Useless extension?

borochris

I bought a 2.2x extension for my camera while abroad. It seemed to work fine in the shop, but has let me down badly when trying to take wildlife pictures, as they come out in poor definition.
The lens is one of these:
https://www.amazon.com/72MM-High-Definition-2-2x-Telephoto/dp/B001V5UMLU
Is it worth trying to do anything with this (user error), or just cutting my loses?
I have a good Tamron 28-270mm and I'm now thinking of supplementing this with a 150-600mm either Tamron or Sigma. Any advice?

bruto

I would suggest you cut your losses. This kind of extension is almost always a poor substitute for better glass. An exception to this is the diopter magnifiers that make a lens more macro. Those, though they also can reduce some optical qualities such as linearity and edge acuity, can produce good results, especially if you get a good one, since the qualities lost are rarely missed when you're shooting natural objects.

If your lens is fast enough to begin with, you might want to consider a telextender that goes between lens and camera. Good ones of this sort can also be pretty expensive, as they must include all the electronic connections for AF lenses, and they are usually best when matched well to the lens. Whether your 28-270mm takes well to this I don't know, but it's something to consider. The problem is that a 1.4x extender slows down your lens by a stop, and a 2x by about two stops, whicf/8 at 1.4x, and an f/11 at 2X, and this will make viewing dim and autofocus, if it works at all, slower. Some lenses, such as the highly expensive and exotic Nikon 300mm f/4, play well with an extender. Others may not, and some actually cannot mate mechanically if their glass elements protrude in the wrong places.

If you can afford either the Tamron or the Sigma, those will probably satisfy you more. They both go to f/6.3 at 600mm, which is pretty slow, but doable. I have not tried either version of the Sigma, but did try the Tamron briefly. Sigma makes both a relatively inexpensive version, and one that is quite a bit more, and also said to be quite good. The Tamron was pretty decent, and reasonably sharp, and a raging bargain. Tamron has just come out with a newer and better design, which might be worth looking at, and this might make the older one even cheaper as well. I was not greatly impressed with the vibration reduction in the Tamron, and since I could afford a little extra, I went with the Nikon 200-500mm f/5.6. It's hefty, and a little shorter focal length than 600mm, but sharp, nicely made, and it has incredibly good VR, making it a champ for hand held telephoto shots. If you can shop around, and if you can afford to throw in a few hundred more bucks, you should give that a try.

I've heard varying reports on sample variation in these. My Nikon is good and sharp, and I got to try it in the store before buying, but I've heard some complaints from some commentators about having to try several before they got the best. The same goes with the others, perhaps more so. If you buy any of these, I highly recommend you go with a reputable dealer who will take returns, and then test them mercilessly during the return period. The Tamron is a mighty tempting bargain and about $400 less than the Nikon. I'm guessing that it will deliver pretty nice results too, but probably will need a tripod more often.

In the general sense, remember that a really good lens will outlast the next several cameras. You're almost always going to get better results by improving the glass than by improving the camera.

And if you want good super telephoto shots, a good super telephoto lens is unbeatable.

Back during the recent lunar eclipse, I borrowed my wife's old 500mm f/4 AI lens, a huge beast of a thing, and probably one of the sharpest long lenses ever made, and carefully set it up on a tripod, and carefully did this and that to aim and focus my D3200, and indeed, I got some very nice shots though vibration was an issue and aiming that high was a bit tricky on the tripod. This spring, I was walking around the yard chasing a bird, and there was the moon out in the daylight, and so I grabbed the new zoom and snapped a hand held shot with the same A priority setting I'd been using, and auto focus. It was nicely exposed and sharp as a tack.