Kenko 1.4X Teleplus Pro 300 DG with Canon 85mm f1.8

The Adorama (and B & H) info for the Kenko 1.4X Teleplus Pro 300 DG Tele Converter (sells for about $199) states that when used with a Canon 85mm f1.8 lens the lens-tele converter combination will not autofocus. This seems strange to me, as the combination's net f-stop would be well below the f5.6 limit of my 40D or 50D.

I've tried searching the postings reporting on this combination and there seems to be some disagreement whether this information is true or not.

Would an user/owner of this combination reply and confirm or refute the warning given by Adorama/B & H please?

Also, the primary use of the tele converter will be with a Canon 70-200 f4 L IS lens. I would like some opinions of the loss (if any) of image quality using the Kenko 1.4X Teleplus Pro 300 DG instead of the Canon 1.4X.

Thanks in advance to all the experts who reply!

Maxdave

this thread has some shots, mine is the NON IS version, with the older 1.4 TC (it is a pro, doesn't say DG on it - from what I understand it is the same optics). Mine is the white version, good color match:

I have never put it on my 85 1.8. I will try it later today when i get a chance:

https://photography-on-the.net …hp?p=7964527&po​stcount=15

put it on the 85MM and I think I need to go back and do some more experimenting. these are very unscientific results:

- it did autofocus, and according to the display settings (and according to DPP) I was at f1.8!!

- but, DPP did not report the 1.4x was on (but it does show that its on when used on the 70-200 (assume this is because of the 7 vs 9 contacts??)

the interesting thing is the shots with the 85 (85MM reported) are definelty "zoomed in" more than the same shots I took with the 70-200 at 70 (98 MM reported with the extender).

This was all done hand held, very cloudy in our sunroom.

lenses not designed for TC will not report the change in FL or Apature. So although it says 85 f1.8 it actually is 1xxmm and f2.5. It works, it just doesnt report.

I think the question is about image quality though?

Hi jxg

Thank you for going to the trouble to test this out. I was most concerned that the autofocus would work (and that iamge quality would be satisfactory). I'm not surprised that the teleconvertor does not report the aperture and focal legth to the camera, but since you could apply exposure compensation for that (if necessary) and even allow for it when using flash, it seems to me to be of little importance ... I get a 119 mm f2.5 lens as a bonus (was going to get the TC anyway for the 70-200 f4). Thanks again!

Maxdave

madspartus wrote in post #8035560
lenses not designed for TC will not report the change in FL or Apature. So although it says 85 f1.8 it actually is 1xxmm and f2.5. It works, it just doesnt report.

I think the question is about image quality though?

the image quality was in concern to the 70-200, which i thought I answered with my link in the first post. I think I notice very little IQ lost with the TC.

my comments on the 85 were what i had from playing for just 5 minutes during my lunch today

jxg wrote in post #8034793
this thread has some shots, mine is the NON IS version, with the older 1.4 TC (it is a pro, doesn't say DG on it - from what I understand it is the same optics). Mine is the white version, good color match:

I have never put it on my 85 1.8. I will try it later today when i get a chance:

https://photography-on-the.net …hp?p=7964527&po​stcount=15

Thanks for the link

Byte size: ZERO | Content warning: NOT AN IMAGE

Byte size: ZERO | Content warning: NOT AN IMAGE

I have both the Kenko Pro DG 1.4 and a Canon 1.4 . I have used both on the 70-200/4 non IS and 400/5.6 and IMO there is very little in it as far as IQ goes. I also use the Kenko on my Canon 100/2.8 macro and it works very well.

Thanks for the info, Roy!

Maxdave

My Kenko Pro300DG 1.4x Teleplus arrived this morning, so I immediately tried it out with my Canon 85mm f/1.8.

The combination autofocused with no problem, even under my relatively dim fluorescent home office lightning. I shot the same subject at f/1.8 both and without the Kenko. The reported camera info was unchanged, i.e f/1.8, but the resulting exposure was correct, and virtually identical to the shot taken without the Kenko.

I processed the two images in DPP (the EXIF Info reported for both was identical), applied no noise reduction, and similar sharpening. I then converted both to 16-bit TIF, and imported them into CS2, and prepared these comparison 100% crops of the centre of each image.

I think the sharpness of the Kenko+lens combination is nearly as good, but the depth of focus is reduced. I actually bought the Kenko to use with a 70-200 f/4 IS, but getting what is effectively a 120mm f/2.5 from my 85mm f/1.8 is a bonus!

Maxdave

HOSTED PHOTO
please log in to view hosted photos in full size.