[jpzk]

Just thought about it ...

I received my Pentax HD 1.4X TC recently and I admit this is the best TC I have in my gear, especially paired with my DA*300/4 on the K5.

Now I wonder if it is worth keeping the following:

1. Pentax-F AF 1.7X
2. Tamron 1.4X Pz-AF MC4

Can these be used in a "stacking" set up, along with the newer HD 1.4X TC ?

Thanks!

JP

[Adam]

Well the Pentax F adapter is nice to have in case you want to get AF support with some of your manual lenses, but I doubt you'd use it much otherwise. It's still worth a lot if you want to cash it in!

[PJ1]

You can stack teleconverters. But, as with many other things, just because you can doesn't mean you should
Do the maths - if you stacked two 1.4s and a 1.7 you would lose at least 4.5 stops and you would have to expect some pretty severe image degradation.

[Mistlefoot]

You can stack teleconverters. But, as with many other things, just because you can doesn't mean you should
Do the maths - if you stacked two 1.4s and a 1.7 you would lose at least 4.5 stops and you would have to expect some pretty severe image degradation.

by my math that would turn a 300mm into a 1500mm. Might be fun for being silly with......Say Saturn or such....but I'd expect the quality to be lacking for sure.....

(300 x 1.4 x 1.4 x 1.7 x 1.5 (crop factor))

[calculator01]

by my math that would turn a 300mm into a 1500mm. Might be fun for being silly with......Say Saturn or such....but I'd expect the quality to be lacking for sure.....

(300 x 1.4 x 1.4 x 1.7 x 1.5 (crop factor))

Add the Q in their as well

[snostorm]

Hi JP,

I'll add my 2¢.

I'd keep both the Tamron 1.4x and the 1.7x AFA. They are both quality items, useful for different purposes, and could become more useful if when considering other lens options in the future. With the DA* 300/4, your the P HD AW 1.4x is almost the only game in town because of the SDM, other than the 1.7x AFA, to get reliable AF. All of the other fast ultra and super tele options for Pentax are screw drive or MF, so either of these can be used effectively.

Both of these originally sold for about $79 USD market price new. As you probably know, they don't anymore. . .and they would most likely be even more expensive to repurchase in the future if you found a need for them.

To stack TCs practically, you really need a faster lens. In my experience, Pentax bodies really need a max aperture of faster than f8 to AF reliably in reasonable light. The newer bodies are better, but f8 is still a realistic limit, for practical use. All of the options for faster or longer ultra/super tele AF lenses are screw drive with the exception of the DA 560, and it's f5.6, so with a 1.4x, it will become f8, and will most likely need very good light to AF effectively. With all of the other long lenses, either or both of your old TCs will give you some options.

The only lenses which might give you some advantage with the Pentax TC are the FA* 600/4 and the FA* 300/2.8, and the main advantage you'd get would be an automatic set of FL for SR, which, to be frank, is not much of anything because you'd likely be shooting these on a tripod, where SR is of questionable help. It would, of course, give you auto corrections for Av, but that's really minor, unless you want to shoot with a P-TTL flash, and you'd actually be better off saving the power for the main flash and use a flash manually anyway. A 300 f2.8 will allow you to stack TCs with very good results, but even with two Pentax TCs, you'd only get the advantages of one since only one will convert FL and Av, so the Tamron would do as well when stacked on a Pentax chipped lens at a much more attractive price.

Take a look at brandrx's recent thread on DPR to see what two stacked 1.4x TCs can accomplish on a Sigma 300/2.8. Be sure to look at the robin shot at full res as the downsized version does it no justice. The naysayers are only guessing when they talk about optical degradation caused by TCs because few have ever really tried it with premium ultra tele lenses. I'm speaking here from the standpoint of an advanced amateur, not a perfectionist, and I really doubt that very many photographers can really consistently shoot up to the potential of a Sigma or Pentax 300/2.8 + stacked quality TCs, whether it be two 1.4xs or a 1.7x AFA + a quality 1.4x.

