Kenko releases converters for Canon & Nikon

[ppaaoolloo]

KENKO TelePlus PRO 300 AF 2.0X DGX Teleconverter



KENKO TelePlus MC4 AF 1.4X DGX Teleconverter



KENKO TelePlus MC7 AF 2.0X DGX Teleconverter

Anyone care to translate the technobabble? I am wondering why there are two 2x TCs.

[gabriel buluran]

thanks for this pao.

I have a question for TCs: What does "Full AF operation with the TelePlus MC4 AF 1.4X is possible using camera lenses with open apertures of F4 or brighter." mean?

If I am using a Bigma which is 4-6.3, does that mean it would only work fully if the lens is open wide at 50mm? Or does it mean that given it's an f4-f6.3, the TC will fully function even if my focal length is 500 and the aperture is 6.3?

thanks in advance?

[Bobby Kintanar]

Jan 25, 2010 23:59:45 GMT gabriel buluran said:

thanks for this pao.

I have a question for TCs: What does "Full AF operation with the TelePlus MC4 AF 1.4X is possible using camera lenses with open apertures of F4 or brighter." mean?

If I am using a Bigma which is 4-6.3, does that mean it would only work fully if the lens is open wide at 50mm? Or does it mean that given it's an f4-f6.3, the TC will fully function even if my focal length is 500 and the aperture is 6.3?

thanks in advance?

It simply means that if your lens' widest aperture is f/4.0 it will allow AF to function. In the case of the Bigma, it will AF at f/4.0 alright, but only until around 300 mm (not sure), but beyond that (from 300-500mm), as the aperture goes down to f/6.3, you will lose AF.

If you have, say the 500mm f/4.0, the TC will allow full AF functions, however, if you have the 400mm f/5.6, AF will not function properly - unless you have a 1D-Series Body. The 1D's will AF with lenses that have up to f/8.0 apertures.

There is a method to trick a lower-model camera into thinking that you don't have a TC attached to your f/5.6 lens though - and allow AF to function quite well in most circumstances. Try this:

photo.net/canon-eos-digital-camera-forum/0078YS

It will work on the Kenko 1.4 X Model. :-)

[Tonji Ramos]

I wonder if these guys will be better than the OEM stuff, Nikon and Canon.

If they made a 1.7x tc that could autofocus with an f4 that would have been sweet.

[Bobby Kintanar]

Jan 26, 2010 1:44:03 GMT Tonji Ramos said:

I wonder if these guys will be better than the OEM stuff, Nikon and Canon.

If they made a 1.7x tc that could autofocus with an f4 that would have been sweet.

The limitation for AF function is not in the teleconverter, but in the camera body. The EOS 1D Series will AF even with a lens rated at f/8.0, however, the rest, even the latest 7D, are designed to AF only at a maximum of f/5.6. :-)

[Mark Itol]

Jan 26, 2010 2:58:02 GMT Bobby Kintanar said:

The limitation for AF function is not in the teleconverter, but in the camera body. The EOS 1D Series will AF even with a lens rated at f/8.0, however, the rest, even the latest 7D, are designed to AF only at a maximum of f/5.6. :-)

This actually makes me wonder, why Canon cannot (or doesn't) make their lower-end bodies AF at f/8 in the same way Nikon does with their lower-end bodies (no taping of contact points). Perhaps Canon folks adhere to the mantra of "super fast AF or no AF at all?" ;D

[gabriel buluran]

I see. Thanks Bobby!

[Edu Lorenzo Jr]

hmmm.. nice post pao and an even nicer discussion. Am also considering a 2x TC for videos and my lens, having an aperture ring that can effectively give me an 800 4.5 should be nice. I hope I can AF with any of these.

[Bobby Kintanar]

Well, with modern cameras, such as the Canon 450D, 50D, 7D, and 5DM2 - all with Live View - you can use even an f/16 lens to AF! In Live View, switch the AF Mode to Live View Mode (not Quick Mode) in the appropriate menu, and you'll have AF functions, though at a much slower rate and perhaps a bit less accuracy, depending on the light levels.

This is because in normal AF Mode the system uses a method called "phase-difference AF " which allows for faster AF, but is limited to f/5.6 on most models. Phase-detection AF uses separate AF sensors in the camera to detect correct point of focus. In "Live View AF Mode", the system switches to "contrast-detection" wherein the contrast between pixels in the image sensor itself is used to determine the point-of-focus, hence, there is practically no aperture limit with this type of AF sensing, but due to the complexities involved, it will work slower than the conventional phase-detection AF system, at least in today's models.

[Renoir Abrea]

hi' theirs a Kenko Teleplus PRO 300 1.4x. how is this TC compared with the Kenko Teleplus MCR AF 1.4x?

[Retzel Orquiza]

Jan 26, 2010 1:44:03 GMT Tonji Ramos said:

If they made a 1.7x tc that could autofocus with an f4 that would have been sweet.

kenko made one before. i own one which i pair with my 70-200 f/4 IS

[Toto Gamboa]

Jan 26, 2010 23:09:46 GMT Bobby Kintanar said:

In "Live View AF Mode", the system switches to "contrast-detection" wherein the contrast between pixels in the image sensor itself is used to determine the point-of-focus, hence, there is practically no aperture limit with this type of AF sensing, but due to the complexities involved, it will work slower than the conventional phase-detection AF system, at least in today's models.

Been using this AF type a lot everytime i use my 2X on a 400mm f5.6 and so far I am happy with the results. The most challenging was with the very tiny IBKF in dimly lit streams of Villa Escudero.


Indigo Banded Kingfisher
Canon 50D, EF 400mm f5.6L, Manfrotto 755XB/Gimbal, Kenko Pro DG 2x TC, 1x2 pounds "rice" bag
Shot @ 800mm, f11, 1/15", ISO1250, 70% pixels wasted, Liveview, Remote Shutter

Of course it helps when the subject remains motionless for at least 10 seconds like the IBKFs of VE. ;D

[ppaaoolloo]

Contrast-based AF doesn't work well with the moon regardless of body.