[John Kovarik]

The Thread that will never die! Over a year and a half now! Weighing on the Sigma/Tamron TC matter, in general my subjective view is that the Tamron gives superior results on my K20 when used with the DA* 200 or 300 in comparison with the Sigma TC and EX 100-300. I realize that the prime v. zoom comparison is somewhat unfair but I have ceased using the Sigma combo because of the difference

Regards to all...............JK

[jgredline]

The Thread that will never die! ...............JK

LOL, I was thinking the same thing. But still, one thing that is certain to me...It is tough to beat that Tamron 1.4 MC-4 TC!

[danielchtong]

The Thread that will never die! Over a year and a half now! Weighing on the Sigma/Tamron TC matter, in general my subjective view is that the Tamron gives superior results on my K20 when used with the DA* 200 or 300 in comparison with the Sigma TC and EX 100-300......JK

Of course. More info' comes to light
Sigma & Tamron 70-200mm were not even available a year ago. And it will take time for people to gather and compile info'
It is ever changing

Daniel

[danielchtong]

The Thread that will never die! Over a year and a half now! Weighing on the Sigma/Tamron TC matter, in general my subjective view is that the Tamron gives superior results on my K20 when used with the DA* 200 or 300 in comparison with the Sigma TC and EX 100-300......JK

TC works better with prime is logical as it has less elements and less refraction and less movement of elements

Daniel

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Last edited by danielchtong; 09-12-2009 at 04:01 PM.

[John Kovarik]

Yes. but I have no PTX zoom ( DA* 50-135 or 60-250 ) yet. Maybe this is the time to get one...........Ha!

[ScooterMaxi Jim]

After some extensive testing using resizing, and including comparison shots using the Tamron 1.4x SP, I have found the Kenko Pz-AF Teleplus SHQ to be a 1.4x. The SP magnification matched, but that TC has more glass width and clearly is for use with larger glass (designed for F2.8 and no less than 90mm as stated on the Tamron website).

Although I do not own the MC4 version, it is very clear from the photos posted here and elsewhere that the physical packaging of the Kenko SHQ is exactly the same as the Tamron MC4. This is not to say they are the same converter; the coatings might differ, and less likely the glass design might be different.

The Kenko claim of one stop at 1.5x, of course, was physically impossible - the maximum theoretically possible with no light loss is 1.414; obviously adding glass slightly reduces light flow.

I think it is a shame that folks have compared the Tamron MC4 to the non-SHQ Kenko - clearly not apples-to-apples. It would be nice if someone could compare the MC4 to the SHQ directly, as the differences appear to be small, if any.

[Class A]

The Kenko claim of one stop at 1.5x, of course, was physically impossible - the maximum theoretically possible with no light loss is 1.414; obviously adding glass slightly reduces light flow.

Your "1.414" is a factor, which corresponds to one stop. I don't see where the invalidity of the Kenko claim is.

[jgredline]

After some extensive testing using resizing, and including comparison shots using the Tamron 1.4x SP, I have found the Kenko Pz-AF Teleplus SHQ to be a 1.4x. The SP magnification matched, but that TC has more glass width and clearly is for use with larger glass (designed for F2.8 and no less than 90mm as stated on the Tamron website).

Although I do not own the MC4 version, it is very clear from the photos posted here and elsewhere that the physical packaging of the Kenko SHQ is exactly the same as the Tamron MC4. This is not to say they are the same converter; the coatings might differ, and less likely the glass design might be different.

The Kenko claim of one stop at 1.5x, of course, was physically impossible - the maximum theoretically possible with no light loss is 1.414; obviously adding glass slightly reduces light flow.

I think it is a shame that folks have compared the Tamron MC4 to the non-SHQ Kenko - clearly not apples-to-apples. It would be nice if someone could compare the MC4 to the SHQ directly, as the differences appear to be small, if any.

You should contact Kenko and tell them they are falsely advertising their product.