When I went with a 300/2.8, I found that I missed the quick response and handling of my FA* 300/4.5 with or without TCs. I started carrying two bodies, one with the 300/2.8 and TCs, and one with the 300/4.5 with or without TCs. I mounted the big lens on a tripod and had the f4.5 on a strap ready for those quick shots that required a faster response. As the light waned later in the afternoon, I dropped the TCs and used the max apertures available to me to keep shooting. With two 1.4x TCs (a Tamron like yours and a Sigma EX 1.4x APO) and two AFAs, I had available to me 300/2.8, 300/4.5, 420 f4, 420 f6.3, 510 f4.8, 510 f7.7, 588 f5.6, and 714 f6.7. The FA* 300/4.5 would actually AF in very good light with stacked 1.4xs, so I also had 588 f8.8, and the Sigma or FA* 300/2.8s will also AF with two stacked 1.4xs + the AFA for 1000mm f9.8, in very good light. Stacked AFAs would also work on the 300/2.8s to give 867mm f8.1, but the AFA closest to the lens must be focused at infinity before mounting onto the other, and IQ became questionable with any of these combos, either because of degradation or my lack of technique shooting at these FLs (or limitations of my support gear), so I really never used them. except to see if they might work.

Bottom line, I'd keep my options open by keeping these, but it's your choice.

Scott

[clackers]

Very handy info, Scott!

[jpzk]

Well the Pentax F adapter is nice to have in case you want to get AF support with some of your manual lenses, but I doubt you'd use it much otherwise. It's still worth a lot if you want to cash it in!

Late responding ....
I forgot that I still have a couple of good manual lenses which could possibly be used with the Pentax F 1.7X adapter.

let's see ....
My Zeiss 85/1.4: 145mm with that TC (f-stop ?)
My Vivitar 135/2.8 Close focus : 230mm (f-stop ?)
but then , wnat would one use these focal lengths for?

JP

---------- Post added 08-06-14 at 02:13 PM ----------

You can stack teleconverters. But, as with many other things, just because you can doesn't mean you should
Do the maths - if you stacked two 1.4s and a 1.7 you would lose at least 4.5 stops and you would have to expect some pretty severe image degradation.

Thanks for the reply!
Yes,I can see the problem with any stacking and loosing a lot of "light" and quality in the process.
Not really a great idea.

JP

---------- Post added 08-06-14 at 02:14 PM ----------

by my math that would turn a 300mm into a 1500mm. Might be fun for being silly with......Say Saturn or such....but I'd expect the quality to be lacking for sure.....

(300 x 1.4 x 1.4 x 1.7 x 1.5 (crop factor))

As I mentioned in the previous post: not a good idea unless it is just for fun, as you say.

---------- Post added 08-06-14 at 02:15 PM ----------

Add the Q in their as well

I sold my Q a while back ....

---------- Post added 08-06-14 at 02:28 PM ----------

Hi JP,

I'll add my 2¢.

I'd keep both the Tamron 1.4x and the 1.7x AFA. They are both quality items, useful for different purposes, and could become more useful if when considering other lens options in the future. With the DA* 300/4, your the P HD AW 1.4x is almost the only game in town because of the SD M, other than the 1.7x AFA, to get reliable AF. All of the other fast ultra and super tele options for Pentax are screw drive or MF, so either of these can be used effectively.

Both of these originally sold for about $79 USD market price new. As you probably know, they don't anymore. . .and they would most likely be even more expensive to repurchase in the future if you found a need for them.
I thought of keeping them, just in case and then I am not at all sure on what lens I would couple any of those TC's. I have a Zeiss 85/1.4 ZK and a Vivitar 135/2.8 Close focus but that is it for manual lenses.
The HD 14.x works great with the DA*300/4.
To stack TCs practically, you really need a faster lens. In my experience, Pentax bodies really need a max aperture of faster than f8 to AF reliably in reasonable light. The newer bodies are better, but f8 is still a realistic limit, for practical use. All of the options for faster or longer ultra/super tele AF lenses are screw drive with the exception of the DA 560, and it's f5.6, so with a 1.4x, it will become f8, and will most likely need very good light to AF effectively. With all of the other long lenses, either or both of your old TCs will give you some options.

