P/KA: Tokina Doubler/ 2X-converter RMC

Hi,

Anyone ever heard of or used one of these? I might be able to get my hands on one fairly cheap and just wondered if it's worth the hassle. By that, I mean, I want to get a converter but won't bother with this one if I'll just have to end up getting another one because this one is poor...If you know what I mean!

Thanks

La Poder

2X teleconverters generally don't give very good results. Stick with 1.4x. And TCs give their best results with prime lenses.

BTW, Kenko made the TCs for Tokina and Tamron, as well as it's own. I have the 7-element Tamron TC, which is probably the same as the one you are looking at. It is terrible.

Joe

Why are they terrible?

I have this one, not too bad, definitely worth it if its cheap. Just use it wisely, on tele lenses with not very fast apertures the results will disapoint.

Terrible is a harsh word. On a lens with outstanding resolution, a well made 2x TC can give usable results. I usually keep a Sigma 2x EX TC around for the odd moment when an F2.8 lens and 1.4x TC is not enough. Using one on a lens that is slower than F2.8 can be a waste of time as often the AF is very hit or miss.
Kent Gittings

KentG said:

Terrible is a harsh word. On a lens with outstanding resolution, a well made 2x TC can give usable results. I usually keep a Sigma 2x EX TC around for the odd moment when an F2.8 lens and 1.4x TC is not enough. Using one on a lens that is slower than F2.8 can be a waste of time as often the AF is very hit or miss.
Kent Gittings

Click to expand...

Ditto the Sigma matched converters produce very good results with the correct lenses.

The sigma converters have a protruding font element so can only be used with some Lenses.

If you fit it to a lens that isn't compatible you'll crash the rear element of the lens into the converters front element likely destroying both.

I also use a Tamron SP 7 element converter with my non Sigma glass this also produces exceptable results with decent glass.

MF isn't an issue as its a MF converter

Using poor converters on cheap lenses gives awful results.
poor converters on good lenses gives awful results
good converters on cheap lenses gives awful results
good converters on good glass gives good results.

If you don't see the words MC7 or similar give it a miss.

4 element 2X converters are uniformly poor they will generally have MC4 on them.

Given the size of the Tokina Doubler/ 2X-converter RMC it would appear to be a 7 element variant.

My only real concern would be if Tokina had developed it themselves as their coatings were slightly inferior to everybody elses.

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La Poder said:

Why are they terrible?

Click to expand...

Well, I should clarify that the TC is not terrible, but the images made with it were. They were soft with color shifts.

If you want a 2X TC, I would look for the best--the Pentax A ones, discontinued long ago.

Joe

Joseph Tainter said:

La Poder said:

Why are they terrible?

Click to expand...

Well, I should clarify that the TC is not terrible, but the images made with it were. They were soft with color shifts.

If you want a 2X TC, I would look for the best--the Pentax A ones, discontinued long ago.

Click to expand...

I'm pretty sure that those are no longer "the best". The new Tamron and Sigma offerings are coated for digital and continue to allow HSM autofocus. The A series are good but I'd call brand snobbery on this one.

Joseph Tainter said:

Joe

Click to expand...

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chrswggl said:

Joseph Tainter said:

La Poder said:

Why are they terrible?

Click to expand...

Well, I should clarify that the TC is not terrible, but the images made with it were. They were soft with color shifts.

If you want a 2X TC, I would look for the best--the Pentax A ones, discontinued long ago.

Click to expand...

I'm pretty sure that those are no longer "the best". The new Tamron and Sigma offerings are coated for digital and continue to allow HSM autofocus. The A series are good but I'd call brand snobbery on this one.

Click to expand...

The new Kenko Pro 300 series are supposed to be very good, but they are not available for Pentax.

I have the older Sigma 1.4x. I believe the optics are the same as the current version, but it does not have the new coatings. I have tried it with my F* 600 F4 and found it to give acceptably sharp results. However, it also gave less contrast. Still, that's fixable in post-processing.

Joe

Joseph Tainter said:

chrswggl said:

Joseph Tainter said:

La Poder said:

Why are they terrible?

Click to expand...

Well, I should clarify that the TC is not terrible, but the images made with it were. They were soft with color shifts.

If you want a 2X TC, I would look for the best--the Pentax A ones, discontinued long ago.

Click to expand...

I'm pretty sure that those are no longer "the best". The new Tamron and Sigma offerings are coated for digital and continue to allow HSM autofocus. The A series are good but I'd call brand snobbery on this one.

Click to expand...

