Kenko Teleconverters

[harvey]

I'm struggling to choose between these two:

• Kenko Teleplus PRO 300 DG 2X
• Kenko Teleplus MC7 DG

The only difference seems to be the element grouping and the PRO 300 is a bit larger.

Does anyone have experience of these?
I would use with 135mm and 200mm Minolta lenses.

[David Kilpatrick]

I've got a 1.4X 300 and a 2X DG7 - I reckon the Pro 300 is worth the extra, probably is at 2X as well.

David

[harvey]

The only operational difference I can see in the description of these products is that the PRO 300 is supposedly
optimized for lenses of 100mm or more and works with zooms:

The PRO 300 family are designed specifically to be used with prime telephoto lenses of 100mm or above, such as the Tokina AT-X 300 AF PRO, 300 mm f/2.8 lens, and work best with telephoto lenses of 200mm to 500mm. The PRO 300 can be used with telephoto zoom lenses as well as prime lenses. However, Kenko does not recommend them for zoom lenses that have a range starting under 50 mm.

Some description on their web pages and in the catalogue

http://www.thkphoto.com/products/kenko/index.html
http://www.thkphoto.com/pdf/KenkoCatalog09.pdf

Both are multielement with Hoya multicoated glass.

[David Kilpatrick]

They are different. The 1.4X has the largest elements of any converter I've seen, and there are many lenses it can not be fitted to as the glass ends up touching. Words about the 300 being optimized for lenses over 100mm are just the same as Minolta's old 300-L and 300-S converters - technically, the 300 Kenko would be classed as an S type, not and L (the L type was designed for lenses of 300mm+, the S for 100 to 300mm).

My secondhand bargain 300 1.4X would be fine but although it has eight contacts (technically xi compatible) the chip is not working correctly and it fails to report the change in focal length or aperture to the camera, so when you actually set f/5.6 you see f/4 in the displays/finder and get the same in the EXIF data.

It could be that a new 1.4X would be more useful anyway. It might just focus properly with the 70-300mm SSM at 300mm, boosted to 450mm.

David