Kenko 2.0X PRO 300 Teleconverter DGX for NIKON AF Digital SLRs

To confirm another review on this extender, autofocus does work with this extender on f4 lenses (at least my Canon 300 f4 IS and Canon 70-200 f4 non-IS version). I have found the picture quality to be very good with with these lenses. I am shooting with Canon xsi and t2i bodies, and both work fine with this extender. Also, camera information is retained and the changes caused by the extender are properly accounted for.One thing I've observed with my extenders is that they also magnify the softness, noise, blur from shake, etc. A lens that tends to be soft will yield unacceptably soft pictures with the extender. I tried my 1.4x extender on my Sigma 18-250, which is a soft lens, and the results were very poor. This is important to know, because I think extenders are taking the blame for the lenses in many cases. I have found that both the Kenko 1.4x and 2x DGX Pro 300 extenders work very well on high quality L-glass, and also on my Tamron 28-75 f/2.8, which is also a very sharp lens.Also worth noting here, the fact that the f-stop doubles with a 2x extender, the reduced speed increases possible blur from shake, especially when hand holding. This fact, compounded by a 2x focal lengh, and you have a worthless picture. Another thing to watch for is with smaller aperatures and/or lower light, the camera will default to higher ISO speeds if ISO is set on auto, which with the extender will tend to magnified the noise caused by high ISO. Again, with a 2x focal length the noise is also magnified and may yield unacceptable pictures.Both of these Kenko DGX Pro 300 extenders are fine quality with high quality glass. They will produce high quality shots when used with quality lenses and good shooting skills and optimum camera settings.I hope this is helpful!

I've been hesitant to buy a teleconverter for my Canon 100-400L f/4.5-5.6 lens after reading so many reviews about the Canon version losing auto-focus with such narrow apertures. The reasons given by the experts is that the camera cannot auto-focus on apertures above 5.6 because not enough light can enter the lens to allow the autofocus to work. Adding a 2X teleconverter effectively narrows the aperture by two whole stops, so a lens that is already 5.6 at its widest setting becomes effectively f/11, which cannot autofocus. This didn't make any sense to me because I shoot on my Canon 5D Mark II at f/11 all the time without any auto-focus issues, assuming I have enough light. Then I read in some forums where people could place tape over one of the contacts on the Canon teleconverter which would allow focus, which leaves me to think that Canon intentionally designed their teleconverter to stop autofocus on lenses f/5.6 or higher, even in cases where there may otherwise be enough light. That is very frustrating to me because I think the photographer should decide whether or not to use autofocus. If you find there is not enough light and the autofocus is "hunting" too much, switch to manual and move on, otherwise, if there is enough light to autofocus, you should be able to make the choice.So I read other reviews that said not only does this Kenko teleconverter NOT have the intentional auto-focus limitation, but people have said it is every bit as sharp as the Canon version, at half the price. That was enough for me to make the choice to purchase this product. Since I don't own the Canon version, I can't compare image quality, but I can say this. When I fully extend my lens to 400mm f/5.6, making an effective 800mm f/11 lens, the images (handheld, image stabilized) are every bit as sharp as without the converter. I tried this outside, on an overcast day, with ISO 800 and the autofocus works perfectly. On a brighter day, I can probably dial down the ISO and still get good results. I'll post some pictures soon to show just how sharp this teleconverter is. I can't imagine getting better results with the Canon version.Please bear in mind that this review is based on use with a Canon 5D, which is known for its low-light capabilities. It is possible that with crop-sensor cameras, the auto-focus will require more light.I did have to knock off one star because I found the connection to be a little too tight and I can feel the metal scraping as I twisted it in place. I was very nervous that I was going to damage my camera or lens, or get it stuck, as one reviewer complained about. Thankfully this did not happen and I can add and remove it without problem, but I think the manufacturing tolerances need to be a little bit better. Other than this, the product seems solid and well built.

I do mostly wildlife photography so I want as much reach as possible. A 2 x teleconverter is somewhat of an over-reach anyway you want to look at it. Canon's is really expensive and had fewer problems but does have some still. Kenko is probably a third tier lens manufacturer but for the price, I'd try it. Auto-focus is not possible even though the electrical connections are there, it does not do a very good job. I have to go to live view and use my Lens Hood viewer to manually focus. Tripod is a must and remote shutter control is preferred. I don't use it much as it is fussy and difficult to get really sharp focus and exposure. I'm going to rent a Sigma and Canon 1.4 x and try them out before I purchase another teleconverter. I gave this 3 stars, even though it did not meet my expectations because I don't think any 2 x would have.

I decided to purchase this lens extender for my Canon 70-200mm IS F/4, based on favorable reviews and Kenko's claim that the AF would work for F4 and faster lenses. Well, the AF was operating, but it would not focus correctly (way out of focus). I also tried it on another F/4 L lens (Canon 24-105mm), and had the same result.It is possible that my copy was bad, I'm just reporting my experience. So needless to say, I returned the items back to Adorama. The bad news for me was that I ended up paying to have the lens shipped to me, and then paid to have it returned all at my expense. Adorama only refunded the lens cost, even though they sent me a defective lens.This is my second time purchasing lenses from Adorama (through Amazon) with the same experience, so I will not be purchasing from them again.2 stars for Amazon's great return policy.