I’ve been wondering for a very long time if using a teleconverter, moreover a 2x one, was worth it or not. I’ve heard a lot on forums that I would lose light, the aperture is reduced 2x (f/2.8 becomes f/5.6) that it is not sharp at all and that I would even lose autofocus. That made me doubt a lot even if it is not that expensive, but still, from $120 to $180 on average, that is always money coming out of you wallet that would be lost in the end if this is really bad!
I use this Sigma 150mm f2.8 APO macro lens for all my macro work that is very good but also big and heavy. I wanted to have this extra reach to do some wildlife photography without adding the bulk and weight to my backpack and without paying $1500-$2000 for a 300mm lens. A teleconverter then seemed like a good idea so I gave it shot. I bought this Bower Teleconverter on Amazon for $126.
I am extremely pleased with my purchase. This adapter is pretty small, 1 inch (2.5cm) wide, about 7oz (200g) so this is not much of a big deal to always have it with me in my backpack. As a reminder, I shoot with an Sony A7 mark II and use the Sony LA-EA4 adapter specifically for this Sigma lens. I thus add the teleconverter (A-mount) in between the lens and the LA-EA4 adapter.
It performs extremely well! Sure it is not perfect. It cannot make your lens sharper but it is more than just usable. I wouldn’t have been able to have such close shots of the moon without it. 150mm is definitely not enough and if you crop your picture too much the moon will look blurry. Underneath, the picture of the tree would be much far away of course and if you crop to have the same frame, you will lose sharpness and size, that goes without saying.
It adds just a little bit of bulk to the already big Sigma 150mm lens especially with the LA-EA4 adapter but a 300mm lens would be even bigger anyway. The aperture is reduced from f/2.8 to f/5.6 but for such a long focal that is not such a problem. The depth of field is still pretty shallow! And for instance, if you try it with the Samyang 85mm f/1.4Samyang 85mm f/1.4 it would transform it in a 170mm f/2.8. Interesting, isn’t it?
So, as I was saying, most 300mm lenses would be f4 which is not that different in this end with this final f5.6, especially considering the price. It appears that I am not losing that much light, the shutter speed is actually identical but what surprised me is the AF. It is exactly the same as with the original lens without any adapter. It works perfectly, quickly (as much as the A7II with the LA-EA4 adapter can be) and is accurate. Of course, I lose some sharpness and in some shots cropped at 100% it seems like there is a little bit of fringe but it is not that problematic. It is still sharp. As long as you do not have to crop at 100%, it remains perfectly sharp. Even if you crop slightly your image.
As this Sigma lens is a macro lens, it keeps its “macro” ability but with the very good surprise that the adapter works a little bit like extension tubes like you can see in the pictures above. Well, it depends on how you look at it. The minimum focus distance remains the same as when it is used as a 150mm lens, which then gives a 1:1 ratio way better with the teleconverter. With an actual 300mm lens the minimum focus distance would be much longer. I cannot tell exactly which ratio it would be but that the extra bonus this teleconverter is providing is very good!
I also have to mention that the excellent stabilization system of the Sigma lens also works perfectly using the teleconverter. If you were afraid of having to use the tripod every time you want to use that 2x teleconverter, you can be reassured. Of course the “macro” pictures I displayed here are taken with a tripod though. Even with a 90mm that type of picture would require a tripod.
I can only recommend that accessory that can be used on most lenses and will provide you with this extra reach without spending a lot of money, without the bulk and without the backache. The one I chose is the one with only 4 elements. You can usually find 4 or 7 elements. I was under the impression that people complain more about their 7 element teleconverter. Just know that the 4 elements works just fine but also know that it is a lot better to use such a converter with fast primes than with kit lenses or zoom lenses with small aperture such a f/3.5-5.6. If the original lens has an aperture above f/4 the AF usually doesn’t work.
Here are some more pictures that I took with this combo (A7II + Sigma 150mm f/2.8 + X2 teleconverter)
- Light and small
- Doubles the focal length of your lens without having another lens in your backpack
- Depth of field still shallow
- Shutter speed remains identical
- OS still perfectly working
- Perfectly dealing with glare
- For those using a LA-EA4 adapter, yes it works fine!
- Loosing a bit of sharpness when cropped from 80% to 100%
- Sometimes. depending on the lighting, a sort of little haze/fringe effect around subjects far away can be visible when cropped at about 60% and more.