The new Kenko Pro 300 series are supposed to be very good, but they are not available for Pentax.

I have the older Sigma 1.4x. I believe the optics are the same as the current version, but it does not have the new coatings. I have tried it with my F* 600 F4 and found it to give acceptably sharp results. However, it also gave less contrast. Still, that's fixable in post-processing.

Click to expand...

The Sigma converters are matched converter, Matched to a small number of Sigma lenses.

Their design is such that they fit up inside the rear lens hole to optically couple correctly with a select few Sigma lenses.

There use with none Sigma lenses is neither recommended or advised.

They are not general purpose converters.

Joseph Tainter said:

Joe

Click to expand...

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This is most likely an older TC, as RMC is an older classification and Hoya has marketed under the Kenko name for several years.

The point made that 1.4x is the better way to go is valid - even if only 4-element. However, I have a very old 7-element P-mount Tokina 2x (manual focus) that can do very nicely in a pinch with quality lens glass.

The comment about Tokina coatings simply is incorrect. Even 25 years ago when I sold a wide variety lenses from the major players - Tokina multi-coats were far better than at least two of the major manufacturers. Not up to SMC standards, but good. And very little has changed in the world of coatings since then. Tokina did indeed put out its share of overly complex extended range zooms before the days of computer design. These lenses would have ghosted and flared no matter how good the coating.

As for "coatings designed for digital," some folks simply fall in love with empty marketing language. The coatings on a 25-year-old Pentax 35-105 would perform at least as well as these supposed special digital coatings.

http://cdn-3-service.phanfare.com/images/5081489_4280707_78368165_WebSmall_2/Image-5081489-78368165-2-WebSmall_0_c485d18ce5e2c26624fc173b7a787173_1

--JNR

Well Kenko is one of their component companies I think so they are in fact Tokina I presume. The Kenko Pro models are supposed to be good but they have never released them in Pentax I don't think.
Kent Gittings

Yes however they are designed actually for telephotos with recessed rear elements. This not only includes the Sigma 70-200/2.8, 300/2.8, 500/4.5, 800/5.6 and 1000/8 (only the first 3 will do AF) but also the long telephotos of the camera makers like the Pentax 300/2.8, 400/2.8, 600/4, 600/5.6. The Pentax -L TCs are similar to the Sigma as they also have protruding front elements designed to get in close to the rear glass of the tele. The Tamron AD-2 200F 2x
TC is of that design type also.
Kent Gittings

Correct.

The early manual Tokina TCs we are discussing are necessarily generic and should work with any lens. Of course, they won't perform quite as well as the matched protuding versions, but they can be quite good if you have good glass in front. Be prepared to focus manually no matter the TC. As such, any TC is at its best in non-action situations. Even a 1.4x with a longer f/2.8 is best used with a tripod.

Given a great prime mated with a decent TC, I have found that combination to easily outpace a consumer zoom (the typicall f5.6 300mm or 400mm).

So it is frustrating to find so little available in the Pentax mount.

JNR said:

This is most likely an older TC, as RMC is an older classification and Hoya has marketed under the Kenko name for several years.

The point made that 1.4x is the better way to go is valid - even if only 4-element. However, I have a very old 7-element P-mount Tokina 2x (manual focus) that can do very nicely in a pinch with quality lens glass.

The comment about Tokina coatings simply is incorrect.

Click to expand...

http://www.fredmiranda.com/forum/topic/734754

One of many complaints on Tokinas coating flare control, Which in my own experience is inferior to everybody else's.

JNR said:

Even 25 years ago when I sold a wide variety lenses from the major players - Tokina multi-coats were far better than at least two of the major manufacturers.

Click to expand...

Who

JNR said:

Not up to SMC standards,

Click to expand...

Do you actually know who developed SMC and why and what it means today.?

JNR said:

but good. And very little has changed in the world of coatings since then.

Click to expand...

You are kidding me Super protect coatings harder than diamond , Ghost less interior coatings.
Modern coating transfer light over a 100 times better than 25 Year old coatings.

JNR said:

Tokina did indeed put out its share of overly complex extended range zooms before the days of computer design. These lenses would have ghosted and flared no matter how good the coating.

As for "coatings designed for digital," some folks simply fall in love with empty marketing language. The coatings on a 25-year-old Pentax 35-105 would perform at least as well as these supposed special digital coatings.

http://cdn-3-service.phanfare.com/images/5081489_4280707_78368165_WebSmall_2/Image-5081489-78368165-2-WebSmall_0_c485d18ce5e2c26624fc173b7a787173_1

--JNR

Click to expand...

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