intend this to be a universal TC
11-03-2008, 03:28 AM   #6
Veteran Member
Ben_Edict's Avatar

Join Date: Jul 2007
Location: SouthWest "Regio"
Photos: Albums
Posts: 3,303
QuoteOriginally posted by Lowell Goudge Quote
The sheet with my 1.4X (non DG TC) states

Sigma APO 300 F4, APO 400 F5.6, and APO 70-200 F2.8

Pentax FA 200 F2,8 ED (IF), FA 300 F2,8 ED (IF), FA 400 F2,8 ED (IF)

By the time I bought my 2X they deleted all pentax references and add
180mm F3.5 Macro, 300mm F2.8, 500mm F4.5, 800mm F5.6 and the Bigma

They really don't intend this to be a universal TC
Sigma obviously wants not to be held liable for the combination of their tc with a another brand lens. That's fully understandable.

Generally the 2x Apo tc will fit any lens on the official Sigma list + any lens, that is compatible with the Pentax L convertors. The limitations are purely mechanical, due to the slightly protruding front element of the tc.

BUT a mechanical match does not signify, that the combo will deliver good image quality.

Ben
11-03-2008, 04:47 AM   #7
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
QuoteOriginally posted by Ben_Edict Quote
Sigma obviously wants not to be held liable for the combination of their tc with a another brand lens. That's fully understandable.

Generally the 2x Apo tc will fit any lens on the official Sigma list + any lens, that is compatible with the Pentax L convertors. The limitations are purely mechanical, due to the slightly protruding front element of the tc.

BUT a mechanical match does not signify, that the combo will deliver good image quality.

Ben
Ben I don't disagree, but I believe Sigma is, with their TC not intending to be in the universal TC market.

the list is very short, limited to only specific long lenses and a couple of zooms. BUT I can attest that on the 70-200 F2.8, it is an excellent performer.

I have previoulsy posted results from this combo to prove it.
11-03-2008, 07:03 AM   #8
Veteran Member
Ben_Edict's Avatar

Join Date: Jul 2007
Location: SouthWest "Regio"
Photos: Albums
Posts: 3,303
QuoteOriginally posted by Lowell Goudge Quote
Ben I don't disagree, but I believe Sigma is, with their TC not intending to be in the universal TC market.

the list is very short, limited to only specific long lenses and a couple of zooms. BUT I can attest that on the 70-200 F2.8, it is an excellent performer.

I have previoulsy posted results from this combo to prove it.
Lowell, I know your combination works great. I did not intend to disqualify the Sigma tc at all. If my post could be understood that way, I choose the wrong expressions. I just wanted to make clear, that a tc might work nicely with one specific lens (and the Sigma tcs are dedicated for only a handful lenses), but might not work at all satisfyingly with another lens. There is simply no AF tc currently on the market that I know off, which could be used with every sensible lens (that excludes wide-angle lenses, super-zooms and the like anyway). It is always a matter of trial and error and one must be able to make compromises.

Ben

11-03-2008, 07:42 AM   #9
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
QuoteOriginally posted by Ben_Edict Quote
Lowell, I know your combination works great. I did not intend to disqualify the Sigma tc at all. If my post could be understood that way, I choose the wrong expressions. I just wanted to make clear, that a tc might work nicely with one specific lens (and the Sigma tcs are dedicated for only a handful lenses), but might not work at all satisfyingly with another lens. There is simply no AF tc currently on the market that I know off, which could be used with every sensible lens (that excludes wide-angle lenses, super-zooms and the like anyway). It is always a matter of trial and error and one must be able to make compromises.

Ben
I think this is why sigma limited the recommended use. It is almost like the old "matched multipliers" intended only for specific lenses to work acceptibly (from an optical point of view)

TC's that are designed to work over a wide range of lenses may on average work well, but not as good as one of these, one the specific lens listed.
11-03-2008, 07:53 AM   #10
Veteran Member
Ben_Edict's Avatar

Join Date: Jul 2007
Location: SouthWest "Regio"
Photos: Albums
Posts: 3,303
QuoteOriginally posted by Lowell Goudge Quote
I think this is why sigma limited the recommended use. It is almost like the old "matched multipliers" intended only for specific lenses to work acceptibly (from an optical point of view)

TC's that are designed to work over a wide range of lenses may on average work well, but not as good as one of these, one the specific lens listed.
Yes, this is exactly right. The basic physical dimension, that should be fixed (within a certain limit) is the distance between the lens optical center and the tc - this is only the case for very few lenses, and I would expect, that those len-tc-combos recommende by Sigma fullfill this basic criterion. With any other lens, this would just be a coincidental match.

Ben
11-03-2008, 01:51 PM   #11
Site Supporter




Join Date: Apr 2007
Location: Warwick, RI
Photos: Gallery
Posts: 740
Original Poster
It sounds like I should just bring my lens in and try it on the 2x
11-03-2008, 02:12 PM   #12
Senior Member
Talisker's Avatar

Join Date: Nov 2007
Location: Isle of Skye, Scotland
Photos: Gallery
Posts: 262
I've just dug out my old 80-320mm and I don't think it will fit for the reason palmor stated - the rear element and inner barrel on this lens are flush with the back of mount. It certainly won't fit a Sigma APO 1.4 - I've just checked. Palmor's Tokina 400mm is a classic telephoto design with the rear element way up the barrel so no problems...
11-03-2008, 02:26 PM   #13
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
I have both the 1.4x and 2x, and the element design is similar, i.e. the front element of the TC sticks out to the edge of the lens mount, perhaps a little past. youo need to have a lens with a completely recessed rear element, with a circle diameter of about 35mm that goes streight down the lens barrel to accept the TC
03-30-2012, 12:35 PM   #14
Junior Member
kokezuniga's Avatar

Join Date: Dec 2010
Location: Temuco
Photos: Gallery
Posts: 25
does anybody knows if it will fit a Tamron SP AF 70-200mm F2.8 Di LD [IF] Macro???
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
2x, apo, apo teleconverter 2x, k-mount, lens, pentax, pentax lens, review, sigma, sigma apo teleconverter, slr lens, teleconverter
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
will Sigma 2.0x TeleConverter EX DG APO work with K7 Ivo_Spohr Pentax DSLR Discussion 3 12-05-2010 10:11 PM
1.4 sigma apo teleconverter and 300 da* garyk Pentax SLR Lens Discussion 4 08-01-2010 08:22 PM



All times are GMT -7. The time now is 04:31 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top