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08-30-2009, 10:08 AM   #526
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The onle TC I use with my da300 is the 1.7x afa because with the way the focus hunts with my kenko I thought it would be bad for the focus motor. The canon 1.4x is said to slow the focus down so it locks better albeit slower. That made me wonder if they need to reprogram the AF for use with a TC somehow.

08-30-2009, 01:05 PM   #527
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Tamron-F Pz-AF MC4 1.4x both SDM & AF works for my Sigma 150-500mm APO HSM lens, & AF on the Sigma 105mm EX DG 2.8.


Last edited by Fl_Gulfer; 08-30-2009 at 01:48 PM. Reason: added photo
09-03-2009, 01:42 PM   #528
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QuoteOriginally posted by danielchtong Quote
Apparently only 2 TC out of many (one 1.5x & one 1.4x) are SDM lens compatible. And there is no Pentax TC competition at all. See the list I have compiled earlier

+++++++++++++++++++++++++++++++++++++++++++++++++++

This is the list I have compiled / updated with emphasis on DA* lenses with SDM . And this was updated 090430
*Tamron 1.4x Pz-AF MC4 AF works. SDM no re Brad (photo.net)
*Tamron-F Pz-AF MC4 1.4x both SDM & AF works for DA*300mm re Dave (photo.net)
*Tamron-F Pz-AF MC4 1.4x both SDM & AF works for DA*300mm as per Toshi, moderator of Pentaxforums.com.
*Tamron-F Pz-AF MC4 1.4x both SDM & AF works only 10% of the time for DA* 50-135mm but hunts a lot re Miserere
*Tamron-F Pz-AF MC4 1.4x with the Sigma 70-200mm -new with HSM . The HSM AF works. It really didn't work all that well indoors at night according to Dave Hollander of Photo.net
*Kenko DG Pz-AF 1.5x TELEPLUS MC no AF no SDM on DA*300mm re Dave (photo.net)
*Kenko DG Pz-AF 1.5x TELEPLUS MC AF works on older AF lens re Dave (photo.net)
*Kenko Pz-AF 1.5X TELEPLUS MC only AF works; SDM no as per jgredline of Pentaxforums.com
*Kenko Pz-AF 1.5x TELEPLUS SHQ both AF & SDM works for DA*200mm and all older AF lens re Daniel
*Kenko Pz-AF 1.5x TELEPLUS SHQ both AF & SDM works for DA*300mm re Borno (Tom) of Pentaxforums.com .SDM hunts a bit with DA*300mm
palmor of Pentaxforums.com confirmed it did not hunt as much with DA*300mm in good light
*Kenko Pz-AF 1.5x TELEPLUS SHQ both AF & SDM works for DA*50-135mm but it does hunt quite a bit and often fails to lock focus according to heliphoto of Pentaxforums ; Buddha Jones of Pentaxforums not happy with its result ;

If I happen to have misquoted the experienced members in the compiled list above, pl let me know so that I can correct them



Daniel
As I said before the Promaster PZ-AF 1.7X has SDM contacts but did not function with my Sigma 70-200 HSM. I just received the Kenko PZ-AF 1.5 SHQ and happy to report the HSM works fast. Relative low light also
Just a breaf trial, but I should give it a good go on next weeks vacation. I had my fingers crossed on this one.
09-05-2009, 12:46 AM   #529
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QuoteOriginally posted by OrenMc Quote
As I said before the Promaster PZ-AF 1.7X has SDM contacts but did not function with my Sigma 70-200 HSM. I just received the Kenko PZ-AF 1.5 SHQ and happy to report the HSM works fast. Relative low light also
Just a breaf trial, but I should give it a good go on next weeks vacation. I had my fingers crossed on this one.

Wow you are the first one reporting mating a SDM TC to the new Sigma zoom. Glad that it works. Hope to hear from you the result so I can add your finding in my compiled list.
That clears a lot of doubts on Sigma HSM zoom.
BTW one suggestion: do not get despaired with IQ if it does not perform that well at 200mm. Try 190mm 180mm as well. The reason is that with a zoom and multiple elements moving, chance is high that iQ varies for different FL.

Daniel


Last edited by danielchtong; 09-05-2009 at 04:56 AM.
09-05-2009, 12:58 AM   #530
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QuoteOriginally posted by Fl_Gulfer Quote
Tamron-F Pz-AF MC4 1.4x both SDM & AF works for my Sigma 150-500mm APO HSM lens, & AF on the Sigma 105mm EX DG 2.8.


