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Kenko 2x MC7 DG AF Teleplus 2X Magnification Review RSS Feed

Kenko 2x MC7 DG AF Teleplus 2X Magnification

Reviews Views Date of last review
7 26,506 Sun February 9, 2014
Recommended By Average Price Average User Rating
71% of reviewers $76.57 8.00
Kenko 2x MC7 DG AF Teleplus 2X Magnification

The 2x DG Teleconverter multiplies the focal length of a lens by 2x, and will cut back the amount of light by 2 f/stops. A 2x teleconverter with a 300 mm lens will effectively increase the focal length to 600 mm & a lens set to f/2.8 will now be f/5.6.

This DG teleconverter has a "Gate-Array IC" circuitry to work better with digital SLR's and some digital SLR lenses. This means that the converter's unique circuitry maintains signal integrity between the camera body and lens.

Magnification 2x
Lens Elements/Groups 7/5
Length 1.4" (36mm)
Diameter Not specified
Weight 9 oz (250g)

Produced by Tokina

This thread is a discussion of diffraction issues when using TC's.
Price History:

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New Member

Registered: December, 2013
Posts: 8
Lens Review Date: February 9, 2014 I can recommend this lens: No | Price: $70.00 | Rating: 8 

Pros: good optical quality
Cons: poor AF-compatibility with SDM lens
Camera Used: K5iis   

Works fine with screw drive lenses having max apperture f2.8 or higher. Sigma 105/2.8 with TC on K5iis works fine, fast AF and almost no hunting, some contrast loss (easily fixed by post processing). Camera can set f2.8 with attached lens and TC, so I did not found any signal conversion promised by "Gate-Array IC". For properly TC functioning it is highly recomended to attach TC to camera body at first and then attach lens to TC (even if camera is switched off).

With TC and DA*50-135/2.8 AF does not works at all, camera displays MF mode. With TC and DA 55-300 AF works fine, but I found poor IQ at f8 (need to be tested further). With TC and Sigma 17-50/2.8 EX HSM AF works, but camera can not focus, hunting all the time.

So I suggest this TC has poor AF-compatibility with SDM lens and must be used on screw drive lenses. Optically TC is very good, it can perform greatly on some lenses with max aperture 2.8 or higher.


While testing different AF TCs I found that sdm-lenses AF is incompatible with TC when used on K5iis. I suppose it is because of a camera firmware that is not able to calculate correct sdm-motor movement range during focusing. So it is highly recommended to use such TCs with screw drive AF lens. May be it will be changed with coming of a new pentax HD TC when producer will be forced to upgrade firmware of all camera models to avoid focusing problems with sdm-lenses.
New Member

Registered: July, 2012
Posts: 6

1 user found this helpful
Lens Review Date: August 11, 2013 I can recommend this lens: No | Price: $85.00 | Rating: 7 

Pros: Works on AF with KX, 2x converter, Pz-AF
Cons: Loss of contrast, 2 f stops & image degradation as expected

Purchased this off eBay to check the quality and to see if it can extend the range of my 300MM without much loss of IQ. While PF-AZ allows for connection of screw drive auto focus, camera can not auto focus even with the brightest of sunlight. If it stops hunting, it will be out of focus

The odd thing is that through the Viewfinder the loss of 2f stop is not that obvious. With Manual focus the image looks without any loss of quality, but once captured the image looks washed out (both contrast and sharpness)

The sharpness loss is mainly due to shake. Camera assumes the lens as 300MM but the actual is 600MM. Due to this the picture unless taken with tripod and MLU does not have any sharpness
If you are shooting in bright sunlight without a tripod, increase the shutter speed to 400 or more and it will take much better picture
Inactive Account

Registered: September, 2011
Location: Melbourne
Posts: 307
Lens Review Date: April 1, 2012 I can recommend this lens: Yes | Price: $71.00 | Rating: 8 

Pros: 2x Magnification, Pz-AF, Quality built
Cons: As expected, hunts in low light, a little off in contrast

After picking it up, I gave it a good work out with my Sigma APO 70-200 f2.8 OS HSM of my K-7 (which is brought it for). being a bit overcast I wasn't expecting to auto focus, but I was happy it did try to focus, which meant for me that the Pz contacts do work on the HSM Lens. Initially I was getting a lot of overexposure, until I got the TC home to check it over properly, I found the aperture mechanism was bent a little (enough to jam up against the bayonet of the lens). Once I straighten this out everything operated perfectly.