The only lenses which might give you some advantage with the Pentax TC are the FA* 600/4 and the FA* 300/2.8, and the main advantage you'd get would be an automatic set of FL for SR, which, to be frank, is not much of anything because you'd likely be shooting these on a tripod, where SR is of questionable help. It would, of course, give you auto corrections for Av, but that's really minor, unless you want to shoot with a P-TTL flash, and you'd actually be better off saving the power for the main flash and use a flash manually anyway. A 300 f2.8 will allow you to stack TCs with very good results, but even with two Pentax TCs, you'd only get the advantages of one since only one will convert FL and Av, so the Tamron would do as well when stacked on a Pentax chipped lens at a much more attractive price.
I don't have the funds any of those very expensive lenses but I understand what you say.
Take a look at brandrx's recent thread on DPR to see what two stacked 1.4x TCs can accomplish on a Sigma 300/2.8. Be sure to look at the robin shot at full res as the downsized version does it no justice. The naysayers are only guessing when they talk about optical degradation caused by TCs because few have ever really tried it with premium ultra tele lenses. I'm speaking here from the standpoint of an advanced amateur, not a perfectionist, and I really doubt that very many photographers can really consistently shoot up to the potential of a Sigma or Pentax 300/2.8 + stacked quality TCs, whether it be two 1.4xs or a 1.7x AFA + a quality 1.4x.

When I went with a 300/2.8, I found that I missed the quick response and handling of my FA* 300/4.5 with or without TCs. I started carrying two bodies, one with the 300/2.8 and TCs, and one with the 300/4.5 with or without TCs. I mounted the big lens on a tripod and had the f4.5 on a strap ready for those quick shots that required a faster response. As the light waned later in the afternoon, I dropped the TCs and used the max apertures available to me to keep shooting. With two 1.4x TCs (a Tamron like yours and a Sigma EX 1.4x APO) and two AFAs, I had available to me 300/2.8, 300/4.5, 420 f4, 420 f6.3, 510 f4.8, 510 f7.7, 588 f5.6, and 714 f6.7. The FA* 300/4.5 would actually AF in very good light with stacked 1.4xs, so I also had 588 f8.8, and the Sigma or FA* 300/2.8s will also AF with two stacked 1.4xs + the AFA for 1000mm f9.8, in very good light. Stacked AFAs would also work on the 300/2.8s to give 867mm f8.1, but the AFA closest to the lens must be focused at infinity before mounting onto the other, and IQ became questionable with any of these combos, either because of degradation or my lack of technique shooting at these FLs (or limitations of my support gear), so I really never used them. except to see if they might work.

Bottom line, I'd keep my options open by keeping these, but it's your choice.
For the moment, that's what I'll do and see what happens in the future. If I can't find some use for those TC's, might as well sell them later.
Scott

Thanks!

[Lowell Goudge]

Just thought about it ...

I received my Pentax HD 1.4X TC recently and I admit this is the best TC I have in my gear, especially paired with my DA*300/4 on the K5.

Now I wonder if it is worth keeping the following:

1. Pentax-F AF 1.7X
2. Tamron 1.4X Pz-AF MC4

Can these be used in a "stacking" set up, along with the newer HD 1.4X TC ?

Thanks!

JP

You can give the others to me, I can always find a use for a second 1.7x AF converter

Seriously I think you were given the best option -Keep them they all have their uses

[jpzk]

You can give the others to me, I can always find a use for a second 1.7x AF converter

Seriously I think you were given the best option -Keep them they all have their uses

Late responding here ...

I have taken the decision to keep them for a while although I have not touched one of them since I got the HD 1.4X.
I'll see what goes and decide if/when to unload them from my stack of unused gear.

[CarlG]

... I have not touched one of them since I got the HD 1.4X.

You could always remove the glass element from the Tamron and use it as a macro tube.

[jpzk]

You could always remove the glass element from the Tamron and use it as a macro tube.

I don't do macro photography, so best for me would be to sell it rather than breaking it !

JP

[CarlG]

You don't have to break it. In most converters the glass element is fixed with a nut or similar contraption, easily removed and stored for future use. However, if you're not going to use it anyway it obviously isn't worth the bother!

[jpzk]

Another late reply here ... thanks for the responses !

I have decided that I will sell the Pentax-F AF 1.7X and the Tamron 1.4X Pz-AF MC4.
I will likely show up in the MarketPlace once I decide on pricing.

I am not very keen on stacking them ... the new Pentax HD 1.4X seems to do the job OK but that too might become a sale.

Cheers!

[wombat2go]

Anyway, don't toss them out !
In my camera building/modification hobby I found that machining bayonet mounts is too difficult, without the original specs, so I scavenge them off dead bodies and dead lenses . I have even purchased off brand t/c-s just to get the shiny bayonet mounts off each end.