Hope you can comment on the resultant IQ and if you are happy with the result. The Sigma zoom with slower speed may have problem in low light situation
09-05-2009, 11:39 AM   #531
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Most people don't realize that a long zoom over F 5 isn't made for low light, mostly for daytime wildlife shooting. On a sunny day I have no problems with the TC hooked to either lens. It will hunt a little if the subject is alot smaller than the background of the shot on the MonsterMa. But that is to be expected when shooting a subject that is in a tree at a great distance I guess.

After the storm moves through I'll take a few shots w & w/o the TC. on both lenses.
09-06-2009, 12:49 PM   #532
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These shots were taken with the Sig 105mm 2.8 w&w/o the Tamron 1.4 TC.
They are unedited and sized to 4000x3000 after clicking the thumbnail.
These are shot from a tripod with a remote wired switch, I think my camera focus needs adjusting ? There was a slight breeze but I tryed to wait for a lull..




09-06-2009, 07:02 PM   #533
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these 2 images was taken on a K20D Tamron 70-200

Tamron 1.4 Tc



Sigma 1.4Tc


also 10 pics in link below first 5 with tammy tc and last 5 with sigma tc i think the tammy tc is better
TC Test - shane33's Photos

09-06-2009, 07:12 PM   #534
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Keep in mind that Sigma really does not make a universal TC, They build them to be used with their lenses.
09-07-2009, 03:55 AM   #535
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QuoteOriginally posted by jgredline Quote
Keep in mind that Sigma really does not make a universal TC, They build them to be used with their lenses.
I'm not sure that this is optically feasible (fine tune a TC for a particular lens).

Considering a single color only, as soon as the rays left the rear element, they run straight to sensor. A perfect TC is a magnifier.

Considering multiple colors, I can imagine a difference with respect to CA depending on how far the TC is away from the rear lens.

The only other option I see is making an imperfect TC correcting known aberrations from a particular lens. Such a 0.6x TC exist for mirror scopes, e.g. from Celestron. But then, the TC should fit a single lens only. I really doubt that the Sigma TC are of this kind.

The Sigma TC aren't universal because they don't work with protuding rear lens elements. It is about mechanical incompatibility, not about optical optimization.
09-07-2009, 04:04 AM   #536
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QuoteOriginally posted by falconeye Quote
I'm not sure that this is optically feasible (fine tune a TC for a particular lens).

Considering a single color only, as soon as the rays left the rear element, they run straight to sensor. A perfect TC is a magnifier.

Considering multiple colors, I can imagine a difference with respect to CA depending on how far the TC is away from the rear lens.

The only other option I see is making an imperfect TC correcting known aberrations from a particular lens. Such a 0.6x TC exist for mirror scopes, e.g. from Celestron. But then, the TC should fit a single lens only. I really doubt that the Sigma TC are of this kind.

The Sigma TC aren't universal because they don't work with protuding rear lens elements. It is about mechanical incompatibility, not about optical optimization.
Though I would subscribe to your basic notion, I would not dismiss the idea, that the Sigma tcs are dedicated to a few special lenses. Apart from the mechanical constraints, the tcs may (I cannot proof that, it is only a theoretical assumption) be optimized to work with a certain rear group of the lens, aka the relay group of the Sigma zoom lenses, which may be sufficiently uniform in performance across the small supported selection, to make a single "dedicated" tc feasable. There is more to the tc, than colour abberrations, namely spherical abberration, and flatness of field.

Ben
09-07-2009, 04:31 AM   #537
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QuoteOriginally posted by Ben_Edict Quote
I would not dismiss the idea, that the Sigma tcs are dedicated to a few special lenses
Ben, you may be right and so I only said I doubt it.

But the more I think about it the more I start to believe that the "optimized Sigma TC" just is another marketing legend. "Optimized" means that they ignored protuding rear lens elements which most Sigma lenses don't have.

It is like calling slow software "optimized for fast processors"

Sigma lists 35 "dedicated lenses", ranging (using the zoom long ends) from 150mm to 1000mm, both zooms and primes, incl. a 150mm/2.8 Macro. Up to f/2.8 and 142mm (800mm/5.6) apertures.

I am almost certain that the Sigma TC have no optical "dedication" whatsoever for any lens.

Last edited by falconeye; 09-07-2009 at 04:37 AM.
09-07-2009, 08:59 AM   #538
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QuoteOriginally posted by falconeye Quote
I'm not sure that this is optically feasible (fine tune a TC for a particular lens).

