Kenko converter 2x

Hello.
I know if someone says this convertor Kenko TELEPLUS 2x, the lens can be used for DA * in digital Pentax k-5 and 50-135mm f2, 8?
Or be of better sigma convertor?

Regards

Not quite sure what you mean but

this page explains quite a lot. Therefore, you must ensure that the converter has the "pz" (for "power zoom") marking on it if it is a Kenko.

I don't think the Sigma converters will be of any use as you physically cannot attach them to many lenses other than those shown on the Sigma list which is linked in the early part of the above thread - because the front elements of the Sigma converters project a long way forward (see the images here). That page also reviews many other teleconverters, and so it whould be useful to read all the reviews there.

John

hello
sorry .
I did not write exactly what I wanted to mention in relation to the Kenko 2x converter
The converter that saw the kenko is this.
http://funchal.olx.pt/kenko-teleconversor-fotografico-2x-pentax-iid-433649958
And I wonder if this converter can be used on the Pentax DA lenses.
He refers PZ Power Zoom as stated in your comment.
I recently adqueri DA * 50-135mm f2, 8, can I use this converter in it.
Thanks for your feedback

Best regards

Looks like it could be this one:

May be a problem with DA lenses?

If I may comment, the one at http://funchal.olx.pt/kenko-teleconversor-fotografico-2x-pentax-iid-433649958 looks like it DOES have the PZ contacts so would autofocus with DA* lenses. You can see them at about the 5 o'clock position on the interior black surround, that is providing the picture is of the actual item and not a stock image in which case who knows! Maybe worth double checking it is the actual thing before purchasing it.

John K

OTOH, the reviews on the other forum indicated some issues with some DA lenses.

I suppose that's possible because the contacts were designed to work a power zoon, not auto-focus. My understanding is that autofocus may not work correctly with too small an aperture, with the K-5 being less affected.

I'm not sure to what issues you are referring to on the other forum so cannot comment - do you have a link?

I've got the 1.4x version with the PZ contacts which only looses a single stop instead of two, so is less prone to lacking light to work.

John K

The link was in my first post!

Just tried my Pz-AF Kenko 1.5x with my DA ED 18-135 F3.5-F5.6 Pentax lens with both the K-5 and the K-R in fairly bright bedroom light and it seems to work fine @ 135mm with both of them (and possibly better with the K-R!!). Of course, what it would do with other DA lenses may be another matter.

However, you probably will have more problems with the 2x TC (I do with the Sigma 2X on the longer non SDM Sigma zooms, so do not use it much)

That link is to this forum, albeit a different thread. By other forum I presumed you meant the American one or somewhere!

John K

The link was in the 1st post but in the 2nd para under the highlighted word "here" in "(see the images here)". As you guessed, it is to the American forum!

Whats the one SRS are selling like, the C-AF1 2x Teleplus MC7?

From the Kenko webpage....

Full AF operation with the TELEPLUS MC4 AF 1.4X and the MC7 AF 2.0X DG is possible using a camera lens with an open aperture of F4 or brighter while the 2.0X DG would require an open aperture of F2.8 or brighter. Please be aware that AF will work properly only if there is enough light and contrast on the subject to activate the camera's AF sensors properly. (Manual focusing may be necessary when using lenses with smaller open f-stop values than those given above.)

I have a Kenko Teleplus 2X MC7.. i just tried it with a Pentax 50mm f1.4 on my K5II or K1. Non would auto focus.. But it it a little dark right now.. Worked perfectly though manually focusing..

2x TC works? = probably with the right lens.

2x TC works well? = not so likely and, nowadays, a 1.4x is as far as I will "go" with either Sigma (dedicated 2x sold a couple of years ago) or Kenko (kept the 1.4 PZ as it is useful at times - and I could probably still sell it for around what I paid - £80 - for it maybe 7-8 yrs ago if I wanted to )