[ScooterMaxi Jim]

Your "1.414" is a factor, which corresponds to one stop. I don't see where the invalidity of the Kenko claim is.

Hi Class A,

Sorry I was so cryptic - the readers of this thread are so into the TC vagaries that I made assumptions and failed to fully explain. Here is what Kenko claims THK Photo Products, Inc.:

An Example:
The Tokina AT-X 100 PRO D 100mm f/2.8 macro lens will focus as close as 11 inches. At that distance the lens has a life-sized reproduction ratio of 1:1. This means that if the subject is only half an inch long it will be half an inch long on the film or CCD. The K1.5x SHQ DG converts the lens into an equivalent 150mm lens with a reasonably bright equivalent f/4 aperture with the same 11 inch minimum focusing distance.

Further down:
If using manual lighting or metering it is import (sic) to remember than the K1.5 has an exposure factor equivalent to a 1 stop light loss.

Also noteworthy is the claim in the text that this is a "5-element design," but the specifications clearly indicate the construction is 4 elements in 4 groups.

Obviously, the emphasis has been on the IQ of the product, not its proper marketing.

One more thought: The fact that the Tamron MC4 no longer provides this TC in Pentax mount, and Hoya/Tokina/Kenko has shifted the Pentax mount entirely to the Pentax brand hints further at the commonality of the MC4 and SHQ.

By the way, there's a betting line in Las Vegas on how long this thread can keep going, but don't place a bet as you'll never see a pay out. Of course, I'm the one who restarted it.

[Samsungian]

New life for a great info filled thread.

Thank You!

LOL, I was thinking the same thing. But still, one thing that is certain to me...It is tough to beat that Tamron 1.4 MC-4 TC!

[Miserere]

Kenko has announced new TCs for Canikon. They're the same optically, but now communicate the effective focal length and aperture of the lens+TC combination to the camera. A version with SDM contacts for Pentax would be very nice as SR would work with the correct focal length.

Does Kenko not realise how many they would sell in Pentax mount? I'm willing to bet the numbers would be similar to Canon or Nikon despite there being fewer Pentax shooters. That's how starved for TCs we are

.

[Ben_Edict]

Kenko has announced new TCs for Canikon. They're the same optically, but now communicate the effective focal length and aperture of the lens+TC combination to the camera. A version with SDM contacts for Pentax would be very nice as SR would work with the correct focal length.

Does Kenko not realise how many they would sell in Pentax mount? I'm willing to bet the numbers would be similar to Canon or Nikon despite there being fewer Pentax shooters. That's how starved for TCs we are

.

The problem with Kenko is: it's Hoya. And just like Tokina (another Hoya daughter) seems to be denied access to the Pentax market, I guess Kenko is also out of the game.

Ben

[wallyb]

The problem with Kenko is: it's Hoya. And just like Tokina (another Hoya daughter) seems to be denied access to the Pentax market, I guess Kenko is also out of the game.

Ben

Maybe I'm missing some kind of business-world ethical agreement, but why would Hoya's subsidiaries ever be unwanted in Pentax, another company they own?

[audiobomber]

The problem with Kenko is: it's Hoya. And just like Tokina (another Hoya daughter) seems to be denied access to the Pentax market, I guess Kenko is also out of the game.

Ben

The other explanation I've heard is much more plausible. Tokina doesn't make lenses for camera brands with less than a 5% market share (I believe this was an official Tokina statement).

If I were making a photography product, I'd be making marketing decisions based on the available market, i.e. Canikon first, others later if warranted. It doesn't matter whether Kenko is a Hoya company, they still need to make a profit.

[Ben_Edict]

Maybe I'm missing some kind of business-world ethical agreement, but why would Hoya's subsidiaries ever be unwanted in Pentax, another company they own?

We don't know, asking ourselves exactly the same question. But it is obvious, that Tokina does not offer their new lenses in Pentax mount and Kenko has never ever produced their Pro series of AF tcs in Pentax mount, too. I find that stupid and annoying, but that doesn't change anything, I fear.

Ben