Considering a single color only, as soon as the rays left the rear element, they run straight to sensor. A perfect TC is a magnifier.

Considering multiple colors, I can imagine a difference with respect to CA depending on how far the TC is away from the rear lens.

The only other option I see is making an imperfect TC correcting known aberrations from a particular lens. Such a 0.6x TC exist for mirror scopes, e.g. from Celestron. But then, the TC should fit a single lens only. I really doubt that the Sigma TC are of this kind.

The Sigma TC aren't universal because they don't work with protuding rear lens elements. It is about mechanical incompatibility, not about optical optimization.
Not often I disagree with you, but here I will. Now I do not know about any of the technical stuff but this I do know.

I will use two of my lenses as examples.
Both my Sigma 100-300 F/4.0 and my Sigma 500F/4.5 work perfectly with the dedicated 1.4 sigma TC with its protruding element. But above and beyond the auto focus speed, the image quality is far superior to the very good Tamron 1.4 TC. It is like night and day, yet the Tamron TC on all my non Sigma lenses lenses works great...Now looking at the Sigma TC and the way it fits into the lenses, it really appears to become one with the lens. This is not so with the Tamron design. This is not a dig on the Tamron TC as I love mine, but I am simply stating a fact as to what I have seen work for me.

So again, your the tech guy and know far more than I do, but I only know what I see.
09-07-2009, 02:18 PM   #539
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QuoteOriginally posted by falconeye Quote
Ben, you may be right and so I only said I doubt it.

But the more I think about it the more I start to believe that the "optimized Sigma TC" just is another marketing legend. "Optimized" means that they ignored protuding rear lens elements which most Sigma lenses don't have.

It is like calling slow software "optimized for fast processors"

Sigma lists 35 "dedicated lenses", ranging (using the zoom long ends) from 150mm to 1000mm, both zooms and primes, incl. a 150mm/2.8 Macro. Up to f/2.8 and 142mm (800mm/5.6) apertures.

I am almost certain that the Sigma TC have no optical "dedication" whatsoever for any lens.
Sigma follows the same route to optimize tc performance by sacrificing the convenience - exactly as Pentax did with their L-series tcs. There is no better tc known to me (on Pentax mount), then the 1.4x-L, with its very protruding front element. Obviously it can also only be used with a small number of lenses.

There is no reason, to believe this is just a coincidence or the tc designers were too lazy or too stupid, to design a more compact tc...

You should not forget, that basically any modern tele photo lens contains a built-in tc at the rear - otherwise they would still be as big as the old Pentax 500/4.5, i.e. basically as long as focal length dictates. And the design with the protruding lens elements is a derivate of these integrated tc elements. By lengthening the distance between the front and the rear element of the tc, you reduce abberrations, mainly spherical abberration and gain a flatter field. On the other hand, this makes a more complicated design necessary, to keep the flange distance, e.g. there is some integrated relay lens. Such a construction can only work perfectly with a small sample of lenses (it would be best to compute such a construction just for exactly one lens, but there is always a tolerance, which may be acceptable to lens designers).

By the way: most Sigma lenses have a rear element, which prevents the useage of their own tcs. So the engineers decided to limit the number of potential customers! With good results as Javier rightly pointed out.

The Tamron tc on the other hand is a universal type - a very good one - but the "dedicated" Sigma tcs are even better, though only with a handful of lenses...

Ben
09-07-2009, 07:00 PM   #540
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QuoteOriginally posted by jgredline Quote
Not often I disagree with you, but here I will.
[...]
the image quality is far superior to the very good Tamron 1.4 TC.
QuoteOriginally posted by Ben_Edict Quote
There is no better tc known to me (on Pentax mount), then the 1.4x-L, with its very protruding front element. Obviously it can also only be used with a small number of lenses.
Ok, I am impressed by Javier's and Ben's feedback.

I will now assume that I am wrong.

Can it be explained? Say, the Pentax or Sigma TCs are better because with the protuding lens element, it is possible to build a "more perfect" TC. This, I can believe easily. Also, I can find that the Sigma 1.4x TC has 5/3 elements/groups rather than 4/4.

But this discussion started out from Javier's remark when comparing Sigma and Tamron TC mounted on Tamron 70-200. Obviously, the Sigma fits the Tamron lens. So, it should still be better than the Tamron TC because it sits closer to the lens rear element and may simply be the better TC optically.

If this is not the case, then Ben must be correct that most compatible Sigma lenses have a universal rear element which the Sigma TC compensates aberrations for. A fascinating possibility.
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