I gave it a run (indoors under 'daylight' fluorescent) on most of my lenses. the only lens to auto-focus was the Sigma 17-70 F2.8-4.5 DC Macro (screw-drive) even at 70mm f4.5 which I was happy about.

The image quality I can't complain about yet, it looks OK to me... the bellow shot was with the about sigma 70-200 @200 f4 support of my knee.

The contrast could be better, but its nothing software could fix... need more testing...

Site Supporter

Registered: September, 2010
Location: Somewhere in the Southern US
Posts: 12,113
Lens Review Date: January 8, 2012 I can recommend this lens: Yes | Price: $40.00 | Rating: 8 

Pros: Works on AF with K5, 2x converter, good build quality
Cons: loss of contrast and 2 f stops

Definitely works with the lenses in AF mode on the K5. I knew there would be some image quality lost but was surprised that the majority of it seems to be in contrast. Everything looks a wee bit greyer with this added. AF is slower than the lens by itself but its not prohibitively slow. It's built well and functions smoothly with a variety of lenses.

UPDATE: 09/16/12 - Tried it with my 18-135WR DC lens and because it has the PowerZoom contacts it does power the DC motor in the 18-135.

UPDATE: 10/25/12 - Got around to trying it with the Tamron 70-200/2.8 - don't bother. The combination hunts and hunts like its in CDAF mode instead of PDAF. It just makes the lens unusable when paired with this TC.
Senior Member

Registered: June, 2007
Location: Europe - Belgium - Antwerp
Posts: 213
Lens Review Date: April 13, 2011 I can recommend this lens: Yes | Price: $130.00 | Rating: 9 

Pros: 2x magnification, good image quality
Cons: image degradation as expected

It's funny how much it looks like a bigger brother of the "Tamron-F 1.4X Pz-AF MC4", there must be some connection between them.
Quality is good for a 2x converter, better than I expected.
Auto focus works fine with the k-5, and sigma 100-300 f4, although a bit slow.
Senior Member

Registered: August, 2010
Location: United States
Posts: 265
Lens Review Date: October 15, 2010 I can recommend this lens: Yes | Price: $65.00 | Rating: 8 

Pros: 2X magnification, Decent Image Quality, compact, AF, reletively inexpensive if you can find one used.
Cons: As to be expected, loss of 2 f stops and some image degredation

Mine is the Vivitar version of this TC. Same model, body, and looks exactly the same.
I own three teleconverters and this is the best of the bunch. The other two are older Vivitar 2x TC's and degraded the image quality to the point that they have been converted to extension tubes. This TC does introduce a little PF, but it is minimal and easily corrected. Loss of two f stops and CA is to be expected with just about any TC so I don't really fault it much for either. AF works fine with both my DA L18-55 and DA L 50-200. I plan on getting a Tamron 18-250 and will update my review when I do. AF does hunt a little but it's not excessive.
Also works great on my Tokina 400mm 5.6. Need to use it on sunny days because of the F stop loss, but otherwise it definitely adds needed reach.
I recommend this TC to anyone who needs more reach with AF capabilities but is not looking to spend as much as a longer lens would cost.

Registered: March, 2007
Location: chicago burbs
Posts: 3,381
Lens Review Date: April 3, 2009 I can recommend this lens: Yes | Price: $75.00 | Rating: 8 

Pros: 2X magnification, Inexpensive, compact, AF works with Tamron 70-200mm and Pentax f*300mm
Cons: loss of 2 stops, some image degradation (both to be expected)

I've used this with good results on the K20D with the Tamron 70-200mm f2.8 and Pentax f*300mm f4.5 (I'd rate image quality with this combo as 8.5). The converter allows full metering and auto-focus with both lenses. When using the TC with the 70-200 on the K20D, it asks for the lens length. The AF is good on the Tamron 70-200mm and hunts a bit, but very slow and hunts a lot on the Pentax f*300mm lens (generally expected when using a teleconverter). Images are reasonably sharp and I find the ability to 'get the long shot' vs IQ loss to be a worthwhile trade-off.

Update: I tried this combination with the K7 and above lenses and it will NOT autofocus.
It would try to focus with the Sigma 70-200mm f2.8 HSMII, but would not lock on.
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